U.S. patent application number 10/862692 was filed with the patent office on 2004-11-04 for compounds useful in the manufacture of an anti-inflammatory androstane derivative.
Invention is credited to Biggadike, Keith, Coote, Steven John, Nice, Rosalyn Kay.
Application Number | 20040220162 10/862692 |
Document ID | / |
Family ID | 9896989 |
Filed Date | 2004-11-04 |
United States Patent
Application |
20040220162 |
Kind Code |
A1 |
Biggadike, Keith ; et
al. |
November 4, 2004 |
Compounds useful in the manufacture of an anti-inflammatory
androstane derivative
Abstract
The present invention relates to, for example, a compound of
formula (XIII) 1 useful in the manufacture of anti-inflammatory
androstane derivatives.
Inventors: |
Biggadike, Keith;
(Stevenage, GB) ; Coote, Steven John; (Stevenage,
GB) ; Nice, Rosalyn Kay; (Stevenage, GB) |
Correspondence
Address: |
DAVID J LEVY, CORPORATE INTELLECTUAL PROPERTY
GLAXOSMITHKLINE
FIVE MOORE DR., PO BOX 13398
RESEARCH TRIANGLE PARK
NC
27709-3398
US
|
Family ID: |
9896989 |
Appl. No.: |
10/862692 |
Filed: |
June 7, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10862692 |
Jun 7, 2004 |
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09958050 |
Oct 2, 2001 |
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09958050 |
Oct 2, 2001 |
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PCT/GB01/03495 |
Aug 3, 2001 |
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Current U.S.
Class: |
514/178 ;
552/610 |
Current CPC
Class: |
A61K 9/0043 20130101;
A61P 11/02 20180101; A61P 27/02 20180101; A61P 5/44 20180101; A61P
11/06 20180101; A61K 31/56 20130101; A61K 31/58 20130101 |
Class at
Publication: |
514/178 ;
552/610 |
International
Class: |
A61K 031/56; C07J
003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 5, 2000 |
GB |
GB0019172.6 |
Claims
1. A compound of formula (XIII) 26
2. A compound of formula (XIV) 27or a salt thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a Divisional application of U.S.
Ser. No. 09/958,050, filed 2 Oct. 2001, which was a national stage
filing of PCT/GB01/03495 filed 3 Aug. 2001 filed under 35 USC 371,
and which claimed priority from British Patent Application
GB0019172.6 filed 5 Aug. 2000.
FIELD OF THE INVENTION
[0002] The present invention relates to a novel compounds, such
compounds having utility in in the manufacture of novel
anti-inflammatory and anti-allergic compounds of the androstane
series.
BACKGROUND OF THE INVENTION
[0003] Glucocorticoids which have anti-inflammatory properties are
known and are widely used for the treatment of inflammatory
disorders or diseases such as asthma and rhinitis. For example,
U.S. Pat. No. 4,335,121 discloses
6.alpha.,9.alpha.-Difluoro-17.alpha.-(1-oxopropoxy)-1-
1.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carboth-
ioic acid S-fluoromethyl ester (known by the generic name of
fluticasone propionate) and derivatives thereof. The use of
glucocorticoids generally, and especially in children, has been
limited in some quarters by concerns over potential side effects.
The side effects that are feared with glucocorticoids include
suppression of the Hypothalamic-Pituitary-Ad- renal (HPA) axis,
effects on bone growth in children and on bone density in the
elderly, ocular complications (cataract formation and glaucoma) and
skin atrophy. Certain glucocorticoid compounds also have complex
paths of metabolism wherein the production of active metabolites
may make the pharmacodynamics and pharmacokinetics of such
compounds difficult to understand. Whilst the modern steroids are
very much safer than those originally introduced, it remains an
object of research to produce new molecules which have excellent
anti-inflammatory properties, with predictable pharmacokinetic and
pharmacodynamic properties, with an attractive side effect profile,
and with a convenient treatment regime.
BRIEF SUMMARY OF THE INVENTION
[0004] We have now identified a novel glucocorticoid compound which
substantially meets these objectives.
[0005] Thus, according to one aspect of the invention, there is
provided a compound of formula (I) 2
[0006] and solvates thereof.
[0007] The chemical name of the compound of formula (I) is
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hy-
droxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester.
[0008] References hereinafter to the compound according to the
invention include both the compound of formula (I) and solvates
thereof, particularly pharmaceutically acceptable solvates.
[0009] The compound of formula (I) has potentially beneficial
anti-inflammatory or anti-allergic effects, particularly upon
topical administration, demonstrated by, for example, its ability
to bind to the glucocorticoid receptor and to illicit a response
via that receptor. Hence, the compound of formula (I) is useful in
the treatment of inflammatory and/or allergic disorders.
[0010] Compound (I) undergoes highly efficient hepatic metabolism
to yield the 17-.beta. carboxylic acid (X) as the sole major
metabolite in rat and human in vitro systems. This metabolite has
been synthesised and demonstrated to be >1000 fold less active
than the parent compound in in vitro functional glucocorticoid
assays. 3
[0011] This efficient hepatic metabolism is reflected by in vivo
data in the rat, which have demonstrated plasma clearance at a rate
approaching hepatic blood flow and an oral bioavailability of
<1%, consistent with extensive first-pass metabolism.
[0012] In vitro metabolism studies in human hepatocytes have
demonstrated that compound (I) is metabolised in an identical
manner to fluticasone propionate but that conversion of (I) to the
inactive acid metabolite occurs approximately 5-fold more rapidly
than with fluticasone propionate. This very efficient hepatic
inactivation would be expected to minimise systemic exposure in man
leading to an improved safety profile.
[0013] Inhaled steroids are also absorbed through the lung and this
route of absorption makes a significant contribution to systemic
exposure. Reduced lung absorption could therefore provide an
improved safety profile. Studies with compound of formula (I) have
shown significantly lower exposure to compound of formula (I) than
with fluticasone propionate after dry powder delivery to the lungs
of anaesthetised pigs.
[0014] An improved safety profile is believed to allow the compound
of formula (I) to demonstrate the desired anti-inflammatory effects
when administered once-per day. Once-per-day dosing is considered
to be significantly more convenient to patients than the twice-per
day dosing regime that is normally employed for fluticasone
propionate.
[0015] Examples of disease states in which the compound of the
invention has utility include skin diseases such as eczema,
psoriasis, allergic dermatitis, neurodermatitis, pruritis and
hypersensitivity reactions; inflammatory conditions of the nose,
throat or lungs such as asthma (including allergen-induced
asthmatic reactions), rhinitis (including hayfever), nasal polyps,
chronic obstructive pulmonary disease, interstitial lung disease,
and fibrosis; inflammatory bowel conditions such as ulcerative
colitis and Crohn's disease; and auto-immune diseases such as
rheumatoid arthritis.
[0016] The compound of the invention may also have use in the
treatment of conjunctiva and conjunctivitis.
[0017] It will be appreciated by those skilled in the art that
reference herein to treatment extends to prophylaxis as well as the
treatment of established conditions.
[0018] As mentioned above, the compound of formula (I) is useful in
human or veterinary medicine, in particular as an anti-inflammatory
and anti-allergic agent.
[0019] There is thus provided as a further aspect of the invention
the compound of formula (I) or a physiologically acceptable solvate
thereof for use in human or veterinary medicine, particularly in
the treatment of patients with inflammatory and/or allergic
conditions, especially for treatment once-per-day.
[0020] According to another aspect of the invention, there is
provided the use of the compound of formula (I) or physiologically
acceptable solvate thereof for the manufacture of a medicament for
the treatment of patients with inflammatory and/or allergic
conditions, especially for treatment once-per-day.
[0021] In a further or alternative aspect, there is provided a
method for the treatment of a human or animal subject with an
inflammatory and/or allergic condition, which method comprises
administering to said human or animal subject an effective amount
of the compound of formula (I) or physiologically acceptable
solvate thereof, especially for administration once-per-day.
[0022] The compound according to the invention may be formulated
for administration in any convenient way, and the invention
therefore also includes within its scope pharmaceutical
compositions comprising the compound of formula (I) or a
physiologically acceptable solvate thereof together, if desirable,
in admixture with one or more physiologically acceptable diluents
or carriers. Pharmaceutical compositions suitable for once-per-day
administration are of particular interest.
[0023] Further, there is provided a process for the preparation of
such pharmaceutical compositions which comprises mixing the
ingredients.
[0024] The compound according to the invention may, for example, be
formulated for oral, buccal, sublingual, parenteral, local or
rectal administration, especially local administration.
[0025] Local administration as used herein, includes administration
by insufflation and inhalation. Examples of various types of
preparation for local administration include ointments, lotions,
creams, gels, foams, preparations for delivery by transdermal
patches, powders, sprays, aerosols, capsules or cartridges for use
in an inhaler or insufflator or drops (eg eye or nose drops),
solutions/suspensions for nebulisation, suppositories, pessaries,
retention enemas and chewable or suckable tablets or pellets (eg
for the treatment of aphthous ulcers) or liposome or
microencapsulation preparations.
[0026] Advantageously compositions for topical administration to
the lung include dry powder compositions and spray
compositions.
[0027] Dry powder compositions for topical delivery to the lung
may, for example, be presented in capsules and cartridges for use
in an inhaler or insufflator of, for example, gelatine.
Formulations generally contain a powder mix for inhalation of the
compound of the invention and a suitable powder base such as
lactose or starch. Each capsule or cartridge may generally contain
between 20 .mu.g-10 mg of the compound of formula (I).
Alternatively, the compound of the invention may be presented
without excipients. Packaging of the formulation may be suitable
for unit dose or multi-dose delivery. In the case of multi-dose
delivery, the formulation can be pre-metered (eg as in Diskus, see
GB 2242134 or Diskhaler, see GB 2178965, 2129691 and 2169265) or
metered in use (eg as in Turbuhaler, see EP 69715). An example of a
unit-dose device is Rotahaler (see GB 2064336). The Diskus
inhalation device comprises an elongate strip formed from a base
sheet having a plurality of recesses spaced along its length and a
lid sheet hermetically but peelably sealed thereto to define a
plurality of containers, each container having therein an inhalable
formulation containing a compound of formula (I) preferably
combined with lactose. Preferably, the strip is sufficiently
flexible to be wound into a roll. The lid sheet and base sheet will
preferably have leading end portions which are not sealed to one
another and at least one of the said leading end portions is
constructed to be attached to a winding means. Also, preferably the
hermetic seal between the base and lid sheets extends over their
whole width. The lid sheet may preferably be peeled from the base
sheet in a longitudinal direction from a first end of the said base
sheet.
[0028] Pharmaceutical formulations which are non-pressurised and
adapted to be administered as a dry powder topically to the lung
via the buccal cavity (especially those which are free of excipient
or are formulated with a diluent or carrier such as lactose or
starch, most especially lactose) are of particular interest.
[0029] Spray compositions may for example be formulated as aqueous
solutions or suspensions or as aerosols delivered from pressurised
packs, such as a metered dose inhaler, with the use of a suitable
liquefied propellant. Aerosol compositions suitable for inhalation
can be either a suspension or a solution and generally contain the
compound of formula (I) and a suitable propellant such as a
fluorocarbon or hydrogen-containing chlorofluorocarbon or mixtures
thereof, particularly hydrofluoroalkanes, especially
1,1,1,2-tetrafluoroethane, 1,1,1,2,3,3,3-heptafluoro-n-propane or a
mixture thereof. The aerosol composition may optionally contain
additional formulation excipients well known in the art such as
surfactants eg oleic acid or lecithin and cosolvents eg ethanol.
One example formulation is excipient free and consists essentially
of (eg consists of) compound of formula (I) (preferably in
unsolvated form eg as Form 1) (optionally in combination with
another therapeutically active ingredient) and a propellant
selected from 1,1,1,2-tetrafluoroethane,
1,1,1,2,3,3,3-heptafluoro-n-propane and mixture thereof. Another
example formulation comprises particulate compound of formula (I),
a propellant selected from 1,1,1,2-tetrafluoroethane,
1,1,1,2,3,3,3-heptafluoro-n-propane and mixture thereof and a
suspending agent which is soluble in the propellant eg an
oligolactic acid or derivative thereof as described in WO94/21229.
The preferred propellant is 1,1,1,2-tetrafluoroethane. As noted
elsewhere in this specification, compound of formula (I) does not
appear to form a solvate with 1,1,1,2-tetrafluoroethane.
Pressurised formulations will generally be retained in a canister
(eg an aluminium canister) closed with a valve (eg a metering
valve) and fitted into an actuator provided with a mouthpiece.
[0030] Pressurised aerosol formulations preferably do not comprise
particulate medicament, a propellant and a stabiliser comprising a
water addition (i.e. water added in addition to nascent formulation
water). Pressurised aerosol formulations also preferably do not
comprise particulate medicament, a propellant and a stabiliser
comprising an amino acid, a derivative thereof or a mixture
thereof.
[0031] Medicaments for administration by inhalation desirably have
a controlled particle size. The optimum particle size for
inhalation into the bronchial system is usually 1-10 .mu.m,
preferably 2-5 .mu.m. Particles having a size above 20 .mu.m are
generally too large when inhaled to reach the small airways. To
achieve these particle sizes the particles of compound of formula
(I) as produced may be size reduced by conventional means eg by
micronisation. The desired fraction may be separated out by air
classification or sieving. Preferably, the particles will be
crystalline, prepared for example by a process which comprises
mixing in a continuous flow cell in the presence of ultrasonic
radiation a flowing solution of compound of formula (I) as
medicament in a liquid solvent with a flowing liquid antisolvent
for said medicament (eg as described in International Patent
Application PCT/GB99/04368) or else by a process which comprises
admitting a stream of solution of the substance in a liquid solvent
and a stream of liquid antisolvent for said substance tangentially
into a cylindrical mixing chamber having an axial outlet port such
that said streams are thereby intimately mixed through formation of
a vortex and precipitation of crystalline particles of the
substance is thereby caused (eg as described in International
Patent Application PCT/GB00/04327). When an excipient such as
lactose is employed, generally, the particle size of the excipient
will be much greater than the inhaled medicament within the present
invention. When the excipient is lactose it will typically be
present as milled lactose, wherein not more than 85% of lactose
particles will have a MMD of 60-90 .mu.m and not less than 15% will
have a MMD of less than 15 .mu.m.
[0032] Formulations for administration topically to the nose (eg
for the treatment of rhinitis) include pressurised aerosol
formulations and aqueous formulations administered to the nose by
pressurised pump. Formulations which are non-pressurised and
adapted to be administered topically to the nasal cavity are of
particular interest. The formulation preferably contains water as
the diluent or carrier for this purpose. Aqueous formulations for
administration to the lung or nose may be provided with
conventional excipients such as buffering agents, tonicity
modifying agents and the like. Aqueous formulations may also be
administered to the nose by nebulisation.
[0033] Other possible presentations include the following:
[0034] Ointments, creams and gels, may, for example, be formulated
with an aqueous or oily base with the addition of suitable
thickening and/or gelling agent and/or solvents. Such bases may
thus, for example, include water and/or an oil such as liquid
paraffin or a vegetable oil such as arachis oil or castor oil, or a
solvent such as polyethylene glycol. Thickening agents and gelling
agents which may be used according to the nature of the base
include soft paraffin, aluminium stearate, cetostearyl alcohol,
polyethylene glycols, woolfat, beeswax, carboxypolymethylene and
cellulose derivatives, and/or glyceryl monostearate and/or
non-ionic emulsifying agents.
[0035] Lotions may be formulated with an aqueous or oily base and
will in general also contain one or more emulsifying agents,
stabilising agents, dispersing agents, suspending agents or
thickening agents.
[0036] Powders for external application may be formed with the aid
of any suitable powder base, for example, talc, lactose or starch.
Drops may be formulated with an aqueous or non-aqueous base also
comprising one or more dispersing agents, solubilising agents,
suspending agents or preservatives.
[0037] If appropriate, the formulations of the invention may be
buffered by the addition of suitable buffering agents.
[0038] The proportion of the active compound of formula (I) in the
local compositions according to the invention depends on the
precise type of formulation to be prepared but will generally be
within the range of from 0.001 to 10% by weight. Generally, however
for most types of preparations advantageously the proportion used
will be within the range of from 0.005 to 1% and preferably 0.01 to
0.5%. However, in powders for inhalation or insufflation the
proportion used will usually be within the range of from 0.1 to
5%.
[0039] Aerosol formulations are preferably arranged so that each
metered dose or "puff" of aerosol contains 1 .mu.g-2000 .mu.g eg 20
.mu.g-2000 .mu.g, preferably about 20 .mu.g-500 .mu.g of a compound
of formula (I). Administration may be once daily or several times
daily, for example 2, 3, 4 or 8 times, giving for example 1, 2 or 3
doses each time. Preferably the compound of formula (I) is
delivered once or twice daily, more preferably once per day. The
overall daily dose with an aerosol will typically be within the
range 10 .mu.g-10 mg eg 100 .mu.g-10 mg preferably, 200 .mu.g-2000
.mu.g.
[0040] Topical preparations may be administered by one or more
applications per day to the affected area; over skin areas
occlusive dressings may advantageously be used. Continuous or
prolonged delivery may be achieved by an adhesive reservoir
system.
[0041] For internal administration the compound according to the
invention may, for example, be formulated in conventional manner
for oral, parenteral or rectal administration. Formulations for
oral administration include syrups, elixirs, powders, granules,
tablets and capsules which typically contain conventional
excipients such as binding agents, fillers, lubricants,
disintegrants, wetting agents, suspending agents, emulsifying
agents, preservatives, buffer salts, flavouring, colouring and/or
sweetening agents as appropriate. Dosage unit forms are, however,
preferred as described below.
[0042] Preferred forms of preparation for internal administration
are dosage unit forms i.e. tablets and capsules. Such dosage unit
forms contain from 0.1 mg to 20 mg preferably from 2.5 to 10 mg of
the compound of the invention.
[0043] The compound according to the invention may in general may
be given by internal administration in cases where systemic
adreno-cortical therapy is indicated.
[0044] In general terms preparations, for internal administration
may contain from 0.05 to 10% of the active ingredient dependent
upon the type of preparation involved. The daily dose may vary from
0.1 mg to 60 mg, eg 5-30 mg, dependent on the condition being
treated, and the duration of treatment desired.
[0045] Slow release or enteric coated formulations may be
advantageous, particularly for the treatment of inflammatory bowel
disorders.
[0046] The pharmaceutical compositions according to the invention
may also be used in combination with another therapeutically active
agent, for example, a .beta..sub.2 adrenoreceptor agonist, an
anti-histamine or an anti-allergic. The invention thus provides, in
a further aspect, a combination comprising the compound of formula
(I) or a physiologically acceptable solvate thereof together with
another therapeutically active agent, for example, a
.beta..sub.2-adrenoreceptor agonist, an anti-histamine or an
anti-allergic.
[0047] Examples of .beta..sub.2-adrenoreceptor agonists include
salmeterol (eg as racemate or a single enantiomer such as the
R-enantiomer), salbutamol, formoterol, salmefamol, fenoterol or
terbutaline and salts thereof, for example the xinafoate salt of
salmeterol, the sulphate salt or free base of salbutamol or the
fumarate salt of formoterol. Examples of anti-histamines include
methapyrilene or loratadine.
[0048] Other suitable combinations include, for example, other
anti-inflammatory agents eg NSAIDs (eg sodium cromoglycate,
nedocromil sodium, PDE4 inhibitors, leukotriene antagonists, iNOS
inhibitors, tryptase and elastase inhibitors, beta-2 integrin
antagonists and adenosine 2a agonists)) or antiinfective agents (eg
antibiotics, antivirals).
[0049] Of particular interest is use of the compound of formula (I)
in combination with a phosphodiesterase 4 (PDE4) inhibitor. The
PDE4-specific inhibitor useful in this aspect of the invention may
be any compound that is known to inhibit the PDE4 enzyme or which
is discovered to act as a PDE4 inhibitor, and which are only PDE4
inhibitors, not compounds which inhibit other members of the PDE
family as well as PDE4. Generally it is preferred to use a PDE4
inhibitor which has an IC.sub.50 ratio of about 0.1 or greater as
regards the IC.sub.50 for the PDE4 catalytic form which binds
rolipram with a high affinity divided by the IC.sub.50 for the form
which binds rolipram with a low affinity. For the purposes of this
disclosure, the cAMP catalytic site which binds R and S rolipram
with a low affinity is denominated the "low affinity" binding site
(LPDE 4) and the other form of this catalytic site which binds
rolipram with a high affinity is denominated the "high affinity"
binding site (HPDE 4). This term "HPDE4" should not be confused
with the term "hPDE4" which is used to denote human PDE4.
[0050] Initial experiments were conducted to establish and validate
a [.sup.3H]-rolipram binding assay. Details of this work are given
in the Binding Assays described in detail below.
[0051] The preferred PDE4 inhibitors of use in this invention will
be those compounds which have a salutary therapeutic ratio, i.e.,
compounds which preferentially inhibit cAMP catalytic activity
where the enzyme is in the form that binds rolipram with a low
affinity, thereby reducing the side effects which apparently are
linked to inhibiting the form which binds rolipram with a high
affinity. Another way to state this is that the preferred compounds
will have an IC.sub.50 ratio of about 0.1 or greater as regards the
IC.sub.50 for the PDE4 catalytic form which binds rolipram with a
high affinity divided by the IC.sub.50 for the form which binds
rolipram with a low affinity.
[0052] A further refinement of this standard is that of one wherein
the PDE4 inhibitor has an IC.sub.50 ratio of about 0.1 or greater;
said ratio is the ratio of the IC.sub.50 value for competing with
the binding of 1 nM of [.sup.3H]R-rolipram to a form of PDE4 which
binds rolipram with a high affinity over the IC.sub.50 value for
inhibiting the PDE4 catalytic activity of a form which binds
rolipram with a low affinity using 1 .mu.M[.sup.3H]-cAMP as the
substrate.
[0053] Examples of useful PDE4 inhibitors are:
[0054]
(R)-(+)-1-(4-bromobenzyl)-4-[(3-cyclopentyloxy)-4-methoxyphenyl]-2--
pyrrolidone;
[0055]
(R)-(+)-1-(4-bromobenzyl)-4-[(3-cyclopentyloxy)-4-methoxyphenyl]-2--
pyrrolidone;
[0056]
3-(cyclopentyloxy-4-methoxyphenyl)-1-(4-N'-[N2-cyano-S-methyl-isoth-
ioureido]benzyl)-2-pyrrolidone; cis
4-cyano-4-(3-cyclopentyloxy-4-methoxyp-
henyl)cyclohexan-1-carboxylic acid];
[0057]
cis-[4-cyano-4-(3-cyclopropylmethoxy-4-difluoromethoxyphenyl)cycloh-
exan-1-ol];
[0058] (R)-(+)-ethyl
[4-(3-cyclopentyloxy-4-methoxyphenyl)pyrrolidine-2-yl-
idene]acetate; and
[0059] (S)-(-)-ethyl
[4-(3-cyclopentyloxy-4-methoxyphenyl)pyrrolidine-2-yl-
idene]acetate.
[0060] Most preferred are those PDE4 inhibitors which have an
IC.sub.50 ratio of greater than 0.5, and particularly those
compounds having a ratio of greater than 1.0. Preferred compounds
are cis
4-cyano-4-(3-cyclopentyloxy-4-methoxyphenyl)cyclohexan-1-carboxylic
acid,
2-carbomethoxy-4-cyano-4-(3-cyclopropylmethoxy-4-difluoromethoxyphenyl)cy-
clohexan-1-one and
cis-[4-cyano-4-(3-cyclopropylmethoxy-4-difluoromethoxyp-
henyl)cyclohexan-1-ol]; these are examples of compounds which bind
preferentially to the low affinity binding site and which have an
IC.sub.50 ratio of 0.1 or greater.
[0061] Other compounds of interest include:
[0062] Compounds set out in U.S. Pat. No. 5,552,438 issued 03 Sep.,
1996; this patent and the compounds it discloses are incorporated
herein in full by reference. The compound of particular interest,
which is disclosed in U.S. Pat. No. 5,552,438, is
cis-4-cyano-4-[3-(cyclopentyloxy-
)-4-methoxyphenyl]cyclohexane-1-carboxylic acid (also known as
cilomalast) and its salts, esters, pro-drugs or physical forms;
AWD-12-281 from Astra (Hofgen, N. et al. 15th EFMC Int Symp Med
Chem (Sept 6-10, Edinburgh) 1998, Abst P.98); a 9-benzyladenine
derivative nominated NCS-613 (INSERM); D-4418 from Chiroscience and
Schering-Plough; a benzodiazepine PDE4 inhibitor identified as
Cl-1018 (PD-168787; Parke-Davis/Warner-Lambe- rt); a benzodioxole
derivative Kyowa Hakko disclosed in WO 9916766; V-11294A from Napp
(Landells, L. J. et al. Eur Resp J [Annu Cong Eur Resp Soc (Sept
19-23, Geneva) 1998] 1998, 12(Suppl. 28): Abst P2393); roflumilast
(CAS reference No 162401-32-3) and a pthalazinone (WO 9947505) from
Byk-Gulden; or a compound identified as T-440 (Tanabe Seiyaku;
Fuji, K. et al. J Pharmacol Exp Ther, 1998, 284(1): 162).
[0063] Phosphodiesterase and Rolipram Binding Assays
[0064] Assay Method 1A
[0065] Isolated human monocyte PDE4 and hrPDE (human recombinant
PDE4) was determined to exist primarily in the low affinity form.
Hence, the activity of test compounds against the low affinity form
of PDE4 can be assessed using standard assays for PDE4 catalytic
activity employing 1 .mu.M [.sup.3H]cAMP as a substrate (Torphy et
al., J. of Biol. Chem., Vol. 267, No. 3 pp1798-1804, 1992).
[0066] Rat brain high speed supernatants were used as a source of
protein and both enantiomers of [.sup.3H]-rolipram were prepared to
a specific activity of 25.6 Ci/mmol. Standard assay conditions were
modified from the published procedure to be identical to the PDE
assay conditions, except for the last of the cAMP: 50 mM Tris HCl
(pH 7.5), 5 mM MgCl.sub.2, 50 .mu.M 5'-AMP and 1 nM of
[.sup.3H]-rolipram (Torphy et al., J. of Biol. Chem., Vol. 267, No.
3 pp1798-1804, 1992). The assay was run for 1 hour at 30.degree. C.
The reaction was terminated and bound ligand was separated from
free ligand using a Brandel cell harvester. Competition for the
high affinity binding site was assessed under conditions that were
identical to those used for measuring low affinity PDE activity,
expect that [.sup.3H]-cAMP was not present.
[0067] Assay Method 1B
[0068] Measurement of Phosphodiesterase Activity
[0069] PDE activity was assayed using a [.sup.3H]cAMP SPA or
[.sup.3H]cGMP SPA enzyme assay as described by the supplier
(Amersham Life Sciences). The reactions were conducted in 96-well
plates at room temperature, in 0.1 ml of reaction buffer containing
(final concentrations): 50 mM Tris-HCl, pH 7.5, 8.3 mM MgCl.sub.2,
1.7 mM EGTA, [.sup.3H]cAMP or [.sup.3H] cGMP (approximately 2000
dpm/pmol), enzyme and various concentrations of the inhibitors. The
assay was allowed to proceed for 1 hr and was terminated by adding
50 .mu.l of SPA yttrium silicate beads in the presence of zinc
sulfate. The plates were shaken and allowed to stand at room
temperature for 20 min. Radiolabeled product formation was assessed
by scintillation spectrometry.
[0070] [.sup.3H]R-rolipram Binding Assay
[0071] The [.sup.3H]R-rolipram binding assay was performed by
modification of the method of Schneider and co-workers, see
Nicholson, et al., Trends Pharmacol. Sci., Vol. 12, pp.19-27 (1991)
and McHale et al., Mol. Pharmacol., Vol. 39, 109-113 (1991).
R-Rolipram binds to the catalytic site of PDE4 see Torphy et al.,
Mol. Pharmacol., Vol. 39, pp. 376-384 (1991). Consequently,
competition for [.sup.3H]R-rolipram binding provides an independent
confirmation of the PDE4 inhibitor potencies of unlabeled
competitors. The assay was performed at 30.degree. C. for 1 hr in
0.5 .mu.l buffer containing (final concentrations): 50 mM Tris-HCl,
pH 7.5, 5 mM MgCl.sub.2, 0.05% bovine serum albumin, 2 nM
[.sup.3H]R-rolipram (5.7.times.104 dpm/pmol) and various
concentrations of non-radiolabeled inhibitors. The reaction was
stopped by the addition of 2.5 ml of ice-cold reaction buffer
(without [.sup.3H]-R-rolipram) and rapid vacuum filtration (Brandel
Cell Harvester) through Whatman GF/B filters that had been soaked
in 0.3% polyethylenimine. The filters were washed with an
additional 7.5 ml of cold buffer, dried, and counted via liquid
scintillation spectrometry.
[0072] The invention thus provides, in a further aspect, a
combination comprising the compound of formula (I) or a
physiologically acceptable solvate thereof together with a PDE4
inhibitor.
[0073] The combination referred to above may conveniently be
presented for use in the form of a pharmaceutical formulation and
thus pharmaceutical formulations comprising a combination as
defined above together with a physiologically acceptable diluent or
carrier represent a further aspect of the invention.
[0074] The individual compounds of such combinations may be
administered either sequentially or simultaneously in separate or
combined pharmaceutical formulations. Appropriate doses of known
therapeutic agents will be readily appreciated by those skilled in
the art.
[0075] Surprisingly, the compound of formula (I) has demonstrated a
significant propensity to form solvates with commonly used organic
solvents. Such solvates are essentially stoichiometric eg the ratio
of compound of formula (I) to solvent is close to 1:1 eg according
to Applicant's analysis has been determined to be in the range
0.95-1.05:1. For example, we have prepared solvates with solvents
such as acetone, dimethylformamide (DMF), dimethylacetamide (DMAc),
tetrahydrofuran (THF), N-methyl-2-pyrrolidone, isopropanol and
methylethylketone. The salvation of compound of formula (I) is not
predictable however since we have found that even though it does
form a solvate with isopropanol it does not appear to form a
solvate with ethanol or methanol. Furthermore it does not appear to
form a solvate with 1,1,1,2-tetrafluoroethane, ethylacetate,
methylacetate, toluene, methylisobutylketone (MIBK) or water
either. However due to the toxicity of many organic solvents it has
been necessary to develop special final stage processing conditions
(discussed later) in order to permit the compound of formula (I) to
be produced in unsolvated form. Thus according to another aspect of
the invention there is provided a compound of formula (I) in
unsolvated form.
[0076] Surprisingly we have also discovered that the compound of
formula (I) in unsolvated form may exist in a number of polymorphic
forms. Specifically we have identified polymorphic forms which may
be distinguished by means of X-Ray Powder Diffraction (XRPD) which
we have named as Form 1, Form 2 and Form 3. Form 3 appears to be an
unstable minor polymorphic modification of Form 2.
[0077] Broadly speaking the Forms are characterised in their XRPD
profiles as follows:
[0078] Form 1: Peak at around 18.9 degrees 2Theta
[0079] Form 2: Peaks at around 18.4 and 21.5 degrees 2Theta.
[0080] Form 3: Peaks at around 18.6 and 19.2 degrees 2Theta.
[0081] Within the range 21-23 degrees 2Theta Form 3 shows a single
peak whereas Form 2 shows a pair of peaks. A peak at 7 degrees
2Theta is present in all cases however it is present at much higher
intensity in the case of Forms 2 and 3 than is the case for Form
1.
[0082] The XRPD patterns of the polymorphs are shown overlaid in
FIG. 1. The conversion of Form 2 to Form 1 with time in an aqueous
slurry at ambient temperature is shown in FIG. 2. In the conversion
of Form 2 to Form 1 the loss of a peak characteristic of Form 2
(labelled B) at around 18.4 degrees 2Theta, a marked reduction in
intensity in the peak at around 7 degrees 2Theta (labelled A) and
the appearance of a peak characteristic of Form 1 (labelled C) at
around 18.9 degrees 2Theta are particularly noticeable.
[0083] The temperature dependence of Form 3 is shown in FIG. 4. The
temperature was varied according to the profile shown in FIG. 5.
From FIG. 4 it can be seen that Form 3 converts first to Form 2
over the temperature range 30-170.degree. C. and then converts to
Form 1 over the temperature range 170-230.degree. C. In the
conversion of Form 3 to Form 2 the division of one peak in the
range 21-23 degrees 2Theta into two peaks within the same range and
the shifting leftwards of the peak at around 18.6 degrees 2Theta to
around 18.4 degrees 2Theta are particularly noticeable. In the
conversion of Form 2 to Form 1 similar changes to those noted in
the previous paragraph may be observed.
[0084] The differential scanning calorimetry (DSC) and thermal
gravimetric analysis (TGA) profiles of Form 1 are shown in FIG. 3.
The profiles are characterised by a transition at around
280-300.degree. C. (typically close to 298.degree. C.)
corresponding to an endothermic event in the DSC and chemical
degradation in the TGA. The DSC profiles of Forms 2 and 3 were not
materially different under the conditions of the experiments
performed and thus DSC is not a suitable technique for
distinguishing between the 3 Forms. In FIG. 3 the absence of
activity in the TGA and DSC profiles below around 298.degree. C.
implies that the substance shows good physical and chemical
stability at normal operating temperatures.
[0085] As shown in the Examples, enthalpy of dissolution of Forms 1
and 3 have been determined in certain organic solvents and
accordingly an enthalpy of transition from Form 3 to Form 1 of
5.1-6.7 kJ/mol has been estimated.
[0086] Thus we prefer compound of formula (I) in unsolvated Form 1
since this form appears to be thermodynamically most stable at
ambient temperature and also appears to be least susceptible to
undesirable moisture sorption (see results in Examples section).
Nevertheless Form 2 (or Form 3) may be preferred under other
conditions.
[0087] Although use of a compound of formula (I) in solvated form
is not preferred, nevertheless we have surprisingly found that
certain solvate forms have particularly attractive physicochemical
properties which makes them useful as intermediates in the
preparation of a compound of formula (I) in unsolvated form (eg by
removal of solvent as a final step). For example we have discovered
that certain stoichiometric solvates can be isolated as solids in
highly crystalline form. Thus we also provide as an aspect of the
invention: Compound of formula (I) as the methylethylketone
solvate
[0088] Compound of formula (I) as the isopropanol solvate
[0089] Compound of formula (I) as the tetrahydrofuran solvate
[0090] Compound of formula (I) as the acetone solvate.
[0091] In particular we provide the aforementioned solvates as
solids in crystalline form. A further particular advantage of these
solvates is the fact that desolvation of the solvate (eg by
heating) results in formation of the unsolvated form as the
preferred Form 1. The aforementioned solvates have relatively low
toxicity and are suitable for use in industrial scale manufacture.
Compound of formula (I) as the DMF solvate which may also be
isolated as a solid in crystalline form is also of interest for use
in onward processing to unsolvated Form 1.
[0092] The compound of formula (I) and solvates thereof may be
prepared by the methodology described hereinafter, constituting a
further aspect of this invention.
[0093] A process according to the invention for preparing a
compound of formula (I) or a solvate thereof comprises alkylation
of a thioacid of formula (II) 4
[0094] or a salt thereof.
[0095] In this process the compound of formula (II) may be reacted
with a compound of formula FCH.sub.2L wherein L represents a
leaving group (eg a halogen atom, a mesyl or tosyl group or the
like) for example, an appropriate fluoromethyl halide under
standard conditions. Preferably, the fluoromethyl halide reagent is
bromofluoromethane.
[0096] As noted later, preferably the compound of formula (II) is
employed as a salt, particularly the salt with
diisopropylethylamine.
[0097] In a preferred process for preparing the compound of formula
(I), the compound of formula (II) or a salt thereof is treated with
bromofluoromethane optionally in the presence of a phase transfer
catalyst. A preferred solvent is methylacetate, or more preferably
ethylacetate, optionally in the presence of water. The presence of
water improves solubility of both starting material and product and
the use of a phase transfer catalyst results in an increased rate
of reaction. Examples of phase transfer catalysts that may be
employed include (but are not restricted to) tetrabutylammonium
bromide, tetrabutylammonium chloride, benzyltributylammonium
bromide, benzyltributylammonium chloride, benzyltriethylammonium
bromide, methyltributylammonium chloride and methyltrioctylammonium
chloride. THF has also successfully been employed as solvent for
the reaction wherein the presence of a phase transfer catalyst
again provides a significantly faster reaction rate. Preferably the
product present in an organic phase is washed firstly with aqueous
acid eg dilute HCl in order to remove amine compounds such as
triethylamine and diisopropylethylamine and then with aqueous base
eg sodium bicarbonate in order to remove any unreacted precursor
compound of formula (II). As noted later, if the compound of
formula (I) so produced in solution in ethylacetate is distilled
and toluene added, then unsolvated Form 1 crystallises out.
[0098] Compounds of formula (II) may be prepared from the
corresponding 17.alpha.-hydroxyl derivative of formula (III): 5
[0099] using for example, the methodology described by G. H.
Phillipps et al., (1994) Journal of Medicinal Chemistry, 37,
3717-3729. For example the step typically comprises the addition of
a reagent suitable for performing the esterification eg an
activated derivative of 2-furoic acid such as an activated ester or
preferably a 2-furoyl halide eg 2-furoyl chloride (employed in at
least 2 times molar quantity relative to the compound of formula
(III)) in the presence of an organic base eg triethylamine. The
second mole of 2-furoyl chloride reacts with the thioacid moiety in
the compound of formula (III) and needs to be removed eg by
reaction with an amine such as diethylamine.
[0100] This method suffers disadvantages, however, in that the
resultant compound of formula (II) is not readily purified of
contamination with the by-product 2-furoyldiethylamide. We have
therefore invented several improved processes for performing this
conversion.
[0101] In a first such improved process we have discovered that by
using a more polar amine such as diethanolamine, a more water
soluble by-product is obtained (in this case
2-furoyldiethanolamide) which permits compound of formula (II) or a
salt thereof to be produced in high purity since the by-product can
efficiently be removed by water washing.
[0102] Thus according to this aspect of the invention we provide a
process for preparing a compound of formula (II) which
comprises:
[0103] (a) reacting a compound of formula (III) with an activated
derivative of 2-furoic acid as in an amount of at least 2 moles of
the activated derivative per mole of compound of formula (III) to
yield a compound of formula (IIA) 6
[0104] ; and
[0105] (b) removal of the sulphur-linked 2-furoyl moiety from
compound of formula (IIA) by reaction of the product of step (a)
with an organic primary or secondary amine base capable of forming
a water soluble 2-furoyl amide.
[0106] In two particularly convenient embodiments of this process
we also provide methods for the efficient purification of the end
product which comprise either
[0107] (c1) when the product of step (b) is dissolved in a
substantially water immiscible organic solvent, purifying the
compound of formula (II) by washing out the amide by-product from
step (b) with an aqueous wash, or
[0108] (c2) when the product of step (b) is dissolved in a water
miscible solvent, purifying the compound of formula (II) by
treating the product of step (b) with an aqueous medium so as to
precipitate out pure compound of formula (II) or a salt
thereof.
[0109] In step (a) preferably the activated derivative of 2-furoic
acid may be an activated ester of 2-furoic acid, but is more
preferably a 2-furoyl halide, especially 2-furoyl chloride. A
suitable solvent for this reaction is ethylacetate or methylacetate
(preferably methylacetate) (when step (c1) may be followed) or
acetone (when step (c2) may be followed). Normally an organic base
eg triethylamine will be present. In step (b) preferably the
organic base is diethanolamine. The base may suitably be dissolved
in a solvent eg methanol. Generally steps (a) and (b) will be
performed at reduced temperature eg between 0 and 5.degree. C. In
step (c1) the aqueous wash may be water, however the use of brine
results in higher yields and is therefore preferred. In step (c)
the aqueous medium is for example a dilute aqueous acid such as
dilute HCl.
[0110] According to a related aspect of the invention we provide an
alternative process for preparing a compound of formula (II) which
comprises:
[0111] (a) reacting a compound of formula (III) with an activated
derivative of 2-furoic acid in an amount of at least 2 moles of
activated derivative per mole of compound of formula (III) to yield
a compound of formula (IIA); and
[0112] (b) removal of the sulphur-linked 2-furoyl moiety from
compound of formula (IIA) by reaction of the product of step (a)
with a further mole of compound of formula (III) to give two moles
of compound of formula (II).
[0113] In step (a) preferably the activated derivative of 2-furoic
acid may be an activated ester of 2-furoic acid, but is more
preferably a 2-furoyl halide, especially 2-furoyl chloride. A
suitable solvent for his step is acetone. Normally an organic base
eg triethylamine will be present. In step (b) a suitable solvent is
DMF or dimethylacetamide. Normally an organic base eg triethylamine
will be present. Generally steps (a) and (b) will be performed at
reduced temperature eg between 0 and 5.degree. C. The product may
be isolated by treatment with acid and washing with water.
[0114] This aforementioned process is very efficient in that it
does not produce any furoylamide by-product (thus affording inter
alia environmental advantages) since the excess mole of furoyl
moiety is taken up by reaction with a further mole of compound of
formula (II) to form an additional mole of compound of formula
(II).
[0115] Further general conditions for the conversion of compound of
formula (III) to compound of formula (II) in the two processes just
described will be well known to persons skilled in the art.
[0116] According to a preferred set of conditions, however, we have
found that the compound of formula (II) may advantageously be
isolated in the form of a solid crystalline salt. The preferred
salt is a salt formed with a base such as triethylamine,
2,4,6-trimethylpyridine, diisopropylethylamine or
N-ethylpiperidine. Such salt forms of compound of formula (II) are
more stable, more readily filtered and dried and can be isolated in
higher purity than the free thioacid. The most preferred salt is
the salt formed with diisopropylethylamine. The triethylamine salt
is also of interest.
[0117] Compounds of formula (III) may be prepared in accordance
with procedures described in GB 2088877B.
[0118] Compounds of formula (III) may also be prepared by a process
comprising the following steps: 7
[0119] Step (a) comprises oxidation of a solution containing the
compound of formula (V). Preferably, step (a) will be performed in
the presence of a solvent comprising methanol, water,
tetrahydrofuran, dioxan or diethylene glygol dimethylether. So as
to enhance yield and throughput, preferred solvents are methanol,
water or tetrahydrofuran, and more preferably are water or
tetrahydrofuran, especially water and tetrahydrofuran as solvent.
Dioxan and diethylene glygol dimethylether are also preferred
solvents which may optionally (and preferably) be employed together
with water. Preferably, the solvent will be present in an amount of
between 3 and 10 vol relative to the amount of the starting
material (1 wt, more preferably between 4 and 6 vol., especially 5
vol. Preferably the oxidising agent is present in an amount of 1-9
molar equivalents relative to the amount of the starting material.
For example, when a 50% w/w aqueous solution of periodic acid is
employed, the oxidising agent may be present in an amount of
between 1.1 and 10 wt. relative to the amount of the starting
material (1 wt.), more preferably between 1.1 and 3 wt., especially
1.3 wt. Preferably, the oxidation step will comprise the use of a
chemical oxidising agent. More preferably, the oxidising agent will
be periodic acid or iodic acid or a salt thereof. Most preferably,
the oxidising agent will be periodic acid or sodium periodate,
especially periodic acid. Alternatively (or in addition), it will
also be appreciated that the oxidation step may comprise any
suitable oxidation reaction, eg one which utilises air and/or
oxygen. When the oxidation reaction utilises air and/or oxygen, the
solvent used in said reaction will preferably be methanol.
Preferably, step (a) will involve incubating the reagents at room
temperature or a little warmer, say around 25.degree. C. eg for 2
hours. The compound of formula (IV) may be isolated by
recrystallisation from the reaction mixture by addition of an
anti-solvent. A suitable anti-solvent for compound of formula (IV)
is water. Surprisingly we have discovered that it is highly
desirable to control the conditions under which the compound of
formula (IV) is precipitated by addition of anti-solvent eg water.
When the recrystallisation is performed using chilled water (eg
water/ice mixture at a temperature of 0-5.degree. C.) although
better anti-solvent properties may be expected we have found that
the crystalline product produced is very voluminous, resembles a
soft gel and is very difficult to filter. Without being limited by
theory we believe that this low density product contains a large
amount of solvated solvent within the crystal lattice. By contrast
when conditions of around 10.degree. C. or higher are used (eg
around ambient temperature) a granular product of a sand like
consistency which is very easily filtered is produced. Under these
conditions, crystallisation typically commences after around 1 hour
and is typically completed within a few hours (eg 2 hours). Without
being limited by theory we believe that this granular product
contains little or no solvated solvent within the crystal
lattice.
[0120] Step (b) will typically comprise the addition of a reagent
suitable for converting a carboxylic acid to a carbothioic acid eg
using hydrogen sulphide gas together with a suitable coupling agent
eg carbonyldiimidazole (CDI) in the presence of a suitable solvent
eg dimethylformamide.
[0121] An alternative process for preparing a compound of formula
(II) comprises treating a compound of formula (X) with a reagent
suitable for converting a carboxylic acid to a carbothioic acid eg
using hydrogen sulphide gas together with a suitable coupling agent
such as CDI in the presence of a suitable solvent eg DMF. Compounds
of formula (X) may be prepared by methodology analogous to that
described herein.
[0122] An alternative process for preparing a compound of formula
(I) or a solvate thereof comprises reacting a compound of formula
(VI) 8
[0123] with a fluorine source.
[0124] Examples of suitable sources of fluorine include fluoride
(eg sodium fluoride) or, more preferably, HF. The preferred reagent
is aqueous HF. A solvent such as THF or DMF may be employed.
[0125] A compound of formula (VI) may be prepared by a process
comprising
[0126] (a) alkylating a compound of formula (VII) 9
[0127] or a salt thereof;
[0128] (b) reacting a compound of formula (VIII) 10
[0129] with an epoxide forming reagent; or
[0130] (c) esterifying a compound of formula (IX) 11
[0131] In process (a), analogous conditions to those described
above for the conversion of a compound of formula (II) to a
compound of formula (I) may be employed. Typically compound of
formula (VII) will be reacted with a compound of formula FCH.sub.2L
wherein L represents a leaving group (eg a halogen atom, a mesyl or
tosyl group or the like) for example, an appropriate fluoromethyl
halide under standard conditions. Preferably, the fluoromethyl
halide reagent is bromofluoromethane.
[0132] Process (b) is preferably performed in two steps: (i)
formation of a halohydrin especially a bromohydrin (eg by reaction
with bromodan or equivalent reagent), followed by (ii) treatment
with base such as sodium hydroxide so as to effect ring closure.
The product of step (i) is a compound of formula (IXA) which is a
novel intermedate that may be isolated, if desired: 12
[0133] wherein X represents halogen, especially Br.
[0134] In process (c), a suitable reagent would be an activated
derivative of 2-furoic acid such as an activated ester or
preferably a 2-furoyl halide eg 2-furoyl chloride in the presence
of an organic base eg triethylamine. This reaction may be performed
at elevated temperature eg around 60.degree. C. or else at ambient
temperature in the presence of an acylation catalyst eg
dimethylamino pyridine (DMAP).
[0135] Compounds of formula (VII) may be prepared by a process
comprising esterification of a compound of formula (XI) 13
[0136] Analogous conditions to those described above for the
conversion of a compound of formula (III) to a compound of formula
(II) may be employed. For example, a suitable reagent would be an
activated derivative of 2-furoic acid such as an activated ester or
preferably a 2-furoyl halide eg 2-furoyl chloride in the presence
of an organic base eg triethylamine. Compound of formula (XI) is
known (J Labelled Compd Radiopharm (1997) 39(7) 567-584).
[0137] A compound of formula (VIII) may be prepared by a process
comprising
[0138] (a) alkylating a compound of formula (XII) 14
[0139] or a salt thereof; or
[0140] (b) esterifying a compound of formula (XIII) 15
[0141] In process (a), analogous conditions to those described
above for the conversion of a compound of formula (II) to a
compound of formula (I) may be employed. Typically compound of
formula (XII) will be reacted with a compound of formula FCH.sub.2L
wherein L represents a leaving group (eg a halogen atom, a mesyl or
tosyl group or the like) for example, an appropriate fluoromethyl
halide under standard conditions. Preferably, the fluoromethyl
halide reagent is bromofluoromethane.
[0142] In process (b), analogous conditions to those employed above
for the conversion of a compound of formula (IX) to a compound of
formula (VI) may be employed. For example, a suitable reagent would
be an activated derivative of 2-furoic acid such as an activated
ester or preferably a 2-furoyl halide eg 2-furoyl chloride in the
presence of an organic base eg triethylamine.
[0143] Compounds of formula (IX) and (XIII) may be prepared by
alkylating the corresponding thioacids (XI) and (XIV) (defined
below) using methodology analogous to that already described (eg by
reaction with a compound of formula FCH.sub.2L wherein L represents
a leaving group (eg a halogen atom, a mesyl or tosyl group or the
like) for example, an appropriate fluoromethyl halide under
standard conditions. Preferably, the fluoromethyl halide reagent is
bromofluoromethane. The thioacid (XI) is a known compound (J
Labelled Compd Radiopharm (1997) 39(7) 567-584).
[0144] Compound of formula (XII) may be prepared by a process
comprising esterifying a compound of formula (XIV): 16
[0145] or a salt thereof.
[0146] This process may be performed using methodology analogous to
that already described. For example, a suitable reagent would be an
activated derivative of 2-furoic acid such as an activated ester or
preferably a 2-furoyl halide eg 2-furoyl chloride in the presence
of an organic base eg triethylamine.
[0147] Compounds of formula (XIV) may be prepared from the
corresponding carboxylic acid eg by a process analogous to that
described above for the conversion of a compound of formula (IV) to
a compound of formula (III). The aforesaid corresponding carboxylic
acid is known (Upjohn, WO 90/15816).
[0148] A further alternative process for preparing a compound of
formula (I) or a solvate thereof comprises deprotecting or
unmasking a compound of formula (I) in which the 11-.beta.-hydroxy
group is protected or masked. A first such process comprises
deprotecting a compound of formula (XV) 17
[0149] wherein P represents a hydroxy protecting group.
[0150] Examples of hydroxy protecting groups P are described in
Protective Groups in Organic Chemistry Ed JFW McOmie (Plenum Press
1973) or Protective Groups in Organic Synthesis by Theodora W Green
(John Wiley and Sons, 1991).
[0151] Examples of suitable hydroxy protecting groups P include
groups selected from carbonate, alkyl (eg t-butyl or
methoxymethyl), aralkyl (eg benzyl, p-nitrobenzyl, diphenylmethyl
or triphenylmethyl), heterocyclic groups such as tetrahydropyranyl,
acyl (eg acetyl or benzyl) and silyl groups such as trialkylsilyl
(eg t-butyldimethylsilyl). The hydroxy protecting groups may be
removed by conventional techniques. Thus, for example, carbonate
may be removed by treatment with base and alkyl, silyl, acyl and
heterocyclic groups may be removed by solvolysis eg by hydrolysis
under acid or basic conditions. Aralkyl groups such as
triphenylmethyl may similarly be removed by solvolysis eg by
hydrolysis under acidic conditions. Aralkyl groups such as benzyl
or p-nitrobenzyl may be cleaved by hydrogenolysis in the presence
of a Noble metal catalyst such as palladium on charcoal.
p-Nitrobenzyl may also be cleaved by photolysis.
[0152] The 11-.beta.-hydroxy group may be masked as a carbonyl
group. Thus a second such process comprises reduction of a compound
of formula (XVI) 18
[0153] Reduction to the compound of formula (I) may be achieved eg
by treatment with a hydride reducing agent such as borohydride eg
sodium borohydride.
[0154] The 11-ketone (XVI) may also be masked. Examples of masked
derivatives of compound of formula (XVI) include (i) ketal
derivatives eg ketals formed by treatment of the compound of
formula (XVI) with an alcohol eg methanol, ethanol or
ethan-1,2-diol, (ii) dithioketal derivatives eg dithioketals formed
by treatment of the compound of formula (XVI) with a thiol eg
methanethiol, ethanethiol or ethan-1,2-dithiol, (iii) monothioketal
derivatives eg monothioketals formed by treatment of the compound
of formula (XVI) with eg 1-hydroxy-ethane-2-thiol, (iv) derivatives
formed by treatment of the compound of formula (XVI) with an
alcoholamine eg ephedrine, (v) imines formed by treatment of the
compound of formula (XVI) with amines, (vi) oximes formed by
treatment of compounds of formula (XVI) with hydroxylamines. We
claims such derivatives of compound of formula (XVI) as an aspect
of the invention.
[0155] These masked derivatives may be converted back to the ketone
by conventional means eg ketals, imines and oximes are converted to
carbonyl by treatment with dilute acid and dithioketals are
converted to the ketone by a variety of methods as described by P.
C. Bulman Page et al (1989), Tetrahedron, 45, 7643-7677 and
references therein.
[0156] Compounds of formula (XV) may be prepared by a process
comprising
[0157] (a) alkylating a compound of formula (XVII) 19
[0158] or a salt thereof wherein P represents a hydroxy protecting
group; or
[0159] (b) esterifying a compound of formula (XVIII) 20
[0160] In step (a), analogous conditions to those described above
for the conversion of a compound of formula (II) to a compound of
formula (I) may be employed. Typically compound of formula (XVII)
will be reacted with a compound of formula FCH.sub.2L wherein L
represents a leaving group (eg a halogen atom, a mesyl or tosyl
group or the like) for example, an appropriate fluoromethyl halide
under standard conditions. Preferably, the fluoromethyl halide
reagent is bromofluoromethane.
[0161] In step (b), analogous conditions to those employed above
for the conversion of a compound of formula (IX) to a compound of
formula (VI) may be employed. For example, a suitable reagent would
be an activated derivative of 2-furoic acid such as an activated
ester or preferably a 2-furoyl halide eg 2-furoyl chloride in the
presence of an organic base eg triethylamine.
[0162] Compound of formula (XVIII) may be prepared by alkylating
the corresponding thioacid using methodology analogous to that
already described (eg by reaction with a compound of formula
FCH.sub.2L wherein L represents a leaving group (eg a halogen atom,
a mesyl or tosyl group or the like) for example, an appropriate
fluoromethyl halide under standard conditions. Preferably, the
fluoromethyl halide reagent is bromofluoromethane. The
corresponding thioacids are known compounds or may be prepared by
standard methodology. Compound of formula (XVIII) may alternatively
be prepared by protection of the corresponding hydroxy
derivative.
[0163] Compound of formula (XVII) may be prepared by a process
comprising esterifying a compound of formula (XIX) 21
[0164] or a salt thereof wherein P represents a hydroxy protecting
group.
[0165] This process may be performed using methodology analogous to
that already described for the conversion of compounds of formula
(III) to (II). For example, a suitable reagent would be an
activated derivative of 2-furoic acid such as an activated ester or
preferably a 2-furoyl halide eg 2-furoyl chloride in the presence
of an organic base eg triethylamine.
[0166] Compounds of formula (XIX) may be prepared by protecting the
corresponding hydroxy derivative (III), having first protected the
thioacid which would then be deprotected.
[0167] Compounds of formula (XVI) may be prepared by a process
comprising
[0168] (a) alkylating a compound of formula (XX) 22
[0169] or a salt thereof or a derivative wherein the 1-carbonyl
group is masked; or
[0170] (b) esterifying a compound of formula (XXI) 23
[0171] or a derivative wherein the 11-carbonyl group is masked.
[0172] In step (a), analogous conditions to those described above
for the conversion of a compound of formula (III) to a compound of
formula (II) may be employed. Typically compound of formula (XX)
will be reacted with a compound of formula FCH.sub.2L wherein L
represents a leaving group (eg a halogen atom, a mesyl or tosyl
group or the like) for example, an appropriate fluoromethyl halide
under standard conditions. Preferably, the fluoromethyl halide
reagent is bromofluoromethane.
[0173] In step (b), analogous conditions to those employed above
for the conversion of a compound of formula (IX) to a compound of
formula (VI) may be employed. For example, a suitable reagent would
be an activated derivative of 2-furoic acid such as an activated
ester or preferably a 2-furoyl halide eg 2-furoyl chloride in the
presence of an organic base eg triethylamine.
[0174] Compound of formula (XXI) or a derivative thereof wherein
the 11-ketone group is masked may be prepared by alkylating the
corresponding thioacid using methodology analogous to that already
described (eg by reaction with a compound of formula FCH.sub.2L
wherein L represents a leaving group (eg a halogen atom, a mesyl or
tosyl group or the like) for example, an appropriate fluoromethyl
halide under standard conditions. Preferably, the fluoromethyl
halide reagent is bromofluoromethane. The corresponding thioacids
are known compounds or may be prepared from the corresponding
carboxylic acids by methods analogous to those previously
described.
[0175] Compound of formula (XX) may be prepared by a process
comprising esterifying a compound of formula (XXII) 24
[0176] or a derivative thereof wherein the 11-ketone group is
masked.
[0177] This process may be performed using methodology analogous to
that already described. For example, a suitable reagent would be an
activated derivative of 2-furoic acid such as an activated ester or
preferably a 2-furoyl halide eg 2-furoyl chloride in the presence
of an organic base eg triethylamine.
[0178] Compounds of formula (XXII) and derivatives thereof wherein
the 11-ketone is masked may be prepared by oxidation of the
corresponding hydroxy derivative (IV) followed by masking of the
ketone and subsequent conversion of the carboxylic acid group to
the thioacid (see eg conversion of compounds of formula (IV) to
(III).
[0179] A further alternative process for the preparation of
compounds of formula (I) or a solvate thereof comprises reaction of
a compound of formula (XXIII) 25
[0180] wherein L represents a leaving group (eg halide other than
fluoride such as chloride, iodide or a sulphonate ester such
mesylate, tosylate, triflate) with a fluorine source.
[0181] Preferably the fluorine source is fluoride ion eg KF.
Further details for this conversion may be obtained by reference to
G. H. Phillipps et al., (1994) Journal of Medicinal Chemistry, 37,
3717-3729 or J Labelled Compd Radiopharm (1997) 39(7) 567-584).
[0182] Compounds of formula (XXIII) may be prepared by methods
analogous to those described herein. Corresponding novel
intermediates of formula (VI), (VIII), (IX), (IXA), (XV) and (XVI)
wherein the --CH2F moiety is replaced with a --CH2L moiety (wherein
L represents a leaving group other than fluorine) are claimed as an
aspect of the invention.
[0183] A further alternative process for the preparation of
compounds of formula (I) or a solvate thereof comprises
deprotection or unmasking of a derivative of a compound of formula
(I) in which the 3-carbonyl group is protected or masked.
[0184] The 3-carbonyl group may be masked in a manner analogous to
that described above in relation to masking of the 11-carbonyl
position. Thus the 3-carbonyl may be masked eg as a ketal,
monothioketal, dithioketal, derivative with an alcoholamine, oxime
or imine. The carbonyl group may be recovered by conventional means
eg ketals are converted to carbonyl by treatment with dilute acid
and dithioketals are converted to the ketone by a variety of
methods as described by P. C. Bulman Page et al (1989),
Tetrahedron, 45, 7643-7677 and references therein.
[0185] Certain intermediate compounds are new and we provide these,
together where appropriate with their salts and solvates, as an
aspect of the invention.
[0186] As noted above, we provide as a particular aspect of the
invention a process for preparing a compound of formula (I) in
unsolvated form which comprises:
[0187] (a) Crystallising the compound of formula (I) in the
presence of a non-solvating solvent such as ethanol, methanol,
water, ethyl acetate, toluene, methylisobutylketone or mixtures
thereof; or
[0188] (b) Desolvating a compound of formula (I) in solvated form
(eg in the form of a solvate with acetone, isopropanol,
methylethylketone, DMF or tetrahydrofuran) eg by heating.
[0189] In step (b) the desolvation will generally be performed at a
temperature exceeding 50.degree. C. preferably at a temperature
exceeding 100.degree. C. Generally heating will be performed under
vacuum.
[0190] There is also provided a compound of formula (I) in
unsolvated form obtainable by the aforementioned process.
[0191] There is also provided as a particular aspect of the
invention a process for preparing a compound of formula (I) as
unsolvated Form 1 polymorph which comprises dissolving compound of
formula (I) in methylisobutylketone, ethyl acetate or methyl
acetate and producing compound of formula (I) as unsolvated Form 1
by addition of a non-solvating anti-solvent such as iso-octane or
toluene.
[0192] According to a first preferred embodiment of this process
the compound of formula (I) may be dissolved in ethyl acetate and
compound of formula (I) as unsolvated Form 1 polymorph may be
obtained by addition of toluene as anti-solvent. In order to
improve the yield, preferably the ethyl acetate solution is hot and
once the toluene has been added the mixture is distilled to reduce
the content of ethyl acetate.
[0193] According to a second preferred embodiment of this process
the compound of formula (I) may be dissolved in
methylisobutylketone and compound of formula (I) as unsolvated Form
1 polymorph may be obtained by addition of isooctane as
anti-solvent
[0194] There is also provided a compound of formula (I) as
unsolvated Form 1 polymorph obtainable by the aforementioned
processes.
[0195] A process for preparing a compound of formula (I) as
unsolvated Form 2 polymorph comprises dissolving compound of
formula (I) in unsolvated form in methanol or dry dichloromethane
and recrystallising the compound of formula (I) as unsolvated Form
2 polymorph. Typically the compound of formula (I) will be
dissolved in hot in methanol or dry dichloromethane and allowed to
cool.
[0196] There is also provided a compound of formula (I) as
unsolvated Form 2 polymorph obtainable by the aforementioned
process.
[0197] A process for preparing a preparing a compound of formula
(I) as unsolvated Form 3 polymorph comprises dissolving compound of
formula (I) or a solvate thereof (in particular as the acetone
solvate) in dichloromethane in the presence of water (typically
1-3% water by volume) and recrystallising the compound of formula
(I) as unsolvated Form 3 polymorph.
[0198] There is also provided a compound of formula (I) as
unsolvated Form 3 polymorph obtainable by the aforementioned
process.
[0199] The advantages of the compound of formula (I) and/or its
solvates or polymorphs may include the fact that the substance
appears to demonstrate excellent anti-inflammatory properties, with
predictable pharmacokinetic and pharmacodynamic behaviour, with an
attractive side-effect profile and is compatible with a convenient
regime of treatment in human patients. Further advantages may
include the fact that the substance has desirable physical and
chemical properties which allow for ready manufacture and
storage.
BRIEF DESCRIPTION OF THE FIGURES
[0200] FIG. 1: Overlay of the XRPD profiles of Form 1, Form 2 and
Form 3 polymorphs of unsolvated Compound of formula (I)
[0201] FIG. 2: Overlay of the XRPD profiles of Form 1, Form 2 and a
50:50 mixture of Form 1 and Form 2 polymorphs of unsolvated
Compound of formula (I) together with the time dependence of the
profile of the 50:50 mixture of Form 1 and Form 2
[0202] FIG. 3: DSC and TGA profiles of Form 1 polymorph of
Unsolvated Compound of formula (I)
[0203] FIG. 4: Temperature dependence of the XRPD profile of
Compound of formula (I) Unsolvated Form 3 obtained at 5
timepoints
[0204] FIG. 5: Temperature and time profile for the XRPD
experiments of FIG. 4
DETAILED DESCRIPTION OF THE INVENTION
[0205] The following non-limiting Examples illustrate the
invention:
EXAMPLES
[0206] General
[0207] .sup.1H-nmr spectra were recorded at 400 MHz and the
chemical shifts are expressed in ppm relative to tetramethylsilane.
The following abbreviations are used to describe the multiplicities
of the signals: s (singlet), d (doublet), t (triplet), q (quartet),
m (multiplet), dd (doublet of doublets), ddd (doublet of doublet of
doublets), dt (doublet of triplets) and b (broad). Biotage refers
to prepacked silica gel cartridges containing KP-Sil run on flash
12i chromatography module. LCMS was conducted on a Supelcosil
LCABZ+PLUS column (3.3 cm.times.4.6 mm ID) eluting with 0.1%
HCO.sub.2H and 0.01 M ammonium acetate in water (solvent A), and
0.05% HCO.sub.2H 5% water in acetonitrile (solvent B), using the
following elution gradient 0-0.7 min 0% B, 0.7-4.2 min 100% B,
4.2-5.3 min 0% B, 5.3-5.5 min 0% B at a flow rate of 3 ml/min. The
mass spectra were recorded on a Fisons VG Platform spectrometer
using electrospray positive and negative mode (ES+ve and
ES-ve).
[0208] DSC and TGA profiles were obtained using a Netzsch STA449C
simultaneous thermal analyser using an unsealed pan with nitrogen
gas flow and a thermal gradient of 10.degree. C./min.
[0209] The moisture sorption characteristics were obtained using a
Hiden Igasorb water sorption microbalance. The programme provides
for stepwise increase in relative humidity (RH) from 0 to 90% RH
and then decrease back to 0% RH in steps of 10% RH.
[0210] The XRPD analysis shown in FIGS. 1 and 2 were performed on a
Phillips X'pert MPD powder diffractometer, serial number DY667. The
method runs from 2 to 45 degrees 2Theta with 0.02 degree 2Theta
step size and a 1 second collection time at each step. The XRPD
analysis shown in FIG. 4 employed the same instrument with an Anton
Parr TTK thermal accessory using a method running from 2 to 35
degrees 2Theta with 0.04 degree 2Theta step size and a 1 second
collection time.
[0211] Intermediates
[0212] Intermediate 1:
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcar-
bonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.b-
eta.-carbothioic acid
[0213] A solution of 6.alpha.,9.alpha.-difluoro-11.beta.,
17.alpha.-dihydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-ca-
rbothioic acid (prepared in accordance with the procedure described
in GB 2088877B) (18 g, 43.64 mmol) in anhydrous dichloromethane
(200 ml) and triethylamine (15.94 ml, 114 mmol) was treated at
<5.degree. C. with a solution of 2-furoyl chloride (11.24 ml,
114 mmol) in anhydrous dichloromethane (100 ml) over approximately
40 min. The solution was stirred at <5.degree. C. for 30 min.
The resulting solid was collected by filtration, washed
successively with 3.5% aqueous sodium hydrogen carbonate solution,
water, 1 M hydrochloric acid, and water and dried in vacuo at
60.degree. C. to give a cream coloured solid. The dichloromethane
filtrate was washed successively with 3.5% sodium hydrogen
carbonate solution, water, 1M hydrochloric acid, water, dried
(Na.sub.2SO.sub.4) and evaporated to give a cream coloured solid
which was combined with that isolated above. The combined solids
(26.9 g) were suspended in acetone (450 ml) and stirred.
Diethylamine (16.8 ml, 162 mmol) was added and the mixture stirred
at room temperature for 4.5 h. The mixture was concentrated and the
precipitate collected by filtration and washed with a little
acetone. The washings and filtrate were combined, concentrated and
loaded onto a silica gel Biotage column which was eluted with 24:1
chloroform:methanol. Fractions which contained the more polar
component were combined and evaporated to give a cream coloured
solid. This was combined with the solid isolated above and dried in
vacuo to give a pale beige coloured solid (19.7 g). This was
dissolved in warm water, the pH adjusted to 2 with concentrated
hydrochloric acid and the mixture extracted with ethyl acetate. The
organic extract was dried (Na.sub.2SO.sub.4) and evaporated to
give, after drying at 50.degree. C., the title compound as a cream
coloured solid (18.081 g, 82%): LCMS retention time 3.88 min, m/z
507 MH.sup.+, NMR .delta. (CDCl.sub.3) includes 7.61 (1H, m),
7.18-7.12 (2H, m), 6.52 (1H, dd, J 4, 2 Hz), 6.46 (1H, s), 6.41
(1H, dd, J 10, 2 Hz), 5.47 and 5.35 (1H, 2m), 4.47 (1H, bd, J=9
Hz), 3.37 (1H, m), 1.55 (3H, s), 1.21 (3H, s), 1.06 (3H, d, J=7
Hz).
[0214] Intermediate 1:
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcar-
bonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.b-
eta.-carbothioic acid (first alternative method)
[0215] A stirred suspension of 6.alpha.,9.alpha.-difluoro-11.beta.,
17.alpha.-dihydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-ca-
rbothioic acid (prepared in accordance with the procedure described
in GB 2088877B) (1 wt, 49.5 g) in acetone (10 vol) is cooled to
0-5.degree. C. and treated with triethylamine (0.51 wt, 2.1 eq),
keeping the temperature below 5.degree. C., and stirred for 5 min
at 0-5.degree. C. 2-Furoyl chloride (0.65 wt, 2.05 eq) is then
added over a minimum of 20 min, maintaining a reaction temperature
at 0-5.degree. C. The reaction is stirred for 30 min at 0-5.degree.
C. then sampled for analysis by HPLC. A solution of diethanolamine
(1.02 wt, 4 eq) in methanol (0.8 vol) is added over ca 15 min
followed by a line wash of methanol (0.2 vol) and the reaction
stirred at 0-5.degree. C. for 1 h. The reaction is again sampled
for analysis by HPLC then warmed to approximately 20.degree. C. and
treated with water (1.1 wt). The reaction mixture is then treated
with a solution of HCl (SG1.18 (11.5M), 1 vol) in water (10 vol)
over ca 20 min maintaining a reaction temperature below 25.degree.
C. The suspension is stirred at 20-23.degree. C. for at least 30
minutes then filtered. The filter cake is washed with water
(3.times.2 vol). The product is dried in vacuo at approximately
60.degree. C. overnight to give the title compound as a white solid
(58.7 g, 96.5%).
[0216] Intermediate 1:
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcar-
bonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.b-
eta.-carbothioic acid (second alternative method)
[0217] A stirred suspension of 6.alpha.,9.alpha.-difluoro-11.beta.,
17.alpha.-dihydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-ca-
rbothioic acid (prepared in accordance with the procedure described
in GB 2088877B) (1 wt, 49.5 g) in acetone (10 vol) is cooled to
0-5.degree. C. and treated with triethylamine (0.51 wt, 2.1 eq),
keeping the temperature below 5.degree. C., and stirred for 5 min
at 0-5.degree.. 2-Furoyl chloride (0.65 wt, 2.05 eq) is then added
over a minimum of 20 min, maintaining a reaction temperature at
0-5.degree. C. The reaction mixture is stirred for at least 30
minutes and diluted with water (10 vol) maintaining a reaction
temperature in the range 0-5.degree. C. The resultant precipitate
is collected by filtration and washed sequentially with
acetone/water (50/50 2 vol) and water (2.times.2 vol). The product
is dried under vacuum at approximately 55.degree. C. overnight to
leave
6.alpha.,9.alpha.-difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hy-
droxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-yl
S-(2-furanylcarbonyl)thioanhydride as a white solid (70.8 g, 98.2%)
(NMR .delta. (CD.sub.3CN) 0.99 (3H, d) (J=7.3 Hz), 1.24 (3H, s),
1.38 (1H, m) (J=3.9 Hz), 1.54 (3H, s), 1.67 (1H, m), 1.89 (1H,
broad d) (J=15.2 Hz), 1.9-2.0 (1H, m), 2.29-2.45 (3H, m), 3.39 (1H,
m), 4.33 (1H, m), 4.93 (1H, broad s), 5.53 (1H, ddd) (J=6.9, 1.9
Hz; JHF=50.9 Hz), 6.24 (1H, m), 6.29 (1H, dd) (J=10.3, 2.0 Hz),
6.63 (2H, m), 7.24-7.31 (3H, m), 7.79 (1H, dd) (J=<1 Hz), 7.86
(1H, dd) (J=<1 Hz)). A portion of the product (0.56 g) is mixed
with 6.alpha.,9.alpha.-difluoro-11.beta.,17.alpha.-dihydroxy--
16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic acid
(0.41 g) in a 1:1 molar ratio in DMF (10 volumes wrt total steroid
input). The reaction mixture is treated with triethylamine
(approximately 2.1 equivalents) and the mixture is stirred at
approximately 20.degree. C. for approximately 6 hours. Water (50
vol) containing excess conc HCl (0.5 vol) is added to the reaction
mixture and the resultant precipitate collected by filtration. The
bed is washed with water (2.times.5 vol) and dried in vacuo at
approximately 55.degree. C. overnight to leave the title compound
as a white solid (0.99 g, 102%).
[0218] Intermediate 1A:
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylca-
rbonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.-
beta.-carbothioic acid diisopropylethylamine Salt
[0219] A stirred suspension of
6.alpha.,9.alpha.-difluoro-11.beta.,17.alph-
a.-dihydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioi-
c acid (prepared in accordance with the procedure described in GB
2088877B) (49.5 g) in methylacetate (500 ml) is treated with
triethylamine (35 ml) maintaining a reaction temperature in the
range 0-5.degree. C. 2-Furoyl chloride (25 ml) is added and the
mixture stirred at 0-5.degree. C. for 1 hour. A solution of
diethanolamine (52.8 g) in methanol (50 ml) is added and the
mixture stirred at 0-5.degree. C. for at least 2 hours. Dilute
hydrochloric acid (approx 1M, 550 ml) is added maintaining a
reaction temperature below 15.degree. C. and the mixture stirred at
15.degree. C. The organic phase is separated and the aqueous phase
is back extracted with methyl acetate (2.times.250 ml). All of the
organic phases are combined, washed sequentially with brine
(5.times.250 ml) and treated with di-isopropylethylamine (30 ml).
The reaction mixture is concentrated by distillation at atmospheric
pressure to an approximate volume of 250 ml and cooled to
25-30.degree. C. (crystallisation of the desired product normally
occurs during distillation/subsequent cooling). Tertiary butyl
methyl ether (TBME) (500 ml) is added, the slurry further cooled
and aged at 0-5.degree. C. for at least 10 minutes. The product is
filtered off, washed with chilled TBME (2.times.200 ml) and dried
under vacuum at approximately 40-50.degree. C. (75.3 g, 98.7%). NMR
(CDCl.sub.3) .delta.: 7.54-7.46 (1H, m), 7.20-7.12 (1H, dd),
7.07-6.99 (1H, dd), 6.48-6.41 (2H, m), 6.41-6.32 (1H, dd),
5.51-5.28 (1H, dddd .sup.2J.sub.H-F 50 Hz), 4.45-4.33(1H, bd),
3.92-3.73 (3H, bm), 3.27-3.14 (2H, q), 2.64-2.12 (5H, m), 1.88-1.71
(2H, m), 1.58-1.15 (3H, s), 1.50-1.38 (15H, m), 1.32-1.23 (1H, m),
1.23-1.15 (3H s), 1.09-0.99 (3H, d)
[0220] Intermediate 1B:
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylca-
rbonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.-
beta.-carbothioic acid triethylamine salt
[0221] A stirred suspension of Intermediate 1 (30 g) in
ethylacetate (900 ml) is treated with triethylamine (1.05 molar
equivalents, 8.6 ml) and the mixture is stirred at approximately
20.degree. C. for 1.5 hours. The precipitate is filtered off,
washed with ethylacetate (2.times.2 vol) and dried in vacuo at
45.degree. C. for 18 hours to give title compound as a white solid
(28.8 g, 80%). NMR (CDCl.sub.3) .delta.: 7.59-7.47 (1H, m),
7.23-7.13 (1H, dd), 7.08-6.99 (1H, d), 6.54-6.42 (2H, m), 6.42-6.32
(1H, dd), 5.55-5.26 (1H, dddd .sup.2 J.sub.H-F 50 Hz),
4.47-4.33(1H, bd), 3.88-3.70 (1H, bm), 3.31-3.09 (6H, q), 2.66-2.14
(5H, m), 1.93-1.69 (2H, m), 1.61-1.48 (3H, s), 1.43-1.33 (9H, t),
1.33-1.26 (1H, m), 1.26-1.15 (3H s), 1.11-0.97 (3H, d).
EXAMPLES
Example 1
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hyd-
roxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester Unsolvated Form 1
[0222] A suspension of Intermediate 1 (2.5 g, 4.94 mmol) was
dissolved in anhydrous N,N-dimethylformamide (25 ml) and sodium
hydrogen carbonate (465 mg, 5.53 mmol) was added. The mixture was
stirred at -20.degree. C. and bromofluoromethane (0.77 ml, 6.37
mmol) was added and the mixture was stirred at -20.degree. C. for 2
h. Diethylamine (2.57 ml, 24.7 mmole) was added and the mixture
stirred at -20.degree. C. for 30 min. The mixture was added to 2M
hydrochloric acid (93 ml) and stirred for 30 min. Water (300 ml)
was added and the precipitate was collected by filtration, washed
with water and dried in vacuo at 50.degree. C. to give a white
solid which was recrystallised from acetone/water (to yield the
acetone solvate of
6.alpha.,9.alpha.-difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]--
11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbot-
hioic acid S-fluoromethyl ester) and dried in vacuo at 50.degree.
C. to give the title compound (2.351 g, 88%): LCMS retention time
3.66 min, m/z 539 MH.sup.+, NMR .delta. (CDCl.sub.3) includes 7.60
(1H, m), 7.18-7.11 (2H, m), 6.52 (1H, dd, J=4.2 Hz), 6.46 (1H, s),
6.41 (1H, dd, J 10, 2 Hz), 5.95 and 5.82 (2H dd, J 51, 9 Hz), 5.48
and 5.35 (1H, 2m), 4.48 (1H, m), 3.48 (1H, m), 1.55 (3H, s), 1.16
(3H, s), 1.06 (3H, d, J=7 Hz).
[0223] Pharmacological Activity
[0224] In Vitro Pharmacological Activity
[0225] Pharmacological activity was assessed in a functional in
vitro assay of glucocorticoid agonist activity which is generally
predictive of anti-inflammatory or anti-allergic activity in
vivo.
[0226] For the experiments in this section, compound of formula (I)
was used as unsolvated Form 1.
[0227] The functional assay was based on that described by K. P.
Ray et al., Biochem J. (1997), 328, 707-715. A549 cells stably
transfected with a reporter gene containing the NF-.kappa.B
responsive elements from the ELAM gene promoter coupled to sPAP
(secreted alkaline phosphatase) were treated with test compounds at
appropriate doses for 1 hour at 37.degree. C. The cells were then
stimulated with tumour necrosis factor (TNF, 10 ng/ml) for 16
hours, at which time the amount of alkaline phosphatase produced is
measured by a standard colourimetric assay. Dose response curves
were constructed from which EC.sub.50 values were estimated.
[0228] In this test the compound of Example 1 showed an EC.sub.50
value of <1 nM.
[0229] The glucocorticoid receptor (GR) can function in at least
two distinct mechanisms, by upregulating gene expression through
the direct binding of GR to specific sequences in gene promotors,
and by downregulating gene expression that is being driven by other
transcription factors (such as NF.kappa.B or AP-1) through their
direct interaction with GR.
[0230] In a variant of the above method, to monitor these
functions, two reporter plasmids have been generated and introduced
separately into A549 human lung epithelial cells by transfection.
The first cell line contains the firefly luciferase reporter gene
under the control of a synthetic promoter that specifically
responds to activation of the transcription factor NF.kappa.B when
stimulated with TNF.alpha.. The second cell line contains the
renilla luciferase reporter gene under the control of a synthetic
promotor that comprises 3 copies of the consensus glucocorticoid
response element, and which responds to direct stimulation by
glucocorticoids. Simultaneous measurement of transactivation and
transrepression was conducted by mixing the two cell lines in a 1:1
ratio in 96 well plate (40,000 cells per well) and growing
overnight at 37.degree. C. Test compounds were dissolved in DMSO,
and added to the cells at a final DMSO concentration of 0.7%. After
incubation for 1 h 0.5ng/ml TNF.alpha. (R&D Systems) was added
and after a further 15 hours at 37.degree. C., the levels of
firefly and renilla luciferase were measured using the Packard
Firelite kit following the manufacturers' directions. Dose response
curves were constructed from which EC.sub.50 values were
determined.
1 Transrepression Transactivation (NF.kappa.B) (GR) ED.sub.50 (nM)
ED.sub.50 (nM) Compound of 0.06 0.20 Formula (I) Metabolite (X)
>250 >1000 Fluticasone 0.07 0.16 propionate
[0231] In Vivo Pharmacological Activity
[0232] Pharmacological activity in vivo was assessed in an
ovalbumin sensitised Brown Norway rat eosinophilia model. This
model is designed to mimic allergen induced lung eosinophilia, a
major component of lung inflammation in asthma.
[0233] For the experiments in this section, compound of formula (I)
was used as unsolvated Form 1.
[0234] Compound (I) produced dose dependant inhibition of lung
eosinophilia in this model after dosing as an intra-tracheal (IT)
suspension in saline 30 min prior to ovalbumin challenge.
Significant inhibition is achieved after a single dose of 30 .mu.g
of compound (I) and the response was significantly (p=0.016)
greater than that seen with an equivalent dose of fluticasone
propionate in the same study (69% inhibition with compound (I) vs
41% inhibition with fluticasone propionate).
[0235] In a rat model of thymus involution 3 daily IT doses of 100
.mu.g of compound (I) induced significantly smaller reductions in
thymus weight (p=0.004) than an equivalent dose of fluticasone
propionate in the same study (67% reduction of thymus weight with
compound (I) vs 78% reduction with fluticasone propionate).
[0236] Taken together these results indicate a superior therapeutic
index for compound (I) compared to fluticasone propionate.
[0237] In Vitro Metabolism in Rat and Human Hepatocytes
[0238] Incubation of compound (I) with rat or human hepatocytes
shows the compound to be metabolised in an identical manner to
fluticasone propionate with the 17-.beta. carboxylic acid (X) being
the only significant metabolite produced. Investigation of the rate
of appearance of this metabolite on incubation of compound (I) with
human hepatocytes (37.degree. C., 10 .mu.M drug concentration,
hepatocytes from 3 subjects, 0.2 and 0.7 million cells/mL) shows
compound (I) to be metabolised ca. 5-fold more rapidly than
fluticasone propionate:--
2 17-.beta. acid metabolite production Subject Cell density
(pmol/h) number (million cells/mL) Compound (I) Fluticasone
propionate 1 0.2 48.9 18.8 1 0.7 73.3 35.4 2 0.2 118 9.7 2 0.7 903
23.7 3 0.2 102 6.6 3 0.7 580 23.9
[0239] Median metabolite production 102-118 pmol/h for compound (I)
and 18.8-23.0 pmol/h for fluticasone propionate.
[0240] Pharmacokinetics after Intravenous (IV) and Oral Dosing in
Rats
[0241] Compound (I) was dosed orally (0.1 mg/kg) and IV (0.1 mg/kg)
to male Wistar Han rats and pharmacokinetic parameters determined.
Compound (I) showed negligible oral bioavailability (0.9%) and
plasma clearance of 47.3 mL/min/kg, approaching liver blood flow
(plasma clearance of fluticasone propionate=45.2 mL/min/kg).
[0242] Pharmacokinetics after Intra-Tracheal Dry Powder Dosing in
the Pig.
[0243] Anaesthetised pigs (2) were dosed intra-tracheally with a
homogenous mixture of compound (I) (1 mg) and fluticasone
propionate (1 mg) as a dry powder blend in lactose (10% w/w).
Serial blood samples were taken for up to 8 h following dosing.
Plasma levels of compound (I) and fluticasone propionate were
determined following extraction and analysis using LC-MS/MS
methodology, the lower limits of quantitation of the methods were
10 and 20 pg/mL for compound (I) and fluticasone propionate
respectively. Using these methods compound (I) was quantifiable up
to 2 hours after dosing and fluticasone propionate was quantifiable
up to 8 hours after dosing. Maximum plasma concentrations were
observed for both compounds within 15 min after dosing. Plasma
half-life data obtained from IV dosing (0.1 mg/kg) was used to
calculate AUC (0-inf) values for compound (I). This compensates for
the plasma profile of Compound (I) only being defined up to 2 hours
after an IT dose and removes any bias due to limited data between
compound (I) and fluticasone propionate.
3 C.sub.max and AUC (0-inf) values show markedly reduced systemic
exposure to compound (I) compared to fluticasone propionate:- AUC
Cmax (0-inf) (pg/mL) (hr .multidot. pg/mL) Pig 1 Pig 2 Pig 1 Pig 2
Compound of Formula (I) 117 81 254 221 Fluticasone propionate 277
218 455 495
[0244] The pharmacokinetic parameters for both compound (I) and
fluticasone propionate were the same in the anaesthetised pig
following intravenous administration of a mixture of the two
compounds at 0.1 mg/kg. The clearance of these two glucocorticoids
is similar is this experimental pig model.
Example 1
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hyd-
roxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester Unsolvated Form 1 (First Alternative
Method)
[0245] A mobile suspension of Intermediate 1A (12.61 g, 19.8 mmol;
equivalent to 10 g of Intermediate 1) in ethyl acetate (230 ml) and
water (50 ml) is treated with a phase transfer catalyst
(benzyltributylammonium chloride, 10 mol %), cooled to 3.degree. C.
and treated with bromofluoromethane (1.10 ml, 19.5 mmol, 0.98
equivalents), washing in with prechilled (0.degree. C.) ethyl
acetate (EtOAc) (20 ml). The suspension is stirred overnight,
allowing to warm to 17.degree. C. The aqueous layer is separated
and the organic phase is sequentially washed with 1 M HCl (50 ml),
1% w/v NaHCO.sub.3 solution (3.times.50 ml) and water (2.times.50
ml). The ethylacetate solution is distilled at atmospheric pressure
until the distillate reaches a temperature of approximately
73.degree. C. at which point toluene (150 ml) is added.
Distillation is continued at atmospheric pressure until all
remaining EtOAc has been removed (approximate distillate
temperature 103.degree. C.). The resultant suspension is cooled and
aged at <10.degree. C. and filtered off. The bed is washed with
toluene (2.times.30 ml) and the product oven dried under vacuum at
60.degree. C. to constant weight to yield the title compound (8.77
g, 82%)
Example 1
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hyd-
roxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester
[0246] Unsolvated Form 1 (Second Alternative Method)
[0247] A suspension of
6.alpha.,9.alpha.-difluoro-17.alpha.-[(2-furanylcar-
bonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.b-
eta.-carbothioic acid S-fluoromethyl ester acetone solvate
(prepared eg according to Example 11) (50.0 g) in acetone (1500 ml)
and water (75 ml) was heated to reflux. The resultant mixture was
clarified by hot filtration (Whatman 54 filter paper) during which
time some solid crystallised in the filtrate. Further acetone (200
ml) was added to the filtrate giving a bright solution at reflux.
The solution was distilled at atmospheric pressure until turbidity
was noted whilst at reflux (approx 750 ml solvent collected).
Toluene (1000 ml) was added to the hot solution and distillation at
atmospheric pressure was continued giving crystallisation at a
temperature of approximately 98.degree. C. Distillation of solvent
was continued until a reaction temperature of 105.degree. C. was
achieved (approximately 945 ml solvent collected). The mixture was
cooled to ambient temperature, further cooled and aged at
<10.degree. C. for 10 minutes. The product was filtered off,
washed with toluene (150 ml) and sucked dry. The product was dried
at approximately 60.degree. C. under vacuum for 16 h to leave the
title compound as a dense white solid (37.8 g, 83.7%).
[0248] The XRPD pattern of Example 1 product is shown in FIG. 1.
The DSC and TGA profiles are shown in FIG. 3.
Example 2
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hyd-
roxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester
[0249] Unsolvated Form 2
[0250] A suspension of
6.alpha.,9.alpha.-difluoro-17.alpha.-[(2-furanylcar-
bonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.b-
eta.-carbothioic acid S-fluoromethyl ester (prepared for example
according to Example 1, first method) (6.0 g) in dichloromethane
(180 ml) was heated to reflux giving a bright solution. The
solution was clarified by hot filtration (Whatman 54 filter paper)
and the solution was distilled at atmospheric pressure (approx 100
ml solvent collected) giving crystallisation at reflux. The mixture
was held at reflux for approximately 30 minutes and slowly cooled
to ambient temperature. The mixture was further cooled and aged at
10-20.degree. C. for 2 hours. The slurry was cooled to below
10.degree. C. and the product was filtered off, sucked dry and
dried at approximately 60.degree. C. under vacuum overnight to
leave a white solid (4.34 g, 71%).
[0251] A more pure sample of
6.alpha.,9.alpha.-difluoro-17.alpha.-[(2-fura-
nylcarbonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-dien-
e-17.beta.-carbothioic acid S-fluoromethyl ester unsolvated Form 2
was obtained by a cooling crystallisation of
6.alpha.,9.alpha.-difluoro-17.al-
pha.-[(2-furanylcarbonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-andr-
osta-1,4-diene-17.alpha.-carbothioic acid S-fluoromethyl ester
(prepared eg according to Example 1, first method) in methanol (60
volumes, distilled at atmospheric pressure to approx 37.5 volumes).
The product was isolated by filtration and oven dried at 60.degree.
C. under vacuum for 16 hours to leave a white, electrostatic solid
(4.34 g, 71%).
[0252] The XRPD pattern of Example 2 product is shown in FIG.
1.
Example 3
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hyd-
roxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester
[0253] Unsolvated Form 3
[0254] A suspension of
6.alpha.,9.alpha.-difluoro-17.alpha.-[(2-furanylcar-
bonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.b-
eta.-carbothioic acid S-fluoromethyl ester acetone solvate
(prepared eg according to Example 11) (20.0 g) in dichloromethane
(800 ml, 40 volumes) and water (10 ml, 0.5 volumes) was heated to
reflux giving a bright solution. The solution was clarified by hot
filtration (Whatman 54 filter paper) during which time some solid
crystallised in the filtrate which was fully dissolved upon heating
to reflux. The solution was distilled at atmospheric pressure
(approx 400 ml solvent collected) and allowed to cool to ambient
temperature. The mixture was further cooled and aged at
<10.degree. C. for 10 minutes. The product was filtered off,
sucked dry and dried at approximately 60.degree. C. under vacuum
overnight to leave a white solid (12.7 g, 70%).
[0255] The XRPD pattern of Example 3 product is shown in FIG. 1 and
FIG. 4.
Example 4
Interconversion of Forms 1, 2 and 3 of unsolvated
6.alpha.,9.alpha.-Difluo-
ro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3--
oxo-androsta-1,4-diene-17.beta.-carbothioic acid S-fluoromethyl
ester
[0256] Slurrying a mixture of Form 1 and Form 2 in water at ambient
temperature revealed that the components are transformed entirely
to Form 1 with time.
[0257] XRPD results are shown in FIG. 2. Similar results were
obtained by slurrying a mixture of Form 1 and Form 2 in ethanol at
ambient temperature. From these results it may be concluded that
Form 1 is the thermodynamically more stable polymorphic form out of
the two forms.
[0258] Thermal XRPD studies on Form 3 were performed as shown in
FIG. 4. The temperature and time profile is shown in FIG. 5 and the
5 traces shown in FIG. 4 were obtained at the equilibration points
shown in FIG. 5. The results indicate that Form 3 is converted
first to Form 2 and then to Form 1 as temperature is elevated.
Example 5
Moisture Sorption of Forms 1, 2 and 3 of Unsolvated
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hy-
droxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester
[0259] The moisture sorption characteristics of the three forms
were determined by monitoring the weight change of solid when
exposed to stepwise increased and then decreased humidity. The
results obtained were as follows:
[0260] Form 1: uptake of 0.18% w/w of moisture over the range 0-90%
relative humidity at 25.degree. C.
[0261] Form 2: uptake of 1.1-2.4% w/w of moisture over the range
0-90% relative humidity at 25.degree. C.
[0262] Form 3: uptake of 1.2-2.5% w/w of moisture over the range
0-90% relative humidity at 25.degree. C.
Example 6
Enthalpy of Dissolution of Forms 1 and 3 of Unsolvated
6.alpha.,9.alpha.-difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hy-
droxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester
[0263] Enthalpies of dissolution in DMSO and acetonitrile were
determined at 25.degree. C. The results were as follows:
4 Form I Form 3 Acetonitrile +13.74 +8.62 DMSO +1.46 -5.21 (results
in kJ/mol)
[0264] Form these results it may be determined that the enthalpy of
transition from Form 3 to Form 1 is approximately 5.1-6.7 kJ/mol.
On the assumption that the entropy of transition is small, since
both Forms are unsolvated, the enthalpy of transition may be
equated with the free energy of transition. Thus these data suggest
that Form 1 is the thermodynamically most stable form at 25.degree.
C.
Example 7
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hyd-
roxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester
[0265] Methylethylketone Solvate
[0266] A suspension of
6.alpha.,9.alpha.-difluoro-17.alpha.-[(2-furanylcar-
bonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.b-
eta.-carbothioic acid S-fluoromethyl ester (prepared eg according
to Example 1) (400 mg) in methylethylketone (3.2 ml) is heated to
reflux giving a clear solution. A portion of the solvent is
distilled off at atmospheric pressure (approx 1 ml) and the mixture
cooled to approximately 20.degree. C. The crystallised product is
filtered off, dried at approximately 20.degree. C. under vacuum to
leave the title compound as a white solid (310 mg, 68%). NMR
.delta. (CDCl.sub.3) includes the peaks described in Example 1 for
the parent compound and the following additional solvent peaks:
2.45 (2H, q), 2.14 (3H, s), 1.06 (3H, t).
Example 8
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hyd-
roxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester
[0267] Isopropanol Solvate
[0268] A solution of
6.alpha.,9.alpha.-difluoro-17.alpha.-[(2-furanylcarbo-
nyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.bet-
a.-carbothioic acid S-fluoromethyl ester (prepared eg according to
Example 1) (150 mg) in isopropanol (15 ml) is left to slowly
crystallise over a period of approximately 8 weeks. The resultant
chunky crystals are isolated by filtration to leave the title
compound as a white solid. NMR .delta. (CDCl.sub.3) includes the
peaks described in Example 1 for the parent compound and the
following additional solvent peaks: 4.03 (1H, m), 1.20 (6H, d).
Example 9
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hyd-
roxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester
[0269] Tetrahydrofuran Solvate
[0270] A suspension of
6.alpha.,9.alpha.-difluoro-17.alpha.-[(2-furanylcar-
bonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.b-
eta.-carbothioic acid S-fluoromethyl ester (prepared eg according
to Example 1) (150 mg) in THF (20 vol) is warmed to give a clear
solution. The solvent is allowed to slowly evaporate over a period
of 6 days to leave title compound as a white solid. Alternatively,
the THF solution is added dropwise to solution of potassium
bicarbonate (2% w/w) in water (50 vol) and the precipitated product
collected by filtration to furnish the title compound as a white
solid. NMR .delta. (CDCl.sub.3) includes the peaks described in
Example 1 for the parent compound and the following additional
solvent peaks: 3.74 (4H, m), 1.85 (4H, m).
Example 9
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hyd-
roxy-16.alpha.-methyl-3-oxo-androsta-1.4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester
[0271] Tetrahydrofuran Solvate (Alternative Method)
[0272] A mobile suspension of
6.alpha.,9.alpha.-difluoro-17.alpha.-[(2-fur-
anylcarbonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-die-
ne-17.beta.-carbothioic acid triethylamine salt (prepared eg
according to Intermediate 1B) (1.2 g) in THF (10 ml) is treated
with a phase transfer catalyst (tetrabutylammonium bromide,
typically between 8 and 14 mol %), cooled to approximately
3.degree. C. and treated with bromofluoromethane (0.98
equivalents). The suspension is stirred for between 2 and 5 hours,
allowing to warm to 17.degree. C. The reaction mixture is poured
into water (30 vol), stirred at approximately 10.degree. C. for 30
minutes and filtered off. The collected solid is washed with water
(4.times.3 vol) and the product oven dried under vacuum at
60.degree. C. overnight to give the title compound as a white solid
(0.85 g, 87%).
Example 10
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hyd-
roxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester
[0273] DMF Solvate
[0274] A mixture of Intermediate 1 (4.5 g, 8.88 mmol) in DMF (31
ml) is treated with potassium bicarbonate (0.89 g, 8.88 mmol) and
the mixture is cooled to -20.degree. C. A solution of
bromofluoromethane (0.95 g, 8.50 mmol, 0.98 eqv.) in DMF (4.8 ml)
at 0.degree. C. is added and the mixture is stirred at -20.degree.
C. for 4 hours. The mixture is then stirred at -20.degree. C. for a
further 30 minutes, added to 2M hydrochloric acid (100 ml) and
stirred for a further 30 minutes at 0-5.degree. C. The precipitate
collected by vacuum filtration, washed with water and dried at
50.degree. C. to give the title compound (4.47 g, 82%). NMR 6
(CD.sub.3OD) includes the peaks described in Example 1 for the
parent compound and the following additional solvent peaks: 7.98
(1H, bs), 2.99 (3H, s), 2.86 (3H, s).
Example 11
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbonyl)oxy]-11.beta.-hyd-
roxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.beta.-carbothioic
acid S-fluoromethyl ester
[0275] Acetone Solvate
[0276] A solution of Intermediate 1 (530.1 g, 1 wt) in
dimethylformamide (DMF) (8 vol) is treated with potassium hydrogen
carbonate (0.202 wt, 1.02 eq) and the mixture cooled to
-17.+-.3.degree. C. with stirring. Bromofluoromethane (BFM) (0.22
wt, 0.99 eq) is then added and the reaction stirred at
-17.+-.3.degree. C. for at least 2 h. The reaction mixture is then
added to water (17 vol) at 5.+-.3.degree. C. over ca 10 min
followed by a water (1 vol) line wash. The suspension is stirred at
5-10.degree. C. for at least 30 min and then filtered. The filter
cake (the DMF solvate of
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbo-
nyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-diene-17.bet-
a.-carbothioic acid S-fluoromethyl ester) is washed with water
(4.times.4 vol) and the product is pulled dry on the filter. The
damp cake is returned to the vessel, acetone (5.75 vol) added and
heated at reflux for 2 h. The mixture is cooled to 52.+-.3.degree.
C. and water (5.75 vol) added, keeping temperature at
52.+-.3.degree. C. The mixture is then cooled to 20.+-.3.degree.
C., filtered and dried in vacuo at 60.+-.5.degree. C. overnight to
give the title compound as a white solid (556.5 g, 89%). NMR
.delta. (CDCl.sub.3) includes the peaks described in Example 1 for
the parent compound and the following additional solvent peaks:
2.17 (6H, s).
Example 12
Dry Powder Composition Containing
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-
-furanylcarbonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-
-diene-17.beta.-carbothioic acid S-fluoromethyl ester, Unsolvated
Form 1
[0277] A dry powder formulation was prepared as follows:
5 6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2- 0.20 mg
furanylcarbonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-
androsta-1,4-diene-17.beta.-carbothioic acid S-fluoromethyl ester,
unsolvated Form 1 (prepared according to Example 1, first
alternative method and micronised to a MMD of 3 .mu.m): milled
lactose (wherein not greater than 85% of 12 mg particles have a MMD
of 60-90 .mu.m, and not less than 15% of particles have a MMD of
less than 15 .mu.m):
[0278] A peelable blister strip containing 60 blisters each filled
with a formulation as just described was prepared.
Example 13
Aerosol Formulation Containing
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-fu-
ranylcarbonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-di-
ene-17.beta.-carbothioic acid S-fluoromethyl ester, Unsolvated Form
1
[0279] An aluminium canister was filled with a formulation as
follows:
6 6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-furanylcarbon- yl)oxy]-
250 .mu.g 11.beta.-hydroxy-16.alpha.-methyl-3-oxo-
androsta-1,4-diene-17.beta.-carbothioic acid S-fluoromethyl ester,
Unsolvated Form 1 (prepared according to Example 1, first
alternative method) and micronised to a MMD of 3 .mu.m):
1,1,1,2-tetrafluoroethane: to 50 .mu.l (amounts per actuation) in a
total amount suitable for 120 actuations and the canister was
fitted with a metering valve adapted to dispense 50 .mu.l per
actuation.
Example 14
Nasal Formulation Containing
6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2-fura-
nylcarbonyl)oxy]-11.beta.-hydroxy-16.alpha.-methyl-3-oxo-androsta-1,4-dien-
e-17.beta.-carbothioic acid S-fluoromethyl ester, Unsolvated Form
1
[0280] A formulation for intranasal delivery was prepared as
follows:
7 6.alpha.,9.alpha.-Difluoro-17.alpha.-[(2- 10 mg
furanylcarbonyl)oxy]-11.beta.- hydroxy-16.alpha.-methyl-3-oxo-
androsta-1,4-diene-17.beta.-carbothioic acid S-fluoromethyl ester
Unsolvated Form 1 (prepared according to Example 1, first
alternative method, micronised): Polysorbate 20 0.8 mg Sorbitan
monolaurate 0.09 mg Sodium dihydrogen phosphate dihydrate 94 mg
Dibasic sodium phosphate anhydrous 17.5 mg Sodium chloride 48 mg
Demineralised water to 10 ml
[0281] The formulation was fitted into a spray pump capable of
delivering a plurality of metered doses (Valois).
[0282] Throughout the specification and the claims which follow,
unless the context requires otherwise, the word `comprise`, and
variations such as `comprises` and `comprising`, will be understood
to imply the inclusion of a stated integer or step or group of
integers but not to the exclusion of any other integer or step or
group of integers or steps.
[0283] The patents and patent applications described in this
application are herein incorporated by reference.
* * * * *