U.S. patent application number 13/410867 was filed with the patent office on 2012-06-28 for phenyl-substituted pyrazolopyrimidines.
This patent application is currently assigned to Boehringer Ingelheim International GmbH. Invention is credited to Frank-Gerhard Bo, Nils Burkhardt, Christina Erb, Martin HENDRIX, Adrian Tersteegen, Marja Van Kampen.
Application Number | 20120165349 13/410867 |
Document ID | / |
Family ID | 31501895 |
Filed Date | 2012-06-28 |
United States Patent
Application |
20120165349 |
Kind Code |
A1 |
HENDRIX; Martin ; et
al. |
June 28, 2012 |
Phenyl-Substituted Pyrazolopyrimidines
Abstract
The invention relates to novel phenyl-substituted
pyrazolopyrimidines, process for their preparation, and their use
for producing medicaments for improving perception, concentration,
learning and/or memory.
Inventors: |
HENDRIX; Martin; (Odenthal,
DE) ; Bo ; Frank-Gerhard; (Berkshire, GB) ;
Burkhardt; Nils; (Velbert, DE) ; Erb; Christina;
(Kriftel, DE) ; Tersteegen; Adrian; (Velbert,
DE) ; Van Kampen; Marja; (Dusseldorf, DE) |
Assignee: |
Boehringer Ingelheim International
GmbH
Ingelheim
DE
|
Family ID: |
31501895 |
Appl. No.: |
13/410867 |
Filed: |
March 2, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10525115 |
Aug 31, 2005 |
8158633 |
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PCT/EP03/08923 |
Aug 12, 2003 |
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13410867 |
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Current U.S.
Class: |
514/262.1 ;
544/262 |
Current CPC
Class: |
A61P 25/28 20180101;
C07D 487/04 20130101; A61P 25/00 20180101 |
Class at
Publication: |
514/262.1 ;
544/262 |
International
Class: |
A61K 31/519 20060101
A61K031/519; A61P 25/00 20060101 A61P025/00; A61P 25/28 20060101
A61P025/28; C07D 487/04 20060101 C07D487/04 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 23, 2002 |
DE |
10238723.0 |
Claims
1. A compound of the formula ##STR00031## in which R.sup.1 is
phenyl which is substituted by 1 to 5 substituents independently of
one another selected from the group of halogen,
C.sub.1-C.sub.6-alkyl, trifluoromethyl, trifluoroethoxy, cyano,
hydroxy, nitro and C.sub.1-C.sub.6-alkoxy, R.sup.2 is pentan-3-yl,
C.sub.4-C.sub.6-cycloalkyl, X is oxygen or sulfur, and the salts,
solvates and/or solvates of the salts thereof.
2. A compound as claimed in claim 1, where R.sup.1 is phenyl which
is substituted by 1 to 3 substituents independently of one another
selected from the group of fluorine, chlorine, bromine,
C.sub.1-C.sub.4-alkyl, trifluoromethyl, trifluoromethoxy, cyano,
hydroxy, nitro and C.sub.1-C.sub.4-alkoxy, R.sup.2 is pentan-3-yl,
C.sub.5-C.sub.6-cycloalkyl, X is oxygen or sulfur, and the salts,
solvates and/or solvates of the salts thereof.
3. A compound as claimed in claims 1 and 2 of the formula
##STR00032## in which R.sup.3 is hydrogen or chlorine, R.sup.4 is
fluorine, chlorine, bromine, methyl, trifluoromethyl, R.sup.2 is
pentan-3-yl, cyclopentyl, X is oxygen or sulfur, and the salts,
solvates and/or solvates of the salts thereof,
4. A compound as claimed in claims 1 to 3 of the formula (Ia),
where R.sup.3 is hydrogen or chlorine, R.sup.4 is fluorine,
chlorine, bromine, methyl, trifluoromethyl, R.sup.2 is pentan-3-yl,
cyclopentyl, X is oxygen, and the salts, solvates and/or solvates
of the salts thereof.
5. A process for preparing compounds as claimed in claim 1,
characterized in that [A] compounds of the formula ##STR00033## in
which R.sup.2 has the meanings indicated in claim 1, are converted
by reaction with a compound of the formula
R.sup.1--CH.sub.2--C(O)--Z (IIIa), in which R.sup.1 has the
meanings indicated in claim 1, and is chlorine or bromine,
initially in the presence of a base into compounds of the formula
##STR00034## in which R.sup.1 and R.sup.2 have the meanings
indicated in claim 1, then cyclized in the presence of a base
t.COPYRGT. compounds of the formula ##STR00035## in which R.sup.1
and R.sup.2 have the meanings indicated in claim 1, or [B]
compounds of the formula (II) are reacted with direct cyclization
to (Ib) with a compound of the formula
R.sup.1--CH.sub.2--C(O)--OR.sup.5 (IIIb), in which R.sup.1 has the
meanings indicated in claim 1, and R.sup.5 is methyl or ethyl, in
the presence of a base, or [C] compounds of the formula
##STR00036## in which R.sup.2 has the meanings indicated in claim
1, are converted initially by reaction with a compound of the
formula (IIIa) in the presence of a base into compounds of the
formula ##STR00037## in which R.sup.1 and R.sup.2 have the meanings
indicated in claim 1, and the latter are cyclized in a second step
in the presence of base and of an oxidizing agent to (Ib), and the
compounds of the formula (Ib) are then converted where appropriate
by reaction with a sulfurizing agent such as, for example,
diphosphorus pentasulfide into the thiono derivatives of the
formula ##STR00038## in which R.sup.1 and R.sup.2 have the meanings
indicated in claim 1, and the resulting compounds of the formula
(I) are reacted where appropriate with the appropriate (i) solvents
and/or (ii) bases or acids to give the solvates, salts and/or
solvates of the salts thereof.
6. A compound as claimed in any of claims 1 to 4 for the treatment
and/or prophylaxis of diseases,
7. A medicament comprising at least one of the compounds as claimed
in any of claims 1 to 4 and at least one pharmaceutically
acceptable, essentially non-toxic carrier or excipient.
8. The use of the compounds as claimed in any of claims 1 to 4 for
producing a medicament for the prophylaxis and/or treatment of
impairments of perception, concentration, learning and/or
memory.
9. The use as claimed in claim 8, where the impairment is a
consequence of Alzheimer's disease,
10. The use of the compounds as claimed in any of claims 1 to 4 for
producing a medicament for improving perception, concentration,
learning and/or memory.
11. A method for controlling impairments of perception,
concentration, learning and/or memory in humans or animals by
administering an effective amount of the compounds from claims 1 to
4.
12. The method as claimed in claim 11, where the impairment is a
consequence of Alzheimer's disease.
Description
[0001] The invention relates to novel phenyl-substituted
pyrazolopyrimidines, process for their preparation, and their use
for producing medicaments for improving perception, concentration,
learning and/or memory.
[0002] Cellular activation of adenylate cyclases and guanylate
cyclases brings about the cyclization of respectively ATP and GTP
to 5'-3' cyclic adenosine monophosphate (cAMP) and 5'-3' cyclic
guanosine monophosphate (cGMP). These cyclic nucleotides (cAMP and
cGMP) are important second messengers and therefore play a central
role in cellular signal transduction cascades. Each of them
reactivates inter alia, but not exclusively, protein kinases. The
protein kinase activated by cAMP is called protein kinase A (PKA),
and the protein kinase activated by cGMP is called protein kinase G
(PKG). Activated PKA and PKG are able in turn to phosphorylate a
number of cellular effector proteins (e.g. ion channels,
G-protein-coupled receptors, structural proteins). It is possible
in this way for the second messengers cAMP and cGMP to control a
wide variety of physiological processes in a wide variety of
organs. However, the cyclic nucleotides are also able to act
directly on effector molecules. Thus, it is known, for example,
that cGMP is able to act directly on ion channels and thus is able
to influence the cellular ion concentration (review in: Wei et al.,
Frog. Neurobiol., 1998, 56: 37-64). The phosphodiesterases (PDE)
are a control mechanism for controlling the activity of cAMP and
cGMP and thus in turn these physiological processes. PDEs hydrolyze
the cyclic monophosphates to the inactive monophosphates AMP and
GMP. At least 21 PDE genes have now been described (Exp. Opin.
Investig. Drugs 2000, 9, 1354-3784). These 21 PDE genes can be
divided on the basis of their sequence homology into 11 PDE
families (for proposed nomenclature, see
http://depts.washington.edu/pde/Nomenclature.html.). Individual PDE
genes within a family are differentiated by letters (e.g. PDE1A and
PDE1B). If different splice variants within a gene also occur, this
is then indicated by an additional numbering after the letter (e.g.
PDE1A1).
[0003] Human PDE9A was cloned and sequenced in 1998. The amino acid
identity with other PDEs does not exceed 34% (PDE8A) and is never
less than 28% (PDE5A). With a Michaelis-Menten constant (Km) of 170
nM, PDE9A has high affinity for cGMP. In addition, PDE9A is
selective for cGMP (Km for cAMP=230 .mu.M). PDE9A has no cGMP
binding domain, suggesting allosteric enzyme regulation by cGMP. It
was shown in a Western blot analysis that PDE9A is expressed in
humans inter alia in testes, brain, small intestine, skeletal
muscle, heart, lung, thymus and spleen. The highest expression was
found in the brain, small intestine, heart and spleen (Fisher et
al., J. Biol. Chem., 1998, 273 (25): 15559-15564). The gene for
human PDE9A is located on chromosome 21q223 and comprises 21 exons.
To date, 4 alternative splice variants of PDE9A have been
identified (Guipponi et al., Hum. Genet., 1998, 103: 386-392).
Classical PDE inhibitors do not inhibit human PDE9A, Thus, IBMX,
dipyridamole, SKF94120, rolipram and vinpocetirie show no
inhibition on the isolated enzyme in concentrations of up to 100
.mu.M. An IC.sub.50 of 35 .mu.M has been demonstrated for zaprinast
(Fisher et al., J. Biol. Chem., 1998, 273 (25): 15559-15564).
[0004] Murine PDE9A was cloned and sequenced in 1998 by Soderling
et al. (J. Biol. Chem., 1998, 273 (19): 1555315558). This has, like
the human form, high affinity for cGMP with a Km of 70 nM.
Particularly high expression was found in the mouse kidney, brain,
lung and heart. Murine PDE9A is not inhibited by IBMX in
concentrations below 200 .mu.M either; the IC.sub.50 for zaprinast
is 29 .mu.M (Soderling et al., J. Biol. Chem., 1998, 273 (19):
15553-15558). It has been found that PDE9A is strongly expressed in
some regions of the rat brain. These include olfactory bulb,
hippocampus, cortex, basal ganglia and basal forebrain (Andreeva et
al., J. Neurosci., 2001, 21 (22): 9068-9076). The hippocampus,
cortex and basal forebrain in particular play an important role in
learning and memory processes.
[0005] As already mentioned above, PDE9A is distinguished by having
particularly high affinity for cGMP. PDE9A is therefore active even
at low physiological concentrations, in contrast to PDE2A (Km=10
.mu.M; Martins et al., J. Biol. Chem., 1982, 257: 1973-1979), PDE5A
(Km=4 .mu.M; Francis et al., J. Biol. Chem., 1980, 255: 620-626),
PDE6A (Km=17 .mu.M; Gillespie and Beavo, J. Biol. Chem., 1988, 263
(17): 8133-8141) and PDE11A (Km=0.52 .mu.M; Fawcett et al., Proc.
Nat. Acad. Sci., 200, 97 (7): 3702-3707). In contrast to PDE2A
(Murashima et al., Bio-chemistry, 1990, 29: 5285-5292), the
catalytic activity of PDE9A is not increased by cGMP because it has
no GAF domain (cGMP-binding domain via which the PDE activity is
allosterically increased) (Beavo et al., Current Opinion in Cell
Biology, 2000, 12: 174-179). PDE9A inhibitors may therefore lead to
an increase in the baseline cGMP concentration. This increase in
the baseline cGMP concentration surprisingly led to an improvement
in learning and memory in the social recognition test.
[0006] WO 98/40384 discloses pyrazolopyrimidines which are PDE1, 2
and 5 inhibitors and can be employed for the treatment of
cardiovascular and cerebrovascular disorders and disorders of the
urogenital system.
[0007] CH 396 924, CH 396 925, CH 396 926, CH 396 927, DE 1 147
234, DE 1 149 013, GB 937,726 describe pyrazolopyrimidines which
have a coronary-dilating effect and which can be employed for the
treatment of disturbances of myocardial blood flow.
[0008] U.S. Pat. No. 3,732,225 describes pyrazolopyrimidines which
have an antiinflammatory and blood glucose-lowering effect.
[0009] DE 2 408 906 describes styrenepyrazolopyrimidines which can
be employed as anti-microbial and antiinflammatory agents for the
treatment of, for example, edema.
[0010] The present invention relates to compounds of the
formula
##STR00001##
in which [0011] R.sup.1 is phenyl which is substituted by 1 to 5
substituents independently of one another selected from the group
of halogen, C.sub.1-C.sub.6-alkyl, trifluoromethyl,
trifluoromethoxy, cyano, hydroxy, nitro and C.sub.1-C.sub.6-alkoxy,
[0012] R.sup.2 is pentan-3-yl, C.sub.4-C.sub.6-cycloalkyl, [0013] X
is oxygen or sulfur, [0014] and the salts, solvates and/or solvates
of the salts thereof.
[0015] Compounds of the invention are the compounds of the formula
(I) and the salts, solvates and solvates of the salts thereof; the
compounds which are encompassed by formula (I) and have the
formulae mentioned hereinafter and the salts, solvates and solvates
of the salts thereof, and the compounds which are encompassed by
formula (I) and are mentioned hereinafter as exemplary embodiments
and the salts, solvates and solvates of the salts thereof, where
the compounds which are encompassed by formula (I) and are
mentioned hereinafter are not already salts, solvates and solvates
of the salts.
[0016] The compounds of the invention may, depending on their
structure, exist in stereo-isomeric forms (enantiomers,
diastereorners). The invention therefore relates to the enantiomers
or diastereomers and respective mixtures thereof. The
stereoisomerically pure constituents can be isolated in a known
manner from such mixtures of enantiomers and/or diastereorners.
[0017] Salts which are preferred for the purposes of the invention
are physiologically acceptable salts of the compounds of the
invention.
[0018] Physiologically acceptable salts of the compounds (I)
include acid addition salts of mineral acids, carboxylic acids and
sulfonic acids, e.g. salts of hydrochloric acid, hydrobromic acid,
sulfuric acid, phosphoric acid, methanesulfonic acid,
ethanesulfonic acid, toluenesulfonic acid, benzenesulfonic acid,
naphthalenedisulfonic acid, acetic acid, propionic acid, lactic
acid, tartaric acid, malic acid, citric acid, fumaric acid, maleic
acid and benzoic acid.
[0019] Physiologically acceptable salts of the compounds (1) also
include salts of conventional bases such as, by way of example and
preferably, alkali metal salts (e.g. sodium and potassium salts),
alkaline earth metal salts (e.g. calcium and magnesium salts) and
ammonium salts derived from ammonia or organic amines having 1 to
16 C atoms, such as, by way of example and preferably, ethylamine,
diethylamine, triethylamine, ethyldiisopropylamine,
monoethanolamine, diethanolamine, triethanolamine,
dicyclohexylamine, dimethylaminoethanol, procaine, dibenzylamine,
N-methylmorpholine, dehydroabietylamine, arginine, lysine,
ethylenediamine and methylpiperidine.
[0020] Solvates refers for the purposes of the invention to those
forms of the compounds which form, in the solid or liquid state, a
complex by coordination with solvent molecules. Hydrates are a
specific form of solvates in which the coordination takes place
with water.
[0021] In addition, the present invention also encompasses prodrugs
of the compounds of the invention. The term "prodrugs" encompasses
compounds which themselves may be biologically active or inactive
but are converted (for example by metabolism or hydrolysis) into
compounds of the invention during their residence time in the
body.
[0022] For the purposes of the present invention, the substituents
have the following meaning, unless specified otherwise: [0023]
C.sub.1-C.sub.6-Alkoxy is a straight-chain or branched alkoxy
radical having 1 to 6, preferably 1 to 4, particularly preferably
having 1 to 3 carbon atoms. Preferred examples are methoxy, ethoxy,
n-propoxy, isopropoxy, tert-butoxy, n-pentoxy and n-hexoxy. [0024]
C.sub.1-C.sub.6-Alkyl is a straight-chain or branched alkyl radical
having 1 to 6, preferably to 4, particularly preferably 1 to 3,
carbon atoms. Preferred examples are methyl, ethyl, n-propyl,
isopropyl, tert-butyl, n-pentyl and n-hexyl. [0025]
C.sub.4-C.sub.6- and C.sub.5-C.sub.6-Cycloalkyl are saturated or
partially unsaturated cycloalkyl radicals having 4 to 6, preferably
5 to 6, carbon atoms. Preferred examples are cyclobutyl,
cyclopentyl and cyclohexyl.
[0026] Halogen is for fluorine, chlorine, bromine and iodine.
Fluorine, chlorine, bromine are preferred, and fluorine and
chlorine are particularly preferred.
[0027] When radicals in the compounds of the invention are
optionally substituted, unless otherwise specified substitution by
up to three identical or different substituents is preferred.
[0028] The compounds of the invention may also be in the form of
tautomers as shown by way of example below:
##STR00002##
[0029] A further embodiment of the invention relates to compounds
of the formula (I), in which [0030] R.sup.1 is phenyl which is
substituted by 1 to 3 substituents independently of one another
selected from the group of fluorine, chlorine, bromine,
C.sub.1-C.sub.4-alkyl, trifluoromethyl, trifluoromethoxy, cyano,
hydroxy, nitro and C.sub.1-C.sub.4-alkoxy, [0031] R.sup.2 is
pentan-3-yl, C.sub.5-C.sub.6-cycloalkyl, [0032] X is oxygen or
sulfur, [0033] and the salts, solvates and/or solvates of the salts
thereof.
[0034] A further embodiment of the invention relates to compounds
of the formula
##STR00003##
in which [0035] R.sup.3 is hydrogen or chlorine, [0036] R.sup.4 is
fluorine, chlorine, bromine, methyl, trifluoroethyl, [0037] R.sup.2
is pentan-3-yl, cyclopentyl, [0038] X is oxygen or sulfur, [0039]
and the salts, solvates and or solvates of the salts thereof.
[0040] A further embodiment of the invention relates to compounds
of the formulae (I) and (Ia),
in which [0041] R.sup.3 is hydrogen or chlorine, [0042] R.sup.4 is
fluorine, chlorine, bromine, methyl, trifluoromethyl, [0043]
R.sup.2 is pentan-3-yl, cyclopentyl, [0044] X is oxygen, [0045] and
the salts, solvates and/or solvates of the salts thereof.
[0046] A process for preparing the compounds of the invention has
additionally been found, characterized in that either
[0047] [A] compounds of the formula
##STR00004##
in which [0048] R.sup.2 has the meanings indicated above, [0049]
are converted by reaction with a compound of the formula
[0049] R.sup.1--CH.sub.2--C(O)--Z (IIIa),
in which [0050] R.sup.1 has the meanings indicated above, [0051]
and [0052] Z is chlorine or bromine, [0053] in an inert solvent and
in the presence of a base initially into compounds of the
formula
##STR00005##
[0053] in which [0054] R.sup.1 and R.sup.2 have the meanings
indicated above, [0055] then cyclized in an inert solvent in the
presence of a base to compounds of the formula
##STR00006##
[0055] in which [0056] R.sup.1 and R.sup.2 have the meanings
indicated above, or [0057] [B] compounds of the formula (II) are
reacted with direct cyclization to (Ib) with a compound of the
formula
[0057] R.sup.1--CH.sub.2--C(O)--OR.sup.5 (IIIb),
in which [0058] R.sup.1 has the meanings indicated above, and
[0059] R.sup.5 is methyl or ethyl, [0060] in an inert solvent and
in the presence of a base, or [0061] [C] compounds of the
formula
##STR00007##
[0061] in which [0062] R.sup.2 has the meanings indicated above,
are converted initially by reaction with a compound of the formula
(IIIa) in an inert solvent and in the presence of a base into
compounds of the formula
##STR00008##
[0062] in which [0063] R.sup.1 and R.sup.2 have the meanings
indicated above, and the latter are cyclized in a second step in an
inert solvent and in the presence of a base and of an oxidizing
agent to (Ib), and the compounds of the formula (Ib) are then
converted where appropriate by reaction with a sulfurizing agent
such as, for example, diphosphorus pentasulfide into the thiono
derivatives of the formula
##STR00009##
[0063] in which [0064] R.sup.1 and R.sup.2 have the meanings
indicated above, and the resulting compounds of the formula (I) are
reacted where appropriate with the appropriate (i) solvents and/or
(ii) bases or acids to give the solvates, salts and/or solvates of
the salts thereof.
[0065] Suitable for the first step of process [A] and of process
[C] are inert organic solvents which are not changed under the
reaction conditions. These preferably include ethers such as, for
example, diethyl ether, dioxane, tetrahydrofuran or glycol dimethyl
ether, or toluene or pyridine. It is likewise possible to employ
mixtures of the solvents mentioned. Tetrahydrofuran, toluene or
pyridine are particularly preferred.
[0066] Suitable bases are in general alkali metal hydrides such as,
for example, sodium hydride, or cyclic amines such as, for example,
piperidine, pyridine, dimethylamino-pyridine (DMAP), or
C.sub.1-C.sub.4-alkylamines such as, for example, triethylamine.
Sodium hydride, pyridine and/or diethylaminopyridine are
preferred.
[0067] The base is generally employed in an amount of from l mol to
4 mol, preferably from 1.2 mol to 3 mol, in each case based on 1
mol of the compounds of the formula (II) or (V).
[0068] In a variant, the reaction is carried out in pyridine, to
which a catalytic amount of DMAP is added. It is also possible
where appropriate to add toluene.
[0069] The reaction temperature can generally be varied within a
relatively wide range. It is generally in a range from -20.degree.
C. to +200.degree. C., preferably from 0.degree. C. to +100.degree.
C.
[0070] Solvents suitable for the cyclization in the second step of
processes [A] and [C] are the usual organic solvents. These
preferably include alcohols such as methanol, ethanol, propanol,
isopropanol, n-butanol or tert-butanol, or ethers such as
tetrahydrofuran or dioxane, or dimethylformamide or dimethyl
sulfoxide. Alcohols such as methanol, ethanol, propanol,
isopropanol or tert-butanol are particularly preferably used. It is
likewise possible to employ mixtures of the solvents mentioned.
[0071] Bases suitable for the cyclization in the second step of
processes [A] and [C] are the usual inorganic bases. These
preferably include alkali metal hydroxides or alkaline earth metal
hydroxides such as, for example, sodium hydroxide, potassium
hydroxide or barium hydroxide, or alkali metal carbonates such as
sodium or potassium carbonate or sodium bicarbonate, or alkali
metal alcoholates such as sodium methanolate, sodium ethanolate,
potassium methanolate, potassium ethanolate or potassium
tert-butanolate. Potassium carbonate, sodium hydroxide and
potassium tert-butanolate are particularly preferred.
[0072] The base for carrying out the cyclization is generally
employed in an amount of from 2 mol to 6 mol, preferably from 3 mol
to 5 mol, in each case based on 1 mol of the compounds of the
formula (IV) or (VI).
[0073] Oxidizing agents suitable for the cyclization in the second
step of process [C] are, for example, hydrogen peroxide or sodium
borate. Hydrogen peroxide is preferred.
[0074] The cyclization in processes [A], [B] and [C] is generally
carried out in a temperature range from 0.degree. C. to
+160.degree. C., preferably at the boiling point of the particular
solvent.
[0075] The cyclization is generally carried out under atmosphere
pressure. It is, however, also possible to carry out the process
under elevated pressure or reduced pressure (e.g. in a range from
0.5 to 5 bar).
[0076] Solvents suitable for process [B] are the alcohols listed
above for the second step of processes [A) and [C], with preference
for ethanol.
[0077] Bases suitable for process [B] are alkali metal hydrides
such as, for example, sodium or potassium hydride, or alkali metal
alcoholates such as, for example, sodium methanolate, ethanolate,
isopropoxide or potassium tert-butoxide. Sodium hydride is
preferred.
[0078] The base is employed in an amount of from 2 mol to 8 mol,
preferably from 3 mol to 6 mol, in each case based on I mol of the
compounds of the formula (II).
[0079] The compounds of the formula (II) are known or can be
prepared for example by firstly condensing
ethoxymethylenemalononitrile with hydrazine derivatives of the
formula
R.sup.2--NH--NH.sub.2 (VII),
in which [0080] R.sup.2 has the meanings indicated above, in an
inert solvent to give the pyrazolenitriles of the formula (V), and
then reacting the latter with one of the oxidizing agents listed
above, preferably hydrogen peroxide, in the presence of ammonia
[cf. for example, A. Miyashita et al., Heterocycles 1990, 31,
1309ff].
[0081] The compounds of the formulae (IIIa), (IIIb) and (VII) are
commercially available, known from the literature or can be
prepared in analogy to processes known from the literature.
[0082] The process of the invention can be illustrated by way of
example by the following formula scheme:
##STR00010##
[0083] Further processes for preparing
pyrazolo[3,4-d]pyrimidin-4-ones are known and can likewise be
employed to synthesize the compounds of the invention (see, for
example: P. Schmidt et al., Helvetica Chimica Acta 1962, 189,
1620ff.).
[0084] The compounds of the invention show a valuable range of
pharmacological and pharmacokinetic effects which could not have
been predicted.
[0085] They are therefore suitable for use as medicaments for the
treatment and/or prophylaxis of diseases in humans and animals.
[0086] For the purposes of the present invention, the term
"treatment" includes prophylaxis.
[0087] It has surprisingly been found that selective PDE9A
inhibitors are suitable for producing medicaments for improving
perception, concentration, learning or memory.
[0088] The compounds of the invention can, by reason of their
pharmacological and pharmacokinetic properties, be employed alone
or in combination with other medicaments for improving perception,
concentration, learning and/or memory.
[0089] A PDE9A inhibitor for the purposes of the invention is a
compound which inhibits human PDE9A under the conditions indicated
below with an IC.sub.50 of less than 10 .mu.M, preferably less than
1 .mu.M.
[0090] A selective PDE9A inhibitor for the purposes of the
invention is a compound which inhibits human PDE9A under the
conditions indicated below more strongly than human PDE1C, PDE2A,
PDE3B, PDE4B, PDE5A, PDE7B, PDE8A, PDE10A and PDE11. A preferred
IC.sub.50 (PDE9A)/IC.sub.50 (PDE1C, PDE2A, PDE3B, PDE4B, PDE5A,
PDE7B and PDE10A) ratio is less than 0.2.
[0091] The selective PDE9A inhibitors are particularly suitable for
improving perception, concentration, learning or memory after
cognitive impairments like those occurring in particular in
situations/diseases/syndromes such as mild cognitive impairment,
age-associated learning and memory impairments, age-associated
memory losses, vascular dementia, craniocerebral trauma, stroke,
dementia occurring after strokes (post stroke dementia),
post-traumatic dementia, general concentration impairments,
concentration impairments in children with learning and memory
problems, Alzheimer's disease, Lewy body dementia, dementia with
degeneration of the frontal lobes, including Pick's syndrome,
Parkinson's disease, progressive nuclear palsy, dementia with
corticobasal degeneration, amyotrophic lateral sclerosis (ALS),
Huntington's disease, multiple sclerosis, thalamic degeneration,
Creutzfeld-Jacob dementia, HIV dementia, schizophrenia with
dementia or Korsakoff's psychosis.
[0092] The in vitro effect of the compounds of the invention can be
shown with the following biological assays:
[0093] PDE Inhibition
[0094] Recombinant PDE1C (GenBank/EMBL Accession Number:
NM.sub.--005020, Loughney et al. J. Biol. Chem. 1996 271, 796-806),
PDE2A (GenBank/EMBL Accession Number: NM.sub.--002599, Rosman et
al. Gene 1997 191, 89-95), PDE3B (GenBank/EMBL Accession Number:
NM.sub.----000922, Miki et al. Genomics 1996, 36, 476-485), PDE4I3
(GenBank/EMBL Accession Number: NM.sub.--002600, Obernolte et al.
Gene. 1993, 129, 239-247), PDE5A (GenBank/EMBL Accession Number:
NM.sub.--001083, Loughney et al. Gene 1998, 216, 139-147), PDE7B
(GenBank/EMBL Accession Number: NM.sub.--018945, Hetman et al.
Proc. Natl. Acad. Sci. U.S.A. 2000, 97, 472-476), PDE8A
(GenBank/EMBL Accession Number: AF.sub.--056490, Fisher et al.
Biochem, Biophys. Res. Commun. 1998 246, 570-577), PDE9A (Fisher et
al., J. Biol. Chem, 1998, 273 (25): 15559-15564), PDE10A
(GenBank/EMBL Accession Number: NM.sub.--06661, Fujishige et al. J.
Biol Chem. 1999, 274, 18438-45), PDE11A (GenBank/EMBL, Accession
Number: NM.sub.----016953, Fawcett et al. Proc. Natl, Acad. Sci.
2000, 97, 3702-3707) were expressed in Sf9 cells with the aid of
the pFASTBAC baculovirus expression system (GibcoBRL).
[0095] The test substances are dissolved in 100% DMSO and serially
diluted to determine their in vitro effect on PDE9A. Typically,
serial dilutions from 200 .mu.M to 1.6 .mu.M are prepared
(resulting final concentrations in the assay: 4 .mu.M to 0.032
.mu.M). 2 .mu.L, portions of the diluted substance solutions are
introduced into the wells of microtiter plates (Isoplate; Wallac
Inc., Atlanta, Ga.). Then 50 .mu.L of a dilution of the PDE9A
preparation described above are added. The dilution of the PDE9A
preparation is chosen so that less than 70% of the substrate is
converted during the subsequent incubation (typical dilution:
1:10000; dilution buffer: 50 mM Tris/HCl pH 7.5, 8.3 mM MgCl.sub.2,
1.7 mM EDTA, 0.2% BSA). The substrate, [8-.sup.3H] guanosine
3',5'-cyclic phosphate (1 .mu.Ci/.mu.L; Amersham Pharmacia
Biotech., Piscataway, N.J.) is diluted 1:2000 with assay buffer (50
mM Tris/HCl pH 7.5, 8.3 mM MgCl.sub.2, 1.7 mM EDTA) to a
concentration of 0.0005 The enzyme reaction is finally started by
adding 50 .mu.L (0.025 .mu.Ci) of the diluted substrate. The assay
mixtures are incubated at room temperature for 60 min and the
reaction is stopped by adding 25 .mu.l of a PDE9A inhibitor (e.g.
the inhibitor from preparation example 1, final concentration 10
.mu.M) dissolved in assay buffer. Immediately thereafter, 25 .mu.L
of a suspension containing 18 mg/mL Yttrium Scintillation Proximity
Beads (Amersham Pharmacia Biotech., Piscataway, N.J.) are added.
The microtiter plates are sealed with a film and left to stand at
room temperature for 60 min. The plates are then measured for 30 s
per well in a Microbeta scintillation counter (Wallac Inc.,
Atlanta, Ga.). IC.sub.50 values are determined from the graphical
plot of the substance concentration versus the percentage
inhibition.
[0096] The in vitro effect of test substances on recombinant PDE3B,
PDE4B, PDE7B, PDE8A, PDE10A and PDE11A is determined in accordance
with the assay protocol described above for PDE 9A with the
following adaptations: [5',8-.sup.3H] adenosine 3',5'-cyclic
phosphate (1 .mu.Ci/.mu.L; Amersham Pharmacia Biotech., Piscataway,
N.J.) is used as substrate. Addition of an inhibitor solution to
stop the reaction is unnecessary. Instead, the incubation of
substrate and PDE is followed immediately by addition of the
yttrium scintillation proximity beads as described above and thus
the reaction is stopped. To determine a corresponding effect on
recombinant PDE1C, PDE2A and PDE5A, the protocol is additionally
adapted as follows: with PDE1C, additionally 10.sup.-7M calmodulin
and 3 mM CaCl.sub.2 are added to the reaction mixture. PDE2A is
stimulated in the assay by adding 1 .mu.M cGMP and is assayed with
a BSA concentration of 0.01%. The substrate employed for PDE1C and
PDE2A is [5',8-.sup.3H] adenosine 3',5'-cyclic phosphate (1
.mu.Ci/.mu.L; Amersham Pharmacia Biotech., Piscataway, N.J.), and
for PDE5A is [8-.sup.3H] guanosine 3',5'-cyclic phosphate (1
.mu.Ci/.mu.L; Amersham Pharmacia Biotech., Piscataway, N.J.).
[0097] The PDE9A-inhibiting effect of the compounds of the
invention can be shown by means of the following examples:
TABLE-US-00001 TABLE 1 Example IC.sub.50 [nM] 1 20 2 30 4 30 10 64
13 30
[0098] Increasing the Intracellular Neuronal cGMP Concentration
Cell Cultures
[0099] PDE9A inhibitors increase the intracellular neuronal cGMP in
cultivated primary cortical neurons.
[0100] Rat embryos (embryonic day E17-E19) were decapitated, and
the heads were transferred into dissection dishes filled with
dissection medium (DMEM, penicillin/streptomycin; both from Gibco).
The scalp and roof of the skull were removed, and the exposed
brains were transferred into another Petri dish with dissection
medium. Using a binocular microscope and two forceps, the cerebrum
(cortex) was isolated and cooled to 4.degree. C. using ice. This
dissection and the isolation of the cortical neurons were then
carried out in accordance with a standard protocol using the papain
kit (Worthington Biochemical Corporation, Lakewood, N.J. 08701,
USA) (Huettner et al. J. Neurosci. 1986, 6, 3044-3060). The
mechanically isolated cortical neurons were cultivated at 150 000
cells/well in 200 .mu.l Neurobasal medium/well (Neurobasal; B27
Supplement; 2 mM L-glutamine; in the presence of
penicillin/streptomycin; all agents from Gibco) in 96-well plates
(pretreated with poly-D-lysine 100 .mu.g/ml for 30 min) under
standard conditions (37.degree. C., 5% CO.sub.2) for 7 days. After
7 days, the medium was removed and the cells were washed with HBSS
buffer (Hank's balanced salt solution, Gibco/BRL). Then 100 .mu.l
of the compound of the invention, dissolved in HBSS buffer
(previously dissolved in 100% DMSO: 10 mM), are put on the cells. A
further 100 .mu.l of HBSS buffer are then added, so that the final
concentration of the compounds of the invention is for example in a
range from 20 nM to 10 .mu.M, and incubated at 37.degree. C. for 20
min. The assay buffer is then completely removed. The cells are
then lyzed in 200 .mu.l of lysis buffer (cGMP Kit code RPN 226;
from Amersham Pharmacia Biotech.) and the cGMP concentration is
measured as stated by the manufacturer. All measurements are
carried out in triplicates. The statistical analysis takes place
using Prism Software version 2.0 (GraphPad Software Inc., San
Diego, Calif. USA).
[0101] Incubation of the primary neurons with the compounds of the
invention led to an increase in the cGMP content.
[0102] Long-Term Potentiation
[0103] Long-term potentiation is regarded as a cellular correlate
of learning and memory processes. The following method can be used
to determine whether PDE9 inhibition has an influence on long-term
potentiation:
[0104] Rat hippocampi are placed at an angle of about 70 degrees to
the cutting blade (chopper). 400 .mu.m-thick slices of the
hippocampus are prepared. The slices are removed from the blade
using a very soft, thoroughly wetted brush (marten hair) and
transferred into a glass vessel with cold nutrient solution (124 mM
NaCl, 4.9 mM KCl, 13 mM MgSO.sub.4.times.7 H.sub.2O, 2.5 mM
CaCl.sub.2 anhydrous, 1.2 mM KH.sub.2PO.sub.4, 25.6 mM NaHCO.sub.3,
10 mM glucose, pH 7A) gassed with 95% O.sub.2/5% CO.sub.2. During
the measurement, the slices are kept in a temperature-controlled
chamber under a 1-3 mm-high liquid level. The flow rate is 2.5
ml/min. The preliminary gassing takes place under a slightly
elevated pressure (about 1 atm) and through a microneedle in the
prechamber. The slice chamber is connected to the prechamber in
such a way that a minicirculation can be maintained. The
minicirculation is driven by the 95% O.sub.2/5% CO.sub.2 flowing
out through the microneedle. The freshly prepared hippocampus
slices are adapted in the slice chamber at 33.degree. C for at
least 1 hour.
[0105] The stimulus level is chosen so that the focal excitatory
postsynaptic potentials (fEPSP) are 30% of e maximum excitatory
postsynaptic potential (EPSP). A monopolar stimulation electrode
consisting of lacquered stainless steel, and a constant-current
biphasic stimulus generator (AM Systems 2100) are used for local
stimulation of the Schaffer collaterals (voltage: 1-5 V, pulse
width of one polarity 0.1 ms, total pulse 0.2 ms). Glass electrodes
(borosilicate glass with filament, 1-5 MOhm, diameter: 1.5 mm, tip
diameter: 3-20 .mu.m), filled with normal nutrient solution, are
used to record the excitatory postsynaptic potentials (fEPSP) from
the stratum radiatum. The field potentials are measured versus a
chlorinated silver reference electrode located at the edge of the
slice chamber using a DC voltage amplifier. The field potentials
are filtered through a low-pass filter (5 kHz). The slope of the
fEPSPs (fEPSP slope) is determined for the statistical analysis of
the experiments. The recording, analysis and control of the
experiment takes place with the aid of a software program (PWIN)
which was developed in the Department of Neurophysiology. The
formation of the average fEPSP slopes at the respective time points
and construction of the diagrams takes place with the aid of the
EXCEL software, with automatic data recording by an appropriate
macro.
[0106] Superfusion of the hippocampus slices with a 10 .mu.M
solution of the compounds of the invention leads to a significant
increase in the LTP.
[0107] Social Recognition Test
[0108] The social recognition test is a learning and memory test.
It measures the ability of rats to distinguish between known and
unknown members of the same species. This test is therefore
suitable for examining the learning- or memory-improving effect of
the compounds of the invention.
[0109] Adult rats housed in groups are placed singly in test cages
30 min before the start of the test. Four min before the start of
the test, the test animal is put in an observation box. After this
adaptation time, a juvenile animal is put in with the test animal
and the absolute time for which the adult animal inspects the young
one is measured for 2 min (trial 1). All behaviors clearly directed
at the young animal are measured, i.e. anogenital inspection,
pursuit and grooming, during which the old animal was no further
than 1 cm from the young animal. The juvenile is then removed, and
the adult is treated with a compound of the invention or vehicle
and subsequently returned to its own cage. The test is repeated
after a retention time of 24 hours (trial 2). A diminished social
interaction time compared with trial 1 indicates that the adult rat
remembers the young animal.
[0110] The adult animals receive intraperitoneal injections
directly following trial 1 either with vehicle (10% ethanol, 20%
Solutol, 70% physiological saline) or 0.1 mg/kg, 0.3 mg/kg, 1.0
mg/kg or 3.0 mg/kg compound of the invention dissolved in 10%
ethanol, 20% Solutol, 70% physiological saline. Vehicle-treated
rats show no reduction in the social interaction time in trial 2
compared with trial 1. They have consequently forgotten that they
have already had contact with the young animal. Surprisingly, the
social interaction time in the second run after treatment with the
compounds of the invention is significantly reduced compared with
those treated with vehicle. This means that the substance-treated
rats have remembered the juvenile animal and thus the compounds of
the invention display an improving effect on learning and
memory.
[0111] The present invention further relates to a method for the
treatment and/or prophylaxis of disorders, in particular of the
aforementioned disorders, using an effective amount of the
compounds of the invention.
[0112] The present invention farther relates to medicaments
comprising at least one compound of the invention and one or more
other active ingredients, in particular for the treatment and/or
prophylaxis of the aforementioned disorders.
[0113] The compounds of the invention may have systemic and/or
local effects. They can for this purpose be administered in a
suitable way, such as, for example, by the oral, parenteral,
pulmonary, nasal, sublingual, lingual, buccal, rectal, dermal,
transdermal, conjunctival or otic route or as implant or stent.
[0114] The compounds of the invention can be administered in
suitable administration forms for these administration routes.
[0115] Administration forms suitable for oral administration are
those which function according to the state of the art and deliver
the compounds of the invention in a rapid and/or modified way, and
which contain the compounds of the invention in crystalline and/or
amorphized and/or dissolved form, such as, for example, tablets
(uncoated or coated tablets, for example with coatings which are
resistant to gastric juice or dissolve slowly or are insoluble and
which control the release of the compound of the invention),
tablets which rapidly disintegrate in the mouth, or films/wafers,
films/lyophilisates, capsules (for example hard or soft gelatin
capsules), sugar-coated tablets, granules, pellets, powders,
emulsions, suspensions, aerosols or solutions.
[0116] Parenteral administration can take place with avoidance of
an absorption step (e.g. intravenous, intraarterial, intracardiac,
intraspinal or intralumbar) or with inclusion of an absorption
(e.g. intramuscular, subcutaneous, intracutaneous, percutaneous or
intraperitoneal). Administration forms suitable for parenteral
administration are, inter alia, injection and infusion preparations
in the form of solutions, suspensions, emulsions, lyophilisates or
sterile powders.
[0117] Examples suitable for other administration routes are
medicinal forms for inhalation (inter alia powder inhalators,
nebulizers), nasal drops, solutions, sprays; tablets for lingual,
sublingual or buccal administration, films/wafers or capsules,
suppositories, preparations for the ears or eyes, vaginal capsules,
aqueous suspensions (lotions, shaking mixtures), lipophilic
suspensions, ointments, creams, transdermal therapeutic systems
(such as, for example, patches), milk, pastes, foams, dusting
powders, implants or stents.
[0118] The compounds of the invention can be converted into the
stated administration forms. This can take place in a manner known
per se by mixing with inert, non-toxic, pharmaceutically suitable
excipients. These excipients include, inter alia, carriers (for
example microcrystalline cellulose, lactose, mannitol), solvents
(e.g. liquid polyethylene glycols), emulsifiers and dispersants or
wetting agents (for example sodium dodecyl sulfate, polyoxysorbitan
oleate), binders (for example polyvinylpyrrolidone), synthetic and
natural polymers (for example albumin), stabilizers (e.g.
antioxidants such as, for example, ascorbic acid), colors (e.g.
inorganic pigments such as, for example, iron oxides) and masking
tastes and/or odors.
[0119] The present invention further relates to medicaments which
comprise at least one compound of the invention, normally together
with one or more inert, non-toxic, pharmaceutically suitable
excipients, and to the use thereof for the aforementioned
purposes.
[0120] It has generally proved advantageous on parenteral
administration to administer amounts of about 0.001 to 10 mg/kg of
body weight per day to achieve effective results. The amount per
day on oral administration is about 0.005 to 3 mg/kg of body
weight.
[0121] It may nevertheless be necessary to deviate from the stated
amounts, in particular as a function of body weight, administration
route, individual behavior towards the active ingredient, type of
preparation and time or interval over which administration takes
place. Thus, it may in some cases be sufficient to make do with
less than the aforementioned minimum amount, whereas in other cases
the stated upper limit must be exceeded. Where larger amounts are
administered, it may be advisable to divide them into a plurality
of single doses over the day.
[0122] The percentage data in the following tests and examples arc,
unless indicated otherwise, percentages by weight; parts are parts
by weight. Solvent ratios, dilution ratios and concentration data
for liquid/liquid solutions are in each case based on volume.
ABBREVIATIONS USED
[0123] DCI direct chemical ionization (in MS) [0124] DCM
dichloromethane [0125] DMSO dimethyl sulfoxide [0126] equiv.
equivalent(s) [0127] ESI electrospray ionization (in MS) [0128]
HPLC high pressure, high performance liquid chromatography [0129]
m.p. melting point [0130] MS mass spectroscopy [0131] NMR nuclear
magnetic resonance spectroscopy [0132] TRIS
2-amino-2-(hydroxymethyl)-1,3-propanediol
[0133] Staring Compounds
EXAMPLE 1A
5-Amino-1-cyclohexyl-1H-pyrazole-4-carbonitrile
##STR00011##
[0135] Firstly ethoxymethylenemalononitrile (2.43 g, 19.9 mmol) and
then 8 ml of triethylamine are added to a solution of
cyclohexylhydrazine hydrochloride (3 g, 19.9 mmol) in 36 ml of
ethanol at room temperature. The mixture is refluxed for 20 min and
then cooled. The solvent is stripped of in a rotary evaporator, and
the residue is taken up in DCM, washed with aqueous sodium
bicarbonate solution, dried over sodium sulfate, filtered and
concentrated in vacua. The crude product is chromatographed on
silica gel (mobile phase: dichloromethane/methanol 0-10%).
[0136] Yield: 1.95 g (51% of theory)
[0137] MS (DCI): m/z=191 (M+H).sup.+
[0138] .sup.1H NMR (200 MHz, DMSO-d.sub.6): .delta.=7.5 (s, 1H),
6.5 (s, 2H), 4.0 (m, 1H), 1.95-1.05 (m, 10H) ppm.
EXAMPLE 2A
5-Amino-1-cyclopentyl-1H-pyrazole-4-carbonitrile
##STR00012##
[0140] Preparation takes place in analogy to the method for Example
1A.
[0141] MS (ESI): m/z=177 (M+H).sup.+
[0142] .sup.1H NMR (200 MHz, CDCl.sub.3): .delta.=7.5 (s, 1H), 4.45
(br. s, 2H), 4.35 (m, 1H), 2.2-1.55 (m, 6H) ppm.
EXAMPLE 3A
5-Amino-1-(1-ethylpropyl)-1H-1-pyrazole-4-carbonitrile
##STR00013##
[0144] Preparation takes place in analogy to the method for Example
1A.
[0145] MS (ESI): m/z=179 (M+H).sup.+
[0146] .sup.1H NMR (300 MHz, DMSO-d.sub.6): .delta.=7.55 (s, 1H),
6.45 (s, 2H), 4.0 (m, 1H), 1.8-1.55 (m, 4H), 0.65 (t, 6H) ppm.
EXAMPLE 4A
5-Amino-1-cyclohexyl-1H-pyrazole-4-carboxamide
##STR00014##
[0148] 18 ml of 30% strength hydrogen peroxide solution are added
to a solution of 5-amino-1-cyclohexyl-1H-pyrazole-4-carbonitrile
(1.86 g, 9.81 mmol in a mixture of 73 ml of ethanol and 90 ml of
concentrated aqueous ammonia solution at room temperature, and the
mixture is stirred at room temperature for 1 h. The nonaqueous
solvents are then stripped off in a rotary evaporator. The product
precipitates as solid from the remaining mixture and is filtered
off with suction, washed with a little water and dried under high
vacuum.
[0149] Yield: 1.77 g (86% of theory)
[0150] MS (DCI): m/z=209 (M+H).sup.+
[0151] .sup.1H NMR (300 MHz, DMSO-d.sub.6): .delta.=7.6 (s, 1H),
7.3-6.4 (broad, 2H), 6.1 (s, 2H) 3.95 (m, 1H), 1.95-1.05 (m, 10H)
ppm.
EXAMPLE 5A
5-Amino-1-cyclopentyl-1H-pyrazole-4-carboxamide
##STR00015##
[0153] Preparation takes place in analogy to the method for Example
4A.
[0154] MS (ESI): m/z=195 (M+H).sup.+
[0155] .sup.1H NMR (200 MHz, CDCl.sub.3): .delta.=7.5 (s, 1H),
5.6-4.8 (broad, 4H), 4.35 (m, 1H), 2.2-1.55 (m, 8H) ppm.
EXAMPLE 6A
5-Amino-1-(1-ethylpropyl)-1H-pyrazole-4-carboxamide
##STR00016##
[0157] Preparation takes place in analogy to the method for Example
4A.
[0158] MS (ESI): m/z=197 (M+H).sup.+
[0159] .sup.1H NMR (300 MHz, DMSO-d.sub.6): .delta.=7.65 (s, 1H),
6.9 (br. s, 2H), 6.1 (s, 2H), 3.9 (m, 1H), 1.85-1.6 (m, 4H), 0.7
(t, 6H) ppm.
Exemplary Embodiments
EXAMPLE 1
6-(3-Chlorobenzyl)-1-cyclopentyl-1,5-dihydro-41-1-pyrazolo[3,4-d]pyrimidin-
-4-one
##STR00017##
[0161] Under argon, 180 mg (0.91 mmol) of
5-amino-1-cyclopentyl-1H-pyrazole-4-carboxamide and 575 mg (2.72
mmol; 3 equiv.) of ethyl (3-chlorophenyl)acetate are introduced
into 3.5 ml of absolute ethanol. At 0.degree. C., 127 mg of sodium
hydride (60% dispersion in mineral oil; 3.18 mmol; 15 equiv.) are
slowly added in a countercurrent of argon. The resulting mixture is
slowly warmed and stirred under reflux for 18 h. The mixture is
worked up by adding 50 ml of water and extracted several times with
ethyl acetate. The combined organic phases are dried over sodium
sulfate and concentrated in vacuo. The crude product is purified by
preparative HPLC.
[0162] Yield: 244 mg (81% of theory)
[0163] MS (ESI): m/z=329 (M+H).sup.+
[0164] m.p.: 159.degree. C.
[0165] .sup.1H NMR (200 MHz, DMSO-d.sub.6): .delta.=12.3 (s, 1H),
8.0 (s, 1H), 7.5-7.2 H), 5.05 (m, 1H), 3.95 (s, 2H), 2.2-1.5 (m,
8H) ppm.
EXAMPLE 2
6-(2-Fluorobenzyl)-1-cyclopentyl-1,5-dihydro--4H-pyrazolo[3,4-d]pyrimidin--
4-one
##STR00018##
[0167] The product is obtained in analogy to Example 1 starting
from 100 mg (0.5 mmol)
5-amino-1-cyclopentyl-1H-pyrazole-4-carboxamide and 260 mg (1.51
mmol) of methyl (2-fluorophenyl)acetate.
[0168] Yield: 100 mg (63% of theory)
[0169] MS (DCI): m/z=313 (M+H).sup.+
[0170] m.p.: 180.degree. C.
[0171] .sup.1H NMR (400 MHz, DMSO d.sub.6): .delta.=12.25 (s, 1H),
8.0 (s, 1H), 7.4-7.3 (m, 2H), 7.2-7.1 (m, 2H), 4.95 (m, 1H), 4.05
(s, 2H), 2.05-1.55 (m, 8H) ppm.
EXAMPLE 3
6-(3-Bromobenzyl)-1-cyclopentyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4--
one
##STR00019##
[0173] The product is obtained in analogy to Example 1 starting
from 80 mg (0.4 mmol) of
5-amino-1H-cyclopentyl-1H-pyrazole-4-carboxamide and 277 mg (1.21
mmol) of methyl (3-bromophenyl)acetate.
[0174] Yield: 93 mg (62% of theory)
[0175] MS (ESI): m/z=373 (M+H).sup.+
[0176] m.p.: 159.degree. C.
[0177] .sup.1H NMR (400 MHz, DMSO-d.sub.6): .delta.=12.2 (s, 1H),
8.0 (s, 1H), 7.6 (s, 1H), 7.5-7.35 (m, 3H), 5.05 (m, 1H), 4.0 (s,
2H), 2.1L1.6 (m, 8H) ppm.
EXAMPLE 4
6-(3,4-Dichlorobenzyl)-1-cyclopentyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimid-
in-4-one
##STR00020##
[0179] The product is obtained in analogy to Example 1 starting
from 75 mg (0.38 mmol) of
5-amino-1-cyclopentyl-1H-pyrazole-4-carboxamide and 254 mg (1.14
mmol) of methyl (3,4-dichlorophenyl)acetate.
[0180] Yield: 94 mg (68% of theory)
[0181] MS (EST): m/z=363 (M+H).sup.+
[0182] m.p.: 198.degree. C.
[0183] .sup.1H NMR (400 MHz, DMSO-d.sub.6): .delta.=12.2 (s, 1H),
8.0 (s, 1H), 7.65 (d, 1H, J=1 Hz), 7.55 (d,1H, J=7.5 Hz), 7,3 (dd,
1H, J=7.5 Hz, 1 Hz), 5.05 (m, 1H), 4.0 (s, 2H), 2.1-1.6 (m, 8H)
ppm.
EXAMPLE 5
6-(3,5-Dichlorobenzyl)-1-cyclopentyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimid-
in-4-one
##STR00021##
[0185] The product is obtained in analogy to Example 1 starting
from 150 mg (0.76 mmol) of
5-amino-1-cyclopentyl-1H-pyrazole-4-carboxamide and 507 mg (2.27
mmol) of methyl (3,5-dichlorophenyl)acetate.
[0186] Yield: 159 mg (58% of theory)
[0187] MS (ESI): m/z=363 (M+H).sup.+
[0188] m.p.: 177.degree. C. .sup.1H NMR (200 MHz, DMSO-d.sub.6):
.delta.=12.25 (s, 1H), 8,0 (s, 1H), 7.55 (t, 1H, J=1 Hz), 7.45 (d,
2H, J=1 Hz), 5.05 (m, 1H), 4.0 (s, 2H), 2.2-1.5 (m, 8H) ppm.
EXAMPLE 6
6-(2,3-Dichlorobenzyl)-1-cyclopentyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimid-
in-4-one
##STR00022##
[0190] The product is obtained in analogy to Example 1 starting
from 150 mg (0.76 mmol) of
5-amino-1-cyclopentyl-1H-pyrazole-4-carboxamide and 406 mg (1.82
mmol) of methyl (2,3-dichlorophenyl)acetate.
[0191] Yield: 114 mg (41% of theory)
[0192] MS (PSI): m/z=363 (M+H).sup.30
[0193] imp.: 181.degree. C.
[0194] .sup.1H NMR (200 MHz, DMSO-d.sub.6): .delta.12.35 (s, 1H),
8.0 (s, 1H), 7.6 (m, 1H), 7.4-7.3 (m, 2H), 4.9 (m, 1H), 4.2 (s,
2H), 2.1-1.5 (m, 8H) ppm.
EXAMPLE 7
6-(3-Chlorobenzyl)-1-(1-ethylpropyl)-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimid-
in-4-one
##STR00023##
[0196] The product is obtained in analogy to Example 1 starting
from 150 mg (0.76 mmol) of
5-amino-1-(1-ethylpropyl)-1H-pyrazole-4-carboxamide and 484 mg
(2.29 mmol) of ethyl (3-chlorophenyl)acetate.
[0197] Yield: 210 mg (83% of theory)
[0198] MS (ESI): m/z=331 (M+H).sup.+
[0199] m.p.: 138.degree. C.
[0200] .sup.1NMR (200 MHz, DMSO-d.sub.6): .delta.=12.3 (s, 1H), 8.0
(s, 1H), 7.45-7.25 (m, 4H), 4.45 (m, 1H), 4.0 (s, 2H), 2.0-1.7 (m,
4H), 0.6 (t, 6H, J=7.5 Hz) ppm.
EXAMPLE 1
6-(3-Methylbenzyl)-1-cyclopentyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-
-one
##STR00024##
[0202] The product is obtained in analogy to Example 1 starting
from 200 mg (1.01 mmol) of
5-amino-1-cyclopentyl-1H-pyrazole-4-carboxamide and 550 mg (3.03
mmol) of ethyl (3-methylphenyl)acetate.
[0203] Yield: 222 mg (71% of theory)
[0204] MS (ESI): m/z=309 (M+H).sup.+
[0205] m.p.: 152.degree. C.
[0206] .sup.1H NMR (200 MHz, DMSO-d.sub.6): .delta.=12.2 (s, 1H),
8.0 (s, 1H), 7.3-7.0 (m, 4H), 5.1 (m, 1H), 3.95 (s, 2H), 2.3 (s,
3H), 2.2-1.55 (m, 8H) ppm.
EXAMPLE 9
6-(2,5-Dichlorobenzyl)-1-(1-ethylpropyl)-1,5-dihydro-4H-pyrazolo[3,4-d]pyr-
imidin-4-one
##STR00025##
[0208] The product is obtained in analogy to Example 1 starting
from 200 mg (1.0 mmol) of
5-amino-1-(1-ethylpropyl)-1H-pyrazole-4-carboxamide and 806 mg (3.5
mmol) of methyl (2,5-dichlorophenyl)acetate.
[0209] Yield: 51 mg (14% of theory)
[0210] MS (ESI): m/z=365 (M+H).sup.+
[0211] m.p.: 134.degree. C.
[0212] .sup.1H NMR (300 MHz, DMSO-d.sub.6): .delta.=12.3 (s, 1H),
8.0 (s, 1H), 7.55-7.35 (m, 3H), 4.2 (m, 1H), 4.15 (s, 2H), 1.9-1.65
(m, 4H), 0.55 (t, 6H,=7.5 Hz) ppm.
EXAMPLE 10
6-(3-Methylbenzyl)-1-(1-ethylpropyl)-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimid-
in-4-one
##STR00026##
[0214] The product is obtained in analogy in Example 1 starting
from 200 mg (1.0 mmol) of
5-amino-1-(1-ethylpropyl)-1H-pyrazole-4-carboxamide and 534 mg (3.0
mmol) of ethyl (3-methylphenyl)acetate.
[0215] Yield: 187 mg (60% of theory)
[0216] MS (ESI): m/z=311 (M+H).sup.+
[0217] m.p.: 128.degree. C.
[0218] .sup.1H NMR (200 MHz, DMSO-d.sub.6): .delta.=12.25 (s, 1H),
8.0 (s, 1H), 7.25-7.0 (m, 4H), 4.5 (m, 1H), 3.95 (s, 2H), 2.25 (s,
3H), 2.0-1.7 (m, 41-1), 0.6 (t, 6H, J=7.5 Hz) ppm.
EXAMPLE 11
1-(1-Ethylpropyl)-6-[3-(trifluoroethyl)benzyl]-1,5-dihydro-4H-pyrazolo[3,4-
-d]-pyrimidin-4-one
##STR00027##
[0220] The product is obtained in analogy to Example 1 starting
from 150 mg (0.75 mmol) of
5-amino-1-(1-ethylpropyl-1H-pyrazole-4-carboxamide and 490 mg (2.25
mmol) of methyl (3-trifluoromethylphenyl)acetate.
[0221] Yield: 159 mg (58% of theory)
[0222] MS (ESI): m/z=365 (M+H).sup.+
[0223] m.p.: 120.degree. C.
[0224] .sup.1H NMR (400 MHz, DMSO-d.sub.6): .delta.=12.3 (s, 1H),
8.0 (s, 1H), 7.7 (s, 1H), 7.7-7.5 (m, 3H), 4.4 (m, 1H), 4.1 (s,
2H), 1.95-1.75 (m, 4H), 0.6 (t, 6H, J=7,5 Hz) ppm.
EXAMPLE 12
1-Cyclopentyl-6-(3-nitrobenzyl)-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4--
one
##STR00028##
[0226] The product is obtained in analogy to Example 1 starting
from 668 mg (3.44 mmol) of
5-amino-1-cyclopentyl-1H-pyrazole-4-carboxamide and 3.5 g (117
mmol) of ethyl 3-nitrophenylacetate.
[0227] Yield: 10 mg (1% of theory)
[0228] MS (ESI): m/z=340 (M+H).sup.+
[0229] .sup.1H NMR (300 MHz, DMSO-d.sub.6): .delta.=12.3 (s, 1H),
8.3 (s, 1H), 8.15 (m, 1H), 8.0 (s, 1H), 7.8 (d, 1H, J=8 Hz), 7.6
(t, 1H, J=8 Hz), 5.0 (m, 1H), 4.15 (s, 2H), 2.1-1.6 (m, 8H).
EXAMPLE 13
6-(3-Chlorobenzyl)-1-cyclopentyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidine--
4-thione
##STR00029##
[0231] 50 mg (0.23 mmol, 1.5 equiv.) of diphosphorus pentasulfide
are added to a solution of 50 mg (0.15 mmol) of
6-(3-chlorobenzyl)-1-cyclopentyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin--
4-one (Example 1) in 1 ml of pyridine at room temperature, and the
mixture is then stirred under reflux overnight. After cooling, the
reaction solution is mixed with 10 ml of ice-cold 2.5% strength
sodium bicarbonate solution and extracted three times with ethyl
acetate. The combined organic phases are washed with saturated
brine, dried over sodium sulfate and concentrated in vacuo. The
crude product is purified by preparative HPLC.
[0232] Yield: 36 mg (68% of theory)
[0233] MS (ESI): m/z=345 (M+H).sup.+
[0234] m.p.: 154.degree. C.
[0235] .sup.1H NMR (300 MHz, DMSO-d.sub.6): .delta.=13.6 (s, 1H),
8.15 (s, 1H), 7.5 (s, 1H), 7.4-7.25 (m, 3H), 5.05 (m, 1H), 4.1 (s,
2H), 2.1-1.6 (m, 8H).
EXAMPLE 14
1-Cyclopentyl-6-[2-(trifluoromethoxy)benzyl]-1,5-dihydro-4H-pyrazolo[3,4-d-
]-pyrimidin-4-one
##STR00030##
[0237] The product is obtained in analogy to Example 1 starting
from 50 mg (0.26 mmol) of
5-amino-1-cyclopentyl-1H-pyrazole-4-carboxamide and 301 mg (1.29
mmol) of methyl [2-(trifluoromethoxy)phenyl]acetate.
[0238] Yield: 64 mg (63% of theory)
[0239] MS (DCI): m/z=379 (M+H).sup.+
[0240] m.p.: 161.degree. C.
[0241] .sup.1H NMR (400 MHz, DMSO-d.sub.6): .delta.=12.25 (s, 1H),
8.0 (s, 1H), 7.5-7.3 (m,4H), 4.9 (m, 1H), 4.1 (s, 2H), 2.05-1.5 (m,
8H) ppm.
* * * * *
References