U.S. patent application number 10/951515 was filed with the patent office on 2005-04-07 for benzimidazole derivatives as modulators of ige.
Invention is credited to Campbell, Michael G., Major, Michael W., Richards, Mark L., Sircar, Jagadish C..
Application Number | 20050075343 10/951515 |
Document ID | / |
Family ID | 27375413 |
Filed Date | 2005-04-07 |
United States Patent
Application |
20050075343 |
Kind Code |
A1 |
Sircar, Jagadish C. ; et
al. |
April 7, 2005 |
Benzimidazole derivatives as modulators of IgE
Abstract
This invention relates to a family of benzimidazole analogs,
which are inhibitors of the IgE response to allergens. These
compounds are useful in the treatment of allergy, asthma, or any
diseases where IgE is pathogenic.
Inventors: |
Sircar, Jagadish C.; (San
Diego, CA) ; Richards, Mark L.; (San Diego, CA)
; Campbell, Michael G.; (Durham, NC) ; Major,
Michael W.; (Mequon, WI) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
27375413 |
Appl. No.: |
10/951515 |
Filed: |
September 28, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10951515 |
Sep 28, 2004 |
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09983054 |
Oct 16, 2001 |
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09983054 |
Oct 16, 2001 |
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09422397 |
Oct 21, 1999 |
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6303645 |
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09422397 |
Oct 21, 1999 |
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09316870 |
May 21, 1999 |
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6271390 |
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60086494 |
May 22, 1998 |
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Current U.S.
Class: |
514/252.06 ;
514/310; 514/314; 514/321; 514/338; 514/365; 514/372; 514/374;
514/378; 514/394 |
Current CPC
Class: |
A61K 2300/00 20130101;
A61K 2300/00 20130101; A61K 2300/00 20130101; A61K 45/06 20130101;
A61K 31/4545 20130101; A61K 31/4184 20130101; A61K 31/415 20130101;
A61K 31/4184 20130101; A61K 31/415 20130101; A61K 31/4545 20130101;
A61K 31/00 20130101 |
Class at
Publication: |
514/252.06 ;
514/321; 514/338; 514/310; 514/314; 514/365; 514/372; 514/374;
514/378; 514/394 |
International
Class: |
A61K 031/501; A61K
031/4709; A61K 031/4439; A61K 031/454; A61K 031/425; A61K 031/42;
A61K 031/4184 |
Claims
What is claimed is:
1. A pharmaceutical composition for treating an allergic reaction
associated with increased IgE levels in a mammal comprising the
following compounds: 97wherein X and Y are independently selected
from the group consisting of H, alkyl, alkoxy, aryl, substituted
aryl, hydroxy, halogen, amino, alkylamino, nitro, cyano, CF.sub.3,
OCF.sub.3. CONH.sub.2, CONHR and NHCOR.sub.1; wherein R is selected
from the group consisting of H, CH.sub.3, C.sub.2H.sub.5,
C.sub.3H.sub.7, C.sub.4H.sub.9, CH.sub.2Ph,
CH.sub.2C.sub.6H.sub.4--F(p-), COCH.sub.3,
CO.sub.2CH.sub.2CH.sub.3, aminoalkyl and dialkylaminoalkyl; and
wherein R.sub.1 is a heterocyclic ring comprising a heteroatom or
substituted heterocyclic ring comprising a heteroatom; and wherein
R.sub.2 is selected from the group consisting of aryl, heteroaryl,
thiophene, pyridyl, thiazolyl, isoxazolyl, oxazolyl, pyrimidinyl,
substituted aryl, substituted heteroaryl, substituted thiophene,
substituted pyridyl, substituted thiazolyl, substituted isoxazolyl,
substituted oxazolyl, cycloaryl, cycloheteroaryl, quinolinyl,
isoquinolinyl, substituted cycloaryl, substituted cycloheteroaryl,
substituted quinolinyl, substituted isoqunolinyl, multi-ring
cycloaryl, multi-ring cycloheteroaryl, benzyl, heteroaryl-methyl,
substituted benzyl, substituted heteroaryl-methyl alkyl,
dialkylaminoalkyl, cycloalkyl, cycloalkyl containing 1-3
heteroatoms, substituted cycloalkyl, substitute cycloalkyl
containing 1-3 heteroatoms, multi-ring cycloalkyl, multiring
cycloalkyl containing 1-3 heteroatoms, fused-ring aliphatic,
fused-ring aliphatic containing 1-3 heteroatoms, cyclopropyl,
substituted cyclopropyl, cyclobutyl, substituted cyclobutyl,
cyclopentyl, pyrrole, piperidine, substituted cyclopentyl,
cyclohexyl, substituted cyclohexyl, cycloheptyl, substituted
cycloheptyl, bicycloheptyl, substituted pyrrole, substituted
piperidine, bicyclooctyl, bicyclononyl, substituted bicycloalkenyl,
adamantyl, and substituted adamantyl, heterocyclic ring, and
substituted heterocyclic ring; wherein at least one of R.sub.1 and
R.sub.2 are aromatic groups or heteroaromatic groups; and wherein
R.sub.1 and R.sub.2 cannot both be phenyl groups.
2. The pharmaceutical composition of claim 1, wherein the
substituent is selected from the group consisting of alkyl, aryl,
CF.sub.3, CH.sub.3, OCH.sub.3, OH, CN, CONH.sub.2, CONHR,
CONR.sub.1R.sub.2, COOR, and COOH.
3. The pharmaceutical composition of claim 1, further comprising at
least one additional ingredient which is active in reducing at
least one symptom associated with said allergic reaction.
4. The pharmaceutical composition of claim 3, wherein said at least
one additional ingredient is selected from the group consisting of
a short-acting .beta..sub.2-adrenergic agonist, a long-acting
.beta..sub.2-adrenergic agonist, an antihistamine, a
phosphodiesterase inhibitor, an anticholinergic agent, a
corticosteroid, an inflammatory mediator release inhibitor and a
leukotriene receptor antagonist.
5. The pharmaceutical composition of claim 1, wherein the compound
is selected from the group consisting of: 9899
6. A method for treating an allergic reaction in a mammal wherein
said reaction is caused by an increase in IgE levels comprising
administering an IgE-suppressing amount of at least one compound of
claim 1.
7. The method of claim 6, further comprising administering in
conjunction with at least one additional ingredient which is active
in reducing at least one symptom associated with said allergic
reaction.
8. The method of claim 7, wherein said additional ingredient is
selected from the group consisting of a short-acting
.beta..sub.2-adrenergic agonist, a long-acting
.beta..sub.2-adrenergic agonist, an antihistamine, a
phosphodiesterase inhibitor, an anticholinergic agent, a
corticosteroid, an inflammatory mediator release inhibitor and a
leukotriene receptor antagonist.
9. The method of claim 6, wherein the compound is selected from the
group consisting of: 100101
10. A method for treating asthma in a mammal comprising
administering an IgE-suppressing amount of at least one compound of
claim 1.
11. The method of claim 10 further comprising administering in
conjunction with at least one additional ingredient which is active
in reducing at least one symptom associated with said allergic
reaction.
12. The method of claim 11, wherein said additional ingredient is
selected from the group consisting of a short-acting
.beta..sub.2-adrenergic agonist, a long-acting
.beta..sub.2-adrenergic agonist, an antihistamine, a
phosphodiesterase inhibitor, an anticholinergic agent, a
corticosteroid, an inflammatory mediator release inhibitor and a
leukotriene receptor antagonist.
13. The method of claim 10, wherein the compound is selected from
the group consisting of: 102103
14. A pharmaceutical composition for treating an allergic reaction
associated with increased IgE levels in a mammal comprising the
following compounds: Genus B, 104wherein X and Y are independently
selected from the group consisting of H, alkyl, alkoxy, aryl,
substituted aryl, hydroxy, halogen, amino, alkylamino, nitro,
cyano, CF.sub.3, OCF.sub.3. CONH.sub.2, CONHR and NHCOR.sub.1;
wherein R is selected from the group consisting of H, CH.sub.3,
C.sub.2H.sub.5, C.sub.3H.sub.7, C.sub.4H.sub.9, CH.sub.2Ph,
CH.sub.2C.sub.6H.sub.4--F(p-), COCH.sub.3,
CO.sub.2CH.sub.2CH.sub.3, aminoalkyl and dialkylaminoalkyl; and
wherein R.sub.1 is selected from the group consisting of aryl,
heteroaryl, thiophene, pyridyl, thiazolyl, isoxazolyl, oxazolyl,
pyrimidinyl, substituted aryl, substituted heteroaryl, substituted
thiophene, substituted pyridyl, substituted thiazolyl, substituted
isoxazolyl, substituted oxazolyl, cycloaryl, cycloheteroaryl,
quinolinyl, isoquinolinyl, substituted cycloaryl, substituted
cycloheteroaryl, substituted quinolinyl, substituted isoqunolinyl,
multi-ring cycloaryl, multi-ring cycloheteroaryl, benzyl,
heteroaryl-methyl, substituted benzyl, substituted
heteroaryl-methyl alkyl, dialkylaminoalkyl, cycloalkyl, cycloalkyl
containing 1-3 heteroatoms, substituted cycloalkyl, substitute
cycloalkyl containing 1-3 heteroatoms, multi-ring cycloalkyl,
multiring cycloalkyl containing 1-3 heteroatoms, fused-ring
aliphatic, fused-ring aliphatic containing 1-3 heteroatoms,
cyclopropyl, substituted cyclopropyl, cyclobutyl, substituted
cyclobutyl, cyclopentyl, pyrrole, piperidine, substituted
cyclopentyl, cyclohexyl, substituted cyclohexyl, cycloheptyl,
substituted cycloheptyl, bicycloheptyl, substituted pyrrole,
substituted piperidine, bicyclooctyl, bicyclononyl, substituted
bicycloalkenyl, adamantyl, and substituted adamantyl, heterocyclic
ring, and substituted heterocyclic ring.
Description
RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
application Ser. No. 09/983,054, filed Oct. 16, 2001, which is a
continuation-in-part application of U.S. application Ser. No.
09/422,397, filed on Oct. 21, 1999, issued as U.S. Pat. No.
6,303,645 on Oct. 16, 2001, which is a continuation-in-part
application of U.S. application Ser. No. 09/316,870, filed on May
21, 1999, issued as U.S. Pat. No. 6,271,390 on Aug. 7, 2001, which
claims priority under 35 U.S.C. .sctn. 119(e) to U.S. Provisional
Application No. 60/086,494, filed on May 21, 1998.
BACKGROUND OF THE INVENTION
[0002] This invention relates to small molecule inhibitors of the
IgE response to allergens that are useful in the treatment of
allergy and/or asthma or any diseases where IgE is pathogenic.
[0003] An estimated 10 million persons in the United States have
asthma, about 5% of the population. The estimated cost of asthma in
the United States exceeds $6 billion. About 25% of patients with
asthma who seek emergency care require hospitalization, and the
largest single direct medical expenditure for asthma has been
inpatient hospital services (emergency care), at a cost of greater
than $1.6 billion. The cost for prescription medications, which
increased 54% between 1985 and 1990, was close behind at $1.1
billion (Kelly, Pharmacotherapy 12:13S-21S (1997)).
[0004] According to the National Ambulatory Medical Care Survey,
asthma accounts for 1% of all ambulatory care visits, and the
disease continues to be a significant cause of missed school days
in children. Despite improved understanding of the disease process
and better drugs, asthma morbidity and mortality continue to rise
in this country and worldwide (U.S. Department of Health and Human
Services; 1991, publication no. 91-3042). Thus, asthma constitutes
a significant public health problem.
[0005] The pathophysiologic processes that attend the onset of an
asthmatic episode can be broken down into essentially two phases,
both marked by bronchoconstriction, that causes wheezing, chest
tightness, and dyspnea. The first, early phase asthmatic response
is triggered by allergens, irritants, or exercise. Allergens
cross-link immunoglobulin E (IgE) molecules bound to receptors on
mast cells, causing them to release a number of pre-formed
inflammatory mediators, including histamine. Additional triggers
include the osmotic changes in airway tissues following exercise or
the inhalation of cold, dry air. The second, late phase response
that follows is characterized by infiltration of activated
eosinophils and other inflammatory cells into airway tissues,
epithelial desquamonon, and by the presence of highly viscous mucus
within the airways. The damage caused by this inflammatory response
leaves the airways "primed" or sensitized, such that smaller
triggers are required to elicit subsequent asthma symptoms.
[0006] A number of drugs are available for the palliative treatment
of asthma; however, their efficacies vary markedly. Short-acting
.beta..sub.2-adrenergic agonists, terbutaline and albuterol, long
the mainstay of asthma treatment, act primarily during the early
phase as bronchodilators. The newer long-acting
.beta..sub.2-agonists, salmeterol and formoterol, may reduce the
bronchoconstrictive component of the late response. However,
because the .beta..sub.2-agonists do not possess significant
antiinflammatory activity, they have no effect on bronchial
hyperreactivity.
[0007] Numerous other drugs target specific aspects of the early or
late asthmatic responses. For example, antihistamines, like
loratadine, inhibit early histamine-mediated inflammatory
responses. Some of the newer antihistamines, such as azelastine and
ketotifen, may have both antiinflammatory and weak bronchodilatory
effects, but they currently do not have any established efficacy in
asthma treatment. Phosphodiesterase inhibitors, like
theophylline/xanthines, may attenuate late inflammatory responses,
but there is no evidence that these compounds decrease bronchial
hyperreactivity. Anticholinergics, like ipratopium bromide, which
are used in cases of acute asthma to inhibit severe
bronchoconstriction, have no effect on early or late phase
inflammation, no effect on bronchial hyperreactivity, and
therefore, essentially no role in chronic therapy.
[0008] The corticosteroid drugs, like budesonide, are the most
potent antiinflammatory agents. Inflammatory mediator release
inhibitors, like cromolyn and nedocromil, act by stabilizing mast
cells and thereby inhibiting the late phase inflammatory response
to allergen. Thus, cromolyn and nedocromil, as well as the
corticosteroids, all reduce bronchial hyperreactivity by minimizing
the sensitizing effect of inflammatory damage to the airways.
Unfortunately, these antiinflammatory agents do not produce
bronchodilation.
[0009] Several new agents are currently being developed that
inhibit specific aspects of asthmatic inflammation. For instance,
leukotriene receptor antagonists (ICI-204, 219, accolate),
specifically inhibit leukotriene-mediated actions. The leukotrienes
have been implicated in the production of both airway inflammation
and bronchoconstriction.
[0010] Thus, while numerous drugs are currently available for the
treatment of asthma, these compounds are primarily palliative
and/or have significant side effects. Consequently, new therapeutic
approaches which target the underlying cause rather than the
cascade of symptoms would be highly desirable. Asthma and allergy
share a common dependence on IgE-mediated events. Indeed, it is
known that excess IgE production is the underlying cause of
allergies in general and allergic asthma in particular (Duplantier
and Cheng, Ann. Rep. Med. Chem. 29:73-81 (1994)). Thus, compounds
that lower IgE levels may be effective in treating the underlying
cause of asthma and allergy.
[0011] None of the current therapies eliminate the excess
circulating IgE. The hypothesis that lowering plasma IgE may reduce
the allergic response, was confirmed by recent clinical results
with chimeric anti-IgE antibody, CGP-51901, and recombinant
humanized monoclonal antibody, rhuMAB-E25. Indeed, three companies,
Tanox Biosystems, Inc., Genentech Inc. and Novartis AG are
collaborating in the development of a humanized anti-IgE antibody
(BioWorld.RTM. Today, Feb. 26, 1997, p. 2) which will treat allergy
and asthma by neutralizing excess IgE. Tanox has already
successfully tested the anti-IgE antibody, CGP-51901, which reduced
the severity and duration of nasal symptoms of allergic rhinitis in
a 155-patient Phase II trial (Scrip #2080, Nov. 24, 1995, p.26).
Genentech recently disclosed positive results from a 536 patient
phase-II/II trials of its recombinant humanized monoclonal
antibody, rhuMAB-E25 (BioWorld.RTM. Today, Nov. 10, 1998, p. 1).
The antibody, rhuMAB-E25, administered by injection (highest dose
300 mg every 2 to 4 weeks as needed) provided a 50% reduction in
the number of days a patient required additional "rescue" medicines
(antihistimines and decongestants), compared to placebo. An NDA
filing for this product is projected to be in the year 2000. The
positive results from anti-IgE antibody trials suggest that
therapeutic strategies aimed at IgE down-regulation may be
effective.
SUMMARY OF THE INVENTION
[0012] The present invention discloses a family of related
compounds for use in the treatment of a condition associated with
an excess IgE level. The benzimidazole inhibitors of IgE in
accordance with the present invention are represented by the
generic formula: 1
[0013] wherein X and Y are independently selected from the group
consisting of H, alkyl, alkoxy, aryl, substituted aryl, hydroxy,
halogen, amino, alkylamino, nitro, cyano, CF.sub.3, OCF.sub.3,
CONH.sub.2, CONHR and NHCOR.sub.1;
[0014] wherein R is selected from the group consisting of H,
CH.sub.3, C.sub.2H.sub.5, C.sub.3H.sub.7, C.sub.4H.sub.9,
CH.sub.2Ph, CH.sub.2C.sub.6H.sub.4--F(p-), COCH.sub.3,
CO.sub.2CH.sub.2CH.sub.3, aminoalkyl and dialkylaminoalkyl; and
[0015] wherein R.sub.1 and R.sub.2 are independently selected from
the group consisting of H, aryl, heteroaryl, thiophene, pyridyl,
thiazolyl, isoxazolyl, oxazolyl, pyrimidinyl, substituted aryl,
substituted heteroaryl, substituted thiophene, substituted pyridyl,
substituted thiazolyl, substituted isoxazolyl, substituted
oxazolyl, cycloaryl, cycloheteroaryl, quinolinyl, isoquinolinyl,
substituted cycloaryl, substituted cycloheteroaryl, substituted
quinolinyl, substituted isoqunolinyl, multi-ring cycloaryl,
multi-ring cycloheteroaryl, benzyl, heteroaryl-methyl, substituted
benzyl, substituted heteroaryl-methyl alkyl, dialkylaminoalkyl,
cycloalkyl, cycloalkyl containing 1-3 heteroatoms, substituted
cycloalkyl, substitute cycloalkyl containing 1-3 heteroatoms,
multi-ring cycloalkyl, multiring cycloalkyl containing 1-3
heteroatoms, fused-ring aliphatic, fused-ring aliphatic containing
1-3 heteroatoms, cyclopropyl, substituted cyclopropyl, cyclobutyl,
substituted cyclobutyl, cyclopentyl, pyrrole, piperidine,
substituted cyclopentyl, cyclohexyl, substituted cyclohexyl,
cycloheptyl, substituted cycloheptyl, bicycloheptyl, substituted
pyrrole, substituted piperidine, bicyclooctyl, bicyclononyl,
substituted bicycloalkenyl, adamantyl, substituted adamantyl and
the like, wherein at least one of R.sub.1 and R.sub.2 are aromatic
groups or heteroaromatic groups.
[0016] The substituents on said substituted aryl, substituted
heteroaryl, substituted thiophene, substituted pyridyl, substituted
thiazolyl, substituted isoxazolyl, substituted oxazolyl,
substituted cycloaryl, substituted cycloheteroaryl, substituted
quinolinyl, substituted isoqunolinyl, substituted benzyl,
substituted heteroaryl-methyl alkyl, substituted cycloalkyl,
substitute cycloalkyl containing 1-3 heteroatoms, substituted
cyclopropyl, cyclobutyl, substituted cyclobutyl, substituted
cyclopentyl, substituted cyclohexyl, cycloheptyl, substituted
cycloheptyl, bicycloheptyl, substituted pyrrole, substituted
piperidine, bicyclooctyl, bicyclononyl, substituted bicycloalkenyl,
adamantyl, and substituted adamantyl are independently selected
from the group consisting of alkyl, aryl, CF.sub.3, CH.sub.3,
OCH.sub.3, OH, CN, CONH.sub.2, CONHR, CONR1R2, COOR and COOH.
[0017] In accordance with another aspect of the invention, there is
disclosed a composition for use in the treatment of an allergic
condition comprising the benzimidazole inhibitor of IgE disclosed
above and at least one additional active ingredient, combined in a
pharmaceutically acceptable diluent. The additional active
ingredients may be selected from the group consisting of
short-acting .beta..sub.2-adrenergic agonists, like terbutaline and
albuterol, long-acting .beta..sub.2-adrenergic agonists, like
salmeterol and formoterol, antihistamines, like loratadine,
azelastine and ketotifen, phosphodiesterase inhibitors,
anticholinergic agents, corticosteroids, inflammatory mediator
release inhibitors and leukotriene receptor antagonists.
[0018] In accordance with another aspect of the invention, there is
disclosed a family of symmetric and asymmetric diacyl and monoacyl
benzimidazole compounds for use in the treatment of an allergic
condition comprising the following species:
23456789101112131415161718192021222324-
25262728293031323334353637383940414243
[0019] In accordance with another aspect of the present invention,
there is disclosed a method for the preparation of a medicament for
treatment of a condition associated with an excess IgE level. The
compound has the formula: 44
[0020] X and Y are independently selected from the group consisting
of H, alkyl, alkoxy, aryl, substituted aryl, hydroxy, halogen,
amino, alkylamino, nitro, cyano, CF.sub.3, OCF.sub.3, CONH.sub.2,
CONHR and NHCOR.sub.1. R is selected from the group consisting of
H, CH.sub.3, C.sub.2H.sub.5, C.sub.3H.sub.7, C.sub.4H.sub.9,
CH.sub.2Ph, and CH.sub.2C.sub.6H.sub.4--F(p-). R.sub.1 and R.sub.2
are independently selected from the group consisting of H, aryl,
heteroaryl, thiophene, pyridyl, thiazolyl, isoxazolyl, oxazolyl,
pyrimidinyl, substituted aryl, substituted heteroaryl, substituted
thiophene, substituted pyridyl, substituted thiazolyl, substituted
isoxazolyl, substituted oxazolyl, cycloaryl, cycloheteroaryl,
quinolinyl, isoquinolinyl, substituted cycloaryl, substituted
cycloheteroaryl, substituted quinolinyl, substituted isoqunolinyl,
multi-ring cycloaryl, multi-ring cycloheteroaryl, benzyl,
heteroaryl-methyl, substituted benzyl, substituted
heteroaryl-methyl alkyl, dialkyl, aminoalkyl, cycloalkyl,
cycloalkyl containing 1-3 heteroatoms, substituted cycloalkyl,
substitute cycloalkyl containing 1-3 heteroatoms, multi-ring
cycloalkyl, multiring cycloalkyl containing 1-3 heteroatoms,
fused-ring aliphatic, fused-ring aliphatic containing 1-3
heteroatoms, cyclopropyl, substituted cyclopropyl, cyclobutyl,
substituted cyclobutyl, cyclopentyl, pyrrole, piperidine,
substituted cyclopentyl, cyclohexyl, substituted cyclohexyl,
cycloheptyl, substituted cycloheptyl, bicycloheptyl, substituted
pyrrole, substituted piperidine, bicyclooctyl, bicyclononyl,
substituted bicycloalknyl, adamantyl, substituted adamantyl and the
like, and wherein at least one of R.sub.1 and R.sub.2 are aromatic
groups or heteroaromatic groups. The R.sub.1 and R.sub.2
substitutions are independently selected from the group consisting
of alkyl, aryl, CF.sub.3, CH.sub.3, OCH.sub.3, OH, CN, CONH.sub.2,
CONHR, CONR1R2, COOR and COOH.
[0021] In accordance with another aspect of the present invention,
there is disclosed a method of treating a mammal having a condition
associated with an excess IgE level. The method comprises
administering to the mammal an amount of a compound sufficient to
reduced IgE levels in the mammal. The compound has the formula:
45
[0022] wherein X and Y are independently selected from the group
consisting of H, alkyl, alkoxy, aryl, substituted aryl, hydroxy,
halogen, amino, alkylamino, nitro, cyano, CF.sub.3, OCF.sub.3.
CONH.sub.2, CONHR and NHCOR.sub.1;
[0023] wherein R is selected from the group consisting of H,
CH.sub.3, C.sub.2H.sub.5, C.sub.3H.sub.7, C.sub.4H.sub.9,
CH.sub.2Ph, CH.sub.2C.sub.6H.sub.4--F(p-), COCH.sub.3,
CO.sub.2CH.sub.2CH.sub.3, aminoalkyl and dialkylaminoalkyl; and
[0024] wherein R.sub.1 and R.sub.2 are independently selected from
the group consisting of H, aryl, heteroaryl, thiophene, pyridyl,
thiazolyl, isoxazolyl, oxazolyl, pyrimidinyl, substituted aryl,
substituted heteroaryl, substituted thiophene, substituted pyridyl,
substituted thiazolyl, substituted isoxazolyl, substituted
oxazolyl, cycloaryl, cycloheteroaryl, quinolinyl, isoquinolinyl,
substituted cycloaryl, substituted cycloheteroaryl, substituted
quinolinyl, substituted isoqunolinyl, multi-ring cycloaryl,
multi-ring cycloheteroaryl, benzyl, heteroaryl-methyl, substituted
benzyl, substituted heteroaryl-methyl alkyl, dialkylaminoalkyl,
cycloalkyl, cycloalkyl containing 1-3 heteroatoms, substituted
cycloalkyl, substitute cycloalkyl containing 1-3 heteroatoms,
multi-ring cycloalkyl, multiring cycloalkyl containing 1-3
heteroatoms, fused-ring aliphatic, fused-ring aliphatic containing
1-3 heteroatoms, cyclopropyl, substituted cyclopropyl, cyclobutyl,
substituted cyclobutyl, cyclopentyl, pyrrole, piperidine,
substituted cyclopentyl, cyclohexyl, substituted cyclohexyl,
cycloheptyl, substituted cycloheptyl, bicycloheptyl, substituted
pyrrole, substituted piperidine, bicyclooctyl, bicyclononyl,
substituted bicycloalkenyl, adamantyl, substituted adamantyl and
the like, wherein at least one of R.sub.1 and R.sub.2 are aromatic
groups or heteroaromatic groups.
[0025] The substituents on said substituted aryl, substituted
heteroaryl, substituted thiophene, substituted pyridyl, substituted
thiazolyl, substituted isoxazolyl, substituted oxazolyl,
substituted cycloaryl, substituted cycloheteroaryl, substituted
quinolinyl, substituted isoqunolinyl, substituted benzyl,
substituted heteroaryl-methyl alkyl, substituted cycloalkyl,
substitute cycloalkyl containing 1-3 heteroatoms, substituted
cyclopropyl, cyclobutyl, substituted cyclobutyl, substituted
cyclopentyl, substituted cyclohexyl, cycloheptyl, substituted
cycloheptyl, bicycloheptyl, substituted pyrrole, substituted
piperidine, bicyclooctyl, bicyclononyl, substituted bicycloalkenyl,
adamantyl, and substituted adamantyl are independently selected
from the group consisting of alkyl, aryl, CF.sub.3, CH.sub.3,
OCH.sub.3, OH, CN, CONH.sub.2, CONHR, CONR1R2, COOR and COOH.
[0026] In a variation of the above-disclosed method, at least one
additional active ingredient may be administered in conjunction
with the administration of the compound. The additional active
ingredient may be combined with said compound in a pharmaceutically
acceptable diluent and co-administered to the mammal. The
additional active ingredient may be a short-acting
.beta..sub.2-adrenergic agonist selected from the group consisting
of terbutaline and albuterol. In a variation, the additional active
ingredient may be a long-acting .beta..sub.2-adrenergic agonist
selected from the group consisting of salmeterol and formoterol or
an antihistamine selected from the group consisting of loratadine,
azelastine and ketotifen. In another variation, the additional
active ingredient may be a phosphodiesterase inhibitor, an
anticholinergic agent, a corticosteroid, an inflammatory mediator
release inhibitor or a leukotriene receptor antagonist.
[0027] The compound is preferably administered at a dose of about
0.01 mg to about 100 mg per kg body weight per day in divided doses
of said compound for at least two consecutive days at regular
periodic intervals.
[0028] Other variations within the scope of the present invention
may be more fully understood with reference to the following
detailed description.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] The present invention is directed to small molecule
inhibitors of IgE (synthesis and/or release) which are useful in
the treatment of allergy and/or asthma or any diseases where IgE is
pathogenic. The particular compounds disclosed herein were
identified by their ability to suppress IgE levels in both ex vivo
and in vivo assays. Development and optimization of clinical
treatment regimens can be monitored by those of skill in the art by
reference to the ex vivo and in vivo assays described below.
[0030] Ex Vivo Assay
[0031] This assay begins with in vivo antigen priming and measures
secondary antibody responses in vitro. The basic protocol was
documented and optimized for a range of parameters including:
antigen dose for priming and time span following priming, number of
cells cultured in vitro, antigen concentrations for eliciting
secondary IgE (and other Ig's) response in vitro, fetal bovine
serum (FBS) batch that will permit optimal IgE response in vitro,
the importance of primed CD4+ T cells and hapten-specific B cells,
and specificity of the ELISA assay for IgE (Marcelletti and Katz,
Cellular Immunology 135:471-489 (1991); incorporated herein by
reference).
[0032] The actual protocol utilized for this project was adapted
for a more high throughput analyses. BALB/cByj mice were immunized
i.p. with 10 .mu.g DNP-KLH adsorbed onto 4 mg alum and sacrificed
after 15 days. Spleens were excised and homogenized in a tissue
grinder, washed twice, and maintained in DMEM supplemented with 10%
FBS, 100 U/ml penicillin, 100 .mu.g/ml streptomycin and 0.0005%
2-mercaptoethanol. Spleen cell cultures were established (2-3
million cells/ml, 0.2 ml/well in quadruplicate, 96-well plates) in
the presence or absence of DNP-KLH (10 ng/ml). Test compounds (2
.mu.g/ml and 50 ng/ml) were added to the spleen cell cultures
containing antigen and incubated at 37.degree. C. for 8 days in an
atmosphere of 10% CO.sub.2.
[0033] Culture supernatants were collected after 8 days and Ig's
were measured by a modification of the specific isotype-selective
ELISA assay described by Marcelletti and Katz (Supra). The assay
was modified to facilitate high throughput. ELISA plates were
prepared by coating with DNP-KLH overnight. After blocking with
bovine serum albumin (BSA), an aliquot of each culture supernatant
was diluted (1:4 in phosphate buffered saline (PBS) with BSA,
sodium azide and Tween 20), added to the ELISA plates, and
incubated overnight in a humidified box at 40 C. IgE levels were
quantitated following successive incubations with biotinylated-goat
antimouse IgE (b-GAME), AP-streptavidin and substrate.
[0034] Antigen-specific IgG1 was measured similarly, except that
culture supernatants were diluted 200-fold and biotinylated-goat
antimouse IgG1 (b-GAMG1) was substituted for B-GAME. IgG2a was
measured in ELISA plates that were coated with DNP-KLH following a
1:20 dilution of culture supernatants and incubation with
biotinylated-goat antimouse IgG2a (b-GAMG2a). Quantitation of each
isotype was determined by comparison to a standard curve. The level
of detectability of all antibody was about 200-400 .mu.g/ml and
there was less than 0.001% cross-reactivity with any other Ig
isotype in the ELISA for IgE.
[0035] In Vivo Assay
[0036] Compounds found to be active in the ex vivo assay (above)
were further tested for their activity in suppressing IgE responses
in vivo. Mice receiving low-dose radiation prior to immunization
with a carrier exhibited an enhanced IgE response to sensitization
with antigen 7 days later. Administration of the test compounds
immediately prior to and after antigen sensitization, measured the
ability of that drug to suppress the IgE response. The levels of
IgE, IgG1 and IgG2a in serum were compared.
[0037] Female BALB/cByj mice were irradiated with 250 rads 7 hours
after initiation of the daily light cycle. Two hours later, the
mice were immunized i.p. with 2 .mu.g of KLH in 4 mg alum. Two to
seven consecutive days of drug injections were initiated 6 days
later on either a once or twice daily basis. Typically, i.p.
injections and oral gavages were administered as suspensions (150
.mu.l/injection) in saline with 10% ethanol and 0.25%
methylcellulose. Each treatment group was composed of 5-6 mice. On
the second day of drug administration, 2 .mu.g of DNP-KLH was
administered i.p. in 4 mg alum, immediately following the morning
injection of drug. Mice were bled 7-21 days following DNP-KLH
challenge.
[0038] Antigen-specific IgE, IgG1 and IgG2a antibodies were
measured by ELISA. Periorbital bleeds were centrifuged at 14,000
rpm for 10 min, the supernatants were diluted 5-fold in saline, and
centrifuged again. Antibody concentrations of each bleed were
determined by ELISA of four dilutions (in triplicate) and compared
to a standard curve: anti-DNP IgE (1:100 to 1:800), anti-DNP IgG2a
(1:100 to 1:800), and anti-DNP IgG1 (1:1600 to 1:12800).
[0039] Benzimidazole Inhibitors of IgE
[0040] Several species embraced by the following generic formula
were synthesized and evaluated for their effectiveness in
down-regulating IgE in the ex vivo and in vivo assays. 46
[0041] wherein X and Y are independently selected from the group
consisting of H, alkyl, alkoxy, aryl, substituted aryl, hydroxy,
halogen, amino, alkylamino, nitro, cyano, CF.sub.3, OCF.sub.3.
CONH.sub.2, CONHR and NHCOR.sub.1;
[0042] wherein R is selected from the group consisting of H,
CH.sub.3, C.sub.2H.sub.5, C.sub.3H.sub.7, C.sub.4H.sub.9,
CH.sub.2Ph, CH.sub.2C.sub.6H.sub.4--F(p-), COCH.sub.3,
CO.sub.2CH.sub.2CH.sub.3, aminoalkyl and dialkylaminoalkyl; and
[0043] wherein R.sub.1 and R.sub.2 are independently selected from
the group consisting of H, aryl, heteroaryl, thiophene, pyridyl,
thiazolyl, isoxazolyl, oxazolyl, pyrimidinyl, substituted aryl,
substituted heteroaryl, substituted thiophene, substituted pyridyl,
substituted thiazolyl, substituted isoxazolyl, substituted
oxazolyl, cycloaryl, cycloheteroaryl, quinolinyl, isoquinolinyl,
substituted cycloaryl, substituted cycloheteroaryl, substituted
quinolinyl, substituted isoqunolinyl, multi-ring cycloaryl,
multi-ring cycloheteroaryl, benzyl, heteroaryl-methyl, substituted
benzyl, substituted heteroaryl-methyl alkyl, dialkylaminoalkyl,
cycloalkyl, cycloalkyl containing 1-3 heteroatoms, substituted
cycloalkyl, substitute cycloalkyl containing 1-3 heteroatoms,
multi-ring cycloalkyl, multiring cycloalkyl containing 1-3
heteroatoms, fused-ring aliphatic, fused-ring aliphatic containing
1-3 heteroatoms, cyclopropyl, substituted cyclopropyl, cyclobutyl,
substituted cyclobutyl, cyclopentyl, pyrrole, piperidine,
substituted cyclopentyl, cyclohexyl, substituted cyclohexyl,
cycloheptyl, substituted cycloheptyl, bicycloheptyl, substituted
pyrrole, substituted piperidine, bicyclooctyl, bicyclononyl,
substituted bicycloalkenyl, adamantyl, substituted adamantyl and
the like, wherein at least one of R.sub.1 and R.sub.2 are aromatic
groups or heteroaromatic groups.
[0044] The substituents on said substituted aryl, substituted
heteroaryl, substituted thiophene, substituted pyridyl, substituted
thiazolyl, substituted isoxazolyl, substituted oxazolyl,
substituted cycloaryl, substituted cycloheteroaryl, substituted
quinolinyl, substituted isoqunolinyl, substituted benzyl,
substituted heteroaryl-methyl alkyl, substituted cycloalkyl,
substitute cycloalkyl containing 1-3 heteroatoms, substituted
cyclopropyl, cyclobutyl, substituted cyclobutyl, substituted
cyclopentyl, substituted cyclohexyl, cycloheptyl, substituted
cycloheptyl, bicycloheptyl, substituted pyrrole, substituted
piperidine, bicyclooctyl, bicyclononyl, substituted bicycloalkenyl,
adamantyl, and substituted adamantyl are independently selected
from the group consisting of alkyl, aryl, CF.sub.3, CH.sub.3,
OCH.sub.3, OH, CN, CONH.sub.2, CONHR, CONR1R2, COOR and COOH.
[0045] Synthesis of the Combinatorial Library
[0046] The diacyl benzimidazole compounds of the present invention
were prepared using the following synthesis reactions, wherein the
desired acid chlorides are selected from the R1 and R2 groups
provided in the Table. 47
[0047] Synthesis of 3: 4-Nitro-1,2-phenylenediamine (10 g, 65.3
mmol) and 4-aminobenzoic acid (8.95 g, 65.3 mmol) were taken in a
round bottomed flask and phosphorus oxychloride (95 ml) was added
slowly. The reaction mixture was allowed to stir under reflux
conditions. After 18 h, the reaction was allowed to cool and then
poured slowly into an ice water mixture in an Erlenmeyer flask with
vigorous stirring. Greenish yellow precipitate fell out which was
then filtered and washed with copious amounts of water. The residue
was then dried to obtain 16.9 g of crude desired product. Mass
spectrum analysis (positive ion) indicated presence of 3.
[0048] Synthesis of 4: Benzimidazole 3 (800 mg, 3.14 mmol) was
dissolved in dry pyridine (5 ml) in a scintillation vial and the
desired acid chlorides (1.1 eq) were added slowly. The reactions
were carried out in an oven at 60C. After 16 h, the reaction was
cooled to RT and DI water was added. Precipitation took place,
which was filtered off, washed with water and air dried. The
aqueous layer was extracted with EtOAc (6.times.50 ml), dried over
anhydrous Na.sub.2SO.sub.4 and the solvent was removed in vacuo to
result in a colored solid. By positive ion MS the desired
monoacylated product was found to be present in the initial
precipitate as well as in the organic layer. Hence the solid
residues obtained were combined and used as such for the reduction
step.
[0049] Reduction of 4: Crude monoacylated nitro benzimidazole 4
(1.22 g, 3.40 mmol) was dissolved in MeOH (20 ml) and minimum
amount of THF was added for complete dissolution to occur.
Catalytic amount of 10% Pd on C was added and the solution was
degassed and allowed to stir at 3.4 atm pressure under H.sub.2
atmosphere for 4 h. Upon completion of reaction as observed via
TLC, the reaction mixture was filtered through celite and the
solvent was removed under reduced pressure to afford 979 mg of
crude residue.
[0050] General Organic Analyses
[0051] HPLC/MS data was obtained using a Gilson semi-prep HPLC with
a Gilson 170 Diode Array UV detector and PE Sciex API 100LC MS
based detector. A Waters 600E with a Waters 490E UV detector was
also used for recording HPLC data. The compounds were eluted with a
gradient of CH.sub.3CN (with 0.0035% TFA) and H.sub.2O (with 0.01%
TFA). Both HPLC instruments used Advantage C18 60A 5 .mu.50
mm.times.4.6 mm columns from Thomson Instrument Company. Mass
spectra were obtained by direct injection and electrospray
ionization on a PE Sciex API 100LC MS based detector. Thin layer
chromatography was performed using Merck 60F-254 aluminum backed
precoated plates. Flash chromatography was carried out on Merck
silica gel 60 (230-400 mesh) purchased from EM Scientific.
[0052] Syntheses of Symmetrical Diamides
[0053] The symmetrical diacyl benzimidazole compounds of the
present invention were generally prepared from
2-(4-aminophenyl)-5-aminobenzimida- zole, which was obtained by
reduction of 2-(4-nitrophenyl)-6-nitrobenzimid- azole. 48
[0054] 2-(4-nitrophenyl)-6-nitrobenzimidazole
[0055] The dinitro benzimidazole was prepared as follows: a mixture
of 4-nitrophenylenediamine (6.4 g, 41.83 mmol) and 4-nitrobenzoic
acid (7.86 g, 47 mmol) was dissolved in POCl.sub.3 (250 ml) and
heated to reflux for 2 h. The reaction mixture was cooled, poured
on to ice, and stirred for 30 min. The resulting solid was filtered
and washed with methanol and sodium bicarbonate to remove unreacted
acid and allowed to dry overnight to give the desired product as a
brown solid (5.8 g). The product was characterized by electrospray
mass spectroscopy (mp>300.degree. C.).
[0056] 2-(4-Aminophenyl)-5-aminobenzimidazole was prepared by
suspending the above solid (75 g) in THF (75 ml), to which was
added Pd-C (10% Pd by weight). The flask was purged with hydrogen
and stirred under a balloon of hydrogen over night. TLC and MS
showed starting material was still present so the reaction was
allowed to continue over the weekend. TLC indicated complete
reaction, the reaction was filtered through celite and washed with
methanol. The solvent was removed under reduced pressure to give a
dark brown solid (0.37 g) that was used without further
purification. 49
[0057] 2-(4-aminophenyl)-5-aminobenzimidazole
[0058] Alternatively, the 2-(4-aminophenyl)-5-aminobenzimidazole
was prepared by the following reduction:
2-(4-nitrophenyl)-6-nitrobenzimidazo- le (8.9 g, 31 mmole) was
suspended in concentrated HCl (100 ml) to which was added stannous
chloride (42.3 g 180 mmole). The reaction mixture was heated to
reflux for 5 hrs. The mixture was cooled to RT and the HCl salt of
the desired product was precipitated by the addition of ethanol.
The resulting solid was filtered, re-dissolved in water and the
solution made basic by the addition of concentrated ammonium
hydroxide. The resulting precipitate was filtered and dried
overnight under vacuum to yield the desired product as a gray solid
(6.023 g, 26.9 mmole, 87%). The product characterized by
electrospray mass spectroscopy and HPLC (mp. 222-227.degree.
C.).
[0059] 2-(4-Aminophenyl)-5-methoxy benzimidazole was synthesized
from 2-(4-nitrophenyl)-5-methoxy benzimidazole, which was prepared
as follows: 1,2-diamino-4-methoxybenzene (1.26 g, 10.0 mmole was
mixed with 4-nitrobenzoic acid (1.67 g, 9.8 mmole) and dissolved in
POCl.sub.3 (10 ml) and heated to reflux for 2.5 hours. The reaction
mixture was cooled and cautiously poured onto ice. The resulting
solid was filtered, washed with NaHCO.sub.3 and used without
further purification. 50
[0060] 2-(4-nitrophenyl)-5-methoxy benzimidazole
[0061] 2-(4-Aminophenyl)-5-methoxy benzimidazole was prepared by
dissolving 1 g of the above nitrobenzimidazole in 30%
Na.sub.2S9H.sub.2O (20 ml) with stirring at RT for 21 h. The
reaction mixture was diluted with water and extracted with EtOAc.
The combined organic extracts were dried over sodium sulfate and
concentrated under vacuum. The product was characterized by mass
spectroscopy. 51
[0062] 2-(4-aminophenyl)-5-methoxy benzimidazole
[0063] 2-(4-Aminophenyl)-5,6-dichloro benzimidazole was synthesized
from 2-(4-nitrophenyl)-5,6-dichloro benzimidazole, which was
prepared as follows: 1,2-diamino-4,5-dichlorobenzene (1.68 g, 10.0
mmole) was mixed with 4-nitrobenzoic acid (1.58 g, 9.3 mmole),
dissolved in POCl.sub.3 (10 ml), and heated to reflux for 2.5
hours. The reaction mixture was cooled and cautiously poured onto
ice. The resulting solid was filtered, washed with NaHCO.sub.3 and
used without further purification. 52
[0064] 2-(4-nitrophenyl)-5,6-dichloro benzimidazole
[0065] 2-(4-Aminophenyl)-5,6-dichloro benzimidazole was prepared by
dissolving 1 g of the above nitrobenzimidazole in 30%
Na.sub.2S9H.sub.2O (20 ml) with stirring at RT for 21 h. The
reaction mixture was diluted with water and extracted with EtOAc.
The combined organic extracts were dried over sodium sulfate and
concentrated under vacuum. The product was characterized by mass
spectroscopy. 53
[0066] 2-(4-Aminophenyl)-5,6-dichloro benzimidazole
[0067] 2-(4-aminophenyl)-7-methyl benzimidazole was synthesized
from 2-(4-nitrophenyl)-7-methyl benzimidazole, which was prepared
by mixing 1,2-diamino-3-methylbenzene (1.24 g, 10.0 mmole) with
4-nitrobenzoic acid (1.69 g, 9.8 mmole), dissolved in POCl.sub.3
(10 ml), and heated to reflux for 2.5 hours. The reaction mixture
was cooled and cautiously poured onto ice. The resulting solid was
filtered, washed with NaHCO.sub.3 and used without further
purification. 54
[0068] 2-(4-nitrophenyl)-7-methyl benzimidazole
[0069] 2-(4-Aminophenyl)-7-methyl benzimidazole was synthesized by
dissolving 1 g of the above nitrobenzimidazole in 30%
Na.sub.2S-9H.sub.2O (20 ml) with stirring at RT for 4.5 h. The
reaction mixture was diluted with water and extracted with EtOAc.
The combined organic extracts were dried over sodium sulfate and
concentrated under vacuum. The product was characterized by mass
spectroscopy. 55
[0070] 2-(4-aminophenyl)-7-methyl benzimidazole
[0071] 2-(4-Aminophenyl)-6-methyl benzimidazole was synthesized
from 2-(4-nitrophenyl)-6-methyl benzimidazole, which was prepared
by mixing 1,2-diamino-4-methylbenzene (1.24 g, 9.8 mmole) with
4-nitrobenzoic acid (1.6 g, 9.9 mmole) and dissolved in POCl.sub.3
(10 ml) and heated to reflux for 2.5 hours. The reaction mixture
was cooled and cautiously poured onto ice. The resulting solid was
filtered, washed with NaHCO.sub.3 and used without further
purification. 56
[0072] 2-(4-nitrophenyl)-6-methyl benzimidazole
[0073] 2-(4-Aminophenyl)-6-methyl benzimidazole was synthesized by
dissolving 1 g of the above nitrobenzimidazole in 30%
Na2S.9H.sub.2O (20 ml) with stirring at RT for 4.5 h. The reaction
mixture was diluted with water and extracted with EtOAc. The
combined organic extracts were dried over sodium sulfate and
concentrated under vacuum. The product was characterized by mass
spectroscopy. 57
[0074] 2-(4-aminophenyl)-6-methyl benzimidazole
[0075] 2-(4-Aminophenyl)-5,6-dimethyl benzimidazole was synthesized
from 2-(4-nitrophenyl)-5,6-dimethyl benzimidazole, which was
prepared by mixing 1,2-diamino-4,5-dimethylbenzene (1.38 g, 10.1
mmole) with 4-nitrobenzoic acid (1.69 g, 9.9 mmole) and dissolved
in POCl.sub.3 (10 ml) and heated to reflux for 2.5 hours. The
reaction mixture was cooled and cautiously poured onto ice. The
resulting solid was filtered, washed with NaHCO.sub.3 and used
without further purification. 58
[0076] 2-(4-nitrophenyl)-5,6-dimethyl benzimidazole
[0077] 2-(4-Aminophenyl)-5,6-dimethyl benzimidazole was synthesized
by dissolving 1 g of the above nitrobenzimidazole (31.1) in 30%
Na.sub.2S-9H.sub.2O (20 ml) with stirring at RT for 4.5 h. The
reaction mixture was diluted with water and extracted with EtOAc.
The combined organic extracts were dried over sodium sulfate and
concentrated under vacuum. The product was characterized by mass
spectroscopy. 59
[0078] 2-(4-aminophenyl)-5,6-dimethyl benzimidazole
[0079] The subsequent preparation of symmetrical diamides was
accomplished by one of the following methods:
[0080] Method A: 2-(4-Aminophenyl)-6-aminobenzimidazole (1 mmole)
was suspended in THF (5 ml) to which was added DIEA (2.5 mmole) and
mixture cooled to -78.degree. C. To the above cooled mixture was
added the acid chloride (2.5 mmole) and let warm to RT overnight.
Water (2 ml) is added to the reaction and extracted with EtOAc. The
combined organic extracts were combined washed with NaHCO.sub.3
(aq.) and concentrated under reduced pressure. The resulting
residue was purified on silica gel (hexanes/EtOAc or
MeOH/CH.sub.2Cl.sub.2) or reverse phase HPLC
(CH.sub.3CN/H.sub.2O).
[0081] Method B: 2-(4-Aminophenyl)-6-aminobenzimidazole (1 mmole)
and DMAP (cat.) was dissolved in pyridine (5 ml). To the above
solution was added the acid chloride (2.5 mmole) and the reaction
stirred overnight at 600 C. The reaction was cooled to room
temperature and water added to precipitate the product. The
resulting solid was collected by filtration with the solid being
washed by hexanes and water and NaHCO.sub.3 (aq.). The resulting
residue was purified on silica gel (hexanes/EtOAc or
MeOH/CH.sub.2Cl.sub.2) or reverse phase HPLC
(CH.sub.3CN/H.sub.2O).
[0082] Method C: 2-(4-Aminophenyl)-6-aminobenzimidazole (1 mmole)
was suspended in THF (10 ml) to which was added K.sub.2CO.sub.3
(2.5 mmole) in water (0.5 ml). and mixture cooled to -78.degree. C.
To the above cooled mixture was added the acid chloride (2.5 mmole)
and let warm to RT overnight. Water (10 ml) was added to the
reaction and extracted with EtOAc. The combined organic extracts
were combined washed with NaHCO.sub.3 (aq.) and concentrated under
reduced pressure. The resulting residue was purified on silica gel
(hexanes/EtOAc or MeOH/CH.sub.2Cl.sub.2) or reverse phase HPLC
(CH.sub.3CN/H.sub.2O).
[0083] Method D: The carboxylic acid (2.2 mmole), EDC (2.2 mmole)
and DMAP (cat.) was dissolved in hot pyridine. To the above
solution was added 2-(4-aminophenyl)-6-aminobenzimidazole (1 mmole)
and heated to 60.degree. C. overnight. The cooled reaction mixture
was partitioned between water and EtOAc. The organic layer was
washed with NaHCO.sub.3, dried over Na.sub.2SO.sub.4 and
concentrated under vacuum. The resulting residue was purified on
silica gel (hexanes/EtOAc or MeOH/CH.sub.2Cl.sub.2) or reverse
phase HPLC (CH.sub.3CN/H.sub.2O).
[0084] Benzimidazole Species
[0085] The following species encompassed within the disclosed
generic formula were synthesized and tested for their ability to
suppress IgE. The species are presented below.
606162636465666768697071727374757677787-
98081828384858687888990919293949596
[0086] Suppression of IgE Response
[0087] The inhibitory activity of the small molecules of the
present invention were assayed using both the ex vivo and in vivo
assays as described above. All of the compounds presented above
were active in suppressing the IgE response. In the ex vivo assay,
compounds in genuses I-XI produced 50% inhibition at concentrations
ranging from 1 pM to 100 .mu.M. In the in vivo assay, the compounds
were effective at concentrations ranging from less than about 0.01
mg/kg/day to about 100 mg/kg/day, when administered in divided
doses (e.g., two to four times daily) for at least two to seven
consecutive days. Thus, the small molecule inhibitors of the
present invention are disclosed as being useful in lowering the
antigen-induced increase in IgE concentration, and consequently, in
the treatment of IgE-dependent processes such as allergies in
general and allergic asthma in particular.
[0088] Treatment Regimens
[0089] The amount of the IgE inhibitor compound which may be
effective in treating a particular allergy or condition will depend
on the nature of the disorder, and can be determined by standard
clinical techniques. The precise dose to be employed in a given
situation will also depend on the choice of compound and the
seriousness of the condition, and should be decided according to
the judgment of the practitioner and each patient's circumstances.
Appropriate dosages can be determined and adjusted by the
practitioner based on dose response relationships between the
patient's IgE levels as well as standard indices of pulmonary and
hemodynamic changes. Moreover, those skilled in the art will
appreciate that dose ranges can be determined without undue
experimentation by following the protocol(s) disclosed herein for
ex vivo and in vivo screening (See for example Hasegawa et al., J.
Med. Chem. 40: 395-407 (1997) and Ohmori et al., Int. J.
Immunopharmacol. 15:573-579 (1993); employing similar ex vivo and
in vivo assays for determining dose-response relationships for IgE
suppression by naphthalene derivatives; incorporated herein by
reference).
[0090] Initially, suitable dosages of the compounds will generally
range from about 0.001 mg to about 300 mg per kg body weight per
day in divided doses, more preferably, between about 0.01 mg and
100 mg per kg body weight per day in divided doses. The compounds
are preferably administered systemically as pharmaceutical
formulations appropriate to such routes as oral, aerosol,
intravenous, subcutaneously, or by any other route which may be
effective in providing systemic dosing of the active compound. The
compositions of pharmaceutical formulations are well known in the
art. The treatment regimen preferably involves periodic
administration. Moreover, long-term therapy may be indicated where
allergic reactions appear to be triggered by continuous exposure to
the allergen(s). Daily or twice daily administration has been
effective in suppressing the IgE response to a single antigen
challenge in animals when carried out continuously from a period of
two to seven consecutive days. Thus, in a preferred embodiment, the
compound is administered for at least two consecutive days at
regular periodic intervals. However, the treatment regimen,
including frequency of dosing and duration of treatment may be
determined by the skilled practitioner, and modified as needed to
provide optimal IgE down-regulation, depending on nature of the
allergen, the dose, frequency, and duration of the allergen
exposure, and the standard clinical indices.
[0091] In one embodiment of the present invention, an
IgE-suppressing compound may be administered in conjunction with
one or more of the other small molecule inhibitors disclosed, in
order to produce optimal down-regulation of the patient's IgE
response. Further, it is envisioned that one or more of the
compounds of the present invention may be administered in
combination with other drugs already known or later discovered for
treatment of the underlying cause as well as the acute symptoms of
allergy or asthma. Such combination therapies envisioned within the
scope of the present invention include mixing of one or more of the
small molecule IgE-inhibitors together with one or more additional
ingredients, known to be effective in reducing at least one symptom
of the disease condition. In a variation, the small molecule
IgE-inhibitors herein disclosed may be administered separately from
the additional drugs, but during the same course of the disease
condition, wherein both the IgE-inhibitor(s) and the palliative
compounds are administered in accordance with their independent
effective treatment regimens.
[0092] While a number of preferred embodiments of the invention and
variations thereof have been described in detail, other
modifications and methods of use will be readily apparent to those
of skill in the art. Accordingly, it should be understood that
various applications, modifications and substitutions may be made
of equivalents without departing from the spirit of the invention
or the scope of the claims.
* * * * *