Cross-Reference to Related Applications
Field of the Invention
[0002] This invention is in the field of medicinal chemistry and relates to novel compounds,
and pharmaceutical compositions thereof, that inhibit caspases that mediate cell apoptosis
and inflammation. The invention also relates to the use of the compounds and pharmaceutical
compositions of this invention for the preparation of pharmaceutical compositions
for treating diseases where caspase activity is implicated.
Background of the Invention
[0003] Apoptosis, or programmed cell death, is a principal mechanism by which organisms
eliminate unwanted cells. The deregulation of apoptosis, either excessive apoptosis
or the failure to undergo it, has been implicated in a number of diseases such as
cancer, acute inflammatory and autoimmune disorders, ischemic diseases and certain
neurodegenerative disorders (see generally
Science, 1998, 281, 1283-1312;
Ellis et al., Ann. Rev. Cell. Biol., 1991, 7, 663).
[0004] Caspases are a family of cysteine protease enzymes that are key mediators in the
signaling pathways for apoptosis and cell disassembly (
Thornberry, Chem. Biol., 1998, 5, R97-R103). These signaling pathways vary depending on cell type and stimulus, but all apoptosis
pathways appear to converge at a common effector pathway leading to proteolysis of
key proteins. Caspases are involved in both the effector phase of the signaling pathway
and further upstream at its initiation. The upstream caspases involved in initiation
events become activated and in turn activate other caspases that are involved in the
later phases of apoptosis.
[0005] Caspase-1, the first identified caspase, is also known as interleukin converting
enzyme or "ICE." Caspase-1 converts precursor interleukin-1β ("pIL-1β") to the pro-inflammatory
active form by specific cleavage of pIL-1β between Asp-116 and Ala-117. Besides caspase-1
there are also eleven other known human caspases, all of which cleave specifically
at aspartyl residues. They are also observed to have stringent requirements for at
least four amino acid residues on the N-terminal side of the cleavage site.
[0006] The caspases have been classified into three groups depending on the amino acid sequence
that is preferred or primarily recognized. The group of caspases, which includes caspases
1, 4, and 5, has been shown to prefer hydrophobic aromatic amino acids at position
4 on the N-terminal side of the cleavage site. Another group which includes caspases
2, 3 and 7, recognize aspartyl residues at both positions 1 and 4 on the N-terminal
side of the cleavage site, and preferably a sequence of Asp-Glu-X-Asp. A third group,
which includes caspases 6, 8, 9 and 10, tolerate many amino acids in the primary recognition
sequence, but seem to prefer residues with branched, aliphatic side chains such as
valine and leucine at position 4.
[0007] The caspases have also been grouped according to their perceived function. The first
subfamily consists of caspases-1 (ICE), 4, and 5. These caspases have been shown to
be involved in pro-inflammatory cytokine processing and therefore play an important
role in inflammation. Caspase-1, the most studied enzyme of this class, activates
the IL-1β precursor by proteolytic cleavage. This enzyme therefore plays a key role
in the inflammatory response. Caspase-1 is also involved in the processing of interferon
gamma inducing factor (IGIF or IL-18) which stimulates the production of interferon
gamma, a key immunoregulator that modulates antigen presentation, T-cell activation
and cell adhesion.
[0008] The remaining caspases make up the second and third subfamilies. These enzymes are
of central importance in the intracellular signaling pathways leading to apoptosis.
One subfamily consists of the enzymes involved in initiating events in the apoptotic
pathway, including transduction of signals from the plasma membrane. Members of this
subfamily include caspases-2, 8, 9 and 10. The other subfamily, consisting of the
effector capsases 3, 6 and 7, are involved in the final downstream cleavage events
that result in the systematic breakdown and death of the cell by apoptosis. Caspases
involved in the upstream signal transduction activate the downstream caspases, which
then disable DNA repair mechanisms, fragment DNA, dismantle the cell cytoskeleton
and finally fragment the cell.
[0009] A four amino acid sequence primarily recognized by the caspases has been determined
for enzyme substrates.
Talanian et al., J. Biol. Chem. 272, 9677-9682, (1997);
Thornberry et al., J. Biol. Chem. 272, 17907-17911, (1997). Knowledge of the four amino acid sequence primarily recognized by the caspases
has been used to design caspase inhibitors. Reversible tetrapeptide inhibitors have
been prepared having the structure CH
3CO-[P4]-[P3]-[P2]-CH(R)CH
2CO
2H where P2 to P4 represent an optimal amino acid recognition sequence.and R is an
aldehyde, nitrile or ketone capable of binding to the caspase cysteine sulfhydryl.
Rano and Thornberry, Chem. Biol. 4, 149-155 (1997);
Mjalli, et al., Bioorg. Med. Chem. Lett. 3, 2689-2692 (1993);
Nicholson et al., Nature 376, 37-43 (1995). Irreversible inhibitors based on the analogous tetrapeptide recognition sequence
have been prepared where R is an acyloxymethylketone-COCH
2OCOR'. R' is exemplified by an optionally substituted phenyl such as 2,6-dichlorobenzoyloxy
and where R is COCH
2X where X is a leaving group such as F or C1.
Thornberry et al., Biochemistry 33, 3934 (1994);
Dolle et al., J Med. Chem. 37, 563-564 (1994).
[0010] The utility of caspase inhibitors to treat a variety of mammalian disease states
associated with an increase in cellular apoptosis has been demonstrated using peptidic
caspase inhibitors. For example, in rodent models, caspase inhibitors have been shown
to reduce infarct size and inhibit cardiomyocyte apoptosis after myocardial infarction,
to reduce lesion volume and neurological deficit resulting from stroke, to reduce
post-traumatic apoptosis and neurological deficit in traumatic brain injury, to be
effective in treating fulminant liver destruction, and to improve survival after endotoxic
shock.
Yaoita et al., Circulation, 97, 276 (1998);
Endres et al., J Cerebral Blood Flow and Metabolism, 18, 238, (1998);
Cheng et al., J. Clin. Invest., 101, 1992 (1998);
Yakovlev et al., J Neuroscience, 7, 7415 (1997);
Rodriquez et al., J. Exp. Med., 184, 2067 (1996);
Grobmyer et al., Mol. Med., 5, 585 (1999).
[0011] In general, the peptidic inhibitors described above are very potent against some
of the caspase enzymes. However, this potency has not always been reflected in cellular
models of apoptosis. In addition peptide inhibitors are typically characterized by
undesirable pharmacological properties such as poor oral absorption, poor stability
and rapid metabolism. Plattner and Norbeck, in
Drug Discovery Technologies, Clark and Moos, Eds. (Ellis Horwood, Chichester, England, 1990).
[0012] Recognizing the need to improve the pharmacological properties of the peptidic caspase
inhibitors, peptidomimetic and non-natural amino acid peptide inhibitors have been
reported.
[0013] EP618223 discloses peptides inhibiting interleukin 1-beta release of the formula:

wherein R is a hydrogen, an amino or hydroxy protecting group or optionally ring substituted
benzyloxy, A
3 is-CH
2-X
1-CO-Y
1; -CH
2-O-Y
2; or -CH
2-S-Y
3; wherein X
1 is O or S and Y
1, Y
2, and Y
3 are as defined in the specification.
[0014] WO 97/22619 discloses ICE inhibitors which contain a piperazic acid unit:

wherein R
1 is CO
2H or a bioisosteric replacement of CO
2H; R
2 is H, alkyl, aryl, heteroaryl, or CH
2Y; R
3 is H, R, COOR, CON(R)
2, SO
2R, SO
2NHR, COCH
2OR, COCOR, COCOOR or COCON(R)
2; Y is OR, SR, or -OC=O(R); and R is H, aromatic or alkyl group.
[0015] WO 9816502 discloses ICE inhibitors which contain a proline unit:

wherein R
1 is alkyl or N(R
3)
2; R
2 is H, or OCH
2Aryl; and R
3 is selected from various groups.
[0017] WO95/3538 relates to compounds which are inhibitors of the IL-1ß converting enzyme (ICE), compositions
comprising them and their use against IL-1 mediated diseases.
[0018] WO98/11109 is directed to tricyclic ICE/ced-3 family inhibitor compounds, compositions comprising
them and their use for the treatment of inflammatory, autoimmune and neurodegenerative
diseases and for the prevention of ischemic injuries.
[0019] WO95/33751 discloses fused bicyclic lactams as ICE enzyme inhibitors, compositions comprising
them and their use for the treatment of inflammatory and immune based diseases.
[0020] While a number of caspase inhibitors have been reported, it is not clear whether
they possess the appropriate pharmacological properties to be therapeutically useful.
Therefore, there is a continued need for small molecule caspase inhibitors that are
potent, stable, and penetrate membranes to provide effective inhibition of apoptosis
in vivo. Such compounds would be extremely useful in treating the aforementioned diseases
where caspase enzymes play a role.
Summary of the Invention
[0021] It has now been found that compounds of this invention and pharmaceutical compositions
thereof are effective as inhibitors of caspases and cellular
apoptosis. These compounds have the general formula I:

wherein:
R1 is -CH2Y; wherein Y is F
R2 is CO2H, CH2CO2H, or an ester, or amide thereof;
X2-X1 is N=C, CH=C or C(=O)-N
Ring C is a fused unsubstituted benzene ring;
n is 0, or 1; and
any methylene position in Ring A is optionally and independently substituted by =O,
or one or two groups selected from halogen, C1-4 alkyl, or C1-4 alkoxy.
[0022] The compounds of this invention have potent inhibition properties across a range
of caspase targets with good efficacy in cellular models of apoptosis, and they are
useful for treating caspase-mediated diseases such as those described below.
Detailed Description of the Invention
[0023] This invention provides novel compounds, and pharmaceutically acceptable derivatives
thereof, that are useful as caspase inhibitors. The invention also provides the use
of the compounds for the preparation of a pharmaceutical composition for inhibiting
caspase activity and for treating caspase-mediated disease states in mammals. These
compounds have the general formula I:

wherein:
R1 is -CH2Y;
Y is F;
R2 is CO2H, or an ester, or amide thereof;
X2-X1 is N=C, CH=C or C(=O)-N;
Ring C is a fused unsubstituted benzene ring;
n is 0 or 1; and
each methylene carbon in Ring A is optionally and independently substituted by =O,
or by one or more halogen, C1-4 alkyl, or C1-4 alkoxy.
[0024] When the R
2 group is in the form of an ester or amide, the present compounds undergo metabolic
cleavage to the corresponding carboxylic acids, which are the active caspase inhibitors.
Because they undergo metabolic cleavage, the precise nature of the ester or amide
group is not critical to the working of this invention. The esters in structure of
the R
2 group are selected from esters of R
2 carboxylic acids selected from C
1-12 aliphatic, selected from as C
1-6 alkyl or C
3-10 cycloalkyl, aryl, selected from phenyl, aralkyl, selected from benzyl or phenethyl,
heterocyclyl or heterocyclylalkyl, whereby are selected from R
2 heterocyclyl rings include, are selected from include, 5-6 membered heterocyclic
rings having one or two heteroatoms selected from piperidinyl, piperazinyl, or morpholinyl.
[0025] Amides of R
2 carboxylic acids may be primary, secondary or tertiary. Suitable substituents on
the amide nitrogen are, one or more groups independently selected from the aliphatic,
aryl, aralkyl, heterocyclyl or heterocyclylalkyl groups described above for the R
2 ester alcohol.
[0026] Compounds of this invention where R
2 is CO
2H, γ ketoacids or δ ketoacids respectively, may exist in solution as either the open
form 1 or the cyclized hemiketal form 2 (y=1 for γ-ketoacids, y=2 for δ-ketoacids).
The representation herein of either isomeric form is meant to include the other.

[0027] Likewise it will be apparent to one skilled in the art that certain compounds of
this invention may exist in tautomeric forms or hydrated forms, all such forms of
the compounds being within the scope of the invention. Unless otherwise stated, structures
depicted herein are also meant to include all stereochemical forms of the structure;
i.e., the R and S configurations for each asymmetric center. Therefore, single stereochemical
isomers as well as enantiomeric and diastereomeric mixtures of the present compounds
are within the scope of the invention. Unless otherwise stated, structures depicted
herein are also meant to include compounds that differ only in the presence of one
or more isotopically enriched atoms. For example, compounds having the present structures
except for the replacement of a hydrogen by a deuterium or tritium, or the replacement
of a carbon by a
13C- or
14C-enriched carbon are within the scope of this invention.
[0028] The compounds of this invention have inhibition properties across a range of caspase
targets with good efficacy in cellular models of apoptosis. In addition, these compounds
are expected to have good cell penetration and pharmacokinetic properties and, as
a consequence of their potency, have good efficacy against diseases where caspases
are implicated.
[0029] Ring C is a fused unsubstituted benzene ring.
[0030] Preferred compounds of this invention are compounds of formula I that have the following
features:
- (a) R1 is -CH2Y wherein Y is F;
- (b) R2 is CO2H or an ester thereof;
- (c) X2-X1 is N=C, CH=C, or C(=O)-N;
- (d) Ring C is a benzene; and
- (e) n is 0 or 1.
[0031] Representative tricyclic ring systems of formula I include, those provided in Table
1. Table 2 that follows shows specific representative examples of formula I compounds.
Table 1. Examples of Tricyclic Systems of Formula I where Ring C is a benzo-fused
ring
Table 2. Examples of Formula I compounds
| Example |
R1 |
R2 |
Ring C |
n |
X1 |
X2 |
| |
CH2F |
CO2H |
benzo |
0 |
C |
N |
| 2 |
CH2F |
CO2H |
benzo |
1 |
C |
N |
| 3 |
CH2F |
CO2H |
benzo |
0 |
C |
C-H |
| 4 |
CH2F |
CO2H |
benzo |
1 |
C |
C-H |
| 5 |
CH2F |
CO2H |
benzo |
1 |
N |
C=O |
| 6 |
CH2F |
CO2H |
pyrazino |
1 |
N |
C=O |
[0032] The compounds of this invention may be prepared in general by methods known to those
skilled in the art for analogous compounds, as illustrated by the general Scheme I
below and by the preparative examples that follow.

[0033] Tricyclic ring system 1 is generally prepared as an ester (see Schemes 2-4). Ester
1 (R is any suitable organic radical) is first hydrolyzed using base or, when the ester
is a t-butyl group, using trifluoroacetic acid. The acid
2 is then coupled with the amino alcohol
3. Depending on the nature of R
1 and R
2 an amino ketone may be used, in place of the amino alcohol, which avoids the subsequent
oxidation step. In the case of fluoromethyl ketones where R
1 is CH
2F, the amino alcohol
3 may be obtained according to the method of
Revesz et al., Tetrahedron Lett., 1994, 35, 9693. Finally the hydroxyl in compound
4 is oxidized and the compound treated appropriately according to the nature of R
2. For example, if the product
I requires R
2 to be a carboxylic acid, then R
2 in
3 is preferably an ester and the final step in the scheme is hydrolysis (alternatively
if the ester is a tert-butyl ester, the final step is treatment with trifluoroacetic
acid).
[0034] The parent tricyclic esters
1 may be prepared as outlined in Schemes II, III and IV for
1a,
1b and
1c respectively, as shown below.

[0035] The tricyclic esters
1a where X
2-X
1 is N=C, can be prepared as outlined in Scheme II. The starting aminoacid
5 is first converted into the diazonium salt, and then treated with sodium azide in
aqueous sodium acetate to give the azidoacid
6. The azidoacid
6 is then coupled to the lactam
7 by condensation of the acid chloride of
6 (prepared in situ from reaction of
6 with thionyl chloride), with the lithium salt of lactam
7 (prepared by reaction of LDA with 7) to give
8. Intramolecular aza-Wittig reaction of
8, using triphenylphosphine and refluxing xylene, affords the tricyclic esters
1a.
[0036] The tricyclic esters
1b, where X
1 and X
2 are both carbon, can be prepared as outlined in Scheme III.

[0037] The starting ortho substituted aromatic acid
9 is first brominated (NBS in chloroform) to provide bromide
10. The acid chloride of
10 (prepared by reaction of
10 with thionyl chloride) is then reacted with the lithium salt of lactam
7 (prepared by reaction of LDA with lactam
7) to give
11. Reaction of
11 with triethylphosphite provides
12, which undergoes an intramolecular Wittig-Horner reaction in the presence of a base
in THF to afford tricyclic esters
1b.

[0038] The tricyclic esters
1c, where X
2-X
1 is C (=O) -N, can be prepared by reaction of heterocyclic esters of the type 13 with
aromatic anhydrides
14, as outlined in Scheme IV above.
[0039] The parent heterocyclic esters
7 and
13 used in Schemes II, III and IV, or their acids or derivatives, are either commercially
available or can be prepared using standard methods. The parent heterocyclic acid
7, where n is zero, is commercially available (pyroglutamic acid). In addition, pyroglutamic
acid can be substituted at position 4 using various electrophiles, according standard
methods (
J. Ezquerra et al., Tetrahedron, 1993, 49, 8665-8678;
J.D. Charrier et al., Tetrahedron Lett., 1998, 39, 2199-2202). The parent heterocyclic ester
7, where n is one, can be prepared according to the procedures described in the experimental
section below. The parent heterocyclic acid 7, where n is two, can be prepared by
standard methods (
Perrotti et al., Ann.Chim (Rome), 1966, 56, 1368). The parent heterocyclic esters
13 where n is zero can be prepared by literature methods (
M.R. Mish et al., J. Am. Chem. Soc., 1997, 119, 35, 8379-8380); and the parent heterocyclic esters
13 where n is one also can be prepared by literature methods (
Y. Nakamura et al., Chem. Lett., 1991, 11, 1953-1956).
[0040] The compounds of this invention are designed to inhibit caspases. Therefore, the
compounds of this invention can be assayed for their ability to inhibit apoptosis,
the release of IL-1β or caspase activity directly. Assays for each of the activities
are known in the art and are described below in detail in the Testing section.
[0041] One embodiment of this invention relates to a composition comprising a compound of
formula I or a pharmaceutically acceptable derivative thereof, and a pharmaceutically
acceptable carrier.
[0042] If pharmaceutically acceptable salts of the compounds of this invention are utilized
in these compositions, those salts are preferably derived from inorganic or organic
acids and bases. Included among such acid salts are the following: acetate, adipate,
alginate, aspartate, benzoate, benzene sulfonate, bisulfate, butyrate, citrate, camphorate,
camphor sulfonate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate,
fumarate, glucoheptanoate, glycerophosphate, hemisulfate, heptanoate, hexanoate, hydrochloride,
hydrobromide, hydroiodide, 2-hydroxyethanesulfonate, lactate, maleate, methanesulfonate,
2-naphthalenesulfonate, nicotinate, oxalate, pamoate, pectinate, persulfate, 3-phenyl-propionate,
picrate, pivalate, propionate, succinate, tartrate, thiocyanate, tosylate and undecanoate.
Base salts include ammonium salts, alkali metal salts, such as sodium and potassium
salts, alkaline earth metal salts, such as calcium and magnesium salts, salts with
organic bases, such as dicyclohexylamine salts, N-methyl-D-glucamine, and salts with
amino acids such as arginine, lysine, and so forth.
[0043] Also, the basic nitrogen-containing groups can be quaternized with such agents as
lower alkyl halides, such as methyl, ethyl, propyl, and butyl chloride, bromides and
iodides; dialkyl sulfates, such as dimethyl, diethyl, dibutyl and diamyl sulfates,
long chain halides such as decyl, lauryl, myristyl and stearyl chlorides, bromides
and iodides, aralkyl halides, such as benzyl and phenethyl bromides and others. Water
or oil-soluble or dispersible products are thereby obtained.
[0044] A "pharmaceutically acceptable derivative means any pharmaceutically acceptable salt,
ester, salt of an ester or other derivative of a compound of this invention which,
upon administration to a recipient, is capable of providing, either directly or indirectly,
a compound of this invention or an inhibitorily active metabolite or residue thereof.
Particularly favored derivatives or prodrugs are those that increase the bioavailability
of the compounds of this invention when such compounds are administered to a patient
(e.g., by allowing an orally administered compound to be more readily absorbed into
the blood) or which enhance delivery of the parent compound to a biological compartment
(e.g., the brain or lymphatic system) relative to the parent species.
[0045] Pharmaceutically acceptable carriers that may be used in these compositions include,
but are not limited to, ion exchangers, alumina, aluminum stearate, lecithin, serum
proteins, such as human serum albumin, buffer substances such as phosphates, glycine,
sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable
fatty acids, water, salts or electrolytes, such as protamine sulfate, disodium hydrogen
phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica,
magnesium trisilicate, polyvinyl pyrrolidone, cellulose-based substances, polyethylene
glycol, sodium carboxymethylcellulose, polyacrylates, waxes, polyethylene-polyoxypropylene-block
polymers, polyethylene glycol and wool fat.
[0046] According to a preferred embodiment, the compositions of this invention are formulated
for pharmaceutical administration to a mammal, preferably a human being.
[0047] Such pharmaceutical compositions of the present invention may be administered orally,
parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally
or via an implanted reservoir. The term "parenteral" as used herein includes subcutaneous,
intravenous, intramuscular, intra-articular, intra-synovial, intrasternal, intrathecal,
intrahepatic, intralesional and intracranial injection or infusion techniques. Preferably,
the compositions are administered orally or intravenously.
[0048] Sterile injectable forms of the compositions of this invention may be aqueous or
oleaginous suspension. These suspensions may be formulated according to techniques
known in the art using suitable dispersing or wetting agents and suspending agents.
The sterile injectable preparation may also be a sterile injectable solution or suspension
in a non-toxic parenterally acceptable diluent or solvent, for example as a solution
in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed
are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile,
fixed oils are conventionally employed as a solvent or suspending medium. For this
purpose, any bland fixed oil may be employed including synthetic mono- or di-glycerides.
Fatty acids, such as oleic acid and its glyceride derivatives are useful in the preparation
of injectables, as are natural pharmaceutically-acceptable oils, such as olive oil
or castor oil, especially in their polyoxyethylated versions. These oil solutions
or suspensions may also contain a long-chain alcohol diluent or dispersant, such as
carboxymethyl cellulose or similar dispersing agents which are commonly used in the
formulation of pharmaceutically acceptable dosage forms including emulsions and suspensions.
Other commonly used surfactants, such as Tweens, Spans and other emulsifying agents
or bioavailability enhancers which are commonly used in the manufacture of pharmaceutically
acceptable solid, liquid, or other dosage forms may also be used for the purposes
of formulation.
[0049] The pharmaceutical compositions of this invention may be orally administered in any
orally acceptable dosage form including, but not limited to, capsules, tablets, aqueous
suspensions or solutions. In the case of tablets for oral use, carriers that are commonly
used include lactose and corn starch. Lubricating agents, such as magnesium stearate,
are also typically added. For oral administration in a capsule form, useful diluents
include lactose and dried cornstarch. When aqueous suspensions are required for oral
use, the active ingredient is combined with emulsifying and suspending agents. If
desired, certain sweetening, flavoring or coloring agents may also be added.
[0050] Alternatively, the pharmaceutical compositions of this invention may be administered
in the form of suppositories for rectal administration. These can be prepared by mixing
the agent with a suitable non-irritating excipient which is solid at room temperature
but liquid at rectal temperature and therefore will melt in the rectum to release
the drug. Such materials include cocoa butter, beeswax and polyethylene glycols.
[0051] The pharmaceutical compositions of this invention may also be administered topically,
especially when the target of treatment includes areas or organs readily accessible
by topical application, including diseases of the eye, the skin, or the lower intestinal
tract. Suitable topical formulations are readily prepared for each of these areas
or organs.
[0052] Topical application for the lower intestinal tract can be effected in a rectal suppository
formulation (see above) or in a suitable enema formulation. Topically-transdermal
patches may also be used.
[0053] For topical applications, the pharmaceutical compositions may be formulated in a
suitable ointment containing the active component suspended or dissolved in one or
more carriers. Carriers for topical administration of the compounds of this invention
include, but are not limited to, mineral oil, liquid petrolatum, white petrolatum,
propylene glycol, polyoxyethylene, polyoxypropylene compound, emulsifying wax and
water. Alternatively, the pharmaceutical compositions can be formulated in a suitable
lotion or cream containing the active components suspended or dissolved in one or
more pharmaceutically acceptable carriers. Suitable carriers include, but are not
limited to, mineral oil, sorbitan monostearate, polysorbate 60, cetyl esters wax,
cetearyl alcohol, 2-octyldodecanol, benzyl alcohol and water.
[0054] For ophthalmic use, the pharmaceutical compositions may be formulated as micronized
suspensions in isotonic, pH adjusted sterile saline, or, preferably, as solutions
in isotonic, pH adjusted sterile saline, either with our without a preservative such
as benzylalkonium chloride. Alternatively, for ophthalmic uses, the pharmaceutical
compositions may be formulated in an ointment such as petrolatum.
[0055] The pharmaceutical compositions of this invention may also be administered by nasal
aerosol or inhalation. Such compositions are prepared according to techniques well
known in the art of pharmaceutical formulation and may be prepared as solutions in
saline, employing benzyl alcohol or other suitable preservatives, absorption promoters
to enhance bioavailability, fluorocarbons, and/or other conventional solubilizing
or dispersing agents.
[0056] The above-described compositions are particularly useful in therapeutic applications
relating to an IL-1 mediated disease, apoptosis mediated disease, an inflammatory
disease, autoimmune disease, destructive bone disorder, proliferative disorder, infectious
disease, degenerative disease, disease associated with cell death, excess dietary
alcohol intake disease, and viral mediated disease. Such diseases include uveitis,
inflammatory peritonitis, osteoarthritis, pancreatitis, asthma, adult respiratory
distress syndrome, glomerulonephritis, rheumatoid arthritis, systemic lupus erythematosus,
scleroderma, chronic thyroiditis, Grave's disease, autoimmune gastritis, diabetes,
autoimmune hemolytic anemia, autoimmune neutropenia, thrombocytopenia, chronic active
hepatitis, myasthenia gravis, inflammatory bowel disease, Crohn's disease, psoriasis,
atopic dermatitis, scarring, graft vs host disease, organ transplant rejection, osteoporosis,
leukemias and related disorders, myelodysplastic syndrome, multiple myeloma-related
bone disorder, acute myelogenous leukemia, chronic myelogenous leukemia, metastatic
melanoma, Kaposi's sarcoma, multiple myeloma, haemorrhagic shock, sepsis, septic shock,
burns, Shigellosis, Alzheimer's disease, Parkinson's disease, Huntington's disease,
Kennedy's disease, prion disease, cerebral ischemia,epilepsy, myocardial ischemia,
acute and chronic heart disease, myocardial infarction, congestive heart failure,
atherosclerosis, coronary artery bypass graft, spinal muscular atrophy, amyotrophic
lateral sclerosis, multiple sclerosis, HIV-related encephalitis, aging, alopecia,
neurological damage due to stroke, ulcerative colitis, traumatic brain injury, spinal
cord injury, hepatitis-B, hepatitis-C, hepatitis-G, yellow fever, dengue fever, or
Japanese encephalitis, various forms of liver disease, renal disease, polyaptic kidney
disease, H. pylori-associated gastric and duodenal ulcer disease, HIV infection, tuberculosis,
and meningitis. The compounds and compositions are also useful in treating complications
associated with coronary artery bypass grafts and as a component of immunotherapy
for the treatment of various forms of cancer.
[0057] The amount of compound present in the above-described compositions should be sufficient
to cause a detectable decrease in the severity of the disease or in caspase activity
and/or cell apoptosis, as measured by any of the assays described in the examples.
[0058] The compounds of this invention are also useful in methods for preserving cells,
such as may be needed for an organ transplant or for preserving blood products. Similar
uses for caspase inhibitors have been reported (
Schierle et al., Nature Medicine, 1999, 5, 97). The method involves treating the cells or tissue to be preserved with a solution
comprising the caspase inhibitor. The amount of caspase inhibitor needed will depend
on the effectiveness of the inhibitor for the given cell type and the length of time
required to preserve the cells from apoptotic cell death.
[0059] According to another embodiment, the compositions of this invention may further comprise
another therapeutic agent. Such agents include, but are not limited to, thrombolytic
agents such as tissue plasminogen activator and streptokinase. When a second agent
is used, the second agent may be administered either as a separate dosage form or
as part of a single dosage form with the compounds or compositions of this invention.
[0060] It should also be understood that a specific dosage and treatment regimen for any
particular patient will depend upon a variety of factors, including the activity of
the specific compound employed, the age, body weight, general health, sex, diet, time
of administration, rate of excretion, drug combination, and the judgment of the treating
physician and the severity of the particular disease being treated. The amount of
active ingredients will also depend upon the particular compound and other therapeutic
agent, if present, in the composition.
[0061] In a preferred embodiment, the invention provides the use of a pharmaceutically acceptable
composition described above for the preparation of a medicament for treating a mammal,
having one of the aforementioned diseases. In this embodiment, if the patient is also
administered another therapeutic agent or caspase inhibitor, it may be delivered together
with the compound of this invention in a single dosage form, or, as a separate dosage
form. When administered as a separate dosage form, the other caspase inhibitor or
agent may be administered prior to, at the same time as, or following administration
of a pharmaceutically acceptable composition comprising a compound of this invention.
[0062] In order that this invention be more fully understood, the following preparative
and testing examples are set forth. These examples are for the purpose of illustration
only and are not to be construed as limiting the scope of the invention in any way.
Experimental
[0063] In the following Examples,
19F NMR are
1H decoupled and all peaks are singlets unless otherwise stated.
Example 1
[3S/R(1S)]-3-(2,3-Dihydro-1H-9-oxo-pyrrolo[2,1-b]quinazolin-1-carboxamido)-5-fluoro-4-oxo-pentanoic acid
[0064]

Method A:
(S)-1-(2-Azido-benzoyl)-5-oxo-pyrrolidine-2-carboxylic acid tert-butyl ester
[0065]

A stirred solution of (2S)-5-oxo-proline tert-butyl ester (
T. Kolasa and M.J. Miller, J. Org. Chem., 1990, 55, 1711-1721) (1.13g, 6.13mmol) in anhydrous THF (15mL) was treated at -78°C with LDA (9.19mmol)
and the reaction was stirred for 15min. A solution of 2-azidobenzoyl chloride (
T. Okawa, T. Sugimori, S. Eguchi and A. Kakehi, Heterocycles, 1998, 47, 1, 375-382) (6.13mmol) in anhydrous THF (5mL) was then added dropwise and the reaction mixture
was stirred at -78°C for 1h before being quenched with saturated aq.NH
4Cl. The reaction was allowed to warm to room temperature and the organic layer was
washed with saturated aq.NH
4Cl, dried (MgSO
4), filtered and evaporated to give an oil which was purified by flash chromatography
(20% ethyl acetate in hexane) to afford the title compound as a pale yellow oil (1.67g,
82%):
1H NMR (400MHz, CDCl
3) δ 1.53 (9H, s), 2.14 (1H, m), 2.43 (1H, m), 2.55 (1H, m), 2.69 (1H, m), 4.79 (1H,
dd, J 9.2, 3.2Hz), 7.19-7.22 (2H, m), 7.36 (1H, m), 7.49 (1H, m).
13C NMR (100MHz, CDCl
3) δ 22.1 (CH
2), 28.3 (CH
3), 31.9 (CH
2), 59.3 (CH), 83.0 (C), 118.7 (CH), 125.0 (CH), 127.9 (C), 129.1 (CH), 131.9 (CH),
137.9 (C), 167.5 (C), 170.2 (C), 173.6 (C).
Method B:
(S)-2,3-Dihydro-1H-9-oxo-pyrrolo[2,1-b]quinazolin-1-carboxylic acid tert-butyl ester
[0066]

Triphenylphosphine (1.19g, 4.54mmol) was added portionwise to a solution of (3S/R)-5-fluoro-4-oxo-3-[((S)-9-oxo-1,2,3,9-tetrahydro-pyrrolo[2,1-b]quinazoline-1-carbonyl)-amino]-pentanoic
acid (1.36g, 4.12mmol) in xylene (60mL) at room temperature. The reaction mixture
was stirred at room temperature until the evolution of nitrogen ceased (approx.1h),
and then refluxed for 20h. The volatiles were evaporated and the residue was purified
by flash chromatography (50% ethyl acetate in hexane) to afford the title compound
as a colourless oil (1.05g, 89%):
1H NMR (400MHz, CDC13) δ 1.44 (9H, s), 2.26 (1H, m), 2.51 (1H, m), 3.06 (1H, m), 3.20
(1H, m), 4.99 (1H, dd, J 9.5, 2.8Hz), 7.39 (1H, m), 7.59 (1H, m), 7.68 (1H, m), 8.21
(1H, m).
13C NMR (100MHz, CDCl
3) δ 24.6 (CH
2), 28.3 (CH
3), 31. 5 (CH
2), 60.4 (CH), 83.3 (C), 120. 9 (C), 126.7 (CH), 126.9 (CH), 127.2 (CH), 134.7 (CH),
149.5 (C), 159.4 (C), 160.8 (C), 169.3 (C).
Method C:
(S)-2,3-Dihydro-1H-9-oxo-pyrrolo[2,1-b]quinazolin-1-carboxylic acid
[0067]

A solution of (1S)-9-oxo-1,2,3,9-tetrahydro-pyrrolo[2,1-b]quinazoline-1-carboxylic
acid tert-butyl ester (1.01g, 3.53 mmol) in TFA (20mL) was stirred at room temperature
for 4h. The mixture was concentrated under reduced pressure and the residue was dissolved
in dry DCM. This process was repeated several times to remove excess TFA. The gum
was triturated with diethyl ether, filtrated and washed several times with diethyl
ether to afford the title compound as a white powder (620mg, 76%):
1H NMR (400MHz, CD
3OD) δ 2.40 (1H, m), 2.71 (1H, m), 3.19 (1H, m), 3.27 (1H, m), 4.91 (exchangeable H),
5.19 (1H, dd, J 9.8, 2.8Hz), 7.53 (1H, m), 7.69 (1H, m), 7.85 (1H, m), 8.23 (1H, m).
Method D:
[3S/R, 4S/R, (1S)]-3-(2,3-Dihydro-1H-9-oxo-pyrrolo[2,1-b]quinazolin-1-carboxamido)-5-fluoro-4-hydroxy-pentanoic acid tert-butyl
ester
[0068]

A mixture of (S)-9-oxo-1,2,3,9-tetrahydro-pyrrolo[2,1-b]quinazoline-1-carboxylic acid
(0.10g, 0.434mmol), 3-amino-5-fluoro-4-hydroxy-pentanoic acid tert-butyl ester (0.099g,
0.48mmol), HOBt (0.065g, 0.48mmol), and DMAP (0.058g, 0.48mmol) in anhydrous THF (7mL)
was treated with EDC (0.092g, 0.48mmol) at 0°C with stirring. The reaction mixture
was allowed to warm to room temperature over 18h, after which it was concentrated
under reduced pressure to give a gum. This was purified by flash chromatography (EtOAc)
to afford the title compound as a white powder (155mg, 85%):
1H NMR (400MHz, DMSO-
d6) δ 1.41 (9H, m), 1.99-3.07 (6H, m), 3.53-4.55 (4H, m), 4.91-5.12 (1H, m), 5.37-5.62
(1H, m), 7.42 (1H, m), 7.63 (1H, m), 7.80 (1H, m), 8.08 (1H, m), 8.29-8.57 (1H, m);
19F NMR (376MHz, DMSO-
d6) δ -226.5, -226.5, -226.7, -226.7, -227.9, -228.0, -229.0, -229.0.
Method E:
[3S/R, (1S)]-3-(2,3-Dihydro-1H-9-oxo-pyrrolo[2,1-b]quinazolin-1-carboxamido)-5-fluoro-4-oxo-pentanoic acid tert-butyl
ester
[0069]

A solution of [3S/R(1S)]-5-fluoro-4-hydroxy-3-(9-oxo-1,2,3,9-tetrahydro-pyrrolo[2,1-b]quinazoline-1-carboxamido)-pentanoic
acid tert-butyl ester (0.147g, 0.35mmol) in anhydrous DCM (7mL) was treated with 1,1,1-triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1
H)-one (0.297g, 0.70mmol) with stirring at 0°C. The reaction mixture was allowed to
warm to room temperature and stirred for 18h after which it was diluted with DCM and
washed sequentially with 10% aq. Na
2SO
3.5H
2O, saturated aq. NaHCO
3 and brine. The organic phase was dried (Na
2SO
4) and concentrated to give a gum. This was purified by flash chromatography (5% MeOH
in DCM) to afford the title compound as a white solid (113mg, 77%):
1H NMR (400MHz, CDCl
3) δ 1.35-1.42 (9H, 2s), 2.37-2.62 (2H, m), 2.76-2.82 (1H, m), 2.88-2.97 (1H, m), 3.05-3.12
(1H, m), 3.35-3.42 (1H, m), 4.85-5.30 (4H, m), 7.41-7.89 (4H, m), 8.19-8.23 (1H, m);
13C NMR (100MHz, CDCl
3) 24.1/24.2 (CH
2), 28.2/28.3 (CH
3), 32.0 (CH
2), 36.6 (CH
2), 52.8/52.9 (CH), 60.8/60.8 (CH), 82.7/82.7 (C), 84.7/84.8 (CH
2F), 120.0 (C), 126.8 (CH), 126.9/127.0 (CH), 127.4 (CH), 135.1 (CH), 149.4/149.5 (C),
159.5 (C), 161.5/161.6 (C), 169.4/169.7 (C), 170.2/170.3 (C), 202.6/202.8 (C);
19F NMR (376MHz, CDCl
3) δ -231.9, -232.5.
Method F:
[3S/R(1S)]-3-(2,3-Dihydro-1H-9-oxo-pyrrolo[2,1-b]quinazolin-1-carboxamido)-5-fluoro-4-oxo-pentanoic acid
[0070]

TFA (4mL) was added to a stirred ice cold solution of [3S/R(1S)]-5-fluoro-4-oxo-3-(9-oxo-1,2,3,9-tetrahydropyrrolo[2,1-b]quinazoline-1-carboxamido)-pentanoic
acid tert-butyl ester (80mg, 0.19mmol) in anhydrous DCM (4mL). The mixture was stirred
at 0°C for 0.5h then at room temperature for 0.5h. The mixture was concentrated under
reduced pressure and then the residue was dissolved in dry DCM. This process was repeated
several times in order to remove excess TFA. The gum was triturated with diethyl ether
and the resulting solid collected by filtrated. The solid was washed several times
with diethyl ether to afford the title compound as a white solid (65mg, 94%): IR (solid)
2366, 1793, 1675, 1557, 1194, 1137cm
-1;
1H NMR (400MHz, DMSO-
d6) δ 2.04-2.13 (1H, m), 2.48-3.18 (5H, m), 4.33-5.42 (4H, m), 7.50 (1H, m), 7.64 (1H,
m), 7.82 (1H, m), 8.10 (1H, m), 9.06-9.14 (1H, m), 12.61 (1H, br s);
13C NMR (100MHz, DMSO-
d6) δ 24.2/24.3 (CH
2), 31.0/31.1 (CH
2), 34.6/34.8 (CH
2), 52.1/52.6 (CH), 60.0/60.3 (CH), 84.3/84.4 (2xd, J 177.9, 177.7Hz, CH
2F), 120.47 (C), 126.2 (CH), 126.5 (CH), 127.0 (CH), 134.9 (CH), 149.3 (C), 149.3 (C),
160.1 (C), 160.7/160.8 (C), 170.6 (C), 172.1/172.2 (C), 202.4/202.7 (2xd,
J 14.0, 14.0Hz, CO);
19F NMR (376MHz, DMSO-
d6) δ -226.6 (t), -226.9 (t), -230.2 (t), -231.6 (t), -233.0 (t), -233.1 (t), -75.5
(s, TFA, 1 eq); MS (FAB +ve, HR) calculated for C
17H
17N
3O
5F (MH+) 362.115224, found 362.115448.
Example 2
[3S/R(9S)]-5-Fluoro-4-oxo-3-(11-oxo-6,7,8,9,-tetrahydro-11H-pyrido[2,1-b]quinazolin-9-carboxamido)-pentanoic acid
[0071]

Method G:
(S)-Piperidine-1,2-dicarboxylic acid di-tert-butyl ester
[0072]

To a solution of (S)-piperidine-2-carboxylic acid tert-butyl ester (
M. Egbertson and S.J. Danishefsky, J. Org. Chem., 1989, 54, 1, 11-12) (5.78g, 31.2mmol) in CH
3CN (30mL) at 0°C was added DMAP (763mg, 6.2mmol) followed by BOC
2O (10.22g, 46.8mmol). The reaction mixture was allowed to warm to room temperature
and stirred for 20h. The solvents were evaporated under reduced pressure and the residue
was purified by flash chromatography (10% ethyl acetate in hexane). The title compound
was obtained as a colourless oil which crystallized upon standing (8.33g, 94%):
1H NMR (400MHz, CDCL
3) δ 1.21-1.32 (2H, m), 1.47-1.48 (18H, 2s), 1.59-1.72 (3H, m), 2.18 (1H, m), 2.85-3.00
(1H, m), 3.89-4.01 (1H, 2d,
J 11.9Hz), 4.47-4.58 (1H, 2br s).
Method H:
(S)-6-oxo-piperidine-1,2-dicarboxylic acid di-tert-butyl ester
[0073]

To a vigorously stirred solution of RuCl
3.H
2O (2.39g, 11.5mmol) and NaIO
4 (24.6g, 115.0mmol) in water (250mL) was added (S)-piperidine-1,2-dicarboxylic acid
di-tert-butyl ester (8.22g, 28.8mmol) in ethyl acetate (250mL) at room temperature.
After stirring for 4h, the reaction mixture was partitioned and the aqueous layer
washed with ethyl acetate. To the combined organic layers was added iPrOH (2.5mL)
and stirring was continued for 2 hours in order to destroy excess RuO
4. The precipitate was removed by filtration through a pad of celite and the filtrate
was evaporated under reduced pressure. The residue was purified by flash chromatography
(30% ethyl acetate in hexane) to afford the title compound as a pale yellow oil, which
crystallized upon standing (6.69g, 78%):
1H NMR (400MHz, CDCl
3) δ 1.49 (9H, s), 1.52 (9H, s), 1.75-1.82 (2H, m), 1.97-2.06 (1H, m), 2.15-2.21 (1H,
m), 2.41-2.61 (2H, m), 4.59 (1H, dd, J 3.5Hz)
Method I:
(S)-6-Oxo-piperidine-2-carboxylic acid tert-butyl ester
[0074]

To a solution of (S)-6-oxo-piperidine-1,2-dicarboxylic acid di-tert-butyl ester (6.30g,
21.0mmol) in ethyl acetate (50mL) was added 1.1-M HCl in ethyl acetate (28.7mL, 31.5mmol).
The reaction was stirred at room temperature for 1h, then washed with water, saturated
aq.NaHCO
3 and brine. The organic phase was dried (MgSO
4), filtered and evaporated to afford the title compound as a yellow oil which crystallized
upon standing (3.11g, 74%): 1H NMR (400MHz, CDCl3) δ 1.49 (9H, s), 1.74-1.94 (3H,
m), 2.18 (1H, m), 2.29-2.44 (2H, m), 3.95-3.98 (1H, m), 6.32 (1H, br s); 13C NMR (100MHz,
CDCl3) δ 19.9 (CH
2), 25.9 (CH
2), 28.4 (CH
3), 31.4 (CH
2), 55.7 (CH), 83.0 (C), 170.4 (C), 171.9 (C).
[3S/R(9S)]-5-Fluoro-4-oxo-3-(11-oxo-6,7,8,9,-tetrahydro-11H-pyrido[2,1-b]quinazolin-9-carboxamido)-pentanoic acid
[0075]

This was prepared from (S)-6-oxo-piperidine-2-carboxylic acid tert-butyl ester using
procedures similar to those described in methods A-F. The product was isolated as
a white solid (139mg, 95%): IR (solid) 2361, 2342, 1727, 1665, 1560, 1198, 1126cm
-1;
1H NMR (400MHz, DMSO-
d6) □ 1.66-1.78 (2H, m), 2.14-2.17 (2H, m), 2.72 (2H, m), 2.92 (2H, m), 4.52-4.60 (1H,
m), 4.80-5.30 (3H, m), 7.45-7.49 (1H, m), 7.58-7.60 (1H, m), 7.79-7.83 (1H, m), 8.06-8.09
(1H, m), 8.91 (1H, m), 12.51 (1H, br s);
13C NMR (100MHz, DMSO-
d6) δ 16.6/16.7 (CH
2), 26.2/26.2 (CH
2), 31.7/31.8 (CH
2), 55.3/55.7 (CH), 120.2/120.2 (C), 126.4 (CH), 126.4 (CH), 126.4 (CH), 134.9 (CH),
147.5 (C), 155.2 (C), 161.8 (C), 171.2 (C); Signals for Asp moiety too broad to be
detected in
1H and
13C NMR;
19F NMR (376MHz, DMSO-d
6) □ - 233.0 (br).
Example 3
[3S/R(3S)]-3-(2,3-Dihydro-1H-5-oxo-pyrrolo[1,2-b]isoquinolin-3-carboxamido)-5-fluoro-4-oxo-pentanoic acid
[0076]

Method J:
(S)-1-(2-Bromomethylbenzoyl)-5-oxo-pyrrolidine-2-carboxylic acid tert-butyl ester
[0077]

A stirred solution of α-bromotoluic acid (
L. Garuti, A. Ferranti, M. Roberti, E. Katz, R. Budriesi and A. Chiarini, Pharmazie,
1992, 47, 295-297) (1.0g, 4.7mmol) in SOCl
2 (3.4mL) was heated at 80°C for 2h. The solvent was evaporated and the residue dissolved
in toluene. This process was repeated several times, to remove excess SOCl
2, and to eventually afford the desired acid chloride as a yellow oil. A stirred solution
of (2S)-5-oxo-proline tert-butyl ester (
T. Kolasa, and M.J. Miller, J. Org. Chem., 1990, 55, 1711-1721) (861mg, 4.7mmol) in anhydrous THF (15mL) was treated at -78°C with LDA (7.0mmol)
and the reaction was stirred for 15min. A solution of the 2-α-bromotoluoyl chloride,
prepared above, in anhydrous THF (5mL) was then added dropwise and the reaction mixture
was stirred at -78°C for 1h before being quenched with saturated aq.NH
4Cl. The reaction was allowed to warm to room temperature and partitioned. The organic
layer was washed with saturated aq.NH
4Cl, dried (MgSO
4), filtered and evaporated to give an oil which was purified by flash chromatography
(30% ethyl acetate in hexane) to afford the title compound as a pale yellow oil (1.46g,
82%):
1H NMR (400MHz, CDCl
3) δ 1.55 (9H, s), 2.12-2.19 (1H, m), 2.38-2.59 (2H, m), 2.67-2.76 (1H, m), 4.54 (1H,
d,
J 10.5Hz), 4.70 (1H, d,
J 10.5Hz), 4.86 (1H, dd, J 9.0, 3.7Hz), 7.36-7.50 (4H, m).
13C NMR (100MHz, CDCl
3) □ 22.0 (CH
2), 28.4 (CH
3), 30.5 (CH
2), 32.0 (CH
2), 59.2 (CH), 83.2 (C), 128.3 (CH), 128.4 (CH), 131.0 (CH), 131.0 (CH), 135.2 (C),
135.5 (C), 169.6 (C), 170.4 (C), 173.6 (C).
Method K:
(S)-1-[2-(Diethoxyphosphorylmethyl)benzoyl]-5-oxo-pyrrolidine-2-carboxylic acid tert-butyl
ester
[0078]

A mixture of (S)-1-(2-bromomethyl-benzoyl)-5-oxo-pyrrolidine-2-carboxylic acid tert-butyl
ester (898mg, 2.4mmol) and triethylphosphite (432mg, 2.4mmol) was heated at 70°C for
4h. After cooling, the residue was purified by flash chromatography (ethyl acetate)
to afford the title compound as a clear viscous oil (872mg, 84%):
1H NMR (400MHz, CDCl
3) δ 1.17 (3H, t,
J 7.0Hz), 1.26 (3H, t,
J 7.0Hz), 1.53 (9H, s), 2.07-2.14 (1H, m), 2.43-2.69 (3H, m), 3.12 (1H, dd, J 22.4,
15.0Hz), 3.62 (1H, dd,
J 22.1, 15.0Hz), 3.84-4.06 (4H, m), 4.87 (1H, dd, J 8.9, 4.8Hz), 7.31-7.46 (4H, m).
Method L:
(S)-2,3-Dihydro-1H-5-oxo-pyrrolo[1,2-b]isoquinoline-3-carboxylic acid tert-butyl ester
[0079]

To a solution of (S)-1-[2-(diethoxyphosphorylmethyl)-benzoyl]-5-oxo-pyrrolidine-2-carboxylic
acid tert-butyl ester (865mg, 1.97mmol) in THF (15mL) at -40°C was added drop-wise
1.0-M LHMDS in THF (1.97mL, 1.97mmol). The reaction mixture was stirred at -40°C for
1h, allowed to warm to 0°C over 1h, stirred at 0°C for 1h and allowed to warm to 7°C
over 30min before being quenched with saturated aq.NH
4Cl. The reaction mixture was extracted with ethyl acetate (x2). The combined organic
layers were dried (MgSO
4), filtered and evaporated. The residue was purified by flash chromatography (20%
ethyl acetate in hexane) to afford the title compound as a colourless oil which crystallized
upon standing (286mg, 51%):
1H NMR (400MHz, CDCl
3) δ 1.47 (9H, s), 2.29 (1H, m), 2.47 (1H, m), 3.06 (1H, m), 3.19 (1H, m), 5.08 (1H,
m), 6.42 (1H, s), 7.41-7.49 (2H, m), 7.63 (1H, m), 8.37 (1H, m);
13C NMR (100MHz, CDCl
3) δ 25.8 (CH
2) , 26.9 (CH
3), 28.7 (CH
2), 60.4 (CH), 81.3 (C), 99.3 (CH), 123.7 (C), 124.6 (CHx2), 126.5 (CH), 131.2 (CH),
137.3 (C), 142.4 (C), 160.2 (C), 168.7 (C).
[3S/R(3S)]-3-(2,3-Dihydro-1H-5-oxo-pyrrolo[1,2-b]isoquinolin-3-carboxamido)-5-fluoro-4-oxo-pentanoic acid
[0080]

This was prepared from (S)-2,3-dihydro-(1
H)-5-oxo-pyrrolo[1,2-b]isoquinoline-3-carboxylic acid tert-butyl ester using procedures
similar to those described in methods C-F. The product was isolated as a white solid
(102mg, 89%): IR (solid) 2356, 1742, 1655, 1588, 1209cm
-1;
1H NMR (400MHz, DMSO-
d6) δ 2.07-2.12 (1H, m), 2.40-2.93 (3H, m), 3.07-3.18 (2H, m), 4.34-5.45 (4H, m), 6.56-6.57
(1H, 2s), 7.41-7.45 (1H, m), 7.60-7.70 (2H, m), 8.11-8.16 (1H, m), 8.63-9.06 (1H,
m), 12.49 (1H, br s);
13C NMR (100MHz, DMSO-
d6) δ 26.7/26.8 (CH
2), 29.8/29.9 (CH
2), 34.6/34.9 (CH
2), 52.0/52.7 (CH), 61.4/61.7 (CH), 84.4/84.5 (2xd, J 177.7, 177.3Hz, CH
2F), 99.6/99.7 (CH), 124.4/124.4 (C), 125.8 (CH), 126.2 (CH), 126.9 (CH), 127.0 (CH),
138.6 (C), 145.4/145.4 (C), 160.6 (C), 171.1/171.2 (C), 172.1/172.2 (C), 202.4/202.9
(CO);
19F NMR (376MHz, DMSO-
d6) δ -226.6 (t), -226.9 (t), -233.1 (t), -233.3 (t); MS (FAB +ve, HR) calculated for
C
18H
17N
2O
5F (MH+) 361.119975, found 361.120247.
Example 4
[3S/R(4S)]-5-Fluoro-4-oxo-3-(6-oxo-1,2,3,4-tetrahydro-6H-benzo[b]quinolizin-4-carboxamido)-pentanoic acid
[0081]

This was prepared from (S)-6-oxo-piperidine-2-carboxylic acid tert-butyl ester using
procedures similar to those described in methods J-L and C-F. The product was isolated
as a white solid (108mg, 91%): IR (solid) 2361, 2337, 1736, 1641, 1365, 1217cm
-1;
1H NMR (400MHz, DMSO-
d6) δ 1.66 (2H, m), 2.08-2.13 (2H, m), 2.53-2.94 (4H, m), 4.29-4.69 (1H, m), 5.10-5.44
(3H, m), 6.43-6.46 (1H, m), 7.39-7.43 (1H, m), 7.54-7.56 (1H, m), 7.65-7.71 (1H, m),
8.09-8.14 (1H, m), 8.42-8.96 (1H, m, NH), 12.51 (1H, br s, OH);
13C NMR (100MHz, DMSO-
d6) δ 16.7/16.8 (CH
2), 26.9/27.0 (CH
2), 28.9/29.0 (CH
2), 34.5/34.8 (CH
2), 52.1/52.8 (CH), 54.9/55.2 (CH), 84.3/84.5 (
J 177.7, 177.1Hz, CH
2F), 103.8/103.8 (CH), 123.9 (C), 125.5 (CH), 125.8 (CH), 127.3 (CH), 132.9 (CH), 137.1
(C), 141.0/141.1 (C), 162.7 (C), 172.1/172.2 (C), 172.2/172.3 (C), 202.6/203.1 (
J 14.6, 13.8Hz, CO);
19F NMR (376MHz, DMSO-
d6) δ -226.6 (t), -226.9 (t), -233.2 (t), -233.4 (t).
Example 5
[3S/R(1S)]-3-(6,11-Dioxo-1,2,3,4-tetrahydro-pyridazino[1,2-b]phthalazin-1-carboxamido)-5-fluoro-4-oxo-pentanoic
acid
[0082]

Method M:
(S)-6,11-Dioxo-1,2,3,4-tetrahydro-pyridazino[1,2-b]phthalazin-1-carboxylic acid methyl
ester
[0083]

A solution of (S)-hexahydro-pyridazine-3-carboxylic acid methyl ester hydrochloride
(
Y. Nakamura, C.J Shin, Chem.Lett, 1991, 11, 1953-1956) (370mg, 2.05mmol), phthalic anhydride (318mg, 2.15mmol) and diisopropylethylamine
(291mg, 2.25mmol) was heated in toluene (5mL) for 2h. The reaction mixture was then
cooled and partitioned between ethyl acetate and dilute HCl. The organic phase was
washed with saturated aq. NaHCO
3, dried (MgSO
4), filtered and evaporated. The residue was crystallised from hexane and filtered
to afford the title compound as a white solid (562mg, 82%):
1H NMR (400MHz, CD
3OD) δ 1.59 (1H, m), 1.96 (1H, m), 2.17 (1H, m), 2.55 (1H, m), 3.38 (1H, m), 3.70 (3H,
s), 4.89 (1H, m), 5.74 (1H, m), 7.89 (2H, m), 8.16 (2H, m).
13C NMR (100MHz, CD
3OD) δ 21.2 (CH
2), 25.7 (CH
2), 46.0 (CH
2), 53.8 (CH), 58.1 (CH
3), 129.0 (CH), 129.1 (CH), 130.1 (C), 130.6 (C), 135.3 (CH), 135.7 (CH), 160.4 (C),
162.4 (C), 171.7 (C).
Method N:
(S)-6,11-Dioxo-1, 2, 3, 4-tetrahydro-pyridazino[1, 2-b]phthalazin-1-carboxylic acid
[0084]

To a stirred solution of (S)-6,11-dioxo-1,2,3,4-tetrahydro-pyridazino[1,2-b]phthalazin-1-carboxylic
acid methyl ester (1.078g, 3.93mmol) in MeOH (35mL) was added KOH (232mg, 4.12mmol)
in MeOH (11mL) at 0°C. The reaction mixture was allowed to warm to room temperature
and stirred for 20 hours, then concentrated under reduced pressure. The residue was
dissolved in ethyl acetate and the resulting solution was extracted with water. The
aqueous phase was acidified with 2.0-M HCl then extracted several times with ethyl
acetate. The combined organic extracts were dried (MgSO
4), filtered and concentrated. The residue was crystallized from diethyl ether and
the title compound was obtained as a white solid (744mg, 73%):
1H NMR (400MHz, CD
3OD) δ 1.80 (1H, m), 1.97 (1H, m), 2.16 (1H, m), 2.56 (1H, m), 3.36 (1H, m), 4.83-4.88
(2H, m), 5.71 (1H, m), 7.90 (2H, m), 8.26 (2H, m).
[3S/R(1S)]-3-(6,11-Dioxo-1,2,3,4-tetrahydro-pyridazino[1,2-b]phthalazin-1-carboxamido)-5-fluoro-9-oxo-pentanoic
acid
[0085]

This was prepared from (S)-6,11-dioxo-1,2,3,4-tetrahydro-pyridazino[1,2-b]phthalazin-1-carboxylic
acid using procedures similar to those described in methods D-F. The product was isolated
as a white solid (349mg, 85%): IR (solid) 2356, 2337, 1736, 1651, 1617, 1603, 1346,
1226, 1212cm
-1;
1H NMR (400MHz, DMSO-
d6) δ 1.62 (1H, m), 1.85 (1H, m), 2.11 (2H, m), 2.33 (1H, m), 2.70 (1H, m), 3.33 (1H,
m), 4.54-4.96 (4H, m), 5.48 (1H, m), 7.87-7.94 (2H, m), 8.13-8.19 (2H, m), 8.72 (1H,
m);
13C NMR (100MHz, DMSO-
d6) (signals for Asp moiety not visible) δ 18.8 (2 peaks, CH
2), 24.9/24.1 (CH
2), 43.7 (CH
2), 56.7/56.8 (CH), 127.4/127.5 (CH
ar), 128.5 (2 peaks, Car), 129.2 (C
ar), 133.8/134.2 (CH
ar), 157.3 (CO), 159.4/159.6 (CO), 170.0 (CO);
19F NMR (376MHz, DMSO-
d6 + drop of TFA) δ -232.7, -232.8; MS (FAB +ve, HR) calculated for C
18H
18N
3O
6F (MH+) 392.125789, found 392.125420.
Reference Example 6
[3S/R(5S)]-(9,10-Dioxo-5,6,7,8,9,10-hexahydro-1,4,8a,10a-tetraazaanthracene-5-carboxamido)-5-fluoro-4-oxo-3-pentanoic
acid (not encompassed in the present invention)
[0086]

[0087] This was prepared from furo[3,4-b]pyrazine-5,7-dione using procedures similar to
those described in methods M-N and D-F. The product was isolated as a white solid
(150mg, 90%): IR (solid) 1818, 1740, 1637, 1542, 1477, 1418, 1402, 1345, 1288, 1220,
1182, 1149, 1134, 1140, 1050, 934cm
-1 ;
1H NMR (400MHz, DMSO-
d6) δ 1.57. (1H, m), 1.85(1H, m), 2.10 (1H, m), 2.50-2.95 (2H, m, Asp CH
2), 3.49(1H, m), 4.22-4.72 (2.5H, m), 5.12 (1.5H, m); 5.46 and 5.55 (1H, 2xm), 8.85
(1H, m), 9.16 (2H, d);
13C NMR (100MHz, DMSO-
d6) δ 18.8/19.1 (CH
2), 24.8/25.2 (CH
2), 32.9/33.1/34.5/34.6 (CH
2), 43.5/44.0/44.1 (Asp CH
2), 52.4/52.6 (CH), 57.3/57.4/57.6 (CH), 84.2/84.3 (
J 178.5, 179.3Hz, CH
2F), 140.9/141.0 (C), 141.5 (C), 149.9 (CH), 150.0/150.1 (CH), 156.2/156.3/156.3 (C),
158.4/158.4/158.8 (C), 169.4/169.5/169.8/169.8 (C), 172.0/173.1 (C=O), 202.4/202.5
(
J 14.6, 14.3Hz, C=O);
19F NMR (376MHz, DMSO-d
6) δ -226.54(t), -227.1(t), -229.9(t), -232.7(t), -232.8(t).
Example 7
Enzyme Assays
[0088] The assays for caspase inhibition are based on the cleavage of a fluorogenic substrate
by recombinant, purified human Caspases -1, -3, -7 or -8. The assays are run in essentially
the same way as those reported by
Garcia-Calvo et al. (J. Biol. Chem. 273 (1998), 32608-32613), using a substrate specific for each enzyme. The substrate for Caspase-1 is Acetyl-Tyr-Val-Ala-Asp-amino-4-methylcoumarin.
The substrate for Caspases -3, -7 and-8 is Acetyl-Asp-Glu-Val-Asp-amino-4-methylcoumarin.
[0089] The observed rate of enzyme inactivation at a particular inhibitor concentration,
k
obs, is computed by direct fits of the data to the equation derived by
Thornberry et al. (Biochemistry 33 (1994), 3943-3939) using a nonlinear least-squares analysis computer program (PRISM 2.0; GraphPad software).
To obtain the second order rate constant, k
inact, k
obs values are plotted against their respective inhibitor concentrations and k
inact values are subsequently calculated by computerized linear regression.
[0090] Table 3 below shows inhibition of caspase-1 activity for a selected compound of this
invention as determined by the above method.
Table 3. Caspase-1 Activity
| Example Number |
Kinact (M-1s-1) |
| 2 |
455000 |
[0091] Table 4 below shows inhibition of caspase-3 activity for a selected compound of this
invention as determined by the above method.
Table 4. Caspase-3 Activity
| Example Number |
Kinact (M-1S-1) |
| 1 |
160500 |
[0092] Table 5 below shows inhibition of caspase-7 for a selected compound of this invention
as determined by the above methods.
Table 5. Caspase-7 Activity
| Example Number |
Kinact (M-1s-1) |
| 3 |
229000 |
[0093] Table 6 below shows inhibition of caspase-8 activity for a selected compound of this
invention as determined by the above methods.
Table 6. Caspase-8 Activity
| Example Number |
Caspase-8 Kinact (M-1s-1) |
| 5 |
82000 |
Example 8
Inhibition of IL-1β secretion from Mixed Population of Peripheral Blood Mononuclear
Cells (PBMC)
[0094] Processing of pre-IL-1β by caspase-1 can be measured in cell culture using a variety
of cell sources. Human PBMC obtained from healthy donors provides a mixed population
of lymphocyte and mononuclear cells that produce a spectrum of interleukins and cytokines
in response to many classes of physiological stimulators.
Experimental procedure
[0095] The test compound is dissolved in Dimethyl Sulphoxide (DMSO,Sigma #D-2650) to give
a 100 mM stock solution. This is diluted in complete medium consisting of RPMI containing
10% heat inactivated FCS (Gibco BRL #10099-141), 2mM L-Glutamine (Sigma, #G-7513),
100U penicillin and 100 µg/ml streptomycin (Sigma #P-7539). The final concentration
range of test compound is from 100 µM down to 6 nM over eight dilution steps. The
highest concentration of test compound is equivalent to 0.1% DMSO in the assay.
[0096] Human PBMC are isolated from Buffy Coats obtained from the blood bank using centrifugation
on Ficoll-Paque leukocyte separation medium (Amersham, #17-1440-02) and the cellular
assay is performed in a sterile 96 well flat-bottomed plate (Nunc). Each well contains
100 µl of the cell suspension, 1 x 10
5 cells, 50 µl of compound dilutions and 50 µl of LPS (Sigma #L-3012) at 50 ng/ml final
concentration. Controls consist of cells +/-LPS stimulation and a serial dilution
of DMSO diluted in the same way as compound. The plates are incubated for 16-18h at
37°C in 5% CO
2 & 95% humidity atmosphere.
[0097] After 16-18 h the supernatants are harvested after centrifuging the plates at 100
x g at 18°C for 15 min and assayed for their IL-1β content. Measurement of mature
IL-1β in the supernatant is performed using the Quantikine kits (R&D Systems) according
to manufacturer's instructions. Mature IL-1β levels of about 600-1500 pg/ml are observed
for PBMCs in positive control wells.
[0098] The inhibitory potency of the compounds can be represented by an IC
50 value, which is the concentration of inhibitor at which 50% of the mature IL-1β is
detected in the supernatant as compared to the positive controls. Table 7 shows inhibition
of IL-1β secretion from peripheral blood mononuclear cells for selected compounds
of this invention as determined by the above methods.
Table 7. Inhibition of IL-1β secretion from PBMC
| Example Number |
IC50 (nM) |
| 4 |
569 |
Example 9
Anti-Fas Induced Apoptosis Assay
[0099] Cellular apoptosis may be induced by the binding of Fas ligand (FasL) to its receptor,
CD95 (Fas). CD95 is one of a family of related receptors, known as death receptors,
which can trigger apoptosis in cells via activation of the caspase enzyme cascade.
The process is initiated by the binding of the adapter molecule FADD/MORT-1 to the
cytoplasmic domain of the CD-95 receptor-ligand complex. Caspase-8 then binds FADD
and becomes activated, initiating a cascade of events that involve the activation
of downstream caspases and subsequent cellular apoptosis. Apoptosis can also be induced
in cells expressing CD95 eg the Jurkat E6.1 T cell lymphoma cell line, using an antibody,
rather than FasL, to crosslink the cell surface CD95.
Anti-Fas-induced apoptosis is also triggered via the activation of caspase-8. This
provides the basis of a cell based assay to screen compounds for inhibition of the
caspase-8-mediated apoptotic pathway.
Experimental Procedure
[0100] Jurkat E6.1 cells are cultured in complete medium consisting of RPMI-1640 (Sigma
No) + 10% foetal calf serum (Gibco BRL No. 10099-141) + 2mM L-glutamine (Sigma No.
G-7513). The cells are harvested in log phase of growth. 100ml Cells at 5-8x10
5 cells/ml are transferred to sterile 50ml Falcon centrifuge tubes and centrifuged
for 5 minutes at 100xg at room temperature. The supernatant is removed and the combined
cell pellets resuspended in 25ml of complete medium. The cells are counted and the
density adjusted to 2x10
6cells/ml with complete medium.
[0101] The test compound is dissolved in dimethyl sulphoxide (DMSO)(Sigma No. D-2650) to
give a 100mM stock solution. This is diluted to 400µM in complete medium, then serially
diluted in a 96-well plate prior to addition to the cell assay plate.
[0102] 100µl of the cell suspension (2x10
6 cells) is added to each well of a sterile 96-well round-bottomed cluster plate (Costar
No. 3790). 50µl of compound solution at the appropriate dilution and 50µl of anti-Fas
antibody, clone CH-11 (Kamiya No.MC-060) at a final concentration of 10ng/ml, are
added to the wells. Control wells are set up minus antibody and minus compound but
with a serial dilution of DMSO as vehicle control. The plates are incubated for 16-18hrs
at 37°C in 5% CO
2 and 95% humidity.
[0103] Apoptosis of the cells is measured by the quantitation of DNA fragmentation using
a 'Cell Death Detection Assay' from Boehringer-Mannheim, No. 1544 675. After incubation
for 16-18hrs the assay plates are centrifuged at 100xg at room temperature for 5 minutes.
150µl of the supernatant are removed and replaced by 150µl of fresh complete medium.
The cells are then harvested and 200µl of the lysis buffer supplied in the assay kit
are added to each well. The cells are triturated to ensure complete lysis and incubated
for 30 minutes at 4°C. The plates are then centrifuged at 1900xg for 10 minutes and
the supernatants diluted 1:20 in the incubation buffer provided. 100µl of this solution
is then assayed exactly according to the manufacturer's instructions supplied with
the kit. OD
405nm is measured 20 minutes after addition of the final substrate in a SPECTRAmax Plus
plate reader (Molecular Devices). OD
405nm is plotted versus compound concentration and the IC
50 values for the compounds are calculated using the curve-fitting program SOFTmax Pro
(Molecular Devices) using the four parameter fit option.
[0104] Table 8 shows the results of the activity of selected compounds of this invention
in the FAS induced apoptosis assay.
Table 8. Activity in FAS Induced Apoptosis Assay
| Example Number |
IC50 (nM) |
| 6* |
168 |
[0105] It will be appreciated that the scope of this invention is to be defined by the appended
claims rather than by the specific embodiments, which have been represented by way
of example.