Immunotherapeutic Nitriles

The present invention relates a method of reducing levels of TNF.alpha. in a mammal and to compounds and compositions useful therein.

TNF.alpha., or tumor necrosis factor .alpha., is a cytokine which is released primarily by mononuclear phagocytes in response to various immunostimulators. When administered to animals or hums it causes intimation, fever, cardiovascular effects, hemorrhage, coagulation and acute phase responses similar to those seen during acute infections and shock states.

Excessive or unregulated TNF.alpha. production has been implicated in a number of disease conditions. These include endotoxemia and/or toxic shock syndrome {Tracey et al., Nature 330, 662-664 (1987) and Hinshaw et al., Circ. Shock 30, 279-292 (1990)}; cachexia {Dezube et al., Lancet, 335(8690), 662 (1990)}; and Adult Respiratory Distress Syndrome where TNF.alpha. concentration in excess of 12,000 pg/milliliters have been detected in pulmonary aspirates from ARDS patients {Millar et al., Lancet 2(8665), 712-714 (1989)}. Systemic infusion of recombinant TNF.alpha. also resulted in changes typically seen in ARDS {Ferrai-Baliviera et al., Arch. Surg. 124(12), 1400-1405 (1989)}.

TNF.alpha. appears to be involved in bone resorption diseases, including arthritis where it has been determined that when activated, leukocytes will produce a bone-resorbing activity, and data suggest that TNF.alpha. contributes to this activity {Bertolini et al., Nature 319, 516-518 (1986) and Johnson et al., Endocrinology 124(3), 1424-1427 (1989)}. It has been determined that TNF.alpha. stimulates bone resorption and inhibits bone formation in vitro and in vivo through stimulation of osteoclast formation and activation combined with inhibition of osteoblast function. Although TNF.alpha. may be involved in many bone resorption diseases, including arthritis, the most compelling link with disease is the association between production of TNF.alpha. by rumor or host tissues and malignancy associated hypercalcemia {Calci. Tissue Int. (US) 46(Suppl.), S3-10 (1990)}. In Graft versus Host Reaction, increased serum TNF.alpha. levels have been associated with major complications following acute allogenic bone marrow transplants {Holier et al., Blood, 75(4), 1011-1016 (1990)}.

Cerebral malaria is a lethal hyperacute neurological syndrome associated with high blood levels of TNF.alpha. and the most severe complication occurring in malaria patients. Levels of serum TNF.alpha. correlated directly with the severity of the disease and the prognosis in patients with acute malaria attacks {Grau et at., N. Engl. J. Med. 320(24), 1586-1591 (1989)}.

TNF.alpha. also plays a role in the area of chronic pulmonary inflammatory diseases. The deposition of silica particles leads to silicosis, a disease of progressive respiratory failure caused by a fibrotic reaction. Antibodies to TNF.alpha. completely blocked the silica-induced lung fibrosis in mice {Pignet et al., Nature, 344:245-247 (1990)}. High levels of TNF.alpha. production (in the serum and in isolated macrophages) have been demonstrated in animal models of silica and asbestos induced fibrosis {Bissonnette et al., Inflammation 13(3), 329-339 (1989)}. Alveolar macrophages from pulmonary sarcoidosis patients have also been found to spontaneously release massive quantities of TNF.alpha. as compared with macrophages from normal donors {Baughman et al., J. Lab. Clin. Med. 115(1), 36-42 (1990)}.

TNF.alpha. is also implicated in the inflammatory response which follows reperfusion, called reperfusion injury, and is a major cause of tissue damage after loss of blood flow {Vedder et al., PNAS 87, 2643-2646 (1990)}. TNF.alpha. also alters the properties of endothelial cells and has various pro-coagulant activities, such as producing an increase in tissue factor pro-coagulant activity and suppression of the anticoagulant protein C pathway as well as down-regulating the expression of thrombomodulin {Sherry et al., J. Cell Biol. 107, 1269-1277 (1988)}. TNF.alpha. has pro-inflammatory activities which together with its early production (during the initial stage of an inflammatory event) make it a likely mediator of tissue injury in several important disorders including but not limited to, myocardial infarction, stroke and circulatory shock. Of specific importance may be TNF.alpha.-induced expression of adhesion molecules, such as intercellular adhesion molecule (ICAM) or endothelial leukocyte adhesion molecule (ELAM) on endothelial cells {Munro et al., Am. J. Path. 135(1), 121-132 (1989)}.

Moreover, it is now known that TNF.alpha. is a potent activator of retrovirus replication including activation of HIV-1. {Duh et al., Proc. Nat. Acad. Sci. 86, 5974-5978 (1989); Poll et al., Proc. Nat. Acad. Sci. 87, 782-785 (1990); Monto et al., Blood 79, 2670 (1990); Clouse et al., J. Immunol. 142, 431-438 (1989); Poll et al., AIDS Res. Hum. Retrovirus, 191-197 (1992)}. AIDS results from the infection of T lymphocytes with Human Immunodeficiency Virus (HIV). At least three types or strains of HIV have been identified, i.e., HIV-1, HIV-2 and HIV-3. As a consequence of HIV infection, T-cell mediated immunity is impaired and infected individuals manifest severe opportunistic infections and/or unusual neoplasms. HIV entry into the T lymphocyte requires T lymphocyte activation. Other viruses, such as HIV-1 and HIV-2, infect T lymphocytes after T cell activation and such virus protein expression and/or replication is mediated or maintained by such T cell activation. Once an activated T lymphocyte is infected with HIV, the T lymphocyte must continue to be maintained in an activated state to permit HIV gene expression and/or HIV replication. Cytokines, specifically TNF.alpha., are implicated in activated T-cell mediated HIV protein expression and/or virus replication by playing a role in maintaining T lymphocyte activation. Therefore, interference with cytokine activity such as by prevention or inhibition of cytokine production, notably TNF.alpha., in a HIV-infected individual aids in limiting the maintenance of T lymphocyte activation caused by HIV infection.

Monocytes, macrophages, and related cells, such as kupffer and glial cells, have also been implicated in maintenance of the HIV infection. These cells, like T cells, are targets for viral replication and the level of vital replication is dependent upon the activation state of the cells {Rosenberg et al., The Immunopathogenesis of HIV Infection, Advances in Immunology, 57 (1989)}. Cytokines, such as TNF.alpha., have been shown to activate HIV replication in monocytes and/or macrophages {Poli et al. Proc. Natl. Acad. Sci., 87, 782-784 (1990)}, therefore, prevention or inhibition of cytokine production or activity aids in limiting HIV progression as stated above for T cells. Additional studies have identified TNF.alpha. as a common factor in the activation of HIV in vitro and has provided a clear mechanism of action via a nuclear regulatory protein found in the cytoplasm of cells (Osborn, et al., PNAS 86, 2336-2340). This evidence suggests that a reduction of TNF.alpha. synthesis may have an antiviral effect in HIV infections, by reducing the transcription and thus virus production.

AIDS viral replication of latent HIV in T cell and macrophage lines can be induced by TNF.alpha. {Folks et al., PNAS 86, 2365-2368 (1989)}. A molecular mechanism for the virus inducing activity is suggested by TNF.alpha.'s ability to activate a gene regulatory protein (NF.kappa.B) found in the cytoplasm of cells, which promotes HIV replication through binding to a viral regulatory gene sequence (LTR) {Osborn et al., PNAS 86, 2336-2340 (1989)}. TNF.alpha. in AIDS associated cachexia is suggested by elevated serum TNF.alpha. and high levels of spontaneous TNF.alpha. production in peripheral blood monocytes from patients {Wright et al. J. Immunol. 141(1), 99-104 (1988)}.

TNF.alpha. has been implicated in various roles with other vital infections, such as the cytomegalia virus (CMV), influenza virus, adenovirus, and the herpes family of viruses for similar reasons as those noted.

Preventing or inhibiting the production or action of TNF.alpha. (e.g. with treatment with the compounds of this invention) is, therefore, predicted to be a potent therapeutic strategy for many inflammatory, infectious, immunological or malignant diseases. These include but are not restricted to septic shock, sepsis, endotoxic shock, hemodynamic shock and sepsis syndrome, post ischemic reperfusion injury, malaria, mycobacterial infection, meningitis, psoriasis, congestive heart failure, fibrotic disease, cachexia, graft rejection, cancer, autoimmune disease, opportunistic infections in AIDS, rheumatoid arthritis, rheumatoid spondylitis, osteoarthritis, other arthritic conditions, Crohn's disease, ulcerative colitis, multiple sclerosis, systemic lupus erythrematosis, ENL in leprosy, radiation damage, and hyperoxic alveolar injury. Efforts directed to the suppression of the effects of TNF.alpha. have ranged from the utilization of steroids such as dexamethasone and prednisolone to the use of both polyclonal and monoclonal antibodies {Beutler et al., Science 234, 470-474 (1985); WO 92/11383}.

The nuclear factor .kappa.B (NF.kappa.B) is a pleiotropic transcriptional activator (Lenardo, et al. Cell 1989, 58, 227-29). NF.kappa.B has been implicated as a transcriptional activator in a variety of disease and inflammatory states and is thought to regulate cytokine levels including but not limited to TNF.alpha. and also to be an activator of HIV transcription (Dbaibo, et al. J. Biol. Chem. 1993, 17762-66; Dub et al. Proc. Natl. Acad. Sci. 1989, 86, 5974-78; Bachelerie et al. Nature 1991, 350, 709-12; Boswas et al. J. Acquired Immune Deficiency Syndrome 1993, 6, 778-786; Suzuki et al. Biochem. And Biophys. Res. Comm. 1993, 193, 277-83; Suzuki et al. Biochem. And Biophys. Res Comm. 1992, 189, 1709-15; Suzuki et al. Biochem. Mol. Bio. Int. 1993, 31(4), 693-700; Shakhov et al. 1990, 171, 35-47; and Staal et al. Proc. Natl. Acad. Sci. USA 1990, 87, 9943-47). Thus, inhibition of NF.kappa.B binding can regulate transcription of cytokine gene(s) and through this modulation and other mechanisms be useful in the inhibition of a multitude of disease states. The compounds claimed in this patent can inhibit the action of NF.kappa.B in the nucleus and thus are useful in the treatment of a variety of diseases including but not limited to rheumatoid arthritis, rheumatoid spondylitis, osteoarthritis, other arthritic conditions, septic shock, septis, endotoxic shock, graft versus host disease, wasting, Crohn's disease, ulcerative colitis, multiple sclerosis, systemic lupus erythrematosis, ENL in leprosy, HIV, AIDS, and opportunistic infections in AIDS.

TNF.alpha. and NF.kappa.B levels are influenced by a reciprocal feedback loop. As noted above, the compounds of the present invention affect the levels of both TNF.alpha. and NF.kappa.B. It is not known at this time, however, how the compounds of the present invention regulate the levels of TNF.alpha., NF.kappa.B, or both.

Many cellular functions can be mediated by levels of adenosine 3',5'-cyclic monophosphate(cAMP). Such cellular functions can contribute to inflammatory conditions and diseases including asthma, intimation, and other conditions (Lowe and Cheng, Drugs of the Future, 17(9), 799-807, 1992). It has been shown that the elevation of cAMP in inflammatory leukocytes inhibits their activation and the subsequent release of inflammatory mediators. Increased levels of cAMP also leads to the relaxation of airway smooth muscle.

The primary cellular mechanism for the inactivation of cAMP is the breakdown of cAMP by a family of isoenzymes referred to as cyclic nucleotide phosphodiesterases(PDE). There are seven known members of the family of PDEs. It is recognized, for example, that the inhibition of PDE type IV is particularly effective in both the inhibition of inflammatory mediator release and the relaxation of airway smooth muscle. Thus, compounds that inhibit PDE IV specifically, would exhibit the desirable inhibition of inflammation and relaxation of airway smooth muscle with a minimum of unwanted side effects, such as cardio-vascular or anti-platelet effects. Currently used PDE IV inhibitors lack the selective action at acceptable therapeutic doses.

The compounds of the present invention are useful in the inhibition of phosphodiesterases, particularly PDE III and PDE IV, and in the treatment of disease states mediated thereby.

The present invention is based on the discovery that a class of non-polypeptide imides more fully described herein appear to inhibit the action of TNF.alpha..

The present invention pertains to compounds of the formula: ##STR1## in which: Y is --C.ident.N or ##STR2## m is 0-3; R.sup.5 is: (i) o-phenylene, unsubstituted or substituted with 1 to 3 substituents each selected independently from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, carbamoyl substituted with and alkyl of 1 to 3 carbon atoms, acetoxy, carboxy, hydroxy, amino, amino substituted with an alkyl of 1 to 3 carbon atoms, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo; (it) the divalent residue of pyridine, pyrrolidine, imidizole, naphthalene, or thiophene, wherein the divalent bonds are on vicinal ring carbon atoms; (iii) a divalent cycloalkyl of 4-10 carbon atoms, unsubstituted or substituted with one or more substituents each selected independently of the other from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, phenyl or halo; (iv) di-substituted vinylene, substituted with nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, carbamoyl substituted with and alkyl of 1 to 3 carbon atoms, acetoxy, carboxy, hydroxy, amino, amino substituted with an alkyl of 1 to 3 carbon atoms, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo; or (v) ethylene, unsubstituted or substituted with 1 to 2 substituents each selected independently from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, carbamoyl substituted with and alkyl of 1 to 3 carbon atoms, acetoxy, carboxy, hydroxy, amino, amino, substituted with an alkyl of 1 to 3 carbon atoms, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo;

R.sup.6 is --CO--, --CH.sub.2 --, --CH.sub.2 CO--, or --SO.sub.2 --;

R.sup.7 is (i) straight or branched alkyl of 1 to 12 carbon atoms; (ii) cyclic or bicyclic alkyl of to 12 carbon atoms; (iii) pyridyl; (iv) phenyl substituted with one or more substituents each selected independently of the other from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, straight, branched, cyclic, or bicyclic alkyl of 1 to 10 carbon atoms, straight, branched, cyclic, or bicyclic alkoxy of 1 to 10 carbon atoms, CH.sub.2 R where R is a cyclic or bicyclic alkyl of 1 to 10 carbon atoms, or halo; (v) benzyl substituted with one to three substituents each selected independently from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo; (vi) naphthyl; or (vii) benzyloxy;

and,

where n has a value of 0, 1, 2, or 3;

A first preferred subclass pertains to compounds in which:

Y is --C.ident.N;

R.sup.5 is o-phenylene, substituted or unsubstituted;

R.sup.6 is --CO-- or --CH.sub.2 --;

R.sup.7 is an aryl; and

n is 1.

Typical compounds of this invention include:

The term alkyl as used herein denotes a univalent saturated branched or straight hydrocarbon chain. Unless otherwise stated, such chains can contain from 1 to 18 carbon atoms. Representative of such alkyl groups are methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, isohexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, and the like. When qualified by "lower", the alkyl group will contain from 1 to 6 carbon atoms. The same carbon content applies to the parent term "alkane" and to derivative terms such as "alkoxy".

The term cycloalkyl (or cyclic alkyl) as used herein denotes a univalent saturated cyclic hydrocarbon chain. Unless otherwise stated, such chains can contain from 1 to 18 carbon atoms. Representative of such cycloalkyl groups are methyl, ethyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl, cyclotridecyl, cyclotetradecyl, cyclopentadecyl, cyclohexadecyl, cycloheptadecyl, cyclooctadecyl, cyclic terpenes, and the like. When qualified by "lower", the cycloalkyl group will contain from 3 to 6 carbon atoms. The same carbon content applies to the parent term "cycloalkane" and to derivative terms such as "cycloalkoxy".

The compounds can be used, under the supervision of qualified professionals, to inhibit the undesirable effects of TNF.alpha. and/or phosphodiesterase. The compounds can be administered orally, rectally, or parenterally, alone or in combination with other therapeutic agents including antibiotics, steroids, etc., to a mammal in need of treatment. Oral dosage forms include tablets, capsules, dragees, and similar shaped, compressed pharmaceutical forms. Isotonic saline solutions containing 20-100 milligrams/milliliter can be used for parenteral administration which includes intramuscular, intrathecal, intravenous and intra-arterial routes of administration. Rectal administration can be effected through the use of suppositories formulated from conventional carriers such as cocoa butter.

Dosage regimens must be titrated to the particular indication, the age, weight, and general physical condition of the patient, and the response desired but generally doses will be from about 1 to about 1000 milligrams/day as needed in single or multiple daily administration. In general, an initial treatment regimen can be copied from that known to be effective in interfering with TNF.alpha. activity for other TNF.alpha. mediated disease states by the compounds of the present invention. Treated individuals will be regularly checked for T cell numbers and T4/T8 ratios and/or measures of viremia such as levels of reverse transcriptase or viral proteins, and/or for progression of cytokine-mediated disease associated problems such as cachexia or muscle degeneration. If no effect is observed following the normal treatment regimen, then the amount of cytokine activity interfering agent administered is increased, e.g., by fifty percent a week.

The compounds of the present invention can also be used topically in the treatment or prophylaxis of topical disease states mediated or exacerbated by excessive TNF.alpha. production, such as viral infections, for example those caused by the herpes viruses or viral conjunctivitis, psoriasis, other skin disorders and diseases, etc.

The compounds can also be used in the veterinary treatment of mammals other than humans in need of prevention or inhibition of TNF.alpha. production. TNF.alpha. mediated diseases for treatment, therapeutically or prophylactically, in animals include disease states such as those noted above, but in particular viral infections. Examples include feline immunodeficiency virus, equine infectious anaemia virus, caprine arthritis virus, visna virus, and maedi virus, as well as other lentiviruses.

Certain of these compounds possess centers of chirality and can exist as optical isomers. Both the racemates of these isomers and the individual isomers themselves, as well as diastereoisomers when there are two chiral centers, are within the scope of the present invention. The racemates can be used as such or can be separated into their individual isomers mechanically as by chromatography using a chiral absorbent. Alternatively, the individual isomers can be prepared in chiral form or separated chemically from a mixture by forming salts with a chiral acid, such as the individual enantiomers of 10-camphorsulfonic acid, camphoric acid, alpha-bromocamphoric acid, methoxyacetic acid, tartaric acid, diacetyltartaric acid, malic acid, pyrrolidone-5-carboxylic acid, and the like, and then freeing one or both of the resolved bases, optionally repeating the process, so as to obtain either or both isomers substantially free of the other; i.e., in a form having an optical purity of >95%.

Prevention or inhibition of production of TNF.alpha. by these compounds can be conveniently assayed using methods known in the art. For example, TNF.alpha. Inhibition Assays in LPS stimulated PBMC have been performed as follows:

PBMC isolation: PBMC from normal donors were obtained by Ficoll-Hypaque density centrifugation. Cells were cultured in RPMI supplemented with 10% AB+serum, 2 mM L-glutamine, 100 U/mL penicillin and 100 .mu.g/mL streptomycin.

PBMC suspensions: Drugs were dissolved in DMSO (Sigma Chemical), further dilutions were done in supplemented RPMI. The final DMSO concentration in the presence or absence of drug in the PBMC suspensions was 0.25 wt %. Drugs were assayed at half-log dilutions starting at 50 .mu.g/ml. Drugs were added to PBMC (10.sup.6 cells/ml.) in 96 wells plates one hour before the addition of LPS.

Cell stimulation: PBMC (10.sup.6 cells/mL) in the presence or absence of drug were stimulated by treatment with 1 .mu.g/mL of LPS from Salmonella minnesota R595 (List Biological Labs, Campbell, Calif.). Cells were then incubated at 37.degree. C. for 18-20 hours. Supernatants were then harvested and assayed immediately for TNF.alpha. levels or kept frozen at -70.degree. C. (for not more than 4 days) until assayed.

TNF.alpha. Determination: The concentration of TNF.alpha. in the supernatant was determined by human TNF.alpha. ELISA kits (ENDOGEN, Boston, Mass.) according to the manufacturer's directions.

The compounds can be prepared using methods which are known in general for the preparation of nitriles. General reaction schemes are illustrated by the formulas: ##STR3## where X is CO.sub.2 H, CONH.sub.2, or CN

The following examples will serve to further typify the nature of this invention but should not be construed as a limitation in the scope thereof, which scope is defined solely by the appended claims.

3-Phthalimido-3-(3,4-diethoxyphenyl)propionitrile.

To an ice bath cooled stirred suspension of 3-phthalimido-3-(3,4-diethoxyphenyl)propionamide (0.96 g, 2.5 mmol) and 4-methylmorpholine (0.66 mL, 6 mmol) in DMF (9 mL) under nitrogen, was added thionyl chloride (0.35 mL, 4.8 mmol) dropwise. There was a slight exotherm after which the mixture was stirred at 0.degree.-5.degree. C. for 30 minutes and at room temperature for 2 hours. The reaction was monitored by HPLC (Waters Nova-Pak/C-18 column, 3.9.times.150 mm, 4 micron, 1 mL/min, 240 nm, 50/50 CH.sub.3 CN/H.sub.3 PO.sub.4 0.1% (aq)). The reaction mixture was poured into a mixture of NaHCO.sub.3 (8.5 mL) and ice (40 g) and stirred until the ice had melted. The mixture was filtered and the solid was washed with copious amounts of H.sub.2 O. The wet solid was dissolved in CH.sub.2 Cl.sub.2 (25 mL) and the organic layer was separated and dried over MgSO.sub.4 and concentrated in vacuo to a sticky semi-solid. The solid was purified twice by flash column chromatography (silica gel, 3 % ethyl acetate/methylene chloride) to afford a solid which was dried in vacuo (50.degree. C., <1 mm) to afford 0.5 g (55%) of product as a pale yellow solid; .sup.1 H NMR (CDCl.sub.3) .delta.7.91-7.65(m, 4H), 7.12-6.98(m, 2H), 6.90-6.78(m, 1H), 5.61(dd, J=6.4, 10.3 Hz, 1H), 4.19-3.96(m, 4H), 3.83(dd, J=10.3, 16.8 Hz, 1H), 3.26(dd, J=6.4, 16.8 Hz, 1H), 1.55-1.30(m, 6H); .sup.13 C NMR (CDCl.sub.3).delta.167.7, 149.2, 148.9, 134.3, 131.5, 129.1, 123.6, 120.2, 116.9, 113.2, 112.9, 64.7, 64.5, 51.1, 21.1, 14.7; HPLC 98.4%. Anal. Calcd for C.sub.21 H.sub.20 N.sub.2 O.sub.4. Theoretical: C, 69.22; H,5.53; N,7.69. Found: C, 69.06; H, 5.48; N, 7.58.

3-Phthalimido-3-(3,4- dimethoxyphenyl)propionitrile

To an ice bath cooled stirred suspension of 3-phthalimido-3-(3,4-dimethoxyphenyl)propionamide (1.77 g, 5.00 mmol) and 4-methylmorpholine (1.3 mL, 12 mmol) in DMF (17 mL) under N.sub.2, was added thionyl chloride (0.7 mL, 9.6 mmol) dropwise via a syringe. There was a slight exotherm and after 30 minutes the cooling bath was removed and the reaction mixture was stirred for 2 hours at room temperature. The reaction mixture was poured into a mixture of NaHCO.sub.3 (17 g) and 75 mL of ice water and stirred until the ice had melted. The slurry was filtered and the solid was washed with copious amounts of H.sub.2 O. The wet solid was dissolved in CH.sub.2 Cl.sub.2 (50 mL) and the organic layer was separated, dried over.sub.2 Na.sub.4 SO, and concentrated in vacuo to afford an orange solid. The solid was purified by flash column chromatography (silica gel, 5/95 EtOAc/CH.sub.2 Cl.sub.2, 50 mm id column) to afford 1.32 g (79%) of the product as a white solid: .sup.1 H NMR (CDCl.sub.3) .delta.7.9-7.6(m, 4H), 7.10 (m, 2H), 6.83 (m, 1H), 5.64 (dd, J=6.5, 10.2 Hz, 1H), 3.88 (s, 3H), 3.85 (s, 3H), 3.82 (dd, 1H), 3.30 (dd, J=6.5, 16.8 Hz, 1 H); .sup.13 C NMR (CDCl.sub.3) .delta.167.7, 149.5, 149.2, 134.4, 131.5, 129.1, 123.6, 120.1, 116.9, 111.1, 110.7, 56.0, 55.9, 51.1, 21.1. Anal. Calcd for C.sub.19 H.sub.16 N.sub.2 O.sub.4 --0.18 H.sub.2 O. Theoretical: C, 76.2; H,4.85; N,8.25. Found: C, 67.23; H, 4.79; N, 8.27.

Tablets, each containing 50 milligrams of active ingredient, can be prepared in the following manner:

The solid ingredients are first forced through a sieve of 0.6 mm mesh width. The active ingredient, the lactose, the talc, the magnesium stearate and half of the starch then are mixed. The other half of the starch is suspended in 40 milliliters of water and this suspension is added to a boiling solution of the polyethylene glycol in 100 milliliters of water. The resulting paste is added to the pulverulent substances and the mixture is granulated, if necessary with the addition of water. The granulate is dried overnight at 35.degree. C., forced through a sieve of 1.2 mm mesh width and compressed to form tablets of approximately 6 mm diameter which are concave on both sides.

Tablets, each containing 100 milligrams of active ingredient, can be prepared in the following manner:

All the solid ingredients are first forced through a sieve of 0.6 mm mesh width. The active ingredient, the lactose, the magnesium stearate and half of the starch then are mixed. The other half of the starch is suspended in 40 milliliters of water and this suspension is added to 100 milliliters of boiling water. The resulting paste is added to the pulverulent substances and the mixture is granulated, if necessary with the addition of water. The granulate is dried overnight at 35.degree. C., forced through a sieve of 1.2 mm mesh width and compressed to form tablets of approximately 6 mm diameter which are concave on both sides.

Tablets for chewing, each containing 75 milligrams of active ingredient, can be prepared in the following manner:

All the solid ingredients are first forced through a sieve of 0.25 mm mesh width. The mannitol and the lactose are mixed, granulated with the addition of gelatin solution, forced through a sieve of 2 mm mesh width, dried at 50.degree. C. and again forced through a sieve of 1.7 mm mesh width. The active ingredient, the glycine and the saccharin are carefully mixed, the mannitol, the lactose granulate, the stearic acid and the talc are added and the whole is mixed thoroughly and compressed to form tablets of approximately 10 mm diameter which are concave on both sides and have a breaking groove on the upper side.

Tablets, each containing 10 milligrams of active ingredient, can be prepared in the following manner:

The solid ingredients are first forced through a sieve of 0.6 mm mesh width. Then the active ingredient, lactose, talc, magnesium stearate and half of the starch are intimately mixed. The other half of the starch is suspended in 65 milliliters of water and this suspension is added to a boiling solution of the polyethylene glycol in 260 milliliters of water. The resulting paste is added to the pulverulent substances, and the whole is mixed and granulated, if necessary with the addition of water. The granulate is dried overnight at 35.degree. C., forced through a sieve of 1.2 mm mesh width and compressed to form tablets of approximately 10 mm diameter which are concave on both sides and have a breaking notch on the upper side.

Gelatin dry-filled capsules, each containing 100 milligrams of active ingredient, can be prepared in the following manner:

The sodium lauryl sulphate is sieved into the active ingredient through a sieve of 0.2 mm mesh width and the two components are intimately mixed for 10 minutes. The microcrystalline cellulose is then added through a sieve of 0.9 mm mesh width and the whole is again intimately mixed for 10 minutes. Finally, the magnesium stearate is added through a sieve of 0.8 mm width and, after mixing for a further 3 minutes, the mixture is introduced in portions of 140 milligrams each into size 0 (elongated) gelatin dry-fill capsules.

A 0.2% injection or infusion solution can be prepared, for example, in the following manner:

The active ingredient is dissolved in 1000 milliliters of water and filtered through a microfilter or slurried in 1000 mL of H.sub.2 O. The buffer solution is added and the whole is made up to 2500 milliliters with water. To prepare dosage unit forms, portions of 1.0 or 2.5 milliliters each are introduced into glass ampoules (each containing respectively 2.0 or 5.0 milligrams of active ingredient).