8,10-DIDEAZATETRAHYDROFOLIC ACID DERIVATIVES

Abstract: 8,10-Dideazatetrahydrofolic acid derivatives of formula (I), where R1 and R2 are selected form hydrogen and alkyl having from one to about eight carbon atoms and the carboxylates and acid addition salts thereof, showing strong inhibition of L1210 murine leukemia cells in culture, modest inhibition of glycinamide ribotide transformylase and aminoimidazole carboxamide ribotide transferase, and insignificant inhibition of dihydrofolate reductase and thymidylate synthase enzymes.

Description: 8, 10-DIDEAZATETRAHYDROFOLIC ACID DERIVATIVES ORIGIN OF INVENTION The invention described herein was in part made in the course of work under a grant or award from the National Institute of Health, Department of Health, Education and Welfare. SPEC CAΉON Mead, U.S. Patent No. 3,856,959, patented December 24, 1974, provides a method of inhibiting methotrexate- sensitive leukemia L1210 and methotrexate-resistant leukemias derived from L1210, such as variants L1210/FR-8, L1210/M-46-R, L1210/C-95, and L1210/M-66-3A in mice, employing 5-methyltetrahydro- homofolate utilized as an injectable in a dosage regimen of 12.5-1600 mg/kg/inj/diem. Mead notes that In modern leukemia therapy, the standard drug of comparison for several years has been methotrexate (amethopterin). The modus of action in vivo of this compound in enzymatic reaction is to inhibit the action of dihydrofolate reductase and this and similar drugs constituting 4-amino analogues of folic acid are known as the 4-amino-antifolates. It has recentlv been realized that where leukemia is strongly resistant to the 4-amino-antifolates and is characterized by high levels of dihydrofolate reductase, certain homofolate derivatives show a substantial antileukemic effect - J.A.R. Mead, Ann. N. Y. Acad. Sci., 186, 514-515, Nov., 1971. It has been shown that tetrahydrohomofolate is a potent inhibitor in vitro in the enzymatic reaction of thymidylate synthetase and the enzyme is metabolically beyond or below the action of the dihydrofolate reductase. Thus, it is considered possible that dihydrohomofolate and possibly homofolate by conversion in vivo to a specific inhibitor of thymidylate synthesis might block the growth of amethopterin-resistant cells' hjaving high levels of dihydrofolate reductase -J.A.R. Mead et al., dancer Research, 2374-2379 (1966). Whereas the known compounds utilized have been active at (2) in Mead's Chart I, the tetrahydrohomofolates are active at (3), and Mead believed 5-methyltetrahydro- homofolate (5-MeTHHF) is active at (4) relative to the action of methionine synthetase. Chart I Enzymic Reactions of Folates SUBSTITUTE SHEET -3a- I ' 1 Conjugase • *■ , | * 2 Dihydrofolate reductase 3 Thymidylate synthetase 4 Methionine synthetase 5 Formylglutamate formyl transferase 6 N5, Njo-methylenetetrahydrofolate reductase 7 L-Serine hydroxymethyl transferase 8 Formiminoglutamate Formimino Transferase 9 Nio-formyltetrahydrofolate synthetase 10 N5-formyltetrahydrofolate isomerase 11 N5, Njo-methylenetetrahydrofolate dehydrogenase 12 N5-formiminotetrahydrofolate cyclodeaminase 13 N5, Nj -methenyltetrahydrofolate cyclohydrolase 14 5-Amino-4-imidazole carboxamide ribonucleotide transformylase 15 Glycinamide ribonucleotide transformylase 5 -Methyl tetrahydrohomofolate has the formula DeGraw, Jr. et al, U.S. Patent No. 4,369,319, patented January 18, 1983, provides a process and composition employing 10-deazaminopterin and 10-alkyl derivatives thereof for the treatment of leukemia, as well as other tumor systems including those of ascitic character, and also a process for preparing 10-deazaminopterin compounds. These 10-deazaminopterin compounds have the structure: In the compound 10-deazaminopterin, R j and R 2 are both hydrogen. In the alkyl derivatives, either or both of Rj and R 2 can be alkyl having from one to about eight, preferably one or two carbon atoms. When only one of W\ and R 2 is alkyl. the other is hydrogen. Temple et al, U.S. Patent No. 4,431 ,805, patented February 14, 1984, report that the 5-deaza analogs of folic acid, N^-methylfolic acid, aminopterin, methotrexate- and the diethyl ester of aminopterin, inhibit the growth of human epidermoid carcinoma cells No. 2 and are active against leukemia in laboratory animals. The 5-deaza E SHEET -5- analogs of folic acid, N^-methylfolic acid, aminopterin and methotrexate have the following structures: and II wherein R is either hydrogen or methyl. DeGraw et al, U.S. Patent No. 4,460,591, patented July 17, 1984, and 4,532,241, patented July 30, 1985, provide 10-alkyl-8,10-dideazaminopterins of the formula: where R is hydrogen or alkyl of 1 to about 8 carbon and their carboxylate and acid addition salts are described. These compounds exhibit antineoplastic activity that is similar to, but more effective than, methotrexate. -6- DeGraw et al note that Aminopterin and its N-10-methyl derivative, methotrexate, have long been recognized as powerful antineoplastic agents. Methotrexate has enjoyed some thirty years of acceptance as a clinically useful anti-cancer drug. The drugs are antimetabolites inhibiting dihydrofolate reductase (DHFR). They affect both neoplastic and normal host tissue. Alterations of the pteridine ring of folic acid have also been investigated. The synthesis and antifolate activity of 8-deazafolic acid was reported by J. I. DeGraw, R. L. Kisliuk, Y. Gaumont and C. M. B augh /Λ ed Chem, (1974) 17,470 and 8,10-dideazafolic acid was reported in J. I. DeGraw, R. L. Kisliuk, V. H. Brown and Y. Gaumont, Chem Biol Pteridines, 6,229 (1979). Both of these compounds were active antifolates, but did not significantly affect DHFR. A. Srinivasan and A. D. Broom, J Org Chem, 46, 1777 (1981) reported the preparation of 8-deazaminopterin and 8-deazamethotrexate, but did not report biological activity for the compounds. Temple et al, U.S. Patents Nos. 4,526,964, patented July 2, 1985, and 4,536,575, patented August 20, 1985, indicate that The 5-deaza analogs of folic acid, N- "-substituted folic acid, aminopterin, N^-substituted aminopterin and the diethyl ester of aminopterin inhibit the growth of human epidermoid carcinoma cells SUBSTITUTE SHEET -7- o. 2 and are active against leukemia in laboratory animals. The 5-deaza analogs of folic acid and N ^-substituted folic acid referred to herein have the following structure: and the 5-deaza analogs of aminopterin and N* "-substituted aminopterin referred to herein have the following structure: II wherein R is hydrogen, CH 3 , CH 3 CH 2 , CH 3 CH 2 CH 2 , CH 2 =CHCH 2 or CH=CCH 2 . Taylor et al, U.S. Patent No. 4,684,653, patented August 4, 1987, provides (ia) pyrido[2,3-d]pyrimidines of the formula: IA wherein R s amino or hydroxy; and R^ is hydrogen, methyl, or ethyl; the configuration about the carbon atom designated * -7a- being L; (ib) 5,6,7,8-tetrahydr9pyrido[2,3-d]-pyrimidines of the formula: ' ■ IB wherein R s amino or hydroxy; and R^ is hydrogen, methyl, or ethyl; the configuration about the carbon atom designated * being L; (ii) the tautomeric forms thereof; and (iii) the pharmaceutically acceptable alkali metal, alkaline earth metal, non-toxic metal, ammonium, and substituted ammonium salts thereof. These compounds are antineoplastic agents, and have an effect on one or more enzymes which utilize folic acid, and in particular metabolic derivatives of folic acid, as a substrate, including dihydrofolate reductase, thymidylate syntheiase and folate polyglutamate syntheiase. N-(4-2-(2-amino-4-hydroxy-5,6,7,8-tetrahydroρyrido[2,3-d]- pyrimidin-6-yl)-ethyl]benzoyl)-L-glutamic acid in particular is a unique antimetabolite. While maintaining good activity against L-1210 leukemia which is comparable to methotrexate, the compound is a weak inhibitor of dihydrofolate reductase, indicating probable activity against the folate-related enzyme targets other than DHFR. HEET -8- In accordance with the present invention, 8, 10- dideazatetrahydrofolic acid) erivatives are provided of the ' ' \ formula: where R- and R 2 are selected from hydrogen and alkyl having from one to about eight carbon atoms and the carboxylates and acid addition salts thereof. These compounds, unlike prior folic acid derivatives, such as 2, 4-diamino antifolates, and 5-methyltetrahydrohomo- folate, they show only insignificant inhibition of dihydrofolate reductase and thymidylate synthase enzymes, and it is accordingly surprising that they show strong inhibition of L1210 murine leukemia cells in culture, and modest inhibition of glycinamide ribotide transformylase and aminoimidazole carboxamide ribotide transferase. Exemplary 8, 10-dideazatetrahydrofolic acid derivatives falling within the invention include: and the carboxylate and acid addition salts thereof. In accordance with the invention, the 8, 10-dideazatetra- hydrofolic acid derivatives of Formula I are provided as new compounds, with distinctive and valuable properties, for example, significantly effective in the inhibition of growth of L1210 murine leukemia cells. Also in accordance with this invention, a synthesis is provided that affords 8, 10-dideazatetrahydro folic acid derivatives of Formula I. Accordingly, these 8, 10-dideazatetrahydro folic acid derivatives are expected to have utility in the treatment of human cancer. The invention accordingly also provides a process of treating leukemia and ascitic tumors, which comprises administering to a warm-blooded animal having an abnormal -10- proportion of leukocytes or other evidences of the malignancy, a therapeutic nontoxic amount of an 8, 10-dideazatetrahydro folic acid derivative of Formula I, as such or in the form of a pharmaceutically acceptable carboxylate or acid addition salt thereof. The carboxylates are formed by neutralization of one or both COOH groups, and the addition salts are formed with one or more free NH 2 groups of the 8, 10-dideazatetrahydro folic acid derivative. The process of the invention for the preparation of the 8, 10-dideazatetrahydro folic acid derivative is a synthesis including the following steps, exemplified by R- as methyl CH S and H 2 as hydrogen. Stage l Stage 2 HO CO j CH j CH j I CONHCH Stage 3 A <: C02CH2CH-J Stage* 4 Stages -11- As the synthesis scheme shows, hydrolysis of the 2, -diamino-4-deoxy-8, 10-dideazapteroic acid (1) with hot 10% NaOH effects displacement of the 4-NH 2 group to 4-OH yielding 8, 10-dideazapteroic acid (2). Compound 2 is coupled with diethyl L-glutamate with activation of the benzoate carboxyl group as the mixed anhydride formed by isobutyl chloroformate to afford diethyl 8, 10-dideazafolate (3). Saponification of the diester (3) in 2-methoxyethanol containing IN NaOH yields 8, 10-dideazafolic acid (4). Hydrogenation of 4 over a platinum catalyst in the presence of an equivalent of formaldehyde in an acidic medium afford 5-N-methyl- tetrahydro-8, 10-dideazafolic acid (5). Hydrogenation of the folic acid intermediate (4) in the absence of formaldehycfe yields tetrahydro-8, 10-dideazafolic acid itself, - and R 3 =H. Substitution of other alkyl groups for .- and R 2 in the above scheme are apparent to those skilled in the art, with combinations of either hydrogen and alkyl or different alkyls as R j and R 3 . In Stage 1, the hydrolysis of the 4-amino group of the pyri idine ring may be carried out by treatment with any appropriate alkali metal hydroxide at temperatures of 50-150°C. The hydrolysis may also be conducted in strongly acidic media such as mineral acids at similar temperatures. If 10- alkyl substituted analogs of formula (1), where R 2 = alkyl, are employed the products at Stage 1 and subsequent stages will bear the 10-alkyl substituent. -12- In Stage 2, the benzoic acid moiety is activated by conversion to a mixed anhydride by treatment of its triethylamine salt with isobutyl chloroformate in a polar organic solvent. Other organic tertiary amine bases such as tributylamine, N-methyl morpholine, collidine can be employed as can other esters of chloroformic acid. The mixed anhydride is allowed to react with diethyl L-glutamate at ordinary temperatures and the product is best purified by chromatography on silica gel. In Stage 3, hydrolysis of the esterifying groups is carried out with aqueous alkali at room temperature or above. The diester can be dissolved in a suitable solvent, such as 2- methoxyethanol, and held in the presence of the aqueous alkali until hydrolysis is complete. The hydrolysis product folic acid analog can then be precipitated by addition of acid such as acetic or hydrochloric. The precipitate can be recovered, washed and dried. In Stage 5, the substrate folic acid analog is hydrogenated at room temperature and atmospheric pressure in an aqueous acid medium, preferably containing acetic acid as a cosolvent. A catalyst such as platinum oxide or palladium may be employed. To obtain a 5-N-alkyl product via reductive alkylation it is necessary to incorporate an equivalent of the appropriate aldehyde such as formaldehyde, acetaldehyde, etc. If the aldehyde reagent is deleted one obtains the target compounds containing an NH at the 5-position. The following is illustrative of the procedure: ■ 13- EXAMPLE Stage 1 Stage 2 Stage 3 Stage 4 H 2 -Pt0 2 -HCHO Stage 5 8, 10-Dideazapteroic Acid (2). 2, 4-Diamino-4-deoxy-8, 10-dideazapteroic ac id (ϊ) 0. 88 g, 2. 8 mmol, was heated to 85-90 ° with 15 ml of 10% NaOH solution under an argon atmosphere. HPLC analysis of the reaction indicated maximum conversion after 5 hours. The reaction mixture was cooled to 5 ° for 48 hours. The resulting ppt. (di-sodium salt) was collected and washed with a small -14- amount of ice-cold 10% NaOH solution. The ppt. was stirred 1 . , with a little H • 2 20- and th6*pH adjusted to 5 by addition of HOAc. • \- The suspended solid was stirred for 10 minutes, then collected and washed with a little Hj,0 to yield 0. 52 g of light grey solid after drying. Mass spectrum, m/e 310 (calc'd. 310). Anal, calc'd. for C lβ H M N 4 0 3 - 0. 5H 2 0: C, 60.2; H, 4.42; N, 17. 5. Found: C, 60.2; H, 4. 51; N, 17. 5. 8, 10-Dideazafolic Acid, Diethyl Ester (3). 8, 10-Dideazapteroic acid (2) 0. 52 g, 1. 7 mmol was stirred with 15 ml of dry DMF under an argon atmosphere. Triethylamine (0. 69 g, 6. 8 mmol) was added and the mixture stirred for 15 minutes, then isobutyl chloroformate (0. 87 g, 6.4 mmol) was added. After 1 hour only partial solution was obtained. The reaction was sequentially treated with triethylamine (0.017 g, 1. 7 mmol) and isobutyl chloroformate (0. 23 g, 1. 7 mmol). Complete solution occurred after 20 minutes. Triethylamine (0.81 g, 8. 1 mmol) followed by diethyl-L-glutamic acid diethyl ester in 10 ml of DMF were added and the resulting solution was stirred for 20 hours. The solvent was removed at 40° (0. 1 mm) and the residue was dissolved in CHC1, then washed with H a O and dilute NH 4 0H, dried and the solution evaporated in vacuo. The gummy residue was chromatographed on silica gel with CHC1 3 and CHjOH-CHClj elution. The product, 110 mg of yellow solid, was eluted with CH s OH:CHCl s , 2:98. Anal, calc'd for C 25 H 2 ,N 5 O β - 0. 5H 2 0: C, 59. 5; H, 5. 99; N, 13. 9. Found: C, 59. 3; H, 5. 80; N, 13. 6. -15- 8, 10-Dideazafolic Acid (4). 8, 10-Dideazafolic acid diethyl ester (3) 110 mg, 0. 22 mmol, was treated with 1 ml of IN NaOH solution. and 1 ml of 2-methoxyethanol. The solution was stirred for 15 hours then the solvents were removed at 40 ° (0. 1 mm). The residue was treated with 1 ml of H 2 O and acidified to pH 5. 5 with HOAc. The resulting ppt. was collected, washed with H 2 O and dried to yield 74 mg of product as a yellow solid. Anal, calc 'd. for C 21 H 21 N 5 O 6 ' 2H 2 O: C, 53. 1; H, 5. 30; N, 14. 7. Found: C, 53. 4; H, 4. 67; N, 14. 5. 5-Methyl-8, 10-dideaza-5, 6, 7, 8-tetrahydrofolic Acid (5). 8, 10-Dideazafolic acid (4) 74 mg, 0. 17 mmol was dissolved in 8 ml of acetic acid and 2 ml of H 2 O containing 0.24 mmol of HC1. Pt0 2 (24 mg) was added and the mixture was hydrogenated at atmospheric pressure. Hydrogen uptake ceased after uptake of 15 ml H 2 (theory 12. 4 ml) and formaldehyde (0. 018 ml, 0.20 mmol, of 35% formaldehyde) was added. Continued hydrogenation resulted in the rapid uptake of 4 ml of H 2 (theory 3. 8 ml). The mixture was filtered through Celite and the solvent removed at 40 ° (0. 1 mm). The residue was twice treated with 2 ml of H 2 O and taken to dryness each time to leave 90 mg of white solid. Mass spectrum, m/e (TMS) 457 (calc'd. 457). Anal, calc 'd for C 22 H 24 N 5 0 6 C1 • H 2 0: C, 51. 6; H, 5. 90; N, 13. 6. Found: C, 51. 4; H, 5. 82; N, 13. 2. -16- 8, 10-Dideaza-5, 6, 7, 8-tetrahydrofolic Acid. 8, 10-Dideazafolic acid (4) 100 mg, 0. 23 mmol dissolved in 10 ml of HOAc, 9 ml H 2 O, and 2 ml (0.24 mmol) of HC1 solution was hydrogenated at atmospheric pressure over 25 mg of Pt0 2 . After 1 hour, 15 ml of H 2 (theory 15 ml) had been taken up. The mixture was filtered through Celite then taken to dryness at 0. 1 mm pressure (40°). The residue was twice treated with 10 ml H 2 O and taken to dryness each time to yield 100 mg of white solid. Mass spectrum m/e 443 (calc 'd. 443). The 8/ 10-dideazatetrahydro folic acid can be administered per se, or in association with a pharmaceutically acceptable diluent or carrier. The invention accordingly also provides a pharmaceutica composition in dosage unit form comprising from 0. 1 to about 500 mg of 8, 10-dideazatetrahydro folic acid per dosage unit, together with a pharmaceutically acceptable nontoxic inert carrier or diluent therefor. The 8, 10-dideazatetrahydro folic acid can be used as such, or in the form of their carboxylates .or an acid -17- addition salt. The carboxylates are formed by neutralization of one or two of the COOH groups with an alkali metal or alkaline earth metal or ammonia or a lower aliphatic amine. The acid addition salts are formed with one or more free NH a groups of the tetrahydro folic acid molecule. The acid addition salts are preferably the pharmaceutically acceptable, nontoxic addition salts with suitable acids, such as those with inorganic acids, for example, hydrochloric, hydrobromic, nitric, sulphuric and phosphoric acids, and with organic acids, such as organic carboxylic acids, for example, glycolic, maleic, hydrcKymaleic, malic, tartaric, citric, salicyclic, o-acetylαxy - benzoic, nicotinic and isonicotinic acid, and organic sulphonic acids, for example, methanesulphonic, ethanesulphonic, 2-hydrαxyethane- sulphonic, toluene-p-sulphonic, and naphthalene-2-sulphonic acid. An acid addition salt can be converted into the free compound according to known methods, for example, by trea ing it with a base, such as with a metal hydroxide or alkαxide, or example, an alkali metal or alkaline earth metal hydroxide, for example, lithium hydroxide, sodium hydroxide, potassium hydroxide or calcium hydroxide; with a metal carbonate, such as an alkali metal or an alkaline earth metal carbonate or hydrogen carbonate, for example, sodium, potassium or calcium carbonate or hydrogen carbonate; with ammonia; or with a hydrcxyl ion exchange resin, or with any other suitable reagent. An acid addition salt may also be converted into another acid addition salt according to known methods; for example, a salt with an inorganic acid may be treated with a metal salt, for example a sodium, barium or silver salt, of an acid in a suitable -18- diluent, in which a resulting inorganic salt is insoluble and is thus removed from the reaction medium. An acid addition salt may also be converted into another acid addition salt by treatment with an anion exchange preparation. The 8, 10-dideazatetrahydro folic acid or carboxylate or salt thereof can be administered to the animal by any available route, including oral and parenteral (intravenous, intraperi oneal, subcutaneous, and intramuscular) ad inistration. The amount administered is sufficient to ameliorate the leukemia or the ascitic tumor, and will depend upon the type of leukemia, the species of animal, and the weight of the animal. For example, in human administration, a dosage of 8, 10-dideazatetrahydro folic acid within the range from about 0. 1 mgAg or about 500 mgAg per day should be sufficient. Dosages in the higher part of the range, approaching 500 mgAg*. are normally administered in conjunction with leucovoran (di-5-formyl tetrahydrofolate) to reduce toxicity. In the treatment of lower test animals, a similar dosage range is therapeutic. The upper limit of dosage is that imposed by toxic side effects, and can be determined by trial and error for the animal to be treated, including humans. To facilitate administration, the 8, 10-dideazatetrahydro folic acid or carboxylate or salt thereof can be provided in composition form, and preferably in dosage unit form . While the compound can be administered per se, it is -19- normally administered in conjunction with a pharmaceu ically acceptable carrier therefor, ώch dilutes the compound and facilitates handling. The term "pharmaceutically acceptable" means that the carrier (as well as the resulting composition) is sterile and nontoxic . The carrier or diluent can be solid, semisolid, or liquid, and can serve as a vehicle, excipient, or medium for the 8, 10-dideazatetrahydro folic acid. Exemplary diluents and carriers include lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, mineral oil, cocoa butter, oil of theobroma, alginates, tragacanth, gelatin, syrup, methyl cellulose, polyoxyethylene sorbitan monolaurate, methyl-and propyl-hydroxybenzoate, talc or magnesium stearate. For convenience in handling, the 8, 10- dideazatetrahydro folic acid and carrier or diluent can be enclosed or encapsulated in a capsule, sachet, cachet, gelatin, paper or other container, especially when intended for use in dosage units. The dosage units can Ear example take the form of tablets, capsules, suppositories or cachets. The following Examples illustrate various forms of dosage units in which the 8, 10-dideazatetrahydro folic acid or carboxylates or salts thereof can be prepared. -20- Tablet formulation Mg/t ablet 8, 10-dideazatetrahydro folic acid 15 Lactose 86 Corn starch (dried) 45.5 Gelatin 2.5 Magnesium stearate 1. 0 The 8, 10-dideazatetrahydro folic acid is powdered and passed through a mesh sieve and well mixed with the lactose and 30 mg of the corn starch, both passed through a sieve. The mixed powSers are p_rassed ith a warm gelatin solution, prepared by stirring the gelatin in water and heating to form a 10% ■ /w solution. The mass is granulated by passing through a sieve, and the moist granules dried at 0t . The dried granules are regranulated by passing through a sieve and the balance of the starch and the magnesium stearate is added and thoroughly mixed. The granules are compressed to produce tablets each weighing 150 mg. Example 2 Tablet formulation Mg/tablet 8, 10-dideazatetrahydro folic acid 100 Lactose 39 Corn starch (dried) 80 Gelatin 4.0 Magnesium stearate 2. 0 -21- The method of preparation is identical with that of Example 1 except that 60 mg of starch is used in the granulation process and 20 mg during tabletting. Example 3 Capsule formulation Mg/capsule 8, 10-dideazatetrahydro folic acid 250 Lactose 150 The 8, 10-dideazatetrahydro folic acid and lactose are passed through a sieve and the powders well mixed together before filling into hard gelatin capsules of suitable size, so that each capsule contains 400 mg of mixed powders. Example 4 Suppositories Mg/suppositories 8, 10-dideazatetrahydro folic acid 50 Oil of Theobroma 950 The 8, 10-dideazatetrahydro folic acid is powdered and passed through a sieve and triturated with molten oil of theobroma at 45 °C to form a smooth suspension. The mixture is well stirred and poured into molds, each of nominal 1 g capacity, to produce suppositories . -22- Exa ple 5 Cachets Mg/cachet 8, 10-dideazatetrahydro folic acid 100 5 Lactose 400 The 8, 10-dideazatetrahydro folic acid is passed through a mesh sieve, mixed with lactose previously sieved and fitted into cachets of suitable size so that each contains 500 mg. Exam le 6 MIL 25 8 10-dideazatetrahydro folic acid 15 Sodium citrate 5.7 Sodium carbcKymethylcellulose (low viscosity grade) 2.0 Methyl para-hydrαxybenzoate 1.5 Propyl para-hydrαxybenzoate 0.2 30 Water for injection to 100 ml

Claims: -23- Having regard to the foregoing disclosure, the following is claimed as inventive and patentable embodiments thereof: 1. 8, 10-dideazatetrahydro folic acid compounds having the formula: where R : and R 2 are selected from hydrogen and alkyl having from one to about eight carbon atoms; and the carboxylate and acid addition salts thereof. 2. 8, 10-dideazatetrahydro folic acid compounds according to claim 1 in which - is hydrogen and R s is alkyl. 3. 8, 10-dideazatetrahydro folic acid compounds according to claim 2 in which the alkyl is methyl. 4. 8, 10-dideazatetrahydro folic acid compounds according to claim 1 in which R- and R a are each hydrogen. 5. 8, 10-dideazatetrahydro folic acid compounds according to claim .1 in which R- and R 3 are each alkyL 6. A pharmaceutical composition in dosage unit form for treating leukemia or an ascites tumor comprising an amount per dosage unit within the range from about 0. 1 to about 500 mg - of an 8, 10-dideazatetrahydro folic acid compound according to claim 1, therapeutic ally effective to ameliorate leukemia or the ascites tumor, together with a pharmaceutically acceptable nontoxic carrier or diluent therefor. -24- 7. A pharmaceutical composition according to claim 6 in which the 8, 10-dideazatetrahydro folic acid is in the form of a pharmaceutically acceptable acid addition salt. 8. A pharmaceutical composition according to claim 6 in which the 8, 10-dideazatetrahydro folic acid is in the form of a pharmaceutically acceptable carboxylate. 9. A pharmaceutical composition according to claim 6 in tablet form. 10. A pharmaceutical composition according to claim 6 in capsule form. 11. A pharmaceutical composition according to claim 6 in suppository form. 12. A pharmaceutical composition according to claim 6 in cachet form. 13. A pharmaceutical composition according to claim 6 in sterile aqueous form. 14. A process for treating leukemia and ascites tumors which comprises administering to a warm-blooded animal having an abnormal proportion of leukocytes or other evidence of the malignancy, a therapeutic and relatively nontoxic amount of an 8, 10-dideazatetrahydro folic acid compound according to claim 1, to ameliorate leukemia or ascites tumors. -25- 15. A process according to claim 14 in which the •i 1 8, 10-dideazatetrahydro folic acid compound is administered as a pharmaceutically acceptable acid addition salt thereof. 16. A process according to claim 14 in which the 8, 10-dideazatetrahydro folic acid compound is administered as a pharmaceutically acceptable carboxylate. 17. A process according to claim 14 in which the 8, 10-dideazatetrahydro folic acid compound is administered in an amount within the range from about 0. 1 to about 500 mg per day. 18. A process according to claim 14 in which the 8, 10-dideazatetrahydro folic acid compound is administered with an inert diluent or carrier. 19. A process according to claim 14 in which the 8, 10-dideazatetrahydro folic acid compound is administered orally. 20. A process according to claim 14 in which the 8, 10-dideazatetrahydro folic acid compound is administered parenterally.

Inventors: COLWELL WILLIAM T, DEGRAW JOSEPH I, SIROTNAK FRANCIS M, COLWELL, WILLIAM, T., DEGRAW, JOSEPH, I., SIROTNAK, FRANCIS, M.
Applicants: STANFORD RES INST INT, SRI INTERNATIONAL
Application year: 1989
Main classification: C07D471
IPC codes: A61K31, A61P35, C07D471