5-11-methenyltetrahydrohomofolate and lometrexol

Analogues of N-[4-[[3-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)propyl]amino] benzoyl]-L-glutamic acid (5-DACTHF), in which the phenylene group is replaced by either a thienoyl or a thiazolyl group were synthesized. These compounds were prepared by reductive amination of suitably protected pyrimidinylpropionaldehyde with the aminoaroyl glutamates. These glutamates were in turn synthesized from the corresponding nitroaroyl carboxylic acids by condensation with protected glutamic acid followed by catalytic reduction. The compounds were tested as inhibitors of methotrexate uptake as a measure of binding to the reduced folate transport system, as inhibitors of glycinamide ribonucleotide transformylase, as substrates for folylpolyglutamate synthetase, and as inhibitors of tumor cell growth in cell culture. The thiophene analogue was found to be equal in activity to 5-DACTHF in the MCF-7 cell growth inhibition assay while the thiazole analogue was 9-fold more active. Indeed this thiazole was over 4 times more active in the MCF-7 cell line than the clinically investigated compound 5,10-dideaza-5,6,7,8-tetrahydrofolic acid (DDATHF).

Topics: Adenocarcinoma; Antineoplastic Agents; Breast Neoplasms; Cell Division; Folic Acid Antagonists; Humans; Magnetic Resonance Spectroscopy; Oxidation-Reduction; Substrate Specificity; Tetrahydrofolates; Tumor Cells, Cultured

The synthesis and biological evaluation of a number of analogues of N-[4-[4-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidyl) butyl]benzoyl]-L-glutamic acid (2) (7-DM-DDATHF), an acyclic modification of the novel folate antimetabolite 5,10-dideazatetrahydrofolic acid (DDATHF), are described. The synthetic procedure utilized previously for the synthesis of 2, 15, and 16 was extended to the preparation of analogues modified in the benzoyl region with thiophene and methylene groups replacing the benzene ring (compounds 27a-c) and in the glutamate region with aspartic acid and phenylalanine replacing L-glutamic acid (compounds 36, 37). The 2-amino-4,6-dioxo derivative 33 was obtained from intermediate 30 via a palladium-catalyzed carbon-carbon coupling reaction with diethyl (4-iodobenzoyl)-L-glutamate, followed by reduction and removal of protecting groups with base. Cell culture cytotoxicity studies of all of the above acyclic analogues of DDATHF against CCRF-CEM human lymphoblastic leukemic cells gave IC50s ranging from 0.042 greater than 48 microM. Inhibition and cell culture reversal studies against isolated enzymes suggest the mode of action of these compounds. Compound 2 was only 3-fold less inhibitory toward glycinamide ribonucleotide formyltransferase (GARFT, isolated from L1210 leukemic cells) than DDATHF itself. These acyclic analogues were less efficient substrates for the enzyme folylpolyglutamate synthetase (FPGS) compared with their bicyclic counterparts. Moderate antitumor activity was observed for compound 2 against 6C3HED lymphosarcoma and C3H mammary adenocarcinoma in vivo.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Cell Line; Cells, Cultured; Humans; Leukemia, Lymphoid; Mammary Neoplasms, Experimental; Mice; Mice, Inbred C3H; Structure-Activity Relationship; Tetrahydrofolates

Prompted by recent disclosures concerning the potent antitumor activities of 5-deaza-5,6,7,8-tetrahydrofolic acid and 5,10-dideaza-5,6,7,8-tetrahydrofolic acid (DDATHF), we have prepared 5-deazaisofolic acid (3a) and 5-deaza-5,6,7,8-tetrahydroisofolic acid (4a). Reductive condensation of 2,6-diamino-3,4-dihydro-4- oxopyrido[2,3-d]pyrimidine with di-tert-butyl N-(4-formylbenzoyl)-L-glutamate and subsequent deprotection with trifluoroacetic acid yielded 5-deazaisofolic acid in good yield. Catalytic hydrogenation of this analogue then gave 4a. The 9-CH3 and 9-CHO modifications of 3a and the 9-CH3 derivative of 4a were also synthesized. Each of the new analogues was evaluated with a variety of folate-requiring enzymes as well as MCF-7 cells in culture. Compound 4a had an IC50 of ca. 1 microM against MCF-7 cells and was nearly 100-fold less potent than DDATHF in this regard. The three oxidized isofolate analogues were all poor inhibitors of tumor cell growth.

Topics: Animals; Antineoplastic Agents; Folic Acid; Folic Acid Antagonists; Humans; Structure-Activity Relationship; Swine; Tetrahydrofolates; Thymidylate Synthase