名称:
                                Synthesis and biological evaluation of 5-deazaisofolic acid, 5-deaza-5,6,7,8-tetrahydroisofolic acid, and their N9-substituted analogues
                             
                            
                                摘要:
                                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-mu-M 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.