Protected N4-methyl and N4,N4-dimethyl derivatives of 5-azacytidine 3 and 4 were prepared by selective aminolysis of benzoylated 4-methoxy-1-(β-D-ribofuranosyl)-1,3,5-triazin-2(1H)-one 5, by glycosylation of silylated N4-methyl- or N4,N4-dimethyl-5-azacytosines 7 and 8 with 2,3,5-tri-O-benzoyl-α,β-D-ribofuranosyl chloride (11) or by several modifications of the isocyanate method. By the isocyanate approach, also the α-D anomer of protected N4-methyl-5-azacytidine 17 was obtained as a minor product. The protected dimethyl derivative 4 was also obtained by the reaction of isobiuret 22 with dimethylformamide dimethyl acetal. The free nucleosides 1 and 2 were obtained either by aminolysis of the free methoxy nucleoside 23 with methylamine or dimethylamine, respectively, or by methanolysis or ammonolysis of the corresponding benzoyl derivatives 3 and 4. The free α-D anomer 24 was obtained by methanolysis of its tribenzoate 17. Nucleosides 1 and 2 exhibited a lower antibacterial, antitumor and antiviral activity than the unsubstituted 5-azacytidine.
通过对苯酰化的4-甲氧基-1-(β-D-核糖苷)-1,3,5-三嗪-2(1H)-酮5进行选择性氨解反应,制备了5-氮杂胞嘧啶的保护N4-甲基和N4,N4-二甲基衍生物3和4,通过对硅烷化的N4-甲基或N4,N4-二甲基-5-氮杂胞嘧啶7和8与2,3,5-三-O-苯酰-α,β-D-核糖苷氯化物(11)的糖基化反应,或通过异氰酸酯法的几种修饰方法制备。通过异氰酸酯法,还得到了保护的N4-甲基-5-氮杂胞嘧啶的α-D异构体17作为副产物。保护的二甲基衍生物4也可通过异丁脲22与二甲基甲酰胺二甲基缩醛反应得到。游离核苷1和2可通过游离的甲氧基核苷23分别与甲胺或二甲胺氨解,或通过相应的苯酰衍生物3和4的甲醇解或氨解得到。游离的α-D异构体24可通过其三苯甲酸酯17的甲醇解得到。核苷1和2的抗菌、抗肿瘤和抗病毒活性均低于未取代的5-氮杂胞嘧啶。