Treatment of methoxyribosyltriazinone 4 with hydrazine in methanol afforded crude 4-hydrazino-1-β-D-ribofuranosyl-1,3,5-triazin-2(1H)-one (N4-amino-5-azacytidine) (2), which rearranged rapidly to isomeric 5-ribosylureidotriazole 6. The rearrangement proceeds easily also in water solutions of 2. Alkaline hydrolysis of 6 gave a mixture of 5-ureidotriazole 7 and 5-aminotriazole 8. Acid hydrolysis of 6 afforded only 7. This compound was also prepared by thermal rearrangement of 5-amino-1-carbamoyltriazole 9 or on reaction of cyano(formyl)guanidine 10 with hydrazine hydrochloride. Treatment of benzoylated methoxyribosyltriazinone 4a with hydrazine in methanol gave only the rearranged product 6a. Reaction of tribenzoylribosyl isocyanate 12 with aminotriazole 8 gave 1-triazolecarboxamidotribenzoylribose 13, which afforded by methanolysis oxazoloribofuranose 14 and aminotriazole 8. Compound 14 was also obtained by methanolysis of blocked ribosylcarbamate 16. Reaction of methoxyribosyltriazinone 4 with hydroxylamine in methanol afforded 4-hydroxylamino-1-β-D-ribofuranosyl-1,3,5-triazin-2(1H)-one (N4-hydroxy-5-azacytidine) (3), which on the action of excess hydroxylamine yielded 1-cyano-1-hydroxy-5-β-D-ribofuranosylisobiuret (19). Treatment of methoxy-1,3,5-triazinone 18 with a solution of hydroxylamine in methanol gave 4-hydroxylamino-1-methyl-1,3,5-triazin-2(1H)-one (N4-hydroxy-1-methyl-5-azacytosine) (17). Heating of cyano(formyl)guanidine 10 with hydroxylamine hydrochloride in water lead to the formation of triuret (21). The mechanisms of the reactions of methoxyribosyltriazinone 4 with hydrazine and hydroxylamine are discussed. Compounds 2, 6 and 19 exhibited no significant antibacterial or cytostatic activity.
甲氧基
核糖三嗪醇(4)在
甲醇中与
肼反应生成粗品4-
肼基-1-β-
D-核糖呋喃糖苷-
1,3,5-三嗪-2(1H)-酮(N4-
氨基-
5-氮杂胞苷)(2),迅速重排为异构体5-
核糖尿素三唑(6)。重排在2的
水溶液中也很容易进行。碱
水解6得到混合物5-
尿素三唑(7)和5-
氨基三唑(8)。酸
水解6只得到7。这种化合物也可通过5-
氨基-1-
氨基甲酰基三唑(9)的热重排或
氰(甲酰)
胍氯化
水合物与
肼反应制备。甲酰化的甲氧基
核糖三嗪醇(4a)在
甲醇中与
肼反应只得到重排产物6a。三苯甲酰
核糖异氰酸酯(12)与
氨基三唑(8)反应得到1-三唑羧酰胺基三苯甲酰
核糖(13),经
甲醇解得到
噁唑核糖呋喃糖(14)和
氨基三唑(8)。化合物14也可通过阻断的
核糖氨酸酯(16)的
甲醇解获得。甲氧基
核糖三嗪醇(4)在
甲醇中与
羟胺反应生成4-
羟胺基-1-β-
D-核糖呋喃糖苷-
1,3,5-三嗪-2(1H)-酮(N
4-羟基-
5-氮杂胞苷)(3),在过量
羟胺作用下生成1-
氰基-1-羟基-5-β-
D-核糖呋喃异
尿素(19)。甲氧-
1,3,5-三嗪醇(18)与
甲醇中的
羟胺溶液反应生成4-
羟胺基-1-甲基-
1,3,5-三嗪-2(1H)-酮(N
4-羟基-1-甲基-5-氮杂
胞嘧啶)(17)。
氰(甲酰)
胍氯化
水合物(10)与
羟胺盐酸盐加热反应生成三
尿素(21)。讨论了甲氧基
核糖三嗪醇(4)与
肼和
羟胺的反应机制。化合物2、6和19未表现出明显的抗菌或细胞毒活性。