An alternative synthesis of 2', 3', 5'-tri-O-benzoyl-N, N, 3-trimethyladenosine iodide (9a) was attained by the reaction of N, N, 3-trimethyladenine (11a) with 1-O-acetyl-2, 3, 5-tri-O-benzoyl-β-D-ribofuranose (10) in the presence of SnCl4 followed by treatment with NaI. Although 3-benzyl-N, N-dimethyladenine (11c) did not react with under similar conditions, the ribosylation of 3-ethyl-N, N-dimethyladenine (11b) followed by alkaline hydrolysis led to the first synthesis of 5-(ethylamino)-1-β-D-ribofuranosyl-1H-imidazole-4-carboxamide (15b). A more general procedure for the synthesis of 5-(alkylamino)-1-β-D-ribofuranosyl-1H-imidazole-4-carboxamides (15) was developed via a series of reactions : alkylation of N'-benzyloxy-5-formamido-1-β-D-ribofuranosyl-1H-imidazole-4-carboxamidine (12) with alkyl halides in the presence of K2 CO3, catalytic hydrogenolysis, and alkaline hydrolysis. By means of this method, 5-(benzylamino)- (15c) and 5-(isopropylamino)-1-β-D-ribofuranosyl-1H-imidazole-4-carboxamide (15d) were synthesized for the first time.
N,N,3-三甲基
腺嘌呤(11a)与 1-O-乙酰基-2,3,5-三-O-苯甲酰基-β-D-
呋喃核糖(10)在 SnCl4 的存在下发生反应,然后用 NaI 处理,可合成 2',3',5'-三-O-苯甲酰基-N,N,3-三甲基
腺苷碘化物(9a)。虽然 3-苄基-N,N-二甲基
腺嘌呤(11c)在类似条件下没有发生反应,但 3-乙基-N,N-二甲基
腺嘌呤(11b)的
核糖基化,然后进行碱性
水解,首次合成了 5-(乙基
氨基)-1-β-D-
呋喃核糖基-
1H-咪唑-4-甲酰胺(15b)。通过一系列反应:N'-苄氧基-5-甲酰胺基-1-β-D-
呋喃核糖基-
1H-咪唑-4-
甲脒 (12) 在 K2
CO3 存在下与烷基卤化物发生烷基化反应、催化氢解反应和碱性
水解反应,开发出了合成 5-(烷基
氨基)-1-β-D-
呋喃核糖基-
1H-咪唑-4-甲酰胺 (15) 的更一般的程序。通过这种方法,首次合成了 5-(苄基
氨基)-(15c)和 5-(异丙基
氨基)-1-β-D-
呋喃核糖基-
1H-咪唑-4-甲酰胺(15d)。