A series of 3-deazapurine ribonucleosides 5a-5l bearing diverse C-substituents (alkyl, aryl and heteroaryl) in the position 6 were prepared by Pd-catalyzed cross-coupling reactions of either free 6-chloro-3-deazapurine ribonucleoside 4 or its acetyl protected congener 3 followed by deprotection. An improved synthesis of the starting 4-chloro-1-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-1H-imidazo[4,5-c]pyridine (3) was developed by the application of Vorbrüggen glycosylation of silylated nucleobase with 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose (2). None of compounds 5a-5l showed any considerable cytostatic or antiviral activity.
一系列带有不同C-取代基(烷基,芳基和杂环芳基)的3-去氮嘌呤核苷类化合物5a-5l在6位经过Pd催化的交叉偶联反应中由自由的6-氯-3-去氮嘌呤核苷类化合物4或其乙酰保护的同分异构体3制备而成,随后去保护基。通过使用硅基核苷碱与1,2,3,5-四-O-乙酰-β-D-核糖苷(2)进行Vorbrüggen糖基化反应,改进了起始化合物4-氯-1-(2,3,5-三-O-乙酰-β-D-核糖呋喃基)-1H-咪唑[4,5-c]吡啶(3)的合成方法。化合物5a-5l均未表现出任何显著的细胞毒或抗病毒活性。