Halogenated 7-deazapurine nucleosides: stereoselective synthesis and conformation of 2′-deoxy-2′-fluoro-β-<scp>d</scp>-arabinonucleosides
作者:Xiaohua Peng、Frank Seela
DOI:10.1039/b409648g
日期:——
The stereoselective syntheses of 5-halogenated 7-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl)-7H-pyrrolo[2,3-d]pyrimidine nucleosides 3b-d, 4a-c as well as 7-deaza-2'-deoxyisoguanosine are described. Nucleobase anion glycosylation of 2-amino-4-chloro-7H-pyrrolo[2,3-d]pyrimidine (5) with 3,5-di-O-benzoyl-2-deoxy-2-fluoro-alpha-D-arabinofuranosyl bromide (6) exclusively gave the beta-D-anomer, which was
5-卤代7-(2-脱氧-2-氟-β-D-阿拉伯呋喃糖基)-7H-吡咯并[2,3-d]嘧啶核苷3b-d,4a-c和7-脱氮的立体选择性合成描述了-2'-脱氧异鸟苷。2-氨基-4-氯-7H-吡咯并[2,3-d]嘧啶(5)与3,5-二-O-苯甲酰基-2-脱氧-2-氟-α-D-阿拉伯呋喃糖基的核碱基阴离子糖基化溴化物(6)仅生成β-D-异头物,将其解封(-> 8),在C4处进行胺化(-> 3a),然后在C2处进行选择性脱氨,生成2'-脱氧-2'-氟-β -D-阿拉伯呋喃糖基7-脱氮异鸟嘌呤(2)。5-卤代的4-氯-2-新戊酰基氨基-7H-吡咯并[2,3-d]嘧啶9a-c与6的缩合提供了N7-核苷10a-c以及N2,N7-双糖基化的化合物11a-c。前者转化为相应的2,4-二氨基化合物3b-d,后者用NaOMe / MeOH解封闭,得到4-甲氧基-核苷4a-c。基于邻位[1H,1H]偶合常数对核苷2