Reaction of methyl 2-bromo-2,3-dideoxy-5-O-(4-methylbenzoyl)-D-erythro-pentofuranoside (7) with silylated uracils 9 using trimethylsilyl triflate as catalyst afforded the corresponding 2′-bromonucleosides 10. 2,3-Didehydro sugar 8 was prepared by heating 7 with sodium azide in dimethylformamide. 2,2′-Anhydro nucleosides 1 were prepared by treating the nucleosides 10 with sodium methoxide at room temperature. 1-(2-Azido-2,3-dideoxy-β-D-threo-pentofuranosyl)thymine (15) and its α-anomer (16) were prepared by treating 10c with sodium azide and subsequently methanolic ammonia. Treatment of 1-(2-bromo-2,3-dideoxy-α-D-erythro-pentofuranosyl)thymine (11 c) with excess of sodium methoxide under reflux gave the corresponding 2′,5'′anhydro nucleoside 17.
以三甲基
硅烷基
三氟甲烷为催化剂,将 2-
溴-2,3-二脱氧-5-O-(4-甲基苯甲酰基)-D-赤式戊
呋喃糖苷(7)与
硅化尿
嘧啶 9 反应,得到相应的 2′-
溴核苷 10。将 7 与
叠氮化
钠在二甲基甲酰胺中加热,制备出 2,3-二脱氢糖 8。室温下用
甲醇钠处理核苷 10,制备 2,2′-脱氢核苷 1。1-(2-Azido-2,3-dideoxy-δ²-D-threo-pentofuranosyl)thymine (15) 及其 δ-anomer (16) 是用
叠氮化
钠和
甲醇氨处理 10c 而制备的。在回流条件下,用过量
甲醇钠处理 1-(2-
溴-2,3-二脱氧-δ-D-赤式-戊
呋喃糖基)胸腺
嘧啶(11 c),可得到相应的 2′,5'′脱氢核苷 17。