(1R*,2R*,3R*,4R*,5R*,6S*)-3-Amino-5-(benzyloxy)-6-(hydroxymethyl)bicyclo[2.2.1]heptan-2-ol (18) was prepared in seven easy steps from benzyl (1R*,2S*,3S*,4S*)-3-(benzyloxy)bicyclo[2.2.1]hept-5-ene-2-carboxylate (10). Reaction of amine18with ethylN-((2E)-3-ethoxymethacryloyl)carbamate afforded 1-[(1R*,2R*,3R*,4R*,5S*,6R*)-6-(benzyloxy)-3-hydroxy-5- (hydroxymethyl)bicyclo[2.2.1]heptan-2-yl]-5-methylpyrimidine-2,4(1H,3H)-dione (21) and after deprotection by transfer hydrogenation, free thymine analogue22. The thymine derivative21was converted to 2,3'-anhydronucleoside26. Treatment of the benzyl derivative18with sodium in liquid ammonia led to amine19, which was used as key intermediate for the construction of (1R*,2R*,3R*,4R*,5R*,6S*)-3-(6-chloro-9H-purin-9-yl)-6-(hydroxymethyl)-bicyclo[2.2.1]heptane-2,5-diol (28) and (1R*,2R*,3R*,4R*,5R*,6S*)-3-(2-amino-6-chloro-9H-purin-9-yl)-6-(hydroxymethyl)bicyclo[2.2.1]heptane-2,5-diol (33). Ammonolysis of28led to 6-amino-9H-purine derivative29. 6-(Dimethylamino)-9H-purine analogue30and 6-(cyclopropylamino)-9H-purine analogues31and34were prepared by aminolysis of corresponding chloropurine derivatives.
(1R*,2R*,3R*,4R*,5R*,6S*)-3-
氨基-5-(苄氧基)-6-(羟甲基)
双环[2.2.1]庚烷-2-醇 (18) 是从苄基 (1R*,2S*,3S*,4S*)-3-(苄氧基)
双环[2.2.1]庚-5-烯-2-羧酸乙酯 (10) 经过七个简单步骤制备的。
氨基18与乙基N-((2E)-3-乙氧基甲基
丙烯酰基)
氨基甲酸酯反应得到1-[(1R*,2R*,3R*,4R*,5S*,6R*)-6-(苄氧基)-3-羟基-5-(羟甲基)
双环[2.2.1]庚烷-2-基]-5-
甲基嘧啶-2,4(1H,3H)-二酮 (21),经过转移氢化去保护后得到自由
胸苷类似物22。
胸苷衍
生物21被转化为2,3'-骨架核苷26。苄基衍
生物18经过液
氨中
钠的处理得到
氨基19,它被用作构建(1R*,2R*,3R*,4R*,5R*,6S*)-3-(6-
氯-9H-
嘌呤-9-基)-6-(羟甲基)
双环[2.2.1]庚烷-2,5-二醇 (28) 和 (1R*,2R*,3R*,4R*,5R*,6S*)-3-(2-
氨基-6-
氯-9H-
嘌呤-9-基)-6-(羟甲基)
双环[2.2.1]庚烷-2,5-二醇 (33) 的关键中间体。28的
氨解作用得到6-
氨基-9H-
嘌呤衍
生物29。6-(
二甲胺基)-9H-
嘌呤类似物30和6-(
环丙胺基)-9H-
嘌呤类似物31和34是通过对应
氯嘌呤衍
生物的
氨解制备的。