mesylate 5b. On the other hand the same reaction starting from its isomer 5a did not work and led to the surprising ring contraction products 8a and 8b. Another unexpected ring contraction leading to 15 was pointed out in the course of preparation of the deuteriated compounds 5a′ and 5a″. Position of deuterium in products 8a′ and 8b′ or 8a″ and 8b″ issued from reactions with 5a′ or 5a″ gave useful mechanistic
核苷类似物7是通过
腺嘌呤和
甲磺酸盐5b之间的亲核取代获得的。另一方面,从其异构体5a开始的相同反应无效,并导致令人惊讶的环收缩产物8a和8b。在制备
氘代化合物5a'和5a ''的过程中指出了导致15的另一个意外的环收缩。在产品的
氘位置8A'和8B'或图8a“和8b显示”从与反应发出5A'或5A“ 提供了有关该反应的有用的机理信息。