Kazhkenov Zeinul-Gabiden M, Bush Alexander A, Babaev Eugene V
Chemistry Department, Moscow State University, Moscow 119992, Russia.
Molecules. 2005 Sep 1;10(9):1109-18. doi: 10.3390/10091109.
A series of previously unavailable derivatives of 2-alkyl- and 2-benzylderivatives of oxazolo[3,2-a]pyridines III were obtained via tandem ring opening and ring closure from stable mesoionic 3-acyloxazolo[3,2-a]pyridinium-2-olates I. The key intermediates of this tandem transformation are N-(b-oxoethyl)pyridones-2 II obtained by Dakin-West acylation of (pyridone-2-yl-1)acetic acid. An example of further utilization of this strategy is illustrated by preparation of unknown 2-benzylimidazo[1,2-a]pyridine from the salt I and ammonia.
通过稳定的中氮茚型3-酰氧基恶唑并[3,2-a]吡啶-2-醇盐I进行串联开环和闭环反应，得到了一系列以前无法获得的恶唑并[3,2-a]吡啶III的2-烷基和2-苄基衍生物。该串联转化的关键中间体是通过（吡啶酮-2-基-1）乙酸的达金-韦斯特酰化反应得到的N-（β-氧代乙基）吡啶酮-2 II。由盐I和氨制备未知的2-苄基咪唑并[1,2-a]吡啶说明了该策略的进一步应用实例。
