Regioselectivity of the reactions of 4,5-diphenylimidazole-2-thione with 1-chloro-2,3-epoxy-propane and 1-bromo-propene, efficient precursors for imidazo[2,1-<i>b</i>]thiazine and thiazole. Effect of microwave and solid support
作者:Mohamed. R. Aouad、Nadje T. Rezki、El Sayed H. El Ahsry
DOI:10.1002/jhet.5570450511
日期:2008.9
A regioselective allylation of 1 with allyl bromide in presence of triethylamine gave the S-allyl 8, while in presence of potassium carbonate led to the S,N-bis(allylated) derivative 9. The intramolecular ring closure of 8 in presence of sulfuric acid afforded the imidazothiazole 16. Protection of the sulfur in 1 and subsequent reaction with allyl bromide gave the N-allylated derivative and with 2 gave
在没有溶剂的微波(MW)照射下,固体支持物可以选择性地合成2,3-环氧-丙基-硫代咪唑4,并禁止其环化,从而使咪唑并[2,1- b ]噻嗪3发生反应。 4,5-二苯基咪唑-2-硫酮(1)与1-氯-2,3-环氧丙烷(2)。后者的形成需要成为其唯一产品的基本条件;碱性催化剂的变化改变了常规和微波(MW)条件下两种产物的比例。在三乙胺的存在下,用烯丙基溴对1进行区域选择性烯丙基化,得到S-烯丙基8,而在碳酸钾的存在下导致S,N-双(烯丙基化)衍生物9。在硫酸存在下的分子内8的闭环得到咪唑并噻唑16。在1中保护硫,然后与烯丙基溴反应,得到N-烯丙基化衍生物,与2反应得到N-3-氯-丙-1-基衍生物,这为形成3和4的优选路线提供了线索。理论上已经通过使用AM1方法研究了1与2的烷基化过程中遇到的反应性。