Methodology to Access Thiazo[3’,2’:2,3]pyrido[4,5-d]thiazolo[3,2-a]pyrimidinones
摘要:
A synthesis of model thiazolo[3',2':2,3]pyrido[4,5-d]thiazolo[3,2-a]-pyrimidin-5-ones (5), based on the classical Pictet-Spengler method, is described. The key intermediate, 7-(3-amino-5-phenylaminothiazol-2-yl)-5H-thiazolo-[3,2-a]pyrimidin-5-one (3), was synthesized from 7-chloromethy1-5H-thiazolo-[3,2-cdpyrimidin-5-one (1) with potassium N-phenyl-N'-cyanoimidothiocarbonate (2) by Thorpe-Ziegler isomerization. Cyclocondensation of the intermediate amine with aromatic aldehydes, using sulfamic acid under Pictet-Spengler reaction conditions, delivered the target compounds 5a-m.