An efficient synthesis of novel pyridothieno-fused thiazolo3,2-αpyrimidinones via Pictet–Spengler reaction

摘要

An efficient method for the synthesis of novel pyrido[3'',2'':4',5']thieno[3',2':2,3]pyrido [4,5:d][1,3]thiazolo[3,2-a]pyrimidine-4-one derivatives(5) has been developed using a Pictet–Spengler reaction between 2-(3-aminothieno[2,3-b]pyridin-2-yl)thiazolo[3,2-a] pyrimidin-5-one(3), which could be obtained from the condensation of 7-(chloromethyl)-5H-thiazolo[3,2-a]pyrimidin-5-one(1) with3-cyanopyridine-2-thione(2) via Thorpe–Ziegler isomerization, and aromatic aldehydes under NH_2SO_3 H as catalysis in good yields.