Solid-Phase Synthesis of Tetrasubstituted 2-Imino-1,3-thiazolines

Abstract

The solid-phase synthesis of tetrasubstituted 2-imino-1,3-thiazolines 1 was described. Thus, the reaction of primary amines (R1NH2) with Merrifield resin and CS2, followed by cyclocondensation with α-bromoketones 3 in the presence of n-Bu4NBF4 and TMSCl afforded resin-bound thiazolium salts 4. The treatment of 4 with primary amines (R4NH2) gave the corresponding tetrasubstituted 2-imino-1,3-thiazolines 1 in 33-62% overall yield (11 examples). The polymer-supported thiazolium salts 4 were stable under nitrogen at -5 °C for several days.