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

Significance

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.