Synthesis of a library of N-p-hydroxybenzoyl thioureas using a poly(ethylene glycol) support

A library of N-p-hydroxybenzoyl thioureas has been synthesized using poly(e thylene glycol) (PEG) as soluble polymer support. PEG and para-hydroxybenzo ic acid were linked by oxalyl chloride to give II. Compound II was acylated by thionyl chloride, followed by esterification with ammonium rhodanate to give IV in which PEG itself also acted as phase-transfer catalyst. Compoun d IV reacted with R1R2NH to yield V. Hydrolysis of V gave VI. This syntheti c method is simple and mild, and the yields a-re moderate to high.