SOLID-PHASE SYNTHESIS OF SMALL ORGANIC-MOLECULES BASED ON THIAZOLIDINE SCAFFOLD

2-Substituted thiazolidine-4-carboxylic acids were obtained by reaction of aldehydes with unprotected (R)-cysteine attached to the polymeric support via an ester bond. Subsequent transformation into N-acyl derivatives followed by alkaline hydrolysis provided almost exclusively the corresponding (2R,4R)-stereoisomer. A convenient solid phase synthesis of substituted thiazolidines, including an evaluation of aldehydes, conditions for N-acylation and S-oxidation as well as the stability of thiazolidines to reagents used in solid phase synthesis are described.