Some thiazolidine derivatives were prepared by the introduction of p-aminobenzene-sulfonyl, p-nitrobenzenesulfonyl and p-nitrobenzoyl groups in the nuclear nitrogen of thiazolidine, thiazolidine sulfone and thiazolidine-4-carboxylic acid. Sulfonylation of the nuclear nitrogen in l-thiazolidine-4-carboxylic acid resulted, in most cases, in racemization.
