Synthesis of (4R)-thiazolidine carboxylic acid and evaluation of antioxidant potential

We report here the synthesis as well as antioxidant activity of a series of 2-aryl thiazolidine-4-carboxylic acids, including two novel derivatives. They were synthesized by nucleophilic cyclic condensation of L-cysteine hydrochloride with a range of aromatic aldehydes. Their in vitro antioxidant activity was evaluated by DPPH radical scavenging assay. It was observed that the aromatic substituent at C-2 of thiazolidine ring effects the antioxidant potential of the thiazolidine derivatives. The nature and position of the substituents on aromatic ring were correlated with antioxidant activity. Compounds with -OCH₃ group on aromatic ring showed a better radical scavenging property than the other groups such as -Cl, -F, and -NO2. The presence of phenyl ring thus enhanced radical scavenging activity.