β-Phenylmercapto-cis- and trans-cinnamic Acids

Abstract

β-(p-Chlorophenyl) mercaptocinnamic acid and β-(p-acetamidophenyl) mercaptocinnamic acid were synthesized and separated into cis- and trans-isomers of each. Their configurations were determined by ring closure to be thioflavons under mild conditions. trans-Acids have an absorption band at 8.3μ while cis-acids do not have such band. Other physical methods generally used to determine the geometrical configuration were of no avail for these compounds carrying a bulky group at β-position. cis-Acid was produced via isomerization from the trans-ester during the procedure of saponification.