STRUCTURE OF 2-IMINO-5-ARYLIDENE-4-THIAZOLIDINONES

Article abstract of DOI:10.1007/BF00523070

It was established by means of PMR spectroscopy that, depending on the method of preparation, 2-imino-5-arylidene-4-thiazolidones exist in the form of various geometrical isomers relative to the exocyclic C=N bond.The E isomers are obtained as a result of condensation of 2-imino-4-thiazolidone with the corresponding benzaldehydes, whereas the Z isomers are formed in the solvolysis of hydroxymethyl and piperidinomethyl derivatives.The geometrical isomers retain their individuality in solutions in d₆-DMSO and in ethanol.Upon dissolving in alkali with subsequent neutralization the E isomer of 2-imino-5-benzylidene-4-thiazolidinone is converted to the Z isomer.Reverse conversion of the Z isomer to the E isomer occurs when a solid sample is heated to 180 deg C.