The reaction of malononitrile with thioglycolic acid. A novel procedure for the synthesis of thiazolone derivatives

Malononitrile (I) reacted with thioglycolic acid to yield the thiazolin‐4‐one derivatives II or III depending on the molar ratio of the reactants. Compound II reacted with benzaldehyde in refluxing pyridine to yield the arylidene derivative IV. On the other hand, the benzylidine bis derivative VIII was obtained when II was reacted with benzaldehyde in refluxing ethanol. The structure of IV was established via its synthesis from the reaction of benzylidenemalononitrile (VI) and thioglycolic acid in refluxing acetic acid. Similar to II, compound III condensed with benzaldehyde to yield the benzylidene derivative IX.