PRODUCTION OF 5-(DIALKYLMETHYLIDENE)-RHODANINE DERIVATIVE

PROBLEM TO BE SOLVED: To obtain the subject compound in a high yield by reacting a specific rhodanine compound with a ketone compound using a condensing agent and without using solvents except the aforementioned ketone compound. SOLUTION: This production of a 5-(dialkylmethylidene)-rhodanine derivative is to react a compound expressed by formula I [(n) is 1-3], (e.g. 3- carboxymethylrohdanine, 3-carboxypropylrohdanine, etc.), with a compound expressed by formula II (R1 and R2 are each a 1-6C alkyl, alkenyl or the like), (e.g. acetone, diethyl ketone, etc.), by using a condensing agent (e.g. ammonium acetate, acetic acid, etc.), without using a solvent except a compound of formula II to obtain a compound of formula III [e.g. 3-carboxymethyl-5-(1- methylethylidene)-rhodanine, etc.]. When ammonium acetate is used together with acetic acid in the aforementioned reaction, ammonium acetate is preferably used in 0.1-2 times mole to the compound of formula I and acetic acid in 0.2-3 times mole.