Investigation of the reactivities and tautomerism of azolidines. 42. 2-Iminothiazolidin-4-ones in the mannich reaction with secondary amines
The aminomethylation of 2-iminothiazolidin-4-one with aqueous formaldehyde and piperidine gives 2-piperidinomethylamino-5-hydroxymethyl-5-piperidinomethylthiazolin-4-one, as well as a compound with an unestablished structure, rather than 3-piperidinomethyl-2-iminothiazolidin-4-one, as was previously assumed. The aminomethylation of 2-iminothiazolidin-4-one with diphenylamine and diethylamine leads to the formation of 2-monoaminomethyl derivatives. 2-Imino-5-benzylidenethiazolidin-4-one reacts with paraformaldehyde and piperidine in benzene to give 2-piperidinomethylimino-3-[(3-piperidinomethyl-4-oxo-5-benzylidenethiazolidin-2-ylidene)iminomethyl]-5-benzylidenethiazolidin-4-one.