Search

The one-pot four-component reaction of benzohydrazide, acetylenedicarboxylate, aromatic aldehydes and malononitrile in ethanol with triethylamine as base catalyst afforded functionalized 1-benzamido-1,4-dihydropyridines in satisfactory yields. Under similar conditions, picolinohydrazide or nicotinohydrazide can also be successfully utilized in the reactions to give corresponding functionalized 1,4-dihydropyridines. 1H NMR data indicated that an equilibrium of cis/trans-conformations exist in 1-benzamido-1,4-dihydropyridines. [ABSTRACT FROM AUTHOR]

In the presence of zinc chloride, the in situ generated β-enamino ester from the reaction of morpholine, piperidine and pyrrolidine with methyl propiolate reacted, with aromatic aldehydes and thiourea in ethanol resulting in the functionalized tetrahydropyrimidin-2-thiones in satisfactory yields and with good diastereoselectivity. When aromatic aldehydes bearing electron-withdrawing group were used in the reaction, the 4-hydroxytetrahydropyrimidin-2-thione derivatives were obtained as the main product. [ABSTRACT FROM AUTHOR]