Synthesis of 4,6-dimethyl-2-thioxo-1,2-dihydropyridine-3-carbonitrile by condensation of cyanothioacetamide with acetaldehyde and 1-(prop-1-en-2-yl)piperidine

Abstract

Three-component condensation of cyanothioacetamide with acetaldehyde and 1-(prop-1-en-2-yl)piperidine afforded 4,6-dimethyl-2-thioxo-1,2-dihydropyridine-3-carbonitrile which was alkylated with alkyl halides to obtain substituted 2-alkylsulfanyl-4,6-dimethylpyridine-3-carbonitriles, (3-amino-4,6-dimethylthieno-[2,3-b]pyridin-2-yl)(4-cyclohexylphenyl)methanone, and 2,2′-[ethane-1,2-diylbis(sulfanediyl)]bis(4,6-dimethylpyridine-3-carbonitrile).

Recent advances in the chemistry of thieno[2,3-b]pyridines 1. Methods of synthesis of thieno[2,3-b]pyridines

“…The system NaOH/EtOH are also used at 10 С, 44 as well as the system KOH/DMF/H 2 O at room temperature. [45][46][47][48][49][50][51][52][53] It is often impossible to carry out the synthesis one-pot, since further cyclization of nicotinonitriles 2 requires more drastic conditions. In particular, stronger bases and a higher reaction temperature necessary for the generation of key cyclization intermediates, carbanions 5.…”