Studies with polyfunctionally substituted heteroaromatics: New routes for the synthesis of polyfunctionally substituted pyridines and 1,2,4‐triazolo[1,5‐a]pyridines

Abstract

ABSTRACT

Enaminones as Building Blocks in Heterocyclic Syntheses: Reinvestigating the Product Structures of Enaminones with Malononitrile. A Novel Route to 6-Substituted-3-Oxo-2,3-Dihydropyridazine-4-Carboxylic Acids

“…It has been reported earlier [16] that hydrolysis of 18 obtained via condensation of 17 with dimethylformamide dimethylacetal afforded the pyridone derivatives 19. We have repeated this experiment and came to the conclusion that hydrolysis of 18 in KOH affords in fact isomeric pyridone 19, which in turn gives spectra very similar to those of 16.…”

Gas-phase pyrolysis of 2-heteroaromatic-1-dimethylaminoethylenes: Kinetic and mechanistic study

“…(4). From a condensation reaction of 2-phenylethylidenemalononitrile and dimethylformamide dimethylacetal, following the experimental procedure described earlier [12], the product was obtained in 75% yield as violet crystals from ethanol, m.p. 149ЊC.…”

“…1 2-Cyano-5-dimethylamino-3-(2-thienyl)-2,4-pentadienonitrile (5). From a condensation reaction of 2(2Ј-thienyl)ethylidenemalononitrile and dimethylformamide dimethylacetal, following the experimental procedure described earlier [12], the product was obtained in 80% yield as yellow crystals from ethanol, m. (6). From a condensation reaction of 1,2-dihydro-2-oxo-4-methylquinoline-3-carbonitrile and dimethylformamide dimethylacetal, following the experimental procedure described earlier [13], the product was obtained in 65% yield as yellow crystals from ethanol, m.p.…”

New One Pot-synthesis of Functionally Substituted Pyridines from Enaminoketones

“…The elaboration of efficient synthesis protocols for a variety of aromatic and heteroaromatic systems as potential bio‐active agents have been a major area of research interest in our laboratory over the past several years . Recently, enaminones have been successfully utilized as building blocks for the synthesis of polyfunctionalized heteroaromatics and other related condensed systems . In view of our interest in developing an efficient synthesis of polyfunctionally substituted heteroaromatics using the readily obtainable enaminoketones 1a , 1b , 1c , 1d as starting materials, it was worthwhile to explore their potential utilization for the synthesis of polyfunctional substituted pyridines because of their biological and medicinal activities.…”