Structure of the intermediate in the synthesis of 6-methyl-2-oxo-1,2-dihydropyridine-3-carbonitrile

Abstract

4-(Dimethylamino)but-3-en-2-one 1a reacted with malononitrile 2a affording (2E,4E)-2-cyano-5-dimethylamino)hexa-2,4-dienamide 6aa that was isolated as two isomers,1-s-cis and 1-s-trans 6aa as confirmed by X-ray diffraction analysis. Acid-induced cyclization of 1-s-cis 6aa gave the known 1,2-dihydro-6-methyl-2-oxopyridine-3-carbonitrile 3aa, but not 1,2-dihydro-4-methyl-2-oxopyridine-3-carbonitrile 9aa as reported previously. The mechanistic pathway of the 2-pyridone ring formation is discussed.

Application of stable fused dienolates for diversity oriented synthesis of 2,5-dioxo-5,6,7,8-tetrahydro-2H-chromene-3-carboxamides

“…Attempts to synthesize enolates starting from acyclic carbonyl compounds 12 were not successful. 20 According to the data obtained by Mosti's group 21 and the next following reports, [22][23][24] the reaction in this case is accomplished by formation of amides 15 probably via a ring opening of the intermediate iminopyrane 14 (Scheme 2). The reason for the higher stability of the cyclic enolates lies probably in the higher acidity of the cyclic 1,3-dicarbonyl compounds as compared to their acyclic analogs.…”

Synthesis and Characterization of some Disperse Dyes based on Enaminones

“…Conditions for the effective synthesis of enaminones from methylketones and DMFDMA including microwave heating have been accounted for earlier by us and all the more as of late by others [13][14][15][16][17]. We next examined the coupling reaction of enaminone 4a-c with arylidene diazonium chloride.…”

Spectroscopic, Structural, and Conformational Properties of (Z)-4,4,4-Trifluoro-3-(2-hydroxyethylamino)-1-(2-hydroxyphenyl)-2-buten-1-one, C12H12F3NO3: A Trifluoromethyl-Substituted β-Aminoenone

“…The β-aminoenone N–CC–CO system is a structural moiety that constitutes an attractive and intricate subject to study. This conjugated moiety shows physical and chemical properties of both α,β-unsaturated carbonyl and enamine groups and for several decades has generated considerable interest as a useful multifunctional and relatively simple building block in synthetic and medicinal chemistry. − These compounds are another class of unsymmetrical pentad tautomeric systems, being the aminoenone, the iminoenol, and the iminoketone, the most stable tautomers (Scheme ). In this prototropic tautomerism, the migration of three protons takes place; two of them are 1,3 shifts (keto–enol and imine–enamine), and the other one is a 1,5 proton shift (iminoenol–aminoenone) .…”