Synthesis and structure of substituted 3,4-dihydropyridin-2-ones

Unexpected reaction on bromination of 3,4-dihydropyridin-2(1H)-ones with N-bromosuccinimide

“…According to [7], compounds 3 with J 34 < 0.5 Hz exist in the trans-form with Ph and CONH 2 in pseudoaxial positions. In the spectra of compounds 5 J 34 = 11.4-11.6 Hz shows that the groups Ph and CONH 2 Tetradecyl (2S,3S,4R,5R)-3-bromo-5-carbamoyl-2-hydroxy-2-methyl-6-oxo-4-phenylpiperidine-3-carboxylate (5a).…”

Cyanopyridines. Synthesis and Recyclization of Their Quaternary Salts

“…Anhydrous dimethylformamide, 0.1 ml, was added to a suspension of 2.70 g (10 mmol) of ethyl 5-cyano-2-methyl-6-oxo-4-phenyl-1,6-dihydropyridine-3-carboxylate [9] Ethyl 5-cyano-2-methyl-4-phenylpyridine-3-carboxylate (IIg). A solution of 1.98 g (6.6 mmol) of chloropyridine IV in a mixture of 14 ml of acetic acid, 14 ml of ethanol, and 4 ml of water was heated on a water bath to the boiling point, and 2.10 g (26.4 mmol) of zinc dust was added in portions over a period of 1 h. The mixture was cooled and filtered, the filtrate was diluted with water, and the precipitate was filtered off.…”

“…Under these conditions, addition of the β-carbon atom in the enamine fragment of 4-amino-3-penten-2-one to ethoxymethylene derivative of benzoylacetonitrile gave rise to a new carbon-carbon bond and closure of pyridine ring [7,8] (Scheme 2). The synthesis of ethyl 5-cyano-2-methyl-4-phenylpyridine-3-carboxylate (IIg) included structural modification of previously described ethyl 5-cyano-2-methyl-6-oxo-4-phenyl-1,6-dihydropyridine-3-carboxylate [9] via nucleophilic replacement of the hydroxy group by chlorine and subsequent reductive dechlorination (Scheme 3). Nitro- …”

Cyanoacetamides and their thio- and selenocarbonyl analogues as promising reagents for fine organic synthesis

“…The latter is transformed into ethyl 3-cyano-6-methyl-4phenyl-1,2-dihydropyridine-5-carboxylate (220) on treatment with dilute nitric acid. 485 Tetrahydroisoquinolinone 222 has been obtained by the condensation of b-enamino ester 221 with cyanoacetamide (1a). 465 a,b-Unsaturated carbonyl compounds, owing to the substantial difference in reactivities of their nucleophilic centres, react with cyanothioacetamides yet more regioselectively than the corresponding enamino carbonyl compounds.…”