Notes- Unsaturated Lactams. II. The Catalyctic Dehydrogenation of α,β-Unsaturated Valerolactams to Pyridones.

Shamma, Maurice; Rosenstock, Paul

doi:10.1021/jo01351a636

Cited by 4 publications

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“…106-107 "C, vmaX 3 000, 1660, 1570, and 1360 cm-l; 6 7.60-7. 30 (5 H, m), 6.60br (1 H, s), 6.20br (1 H, s), 3.48 (3 H, s), and 2.32 (3 H, s) (Found: C, 78.7; H, 6.4; N, 6.8. C13H1,-NO requires C, 78.4; H, 6.6; N, 7.0%).…”

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confidence: 99%

Preparation and reactions of pyridones: steric and electronic effects on cycloadditions with 2(1H)-pyridones

Gisby¹,

Royall²,

Sammes³

1982

J. Chem. Soc., Perkin Trans. 1

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The reactions of a series of substituted 2(1 H)-pyridones with dimethyl butynedioate have been studied. Cycloadditions across the 3,6-positions can be observed in certain instances and are particularly favoured where steric buttressing occurs between the substituent groups of the starting pyridones. The pyridone could not be induced to react with simple olefins, either by intermolecular or, via incorporation of alkenyl substituents, by intramolecular processes. From the results it is shown that 2-pyridones can be encouraged to behave as reactive classical dienes in cycloaddition reactions.2( ~H)-PYRIL)oNEs have long attracted chemical attention for their hetero-aromatic character.l Studies, on their ability to sustain an induced ring current, led to estimates that they should possess only ca. 35% of the aromaticity of benzene, implying that the conjugated system should act as a diene in Diels-Alder type cycloaddition reactions2 An X-ray crystallographic study on 1-methyl-2-pyridone (1) supports this view, in that it is shown to contain carbon-carbon bonds which are alternately long and short.3 However, early attempts to illustrate such reactivity failed, partly owing to competing nucleophilic addition of the amide group to the dien~phile.~. Thus, ethoxyacetylene produces a mix-

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confidence: 99%