- Synthesis and Chemistry of Azolenines. Part 16. Preparation of both 3H- and 2H-Pyrroles from 2,2-Disubstituted 1,4-Diketones via the Paal-Knorr Reaction, and Isolation of Intermediate 2-Hydroxy-3,4-dihydro-2H-pyrroles
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Treatment of 2,2-disubstituted 1,4-diketones (1) with liquid ammonia gives high yields of isolable isomeric 2-hydroxy-3,4-dihydro-2H-pyrroles (10) and (11), many of which may be dehydrated to 3H-pyrroles (2) together, in certain cases, with isomeric methylene-pyrrolines (14) and (15).When heated in acetic acid with ammonium acetate, the diketones (1) yield 2H-pyrroles (18), sometimes in admixture with 3H-pyrroles (2) from which they are formed by rearrangement.The diketones (1), including some novel examples, are prepared from nitro-ketones (6) by the Nef reaction, as well as other methods.
- Lui, Kon-Hung,Sammes, Michael P.
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p. 457 - 468
(2007/10/02)
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- Novel Synthesis of 3H-Pyrroles, and Novel Intermediates in the Paal-Knorr 1H-Pyrrole Synthesis: 2-Hydroxy-3,4-dihydro-2H-pyrroles from 1,4-Diketones and Liquid Ammonia
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Reaction of 2,2-dimethyl-1,4-diketones with liquid ammonia gives high yields of isolable 2-hydroxy-3,4-dihydro-2H-pyrroles (3) and (5) which are readily dehydrated to give separable mixtures of 3H-pyrroles and methylenedihydropyrroles, while less-substituted 1,4-diketones give analogous hydroxy-compounds (4) and (6) which are hitherto-unsuspected intermediates in the Paal-Knorr 1H-pyrrole synthesis.
- Chiu, Pak-Kan,Lui, Kon-Hung,Maini, Prem Nath,Sammes, Michael P.
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p. 109 - 110
(2007/10/02)
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