- 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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- Trimethylsilyl Cyanide - A Reagent for Umpolung, III: Nucleophilic Acylation of α,β-Unsaturated Carbonyl Compounds with directed 1,2-/1,4-Additions by Solvent Effects
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The anion 7 of O-(trimethylsilyl)cyanohydrine 6, derived from benzaldehyde, attacks numerous α-enones in ether exclusively by 1,4-addition, even if C-3 is alkyl-substituted.In THF and DME the 1,2-adduct is formed predominantly; on addition of HMPT or 12-c
- Huenig, Siegfried,Wehner, Gregor
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p. 302 - 323
(2007/10/02)
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