- Regiochemistry of nucleophilic substitution of pentachloropyridine with N and O bidentate nucleophiles
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Site reactivity of some enol-imines derived from N-aryl formamides with pentachloropyridine under basic conditions in dry CH3CN was investigated. The aromatic nucleophilic substitution of pentachloropyridine with enol-imines occurs at the 4-position of pyridine ring by both oxygen and nitrogen site of enol-imines. Nucleophilic attack by the oxygen of enol-imine gave corresponding oximino compounds as a mixture of E- and Z-isomers. In contrast, nucleophilic attack by the nitrogen of enol-imine gave the unexpected N,N-di-substituted aryl compounds. The structures of all the compounds were confirmed by IR, 1H NMR, 13C NMR and 19F NMR spectroscopy as well as elemental analysis and X-ray crystallography.
- Poorfreidoni, Alireza,Ranjbar-Karimi, Reza,Kia, Reza
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p. 4398 - 4406
(2015/06/16)
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- Polyhalogenoaromatic Compounds. Part 43. Inter- and Intra-molecular Reactions of Polychloroaromatic Compounds with Copper
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The reaction of polychloroiodoarenes with copper in dimethylformamide gives good yields of the biaryls. 4-Bromotetrachloropyridine gives products of halogen exchange and reduction as well as coupling.Pentachloropyridine gave only tetrachloropyridines.Evidence against free radical or pyridyne intermediates is presented, and it is postulated that the reactions proceed via pyridylcopper compounds, although an electron transfer mechanism is not excluded.On reaction with copper, some 4-(o-halogenophenoxy)- and 4-(o-halogenothiophenoxy)-tetrahalogenopyridines give products of cyclisation, reduction, and halogen transfer.Copper reacts initially, at least in part, with the pyridyl group rather than with the o-halogenoaryl group.The results are again consistent with a reaction pathway involving a pyridylcopper intermediate.The products of nucleophilic substitution in pentahalogenopyridines by some phenols, thiophenols, and anilines are reported.
- Mack, Arthur G.,Suschitzky, Hans,Wakefield, Basil J.
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p. 1682 - 1687
(2007/10/02)
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