Reactions of 1,2,3-dithiazoles with halogenated malononitriles
作者:Irene C. Christoforou、Panayiotis A. Koutentis、Charles W. Rees
DOI:10.1039/b202038f
日期:2002.5.10
Dibromomalononitrile 3a reacts with 4-chloro-1,2,3-dithiazole-5-thione 9 and monobromomalononitrile 3c reacts with 4,5-dichloro-1,2,3-dithiazolium chloride 4 (Appel salt) to give 4-chloro-5H-1,2,3-dithiazole-5-ylidenemalononitrile 1 in 76 and 73% yields, respectively, thus providing the best available synthesis of this key intermediate. The reactions were accompanied by the formation of 1-(4-chloro-5H-1,2,3-dithiazol-5-ylideneamino)-1,2-dihaloethene-2-carbonitriles 5, the yields of which increased with reaction temperature. In refluxing toluene, dibromomalononitrile 3a and dithiazolethione 9 give directly 3-bromoisothiazole-4,5-dicarbonitrile 12 (59%); the probable intermediate (dicyanomethylene)dithiazole 1 is readily converted into bromoisothiazole 12 on treatment with anhydrous gaseous HBr at ca. 20 °C (83%). The addition of bromine to dithiazolethione 9 gives 5-bromosulfanyl-4-chloro-1,2,3-dithiazolium bromide 11 almost quantitatively. Mechanisms are proposed for all these reactions.
Koutentis, Panayiotis A.; Rees, Charles W., Journal of the Chemical Society. Perkin transactions I, 1998, # 16, p. 2505 - 2509
作者:Koutentis, Panayiotis A.、Rees, Charles W.
DOI:——
日期:——
Emayan, Kumaraswamy; English, Russell F.; Koutentis, Panayiotis A., Journal of the Chemical Society. Perkin transactions I, 1997, # 22, p. 3345 - 3349
作者:Emayan, Kumaraswamy、English, Russell F.、Koutentis, Panayiotis A.、Rees, Charles W.
DOI:——
日期:——
The reaction of 4,5-dichloro-1,2,3-dithiazolium chloride with dimethylsulfonium dicyanomethylide: an improved synthesis of (4-chloro-1,2,3-dithiazolylidene)malononitrile
作者:Andreas S. Kalogirou、Panayiotis A. Koutentis
DOI:10.1016/j.tet.2009.06.076
日期:2009.8
4,5-Dichloro-1,2,3-dithiazolium chloride 6 (Appel salt) reacts with dimethylsulfonium dicyanomethylide 11 to give 5-(4-chloro-1,2,3-dithiazolylidene)malononitrile 1 and a mixture of E/Z isomers of 3-(4-chloro-5H-1,2,3-dithiazol-5-ylideneamino)-3-chloro-2-(methylthio)acrylonitrile 13. The reaction of 4-chloro-5H-1,2,3-dithiazole-5-thione 10 with dimethylsulfonium dicyanomethylide 11 gives (dithiazolylidene)malononitrile 1 in 92% yield. All new compounds are fully characterised and rational mechanisms are proposed for the formation of all key compounds. (C) 2009 Elsevier Ltd. All rights reserved.
Koutentis, Panayiotis A.; Rees, Charles W.; White, Andrew J. P., Journal of the Chemical Society. Perkin transactions I, 1998, # 17, p. 2765 - 2769
作者:Koutentis, Panayiotis A.、Rees, Charles W.、White, Andrew J. P.、Williams, David J.