- Regioselective hydrodehalogenation of 3,5-dihaloisothiazole-4- carbonitriles: Synthesis of 3-haloisothiazole-4-carbonitriles
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3,5-Dibromoisothiazole-4-carbonitrile 1 treated with Zn or In dust (5 equiv) and HCO2H undergoes regioselective hydrodebromination to give 3-bromoisothiazole-4-carbonitrile 3 in 70-74% yield. Similarly, 5-bromo and iodo 3-chloroisothiazole-4-carbonitriles 8 and 9 give 3-chloroisothiazole-4- carbonitrile 4 in 77 and 85% yields, respectively. Also hydrodeamination of 5-amino-3-chloroisothiazole-4-carbonitrile 7 using isoamyl nitrite gives the latter in 95% yield. The dibromoisothiazole 1 reacts with Zn dust in either DCO2D or HCO2D to give 3-bromo-5-deuterioisothiazole-4- carbonitrile 10 in 71 and 58% yields, respectively. The 3-bromoisothiazole 3 reacts with cyclic dialkylamines to give the corresponding 2- (dialkylaminomethylene)-malononitriles and not the expected 3- dialkylaminoisothiazole-4-carbonitriles. Finally, the 3-bromoisothiazole 3 is readily converted into both 3-bromoisothiazole-4-carboxamide 19 and the carboxylic acid 20. All products are fully characterized.
- Ioannidou, Heraklidia A.,Koutentis, Panayiotis A.
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experimental part
p. 3348 - 3354
(2011/06/17)
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- New regiospecific isothiazole C-C coupling chemistry
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Regioselective palladium catalysed coupling reactions are achieved in good to high yields, starting from either 3,5-dichloro- or 3,5-dibromoisothiazole-4-carbonitriles 1 and 2, providing 3-halo-5-(hetero/aryl, alkenyl and alkynyl)isothiazoles 3, 4, 6-9 fr
- Christoforou, Irene C.,Koutentis, Panayiotis A.
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p. 3681 - 3693
(2008/09/19)
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