- OXIDATION OF 2-MERCAPTOBENZOHETERAZOLES BY DIMETHYLDIOXIRANE. A NEW METHOD FOR A SYNTHESIS OF C-2 SUBSTITUTED BENZIMIDAZOLE, BENZOXAZOLE, AND BENZOTHIAZOLE DERIVATIVES
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New and efficient reactions in which 2-mercaptobenzoheterazoles are selectively converted by dimethyldioxirane, under mild experimental conditions, to several C-2 substituted benzoimidazole, benzoxazole, and benzothiazole derivatives are reported.
- Frachey, Giuseppe,Crestini, Claudia,Bernini, Roberta,Saladino, Raffaele,Mincione, Enrico
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p. 2621 - 2630
(2007/10/02)
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- Reactions of hydroxylamines with ethyl cyanoformate. Preparation of aminonitrones and their synthetic applications
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The reaction of hydroxylamines with ethyl cyanoformate 1 leads to the formation of carbethoxyamino nitrones. 2. UV spectroscopy provided information that suggested the nitrone structure for these compounds in solution. X-ray analysis of 2a confirmed that it exists entirely in the nitrone form in the solid state. These nitrones are shown to be excellent starting materials for a variety of nitrogen containing compounds, namely, imidazoles, benzimidazoles, benzimidazolones, oxadiazolones, N-arylamidines and quinoxalone.
- Branco,Prabhakar,Lobo,Williams
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p. 6335 - 6360
(2007/10/02)
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- o-Nitroaniline Derivatives. Part 9. Benzimidazole N-Oxides Unsubstituted at N-1 and C-2
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Since previous routes to the title compounds (1) have proved unsatisfactory as general methods, a simple new synthesis has been devised.N-Cyanomethyl-o-nitroanilines (5) are cyclised in basic media, giving 2-cyanobenzimidazole N-oxides (12) in good yield.Hydrolysis of these products with hydrochloric acid gives, directly, the title compounds as their hydrochloride salts (13), which may be isolated and purified, and which give the free N-oxides (1) by treatment with aqueous ammonia followed by evaporation. o-Nitrophenylglycine esters (4) may satisfactorily replace the nitriles (5) in certain cases.A modification of this kind in the related nitropyridylglycine series leads to 3H-imidazolpyridine 1-oxide (20).
- Harvey, Ian W.,McFarlane, Michael D.,Moody, David J.,Smith, David M.
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p. 681 - 690
(2007/10/02)
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