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Studies on dehydro--ascorbic acid 2-arylhydrazone 3-oximes: Conversion into substituted triazoles and isoxazolines
Authors:Mohamed Ali El Sekily   Sohila Mancy  Bernard Gross
Abstract:-threo-2,3-Hexodiulosono-1,4-lactone 2-(arylhydrazones) (2) were prepared by condensation of dehydro--ascorbic acid with various arylhydrazines. Reaction of 2 with hydroxylamine gave the 2-(arylhydrazone) 3-oximes (3). On boiling with acetic anhydride, 3 gave 2-aryl-4-(2,3-di-O-acetyl--threo-glycerol-l-yl)-1,2,3-triazole-5-carboxylic acid 5,41-lactones (4). On treatment of 4 with liquid ammonia, 2-aryl-4-(-threo-glycerol-l-yl)-1,2,3-triazole-5-carboxamides (5) were obtained. Acetylation of 5 with acetic anhydride-pyridine gave the triacetates, and vigorous acetylation with boiling acetic anhydride gave the tetraacetyl derivatives. Periodate oxidation of 5 gave the 2-aryl-4-formyl-1,2,3-triazole-5-carboxamides (8), and, on reduction, 8 gave the 2-aryl-4-(hydroxymethyl)-1,2,3-triazole-5-carboxamides, characterized as the monoacetates and diacetates. Controlled reaction of 2 with sodium hydroxide, followed by neutralization, gave 3-(-threo-glycerol-l-yl)-4,5-isoxazolinedione 4-(arylhydrazones), characterized by their triacetates. Reaction of 2 with HBr-HOAc gave 5-O-acetyl-6-bromo-6-deoxy--threo-2,3-hexodiulosono-1,4-lactone 2-(arylhydrazones); these were converted into 4-(2-O-acetyl-3-bromo-3-deoxy--threo-glycerol-l-yl)-2-aryl-1,2,3-triazole-5-carboxylic acid 5,41-lactones on treatment with acetic anhydride-pyridine.
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