STUDIES ON DEHYDRO-L-ASCORBIC ACID 3-OXIME 2-PHENYLHYDRAZONE: CONVERSION INTO SUBSTITUTED TRIAZOLES

Article abstract of DOI:10.1016/S0008-6215(00)88065-9

L-threo-2,3-Hexodiulosono-1,4-lactone 3-oxime 2-(phenylhydrazone) (1) gave 2-(p-bromophenyl)-4-(L-threo-1,2,3-trihydroxypropyl)-1,2,3-triazole-5-carboxylic acid 5,1¹-lactone (2), and this gave a diacetyl and a dibenzoyl derivative.On treatment of 2 with liquid ammonia, methylamine, or dimethylamine, the corresponding triazole-5-carboxamides (5-7) were obtained.Periodate oxidation of 5 gave 2-(p-bromophenyl)-4-formyl-1,2,3-triazole-5-carboxamide (10),and, on reduction, 10 gave 2-(p-bromopheyl)-4-(hydroxymethyl)-1,2,3-triazole-5-carboxamide, characterized as its monoacetate.Condensation of 10 with phenylhydrazine gave the triazole hydrazone.Acetonation of 2 gave the isopropylidene derivative.Reaction of 2 with HBr-HOAc gave 4-(L-threo-2-O-acetyl-3-bromo-1,2-dihydroxypropyl)-2-(p-bromophenyl)-1,2,3-triazole-5-carboxylic acid 5,1¹-lactone.Similar treatment of 1 with HBr-HOAc gave 5-O-acetyl-6-bromo-6-deoxy-L-threo-2,3-hexodiulosono-1,4-lactone 3-oxime 2-(phenylhydrazone).This was converted into 4-(L-threo-2-O-acetyl-3-bromo-1,2-dihydroxypropyl)-2-phenyl-1,2,3-triazole-5-carboxylic acid 5,1¹-lactone on treatment with boiling acetic anhydride.On reaction of 1 with benzoyl chloride in pyridine, dehydrative cyclization occurred, with the formation of 4-(L-threo-2,3-dibenzoyloxy-1-hydroxypropyl)-2-phenyl-1,2,3-triazole-5-carboxylic acid 5,1¹-lactone, which was converted into the amide on treatment with ammonia.