Reactions of the 3-oxime 2-phenylhydrazone and mixed bishydrazones of dehydro-L-ascorbic acid: Conversion into substituted triazoles and pyrazolinediones

L-threo-2,3-Hexodiulosono-1,4-lactone 2-phenylhydrazone(1) reacted with hydroxylamine to give the 3-oxime 2-phenylhydrazone(2). On boiling with acetic anhydride,2 was dehydrated to 4-L-threo-2,3-diacetoxy-(1-hydroxypropyl)]-2-phenyl-1,2,3-triazole-5-car?ylic acid lactone(3), which was converted into 2-phenyl-4-(L-threo-1,2,3-trihydroxypropyl)-1,2,3-triazole-5-car?amide(4) with liquid ammonia. The structure of compound4 was confirmed by acetylation to 2-phenyl-4-(L-threo-1,2,3-triacetoxypropyl)-1,2,3-triazole-5-car?amide(5), and by periodate oxidation followed by reduction, to give 4-(hydroxymethyl)-2-phenyl-1,2,3-triazole-5-car?amide(6). Treatment of compound1 with aryl- or aroyl-hydrazines afforded mixed bishydrazones(7–14), which were acetylated to15–21, and treated with hydrazine to give pyrazolinediones22 and23