Synthesis of Aldehydo Sugar (4-oxoquinazolin-2-yl)hydrazones and their transformation into 1-(alditol-1-yl)-1,2,4-triazolo-[4,3-a]quinazolin-5(4H)-ones

Abstract

A series of the aldehydo-sugar hydrazones 4a-d and 5a-d were prepared by the reaction of 2-hydrazino-quinazolin-4(3H)-one (1) and 3-ethyl-2-hydrazinoquinazolin-4(3H)-one (2) with aldoses 3a-d. Treatment of hydrazones 4a-d and 5a-d with acetic anhydride in pyridine gave hydrazone acetates 6a-d and 7a-d. Compounds 7a-d were also prepared by ethylation of 6a-d. Reaction of compounds 4a-d and 5a-d with hot ethanolic ferric chloride led to oxidative cyclization to angular ring systems 8a-d and 9a-d rather than to the linear system 10. Acetylation of 8a-d afforded the per-O, N-acetyl derivatives 11a-d, which were converted into the corresponding ethyl derivatives 12a-d. Compounds 12a-d were identical with the acetylation products derived from 9a-d.