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

AbstractA 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.