Easy Synthesis of Novel 4-Azolylpyridazin-3-ones

Abstract

Ethyl azol-2-ylglyoxylates react smoothly with acetone in the presence of catalytic amounts of proline and trifluoroacetic acid to give the corresponding azolyl aldols in 93-98% yield. The products are easily transformed into azolyl pyridazinones in 85-98% yield by cyclization with hydrazine hydrate.

Synthesis and Functionalization of 3-Azolylquinoxalin-2(1H)-ones

“…Among many synthetic approaches to quinoxalin-2(1H)ones, [12][13][14][15][16] direct condensation of 1,2-diaminobenzenes with 2-ketocarboxylic acid is probably the most popular. As a part of our research project aimed at the preparation 17 and subsequent functionalization 18 of ethyl azolylglyoxylates, herein we report on their use to obtain the correspondingly substituted quinoxalin-2(1H)-ones. First we examined the condensation of various ethyl 2azolylglyoxylates 1a-k with o-phenylenediamine (2a) (Scheme 1, Table 1).…”