4-Acylhydrazinomethylene-2-phenyloxazol-5(4H)-ones as acylating agents: Synthesis of salicylanilides and 1,2,4-triazolo[4,3-b]pyridazines

Authors
Pozgan, F Polanc, S Kocevar, M
Citation
F. Pozgan et al., 4-Acylhydrazinomethylene-2-phenyloxazol-5(4H)-ones as acylating agents: Synthesis of salicylanilides and 1,2,4-triazolo[4,3-b]pyridazines, HETEROCYCLE, 54(2), 2001, pp. 1011
Citations number
17
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
HETEROCYCLES
ISSN journal
03855414 → ACNP
Volume
54
Issue
2
Year of publication
2001
Database
ISI
SICI code
0385-5414(20010201)54:2<1011:4AAAS>2.0.ZU;2-4
Abstract
A simple and general method for the acylation of an amino or hydrazino grou p by the application of hydrazides has been developed. It starts from hydra zides (2), which are converted with 4-ethoxymethylene-2-phenyloxazol-5 (4H) -one (1) to the corresponding 4-acylhydrazinomethylene-2-phenyloxazol-5(4H) -ones (3). The latter react with nitrogen-containing nucleophiles in 1,4-di oxane in the presence of triethylamine or zirconium(IV) chloride to give th e corresponding amides (7) or mixtures of hydrazides (12) and 1,2,4-triazol o[4,3-b]pyridazines (11). Upon prolonged heating, compounds (11) are the ma in products.