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A new synthesis of s ‐triazoles from 1 H ‐2,3‐benzoxazine 4‐hydrazones
Author(s) -
Pifferi G.,
Consonni P.
Publication year - 1972
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570090320
Subject(s) - chemistry , acylation , alkylation , xylene , catalysis , medicinal chemistry , hydrazone , organic chemistry , stereochemistry , toluene
Aliphatic and aromatic aldehydes react with 4‐hydrazino‐1 H ‐2,3‐benzoxazines (I) to form the corresponding 1 H ‐2,3‐benzoxazine hydrazones (II). Compounds II when heated in the presence of an acid catalyst rearrange to form substituted s ‐triazoles (III) in high yields. In particular, the hydrazones containing one imino hydrogen undergo the same rearrangement by refluxing in xylene. Structure III, in agreement with the analytical and spectroscopic data, was confirmed by univocal syntheses. The N ‐acylation and N ‐alkylation of some unsymmetrically 3,5‐sub‐stituted s ‐triazoles were also investigated and the mechanism of formation of III is briefly discussed.