A new synthesis of pyrazolo[4,3-e][1,2,4]triazines via acid promoted ring closure of the phenylhydrazones of 5-acyl-1,2,4-triazines

Authors
Rykowski, A Mojzych, M Karczmarzyk, Z
Citation
A. Rykowski et al., A new synthesis of pyrazolo[4,3-e][1,2,4]triazines via acid promoted ring closure of the phenylhydrazones of 5-acyl-1,2,4-triazines, HETEROCYCLE, 53(10), 2000, pp. 2175
Citations number
12
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
HETEROCYCLES
ISSN journal
03855414 → ACNP
Volume
53
Issue
10
Year of publication
2000
Database
ISI
SICI code
0385-5414(20001001)53:10<2175:ANSOPV>2.0.ZU;2-K
Abstract
The reaction of various substituted phenylhydrazones of 5-acyl-1,2,4-triazi nes in the presence of 1.1 equivalent of HCl in boiling ethanol-dioxane mix ture has been studied. In all reactions the formation of the corresponding pyrazolo[4,3-e][1,2,4]triazines (3a-r) takes place in good yield. The struc tures of 3a-r were unequivocally established by spectroscopic methods as we ll as by X-Ray analysis of selected 5-methyl-3-phenyl-7-(p-tolyl)pyrazolo[4 ,3-e] [1,2,4]triazine (3a).