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Studies on the synthesis and interconversion of isomeric triazolotheinopyrimidines. Part II. Effect of 5‐substituents on the dimroth rearrangement of 1,2,4‐triazolo[4,3‐ c ]thieno[3,2‐ e ]pyrimidines
Author(s) -
Shishoo C. J.,
Devani M. B.,
Ullas G. V.,
Ananthan S.,
Bhadti V. S.
Publication year - 1985
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.5570220344
Subject(s) - chemistry , isomerization , triethyl orthoformate , formic acid , pyrimidine , medicinal chemistry , stereochemistry , organic chemistry , catalysis
The triazolothienopyrimidines obtained by the cyclization of 4‐hydrazino‐2‐phenylthieno[2,3‐ d ]pyrimidines with triethyl orthoformate or formic acid presumed to be the triazolo[2,3‐ c ] isomers are now assigned the 5‐phenyl‐1,2,4‐triazolo[4,3‐ c ]thieno[3,2‐ e ]pyrimidine structure. While these [4,3‐ c ]triazoles resist isomerization under acidic conditions, they undergo isomerization to 5‐phenyl‐1,2,4‐triazolo[2,3‐ e ]thieno[3,2‐ e ]pyrimidines under basic conditions.