Premium
Ring‐opening reaction of 1,3,4‐oxadiazolone and 1,3,4‐oxadiazolinethione: Reaction of 2‐phenyl‐1,3,4‐oxadiazolin‐5‐one and 2‐phenyl‐1,3,4‐oxadiazoline‐5‐thione with amines
Author(s) -
Saegusa Yasuo,
Harada Shigeo,
Nakamura Shigeo
Publication year - 1988
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.5570250513
Subject(s) - chemistry , aniline , ring (chemistry) , adduct , benzylamine , medicinal chemistry , nitroaniline , ammonia , organic chemistry
The ring‐opening abilities of amines toward 1,3,4‐oxadiazolines, 2‐phenyl‐1,3,4‐oxadiazolin‐5‐one ( 1a ) and 2‐phenyl‐1,3,4‐oxadiazoline‐5‐thione ( 1b ), were investigated with relation to their basicities or p K b values. Oxadiazolines 1a and 1b were easily reacted with amines such as benzylamine and aniline, but not with p ‐nitroaniline, to form the corresponding ring‐opening adducts. The reactions of both 1a and 1b with o ‐phenylenediamine produced benzodiazoles with the liberation of benzoylhydrazide, whereas the reactions with o ‐aminobenzamide furnished quinazolines with the liberation of ammonia. o ‐Aminophenol and o ‐aminothiophenol were also reacted with 1a and 1b both of them giving 1,5‐dibenzoylcarbohydrazide from 1a and 1,2‐dibenzoylhydrazine from 1b. From the conditions affording the corresponding ring‐opening adducts or reaction products, the ring‐opening abilities of the amines toward 1a and 1b are in good correlation with the strength of their basicities or p K b values. The ring‐opening of oxadiazolines were proved to occur with anilines. Therefore, the other reactions are also supposed to proceed via the ring‐opening steps.