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A facile synthesis of 2‐substituted‐4‐(substituted)phenyl‐Δ 2 ‐1,3,4‐oxadiazolin‐5‐ones
Author(s) -
Pilgram Kurt,
Skiles Richard D.
Publication year - 1977
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.5570140611
Subject(s) - chemistry , triethylamine , dimethylamine , acylation , carboxylic acid , medicinal chemistry , organic chemistry , catalysis
The title compounds, 3, are formed at ambient temperature from 4,4‐dimethyl‐2‐(substituted)‐phenylsemicarbazides (1) and carboxylic acid chlorides in the presence of triethylamine. 2‐Dimethylamino‐4‐(substiluted)phenyl‐Δ 2 ‐1,3,4‐oxadiazolin‐5‐ones are formed from 1 and dialkyl‐carbamoyl chlorides at elevated temperature (about 15° ). Acylation of 1 with carboxylic acid anhydrides, also at elevated temperature, is accompanied by loss of dimethylamine from the intermediate l‐acyl‐4,4‐dimethyl‐2‐(substituted)phenylsemicarbazides, 2, to give 3.