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E ‐ and Z ‐isomerism of 2‐acetylthiophene oximes
Author(s) -
Conde Santiago,
Corral Carlos,
Lissavetzky Jaime
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.5570220213
Subject(s) - chemistry , oxime , steric effects , position (finance) , substitution (logic) , stereochemistry , computational chemistry , medicinal chemistry , organic chemistry , finance , computer science , economics , programming language
A study on the oximation of a number of 2‐acetylthiophenes in order to ascertain the validity of contradictory results previously described is reported. The fact that the steric hindrance is smaller in 2‐acetylthiophenes unsubstituted at position‐3 than in acetylbenzenes allows in these cases the formation of Z oximes, which even can predominate on the E oximes in the case of a + M substitution at position‐5. In the paper is also shown that the E/Z ratio of 2‐acetylthiophene oximes can be deduced from the 1 H‐nmr spectrum of the crude oxime mixture.