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Isoxazolium enolates derived from α,β‐unsaturated and 1,3‐dicarbonyl compounds. The through‐space effect of the enolate moiety on the chemical shift of α‐protons
Author(s) -
Zvilichovsky Gury,
Gurvich Vadim
Publication year - 1994
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.5570310525
Subject(s) - chemistry , moiety , enol , betaine , tautomer , enone , proton , enol ether , medicinal chemistry , organic chemistry , stereochemistry , catalysis , physics , quantum mechanics
The reaction of 4‐phenyl‐3,5‐dihydroxyisoxazole with α,β‐unsaturated cyclic ketones and 1,3‐cyclic diketones was studied. β‐Substituted α,β‐unsaturated ketones give pairs of isomeric isoxazolium enolates. The remarkable influence of the heterocyclic betaine on the proton chemical shifts is discussed. 1,3‐Cyclic diketones reacted spontaneously with 4‐phenyl‐3,5‐dihydroxyisoxazole yielding isoxazolium enolate enols and enol ethers.