Stereochemical effects in the nitrosation of some α,β-unsaturated ketoximes. Formation of 1-hydroxypyrazole 2-oxides and 4-oximino-4,5-dihydroisoxazoles

Autor:	John A. Easter, John F. Hansen
Rok vydání:	1994
Předmět:	chemistry.chemical_classification Double bond Organic Chemistry chemistry.chemical_element Pyrazole Oxime Medicinal chemistry Copper Product distribution chemistry.chemical_compound chemistry Pyridine Nitrosation medicine Butyl nitrite medicine.drug
Zdroj:	Journal of Heterocyclic Chemistry. 31:1481-1486
ISSN:	1943-5193 0022-152X
DOI:	10.1002/jhet.5570310633
Popis:	Several α,β-unsaturated ketoximes R1CH=CHC(=NOH)R2 were nitrosated using butyl nitrite in aqueous ethanol in the presence of copper(II) sulfate and pyridine. The product distribution varied depending on whether the oxime hydroxyl group was syn or anti with respect to the carboncarbon double bond. The anti-oximes gave the copper complexes of 1-hydroxypyrazole 2-oxides in high yields. The isomeric syn-oximes gave lower yields of the pyrazole complexes along with 4-oximino-4,5-dihydroisoxazole derivatives. For the syn-oximes where R1 is phenyl and R2 is either methyl or ethyl, conversion of the oximes to the parent ketones was also observed. The results may be explained by processes involving N-nitrosonitrone intermediates.
Databáze:	OpenAIRE
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