59434-82-1Relevant articles and documents
Stereochemical Effects in the Nitrosation of Some α,β-Unsaturated Ketoximes. Formation of 1-Hydroxypyrazole 2-Oxides and 4-Oximino-4,5-dihydroisoxazoles
Hansen, John F.,Easter, John A.
, p. 1481 - 1486 (2007/10/02)
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 carbon-carbon 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.
Synthesis of some new 1-hydroxypyrazole-2-oxides and heterocyclic oximes
Fadda, A. A.
, p. 749 - 753 (2007/10/02)
α,β-Unsaturated oximes (Ia-c) are converted into 1-hydroxypyrazole-2-oxides (IIIa-c) and isoxazole (IV) by reaction with n-butyl nitrite and metal ions in pyridine.Reduction of IIIc with zinc in acetic acid furnishes the pyrazole V.However, reduction of IIIc with sodium dithionite yields the 1-hydroxypyrazole (VI).Acylation of IIIc affords the acyl derivative (VII).Reaction of hydroxylamine hydrochloride and benzaldehyde with oximes VIIIa,b and IXa,b affords O-methyloximinoisoxazoles (Xa,b).
