Regioselective synthesis of polysubstituted pyrazoles and isoxazoles.
A regioselective synthesis has been developed for the preparation of unsymmetrical 1,3,5-triaryl-4-alkylpyrazolines and -pyrazoles by treatment of alpha-benzotriazolyl-alpha,beta-unsaturated ketones with monosubstituted hydrazines followed by alkylation at the 4-position of the pyrazoline ring. Reaction of alpha-benzotriazolyl-alpha,beta-unsaturated ketones with hydroxylamine gives 3,5-disubstituted isoxazoles regioselectively.
Katritzky
A R
AR
Department of Chemistry, University of Canterbury, Christchurch, New Zealand. katritzky@chem.ufl.edu
Wang
M
M
Zhang
S
S
Voronkov
M V
MV
Steel
P J
PJ
D018360:Crystallography, X-Ray; D007555:Isoxazoles / Q000138:chemical synthesis*; D011720:Pyrazoles / Q000138:chemical synthesis*
D007555:Isoxazoles; D011720:Pyrazoles