Reaction in Oximes of 2-Hydroxyacetophenone, Chalcone, Flavanone and Flavone

Abstract

Oximes of 2-hydroxyacetophenone, chalcone, flavanone and flavone were prepared by the action of hydroxylamine hydrochloride on the respective compounds. The oximes gave back the starting material by the action of HCl, nitrous acid or CrO₃ in AcOH. 2-Hydroxyacetophenone oxime with POCl₃ cyclized to give benzoxazole. 2-Hydroxyacetophenone oxime also condensed with aldehyde to give chalcone oxime. With sulphuric acid chalcone oxime gave chalcone, flavanone oxime. With sulphuric acid chalcone oxime gave chalcone, flavanone oxime, flavanone and flavone oxime, isoxazole respectively. The reactions by the oximes in oxygen- nitrogen synthesis are discussed.