Halogenation of N-substituted p-quinone monoimines and p-quinone monooxime ethers: XIII. Specificity of bromination of N-Acetyl(aroyl)-1,4-benzoquinone monoimines

Abstract

6-Hydroxy-2-methyl(aryl)-1,3-benzoxazoles were synthesized by bromination of N-acetyl(aroyl)-1,4-benzoquinone monoimines. * For communication XII, see [1].In the preceding communications of this series we described in detail halogenation of N-aroyl-1,4-benzoquinone monoimines and their reduction products [1][2][3][4][5], as well as of 4-acetylaminophenols having no other substituents in the benzene ring [6]. Various halogen-containing derivatives were obtained and specificity of halogenation related to the effect of strong electron-withdrawing substituent on the nitrogen atom was revealed. In particular, low stability of intermediate cyclohexene structures [1,2], halogenation of methyl groups in the quinoid ring, and formation of 5-aroyloxycyclohex-2-ene-1,4-diones [2, 3] were observed.