QUINOXALINE DERIVATIVES .X. A NOVEL REARRANGEMENT OF CERTAIN QUINOXALINE N-OXIDES TO 2-BENZIMIDAZOLINONES

Quinoxaline 1-oxides, bearing a substituent at C-2, a carbonyl at C-3, and a free hydrogen at N-4, when heated with acetic anhydride, are transformed into 1-acetyl-3-acyl-2-benzimidazolinones or 1,3-diacetyl-2-benzimidazolinones. A mechanism for this novel rearrangement has been proposed and discussed. In the absence of a carbonyl at C-3, the quinoxaline 1-oxides fail to rearrange. On the other hand, if the hydrogen at N-4 is replaced by a methyl, a different type of rearrangement1a,3,4 takes place and an acetoxy group is introduced at C-6 in the quinoxaline molecule with simultaneous loss of the N-oxide function. © 1968, American Chemical Society. All rights reserved.