Formation of 1-aminophenazine from 3,4-dihydrophenazin-1(2 H )-one oxime in the system acetylene–KOH–DMSO

The reaction of 3,4-dihydrophenazin-1(2H)-one oxime with acetylene in the superbasic system KOH–DMSO afforded 1-aminophenazine in 32% yield instead of the expected pyrrolophenazine. The same product was also obtained under analogous conditions in the absence of acetylene.