A DIMERIC AUTOXIDATION PRODUCT OF 2,3-DIMETHYLINDOLE

A product formed in the autoxidation of 2,3-dimethylindole and in the dimerization of 2,3-dimethyl-3-hydroxy-3H-indole has been identified as 3,3a,4,8b-tetrahydro-3′,3a,8b-trimethylspiro-[2H-furo[3,2-6]indole-2, 2′-indoline]-3′-ol (V). on the basis of u.v., i,r., n.m.r., mass spectral, and chemical evidence. Several reactions of (V). involving reduction, cleavage, and rearrangements to pyrrolo[1,2-a:5,4-b′]di-indole derivatives are presented.