The maleyl and fumaryl derivatives of indole: Zmethylindole dimer (Ib) and the maleyl derivatives of skatole: 2-methylindole dimer (cis-Id) and of indole: 2-phenylindole dimer (cis- IC) rearrange under alkaline hydrolysis conditions to the corresponding (2-methyl-3-indo1e) succinic acid (IIb) in the first three cases, or (2-phenyl-3-indo1e) succinic acid (IIc) in the latter case. The 2-substituent labels the indole nucleus to which migration of the maleyl or ...
