Indole adds to ethylideneisopropylamine to form 3-(isopropylaminoethylidene)-indole, a substance similar to a Mannich base but having an ethylidene group in place of the methylene residue. Dibenzyl acetamidomalonate is prepared from diethyl acetamidomalonate and alkylated with the new base. Hydrogenolysis of the alkylation product yields the substituted malonic acid, which is converted to 2-amino-3-(3-indolyl)- ...
