SYNTHESES OF 4-ALKYLINDOLES FROM 2-METHYL-5-NITROISOQUINOLINIUM IODIDE
4-[N-Acetyl-N-methyl]aminomethylindole was prepared economically on a large scale from 2-methyl-5-nitroisoquinolinium iodide. Subsequent alkaline hydrolysis afforded 4-methyiaminomethylindole. Starting from these two compounds, various 3,4-di- and 4-substituted indoles were prepared including 4-formylindole, 4-[N,N-disubstituted]aminomethylindoles, 4-alkylindoles, and benz[cd]indoles. A novel nucleophilic substitution reaction of gramine derivatives by the catalysis of tri-n-butylphosphine was also reported.