The Nitroethylation of Indoles. III.1-3 A Synthetic Route to Substituted Trypta mines

The previously described nitroethylation of indole has been extended successfully to four readily available substituted indoles: 2-methylindole, 1, 2-dimethylindole, 1-methylindole and 2-phenylindole. as had been the case with indole, the best yields of adducts were obtained with β-nitrostyrene, with good yields of adducts also often obtainable from β-methyl-β-nitrostyrene, and lesser yields from the other nitroölefins tried. Catalytic hydrogenation of the adducts yielded the corresponding tryptamines, which were converted to phthalimide derivatives. Indole-nitroölefin addition appears to be a quite general synthetic route to tryptamines from substituted indoles, as well as from indole itself.