Processes for preparing 4-substituted indoles

The method of preparing a 4-substituted indole of the following formula:

• ##STR2## in which R is lower alkoxy, lower alkyl, benzyloxy or carbalkoxy, said alkoxy or alkyl groups being of 1-6 carbons, comprising the steps of;
• (A) reacting a o-nitro-.beta.-dimethylaminostyrene of the formula:
• ##STR3## in which R is as defined above, with semicarbazide or an acid addition salt thereof at ambient temperature in aqueous dimethylformamide or dimethylacetamide until the reaction is substantially complete to give a semicarbazone of the formula ##STR4## in which R is as defined above, and (B) reacting said semicarbazone under standard low pressure catalytic hydrogenation conditions over a noble metal hydrogenation catalyst until the reaction is complete to give the desired 4-substituted indole.