Water → 7-amino-4-methyl-1H-indole-3-carbonitrile

Participants

Reaction Steps

After suspending 400 g (1.99 mol) of the 3-cyano-4-methyl-7-nitro-1H-indole obtained in Example 1A in a mixture of 6 L of ethyl acetate and 6 L of methanol, the suspension was subjected to hydrogenation in the presence of 40 g of 10% palladium-carbon at ordinary temperature, 4 atmospheres. After removing the catalyst by filtration, the filtrate was treated with activated carbon and concentrated to give crude crystals. The crude crystals were dissolved in 6 L of 1,2-dimethoxyethane at an external temperature of 60° C., and then 12 L of water was added dropwise. Upon confirming precipitation of crystals, the mixture was stirred for 1.5 hours while cooling in an ice bath and filtered, and the crystals were washed twice with water (1 L). The crystals were air-dried at 50° C. for 16 hours to give 289 g of the title compound (yield: 84.8%).

Provenance & Evidence