Water → Benzoic acid, 2-[(1-ethyl-2-methyl-1H-indol-3-yl)carbonyl]-

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Reaction Steps

To a stirred suspension of 22.5 g (0.15 mole) of phthalic anhydride and 61.0 g (0.30 mole) of 77.5 percent active 1-ethyl-2-methylindole in 120 ml of ethylene dichloride chilled to 0° to 5° C. by means of an ice bath, there was added in small portions 32.0 g (0.24 mole) of aluminum chloride. The mixture was maintained at 0°-5° C. for an additional 15 minutes, allowed to warm to room temperature and stirred overnight. Then, 240 ml of water was added to the reaction mixture and the ethylene dichloride layer was separated from the acidic aqueous layer. The organic layer was extracted with 600 ml of 3.5 percent aqueous sodium hydroxide. The alkaline extract was acidified with dilute hydrochloric acid and the separated solid collected, washed with water and dried to obtain 24.0 g of 2-[(1-ethyl-2-methyl-3-indolyl)carbonyl]benzoic acid (formula VIII: R°=R1 =R2 = R3 =Y1 =H; R5 =CH3 ; R6 =CH2CH3), a slightly pink solid having a melting point of 184°-185° C.

Provenance & Evidence