Hydrochloric Acid → 5-bromo-1-methyl-3-(1-methylethyl)-1H-indole-7-carboxylic acid

Participants

Reaction Steps

To a stirred solution of 5-bromo-3-(1-methylethyl)-1H-indole-7-carboxylic acid (4.1 g, 14.53 mmol) in DMF (100 mL) at 0° C. was added iodomethane (3.6 mL, 57.6 mmol) followed by sodium hydride 60% dispersion in oil (1.4 g, 35.0 mmol) portionwise over 15 minutes. The reaction was allowed to warm to RT and stirred for 2 h. The reaction was recooled to 0° C., carefully quenched with water (5 mL), and evaporated to near dryness under vacuum. The residue was taken up in MeOH (50 mL) then treated with 6 N NaOH (10 mL, 60.0 mmol). The reaction was heated to 60° C. and stirred for 4 h. After cooling to RT the reaction was concentrated to near dryness, diluted with water, acidified with 6 N HCl (10 mL, 60 mmol), extracted with CH2Cl2, dried (Na2SO4), filtered, and evaporated to dryness to give the crude acid as a brown solid. Purification by silica gel chromatography (Analogix, SF40-120 g, 0 to 50% EtOAc in hexanes) gave material which was triturated with hexanes, filtered and dried under vacuum to give the product 5-bromo-1-methyl-3-(1-methylethyl)-1H-indole-7-carboxylic acid (2.98 g, 10.06 mmol, 69.2% yield) as a white solid. MS (ES)+ m/e 296.3 [M+H]+.

Provenance & Evidence