2-Methylindole → 1-(4-bromobutyl)-3-methyl-1H-indole

Participants

Reaction Steps

The solution of 5.0 g of 2-methylindole in 70 ml of DMPU is admixed with stirring at 0° C. with 3.30 g of sodium hydride dispersion (60%) and stirred at room temperature over 2 hours. Subsequently, 20 ml of 1,4-dibromobutane and 1.40 g of tetrabutylammonium iodide are added (exothermic reaction). The mixture is stirred at room temperature over 20 hours. The reaction mixture is poured onto water (200 ml) and extracted with tert-butyl methyl ether (2×200 ml). The organic phases are washed successively with water (4×200 ml) and brine (1×200 ml), dried over sodium sulphate, filtered and concentrated by evaporation. The excess of 1,4-dibromobutane is evaporated out of the residue under high vacuum and the title compound is obtained as a slightly yellowish oil by means of flash chromatography (SiO2 60F). Rf=0.79 (1:1 EtOAc-heptane); Rt=5.43.

Provenance & Evidence