Hydrochloric Acid → 3-bromo-4-(1H-indol-3-yl)-1-methyl-pyrrole-2,5-dione

Beteiligte Stoffe

Reaktionsschritte

A solution of 1.445 g of indole dissolved in 29 ml of dry tetrahydrofliran is brought to from −20 to −10° C. under argon, and then 26 ml of LiHMDS (1M in hexane) are added dropwise in the course of 15 minutes. After 45 minutes at −10° C., the solution is diluted with an additional 15 ml of tetrahydrofuran and a solution of 2 g of N-methyl-2,3-dibromomaleimide dissolved in 17 ml of tetrahydrofuran is added dropwise in the course of 30 minutes. After 15 minutes at −10° C. and 15 minutes at 0° C., the reaction is stopped by the addition, at 0° C., of 50 ml of a 0.3N hydrochloric acid solution. The reaction mixture is extracted with ethyl acetate, and the organic phases are washed with a saturated NaCl solution, dried over MgSO4 and then evaporated under reduced pressure. The desired product is precipitated using methanol.

Herkunft & Nachweise