Ammonium Chloride → 7-chloro-4-(2-chloroethoxy)-1H-indole

Participants

Reaction Steps

To a solution of 1-(2-chloroethoxy)-4-chloro-3-nitrobenzene (10.00 g, 0.04236 mol) in THF (230 mL) stirred in a cold bath at -50 to -40° C. was added a THF solution of vinylmagnesium bromide (132 mL, 1.0 M, 0.132 mol) over 2 minutes. After stirring in the cold bath for 2-2.5 hours, saturated NH4Cl (150 mL) was added to the cold solution and it was removed from the cold bath. Enough 1 M HCl was added to dissolve the precipitated solids. This two phase system was stirred for 0.5 hour at most. The layers were separated and the aqueous phase was extracted once with Et2O. Combination of the Et2O and THF followed by drying over MgSO4 and evaporation gave 15.43 g of a dark oil. This was purified by chromatography on silica gel using a three component elutant which consisted of 80% CH2Cl2 and 20% of a gradient of EtOAc/hexane. This gave the product as a yellow solid: 3.32 g (34%); mp 68-72° C. MS EI m/e 229, 231, 233 (M+); 1H NMR (400 MHz, DMSO-d6) δ 3.99 (t, 2H, J=5.1 Hz), 4.34 (t, 2H, J=5.0 Hz), 6.51 (t, 1H, J=2.7 Hz), 6.53 (d, 1H, J=7.8 Hz), 7.04 (d, 1H, J=8.0 Hz), 7.29 (t, 1H, J=2.7 Hz), 11.43 (s, 1H).

Provenance & Evidence