Water → (R)-5-Bromo-3-(1-methyl-2-pyrrolidinyl methyl)-1H-indole

Participants

Reaction Steps

A solution of 3-(1-benzyloxycarbonylpyrrolidin-2(R)-ylcarbonyl)-5-bromo-1H-indole (1.04 g) (see Preparation 35) in dry tetrahydrofuran (20 ml) was added dropwise to a stirred suspension of lithium aluminium hydride (0.27 g) in dry tetrahydrofuran (15 ml) at room temperature under an atmosphere of dry nitrogen. The mixture was heated under reflux with stirring for 18 hours and then cooled. Additional lithium aluminium hydride (50 mg) was added and the mixture heated under reflux for an additional 3 hours. The mixture was again cooled, lithium aluminium hydride (40 mg) was added and the mixture heated under reflux for a further 18 hours. The mixture was cooled, water (0.44 ml) was carefully added with stirring followed by 20% aqueous sodium hydroxide (0.44 ml) and then more water (1.33 ml). The mixture was diluted with ethyl acetate and filtered through a cellulose-based filter aid. The filtrate was washed with water then brine and dried (Na2SO4). Evaporation of the solvent gave an oil which was chromatographed on silica gel. Elution with dichloromethane/ethanol/concentrated aqueous ammonia (90:10:0.5) gave, after combination and evaporation of the appropriate fractions, the title compound as a solid, (0.51 g). A small sample was crystallised from dichloromethane/hexane, m.p. 137°-140° C. Found: C, 56.65; H,5.69; N,9.23; C14H17N2Br.0.25 H2O requires: C,56,48; H,5,93; N,9.41%.

Provenance & Evidence