Indole → HCID 57031743, compound

Participants

Reaction Conditions

Reaction Steps

tert-Butyl (2S,5R)-1-tert-butoxycarbonyl-5-(3-indolyl)-2-pyrrolidinecarboxylate may be prepared as follows: a solution of 3.5 g of indole in 30 cm3 of methylene chloride is added to a solution of 10.0 g of tert-butyl (2S,5RS)-1-tert-butyoxycarbonyl-5-methoxy-2-pyrrolidinecarboxylate and 0.6 g of para-toluenesulphonic acid in 100 cm3 of anhydrous methylene chloride, cooled to a temperature in the vicinity of 5° C. At the end of the addition, the reaction mixture is brought to a temperature in the vicinity of 25° C., stirred for 2 hours at that temperature, then hydrolysed by addition of 40 cm3 of a saturated aqueous sodium bicarbonate solution. The organic phase is decanted and the aqueous phase is extracted with 2 times 50 cm3 of methylene chloride. The organic phases are combined, dried over magnesium sulphate and concentrated to dryness under reduced pressure at 30° C. The residue obtained is purified by chromatography on silica [eluent: ethyl acetate/cyclohexane (10/90 by volume)]. The fractions containing the expected product are combined and concentrated to dryness under reduced pressure at 35° C. After vigorous stirring in diisopropyl ether, 1.2 g of tert-butyl (2S,5R)-1-tert-butoxycarbonyl-5-(3-indolyl)-2-pyrrolidinecarboxylate (first elution product), melting at 214° C. and 0.8 g of tert-butyl (2S,5S)-1-tert-butoxycarbonyl-5-(3-indolyl)-2-pyrrolidinecarboxylate (second elution product), melting at 194° C., are thus obtained.

Provenance & Evidence