(+)-Benzyl 3-{1-(1,3-benzodioxol-5-yl)-2-[(2-methoxy-4-methylphenyl)sulfonylamino]-2-oxoethyl}-1-methyl-1H-indole-6-carboxylate → (s)-(+)-3-{1-(1,3-Benzodioxol-5-yl)-2-[(2-methoxy4-methylphenyl)-sulfonylamino]-2-oxoethyl}-1-methyl-1h-indole-6-carboxylic acid

Participants

Reaction Steps

(+)-Benzyl 3-{1-(1,3-benzodioxol-5-yl)-2-[(2-methoxy-4-methylphenyl)sulfonylamino]-2-oxoethyl}-1-methyl-1H-indole-6-carboxylate (from (f), 374 mg) was dissolved in aqueous ethanol (20 ml of 9:1 ethanol/water) and 50 mg of 5% palladium on carbon was added. After 3 h at 414 kPa (60 psi) of hydrogen at room temperature a further 50 mg of catalyst was added and the hydrogenation continued for a further 3 h. The catalyst was removed by filtration and the filtrate evaporated. The residue was azeotroped several times with dichloromethane to give the title compound (290 mg) in >98%ee (determined by chiral HPLC).

Provenance & Evidence