Potassium Hydroxide → (R)-1-[1-benzyl-3-(1-methyl-2-pyrrolidinylmethyl)-1H-indol-5-yl]-N-diphenylmethyl-N-methylmethanesulfonamide

To a stirred solution of 1-[(R)-1-benzyl-3-(1-methyl-2-pyrrolidinylmethyl)-1H-indol-5-yl]-1-cyano-N-diphenylmethyl-N-methylmethanesulfonamide (from step (d), 11.61 g, 19.3 mmol) in ethanol (35 ml) at ambient temperature was added 2N potassium hydroxide solution (35 ml, 70 mmol). The dark brown solution was then brought to reflux and maintained at this temperature for 15 hr. The oily reaction mixture was then cooled to ambient temperature and extracted with ethyl acetate (3×100 ml). The organic extracts were combined and evaporated in vacuo to yield the crude product as a dark brown oil. The oil was diluted with ethanol (35 ml) and stirred at ambient temperature for 12 hr, which resulted in precipitation. The mixture was then filtered and the solid dried in vacuo at 50° C. overnight to yield the title compound (6.82 g, 61%) as a beige solid. m.p. 117-120° C.