Intermediate (8d), 2-[5-amino-2-oxo-1-(2-trimethylsilanyl-ethoxymethyl)-1,2-dihydro-pyridin-3-yl]-5-(tert-butyl-dimethyl-silanyloxymethyl)-indole-1-carboxylic acid tert-butyl ester, (600 mg, 1 mmol) was stirred in dichloromethane (50 mL) at RT with triethylamine (202 mg, 0.278 mL, 2 mmol). The reaction mixture was cooled to 5° C. and then a solution of 1-Benzyl-1H-pyrazole-4-carbonyl chloride (265 mg, 1.2 mmol), which had been prepared according to the protocol below, in dichloromethane (10 ml), was added drop wise. After addition the reaction was stirred at RT for 18 hrs and then the reaction mixture was washed with saturated sodium hydrogen carbonate solution (2×50 mL), brine (50 ml), dried (Na2SO4) and concentrated in vacuo. The resultant crude product was purified by flash chromatography on SiO2 eluting with hexane—50% ethyl acetate/hexane (gradient) to afford the desired compound as a pale green foam, 750 mg, 96%.
