A mixture of 2-(benzo[b]thiophen-7-yl)-2-(phenylamino)acetic acid (I26) (303 mg, 1.07 mmol), (R)-quinuclidin-3-ol (136 mg, 1.07 mmol), DCC (221 mg, 1.07 mmol) and HOBT (164 mg, 1.07 mmol) in THF (20 ml) was stirred at r.t. for three days. THF was evaporated, and the crude product was taken up with EtOAc and washed twice with 2M K2CO3, and then with brine. The organic phase was dried over Na2SO4, filtered and evaporated to dryness. The crude was purified by flash chromatography (EtOAc/MeOH=9/1 to EtOAc/MeOH=9/1+0.5% NH4OH) to obtain (R)-quinuclidin-3-yl 2-(benzo[b]thiophen-7-yl)-2-(phenylamino)acetate (180 mg, 42.9% yield).
