A mixture of ester (C) (0.7 g), lithium hydroxide hydrate (0.41 g), tetrahydrofuran (4 ml), methanol (4 ml), and water (1.6 ml) was stirred overnight. The mixture was then evaporated. The white solid obtained was dissolved in water (50 ml). Acidification of this homogeneous alkaline solution by dropwise addition of 10% v/v hydrochloric acid gave a fine white precipitate which was recrystallized from ethyl acetate (40 ml) to give 4-[6-(2-ethylhexanamido)indol-1-ylmethyl]-3-methoxybenzoic acid (D) (0.13 g; 30%) as a solid; mp 234°-235° C.
