Trifluoroacetic acid → methyl E-4-[5-(2-carboxy-1-propenyl)-1-methylindol-3-ylmethyl]-3-methoxybenzoate

Participants

Reaction Steps

Trifluoroacetic acid (50 ml) was added to a solution of methyl E-4-[5-[2-(t-butoxycarbonyl)-1-propenyl]-1-methylindol-3-ylmethyl]-3-methoxybenzoate (6.4 g) in a small volume of methylene chloride (10 ml) cooled in an ice-bath. After 1.5 hr, the solution was evaporated (at approximately room temperature), and the residue was crystallized from methanol to give methyl E-4-[5-(2-carboxy-1-propenyl)-1-methylindol-3-ylmethyl]-3-methoxybenzoate (4.2 g, 75%) as a white powder: mp 182°-183° C.: partial NMR (250 MHz, DMSO-d6): 2.03(s, 3H, CCH3), 3.75(s, 3H), 3.83(s, 3H), 3.90 (s, 3H), 4.06(s, 2H, ArCH2Ar').

Provenance & Evidence