Benzyl Alcohol → Benzyl 1H-indole-5-carboxylate

Participants

Reaction Steps

A solution of indole-5-carboxylic acid (68.3 g), benzyl alcohol (64.9 g) and triphenylphosphine (157.0 g) in tetrahydrofuran (1.2 L) was cooled to 5° C. and treated dropwise with diethyl azodicarboxylate (90.0 g). Upon completion of the addition, the mixture was allowed to warm to room temperature. The reaction was stirred for 24 hours and then evaporated. The residue was taken up in diethyl ether (1 L) and filtered. The filtrate was evaporated to give a yellow syrup which was purified by flash chromatography, eluting sequentially with 2:1, 1:1 and 1:2 hexane:methylene chloride, to afford a yellow-white solid. This material was triturated with 1:1 hexane: methylene chloride (300 mL) and filtered to give benzyl indole-5-carboxylate as a white solid (74.2 g, 70%); mp 127°-129° C.; partial NMR (300 MHz, CDCl3): 5.39 (s, 2H, CH2), 6.61 (m, 1H, indole-H(2)), 8.56 (br, 1H, NH).

Provenance & Evidence