Pinacol → HCID 24887406, compound

Participants

Reaction Steps

To a mixture of 3-(2-cyano-phenyl)-3-(1H-indol-5-yl)-propionic acid methyl ester and pinacol (1:2 molar ratio, 2.1 g) in methanol (100 mL) was added sodium borohydride (2.6 g, 14 mmol), portionwise over 45 minutes. Stirring continued for 15 hours at room temperature. The reaction mixture was then filtered through Celite, washed with methanol, and the combined filtrates were concentrated. The crude material so obtained was partitioned between ethyl acetate and 5% aqueous ammonium hydroxide. The organic layer was dried over sodium sulfate, filtered and concentrated to a yellow oil which contained a mixture of 5-(1H-Indol-5-yl)-1,2,4,5-tetrahydro-benzo[c]azepin-3-one and uncyclized 3-(2-aminomethyl-phenyl)-3-(1H-indol-5-yl)-propionic acid methyl ester (not shown in Scheme B). This crude oil was suspended in 1,4-dioxane (100 mL) and heated to reflux for 40 hours, then cooled and concentrated to a brown oil and purified by flash chromatography (methanol/ethyl acetate) to afford pure 5-(1H-Indol-5-yl)-1,2,4,5-tetrahydro-benzo[c]azepin-3-one as a white solid (0.50 g). MS (M+H)=277.

Provenance & Evidence