1H-Indole-5-Carboxylic Acid → 1h-Indole-5-carboxamide,n-(cyclopentylmethyl)-

Participants

Reaction Steps

A solution of cyclopentylmethylamine (2.66 g), 5-carboxyindole (4.76 g), 4-(dimethylamino)pyridine (3.60 g) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (5.67 g) in methylene chloride (60 ml) was stirred for 12 hours under an atmosphere of nitrogen. The amber solution was diluted with methylene chloride (150 ml); washed successively wth 10% (w/v) aqueous sodium carbonate, 10% (v/v) hydrochloric acid, water, and brine; dried (MgSO4); and evaporated. The residual amber oil was purified by flash chromatography on silica gel (700 ml), eluting with 1:3 v/v ethyl acetate:chloroform, to yield 5-(N-cyclopentylmethylcarbamoyl)indole (CC) (5.17 g, 80%) as a white crystalline solid; mp 110°-112° C.; NMR (80 MHz, CDCl3): 1.0-2.4(broad m, 9H, cyclopentyl), 3.4(dd, 2H, CH2N), 6.2(broad, 1H, NH), 6.6(m, 1H, H3 -indole), 7.3(t, 1H, H2 -indole), 7.4(d, 1H, H7 -indole), 8.5(broad, 1H, CONH).

Provenance & Evidence