Hydrochloric Acid → 4-(5-carboxy-1-methylindol-3-ylmethyl)-3-methoxy-N-(2-methylphenylsulfonyl)benzamide

Participants

Reaction Conditions

Reaction Steps

A mixture of the product of step d) (15 g, 23.8 mmole), concentrated sodium hydroxide liquor (6.75 ml, 119 mmole), water (85 ml) and tetrahydrofuran (18 ml) was stirred for three hours at 65° C., and the now homogeneous solution cooled to 50°-55° C. and maintained at this temperature during the subsequent acidification and extraction. Concentrated hydrochloric acid was added to a pH of 7-8, followed by addition of tetrahydrofuran (44 ml) and n-butyl acetate (29 ml), and further adjustment of the pH to 1-2. The reaction mixture was allowed to settle and the lower aqueous layer separated. The organic layer was washed with 5% brine solution (2×20 ml). The tetrahydrofuran was removed by distillation (ca 40 ml distillate collected at a jacket temperature of 95° C.), and the residual mixture cooled to 15°-20° C. The product was collected by filtration, washed with butyl acetate (15 ml) and dried at 50° C. The yield of 4-(5-carboxy-1-methylindol-3-ylmethyl)-3-methoxy-N-(2-methylphenylsulfonyl)-benzamide was 11.08 g (94%); m.p. 264°-267° C.; NMR (250 MHz, DMSO-d6): 2.63 (s, 3H, ArCH3), 3.78 (s, 3H, NCH3), 3.95 (s, 3H, OCH3), 4.08 (s, 2H, ArCH2Ar'), 7.18 (d, 1H), 7.22 (s, 1H), 7.38-7.65 (m, 6H), 7.79 (d, 1H), 8.06 (d, 1H), 8.20 (s, 1H).

Provenance & Evidence