Formaldehyde → 2,3,4,9-Tetrahydro-1H-beta-carboline-3-carboxylic acid methyl ester

Participants

Reaction Steps

A mixture of L-tryptophane methyl ester (25.4 g, 100 mmol) and 37% formaldehyde solution (12.5 mL) in aqueous methanol (170 mL; H2O:MeOH, v/v 10:1) was stirred at room temperature for 5 h. The reaction mixture was evaporated to dryness in vacuo. The residue was basified with sodium bicarbonate to give methyl 1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indole-3-carboxylate, 14.4 g (63%); mp 161-162° C. (lit.19 mp 164-165° C.). 1H NMR (DMSO-d6) δ 2.78 (1H, m, CH2), 2.98 (1H, m, CH2), 3.66 (3H, s, COOMe), 3.85 (1H, m, CH), 4.02 (2H, q, J=15.8 Hz, NCH2), 6.92-6.96 (1H, m, ArH), 7.00-7.04 (1H, m, ArH), 7.27-7.29 (1H, m, ArH), 7.37-7.39 (1H, m, ArH), 10.78 (1H, s, exchangeable NH).

Provenance & Evidence