Methanol → 3-(2-Aminoethyl)-4-chloro-5-methoxyindole oxalate

Participants

Reaction Steps

Reductive amination of 3-cyanomethyl-4-chloro-5-methoxyindole (3.82 g, 17.3 mmol) in methanol (200 ml) and dimethylamine (40 ml) over Raney nickel for 21/2 hours at 15 p.s.i. pressure, at room temperature, followed by removal of catalyst and solvent gave a crude product containing two major components. Separation by chromatography (SiO2 ; CHCl3 /MeOH) gave two products. Part of the less polar product (650 mg of 2.13 g) was dissolved in methanol and treated with a solution of excess fumaric acid in methanol. On treatment with diethyl ether and refrigeration, the product, 3-(2-dimethylaminoethyl)-4-chloro-5-methoxyindole fumarate (494 mg) crystallised out, m.p. 223°-5° C. The whole of the more polar product was treated with a solution of oxalic acid in methanol to give 3-(2-aminoethyl)-4-chloro-5-methoxyindole oxalate. Recrystallisation from methanol gave 301 mg, dec > 230° C.

Provenance & Evidence