Piperonal → Methyl (1R,3R)-1-(1,3-benzodioxol-5-yl)-2,3,4,9-tetrahydro-1H-pyrido(3,4-b)indole-3-carboxylate

Participants

Reaction Steps

To a solution of D-Tryptophan methyl ester hydrochloride (100 g) in N,N-Dimethyl acetamide (500 ml), added Piperonal (65 g) and sodium sulphate (56 g) and heated the reaction mass to 65–70° C. for 30–35 hours for completion of reaction. Reaction mass is then diluted with water, basified with sodium bicarbonate solution and extracted twice with dichloromethane (2×750 ml). The organic layer is then treated with aqueous hydrochloric acid (1000 ml). Dichloromethane is evaporated and the reaction mass is stirred for 6–10 hours at 55–60° C. Cooled the reaction mass to an ambient temperature and filtered the crude title compound in hydrochloride salt form. Then wet crude mass is charged in sodium bicarbonate solution and extracted twice with dichloromethane (2×750 ml). Dichloromethane layer is distilled out and the residual material is dissolved in Toluene and crystallized by addition of anti solvent like cyclohexane to get title compound (89.0 g).

Provenance & Evidence