Acetic Acid → N,N-Dimethyl-1-(2,3,4,9-tetrahydrothiopyrano[2,3-b]indol-4-yl)methanamine

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Reaction Steps

To a solution of 4-aminomethyl-2,3,4,9-tetrahydrothiopyrano[2,3-b]indole (1.8 g) in tetrahydrofuran (80 ml) are added acetic acid (2.3 ml), 37% formalin (5.6 ml) and sodium cyanoborohydride (1.35 g) successively. The mixture is stirred at room temperature for 1 hour and evaporated to remove the solvent. The residue is extracted with ether after addition of some pieces of ice and an 10% aqueous solution of sodium hydroxide. The extract is washed with water, dried and evaporated to give an oil (3 g). The oil is chromatographed on a column of basic alumina (70 g) and eluted with ethyl acetate-hexane (1:1). The eluate is evaporated to give crystals of the title compound (1.34 g) melting at 121°-122° C. Yield: 66%

Provenance & Evidence