2-Thiophenecarboxaldehyde → 6-Hydroxy-2-(2-thienylmethyl)-1,2,3,4-tetrahydroisoquinoline

Participants

Reaction Steps

0.6 g of sodium cyanoborohydride is added to a solution of 1.5 g of 6-hydroxy-1,2,3,4-tetrahydroisoquinoline, 1.2 g of thiophene-2-aldehyde and 1.8 g of toluenesulfonic acid monohydrate in 30 ml of ethanol. The mixture is stirred at room temperature for 8 hours, the solvent is removed in vacuo, and the residue is taken up with water/methylene chloride. The organic phase is again skaken with water, dried and evaporated in a rotary evaporator. The crude oily product is purified by chromatography on silica gel using a mixture of ethyl acetate/methylene chloride in the ratio 1:2. 1.7 g of a colorless oil, which crystallizes on standing (69% of theory), is obtained. Melting point: 110°-112° C.

Provenance & Evidence