Acetone → 6-Benzyloxy-1,1-dimethyl-1,3,4,9-tetrahydropyrano[3,4-b]indole

Participants

Reaction Steps

A mixture consisting of 5-benzyloxytryptophol (3.2 g, 0.012 mol), acetone (7 mL), benzene (300 mL) and p-toluene sulfonic acid (500 mg) is refluxed for 3.5 hours using a Dean-Stark trap to remove the water. The reaction mixture is cooled to room temperature and washed with 5% sodium bicarbonate (1×200 mL), water (200 mL) and brine (200 mL). It is dried (MgSO4), filtered and concentrated to give 5.0 g product as thick oil. The crude product is flash chromatographed with 15% ethyl acetate/hexane as an eluent to afford 2.5 g product, m.p. 128°-129° C.

Provenance & Evidence