1-Amino-2-propanol → (RS)-1-(1,4-dihydro-[1]benzothiopyrano[4,3-b]pyrrol-1-yl)-propan-2-ol

Participants

Reaction Steps

A solution of 2 g of 2-(2-oxoethyl)-4-thiochromanone and 120 mg of p-toluenesulfonic acid in 100 ml of anhydrous toluene was heated on a water separator, A solution of 2.9 g of (RS)-1-amino-2-propanol in 20 ml of anhydrous toluene was added dropwise to the boiling solution over a period of 5 minutes. Subsequently, the mixture was boiled for an additional 35 minutes, during which the solvent was reduced to a volume of 20 ml. The cooled reaction mixture was purified by column chromatography on silica gel (ethyl acetate/toluene 1:1). There were obtained 1.8 g (76%) of (RS)-1-(1,4-dihydro-[1]benzothiopyrano[4,3-b]pyrrol-1-yl)-propan-2-ol as a pale brown solid which was used in the next reaction without further recrystallization.

Provenance & Evidence