Triethylamine → 2-oxo-2H-1-benzopyran-7-yl 4-(but-3-enyloxy)-benzoate

Participants

Reaction Steps

4.85 g (0.025 mol of 4-(but-3-enyloxy)-benzoic acid were treated with 9 ml of thionyl chloride and 2 drops of DMF and boiled under reflux for 2 hours. The excess thionyl chloride was removed completely, firstly in a water-jet vacuum and subsequently in a high vacuum. The acid chloride remaining was taken up in 10 ml of dichloromethane and slowly added dropwise at 0° C. to a suspension of 3.9 g (0.024 mol) of 7-hydroxy-coumarin and 3.9 ml of triethylamine in 5 ml of dichloromethane. The batch was stirred at room temperature overnight, filtered and the filtrate was evaporated. For purification, the residue was chromatographed on silica gel wiith dichloromethane and subsequently recrystallized from ethanol. There were isolated 5.2 g of 2-oxo-2H-1-benzopyran-7-yl 4-(but-3-enyloxy)-benzoate in the form of fine white needles; m.p. 108-109° C.

Provenance & Evidence