O-Xylene → HCID 19922115, compound

Participants

Reaction Steps

A mixture of 3.09 g (10.88 mmol) of 1-[2-hydroxy-4-(phenylmethoxy)-3-propylphenyl]ethanone, 1.55 g (13 mmol) of dimethylformamide dimethyl acetal, and 2.7 mL of xylene was stirred and heated in a 120°-130° C. oil-bath as methanol was distilled out using a 3 in. Vigreux column, over a 2 hr period. The bath temperature was then raised to 150°-160° C. and the reaction mixture was stirred at this temperature for an additional 30 min. The mixture was cooled and concentrated at 60° C./ high vacuum. To the viscous, red-brown, oily residue was added 2.48 g (13 mmol) of p-toluenesulfonic acid monohydrate and 25 mL of ethanol. The resulting solution was stirred and refluxed for 1.5 hr, then cooled and diluted with 100 mL of water. Work-up with ether in the usual manner gave a crude product which was purified by flash chromatography on silica gel, eluting with 1:1 hexane-ether. There was obtained 2.8 g (87.5%) of 7-(phenylmethoxy)-8-propyl-4H-1-benzopyran-4-one as a beige solid. An analytical specimen was obtained from another experiment by recrystallization from ethyl acetate-hexane, as a colorless solid, mp 87.5°-89° C.

Provenance & Evidence