Acetic Acid → HCID 54428392, compound

Participants

Reaction Steps

To a stirred solution of 1.5 g of racemic-3,4-dihydro-7-hydroxy-2-methyl-4-oxo-2H-1-benzopyran-2-propanoic acid ethyl ester in 8 ml of dry tetrahydrofuran, with ice bath cooling, was added 1.4 ml of boron trifluoride etherate, over a period of 2 minutes. The mixture was stirred at 0°-5° C. for 5 minutes whereupon 5.4 ml of 1M borane in tetrahydrofuran was added. Stirring was continued at 0°-5° C. for 2.5 hours then the mixture was decomposed by the addition of glacial acetic acid. Solvents were removed in vacuo then the residue was dissolved in methylene chloride. The solution was washed with sodium bicarbonate solution and brine, then dried, filtered and concentrated under reduced pressure. The residual orange oil (1.4 g) was chromatographed on 50 g of silica gel. Elution with 4:1 hexane-ethyl acetate afforded 0.9 g (63.1%) of racemic-3,4-dihydro-7-hydroxy-2-methyl-2H-1-benzopyran-2-propanoic acid ethyl ester as a colorless oil.

Provenance & Evidence