A suspension of 2-(benzyloxymethyl)-6-chromanecarboxylic acid (0.700 g, 2.35 mmol) in oxalyl chloride (5.98 ml) was heated at 75° C. for 35 minutes. The oxalyl chloride excess was evaporated off in a nitrogen stream and the resulting residue was dissolved in the minimum amount of dry methylene chloride. This solution was added at 0° C. and under inert atmosphere to a solution of 3-amino-2-hydroxyacetophenone (0.550 g, 2.37 mmol), pyridine (7 ml) and dry methylene chloride (40 ml). The resulting mixture was left under stirring at room temperature for 18 h, then diluted with methylene chloride (40 ml), washed successively with 1M HCl and a sodium chloride saturated solution, dried and the solvent was evaporated off under reduced pressure. A crude was obtained which was purified by chromatography through a silica gel column, eluting with petroleum ether:chloroform mixtures of increasing polarity. At a 40% chloroform proportion, 0.732 g of the title compound were eluted (72% yield).
