synthesis of khellin and related anti atherosclerotic furochromones application_number US 60339384 A description the present invention is more completely understood by the operation of the following examples sodium methoxide is added to a flame dried 2 l 3 neck round bottomed flask under a blanket of nitrogen the flask is equipped with a mechanical stirrer reflux condenser and addition funnel 500 ml toluene 400 ml is added to the sodium methoxide 6 hydroxy 4 7 methoxy 5 benzofuranyl methyl ketone example 1 u s pat no 4 284 569 100 g and ethyl 2 methylthio acetate 85 2 g are dissolved in toluene 400 ml and briefly heated to obtain a homogeneous solution the resulting homogeneous solution is then transferred to the addition funnel this solution is then added to the sodium methoxide in toluene in a steady stream over 5 min the addition funnel is then rinsed with toluene 15 ml and replaced with a glass stopper the reaction is then heated at reflux for 4 hr and thereafter cooled to 0 u00b0 c in an ice bath and transferred to a 4 l flask and diluted with 2 l of 1 normal aqueous hydrochloric acid this mixture is then vigorously stirred and the toluene layer separated in a separatory funnel the aqueous layer is then extracted with an additional 500 ml of toluene and the total toluene solution is dried over sodium sulphate 200 g and the toluene removed under reduced pressure the resulting dark red oil is then diluted with about 250 ml of toluene and transferred to a 2 l flask the solution.