The cyclization of 2-chlororesorcine (I) with ethyl alpha-(beta-diethylaminoethyl) acetoacetate (II) by means of p-toluenesulfonic acid and polyphosphoric acid gives 8-chloro-3-(beta-diethylaminoethyl)-4-methyl-7-hydroxycoumarin (III), which is then condensed with ethyl chloroacetate (IV) by means of K2CO3 in refluxing acetone.