the aldehyde was added to mixture of 4- hydroxycoumarin (2 mol-equiv)and (0.05 mol-equiv) of ethlyenediammonium diacetate in ethanol
the solution was stirred at room temperature for 4 days
the reaction mixture was allowed to cool
the product was filtered off washed with cool ethanol and recrystallized
4-hydroxycoumarin 1 g (6.17 mmol)was dissolved in 300 ml of boiling water the solution was allowed to cool to 70 c and 10 ml of 40% aqueous formaldehyde was quickly added with stirring
the mixture was the chilled
the crude product was filtered off washed with water
dried and recrystallized with ethanol