In a beaker immersed in an ice bath dissolve 3 g of vanillin in 6 mL of ethanol, slowly start the addition of 0.75 g of sodium borohydride dissolved in 5.7 mL of 1M sodium hydroxide solution with stirring over the course of 20 minutes. Let the solution stand for 15 minutes and thereafter add some 15% HCl to make the mixture acidic, filter and wash with some very cold water. Recrystallize from hot water.
Addition of the borohydride solution
The mixture after the addition of the HCl
The dry product