PROCEDE DE PREPARATION DE LA D, L PANTOLACTONE

1490680 D,L-Pantolactone SOC CHIMIQUE DES CHARBONNAGES 21 June 1976 [7 July 1975] 25630/76 Heading C2C D,L-Pantolactone is made by reacting, in a C 5-6 alcohol, hydroxypivaldehyde with HCN, prepared in situ by adding at 10-20‹ C., HCl and an alkali metal cyanide during 60-70 min., in such proportions that the pH of the reaction mixture is maintained at 8À2-9À2, the amounts added corresponding to an excess of approximately 10% HCl over the stiochiometric quantity, and thereafter hydrolysing the resulting cyanohydrin with an excess of concentrated hydrochloric acid at 100-105‹ C. for 20-30 min. to form the desired pantolactone.