C([O:3][C:4]([CH2:6][N:7]1[CH:12]=[CH:11][CH:10]=[C:9]([OH:13])[C:8]1=[O:14])=[O:5])C.[CH2:15](Cl)[C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1.[OH-].[Na+]>CO.O>[CH2:15]([O:13][C:9]1[C:8](=[O:14])[N:7]([CH2:6][C:4]([OH:3])=[O:5])[CH:12]=[CH:11][CH:10]=1)[C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=11-Ethoxycarbonylmethyl-3-hydroxypyrid-2-one (10 g) is dissolved in methanol/water (9:1 v/v) (400 ml). To this solution is added benzyl chloride (3 molar excess) and NaOH until the pH is above 12. The mixture is then refluxed for six hours to give a clear orange solution. The methanol is removed by rotary evaporation and the aqueous solution is extracted with dichloromethane to remove excess benzyl chloride. The aqueous phase is diluted slightly by adding extra water and then acidified to pH 2 using concentrated hydrochloric acid which results in the precipitation of a beige solid. The mixture is cooled and the precipitate filtered off and washed with diethyl ether. The crude product is recrystallised from ethanol to give 3-benzyloxy-1-carboxymethylpyrid-2-one (5.4 g, 41%), m.p. 176°-177° C.
Loading…
