Sodium Hydroxide → 2-(2-Formamido-5-chlorothiazol-4-yl)-2-methoxyiminoacetic acid
Reaction equation
[OH-].[Na+].[CH:3]([NH:5][C:6]1[S:7][C:8]([Cl:20])=[C:9]([C:11](=[N:17][O:18][CH3:19])[C:12]([O:14]CC)=[O:13])[N:10]=1)=[O:4]>>[CH:3]([NH:5][C:6]1[S:7][C:8]([Cl:20])=[C:9]([C:11](=[N:17][O:18][CH3:19])[C:12]([OH:14])=[O:13])[N:10]=1)=[O:4]Participants
3
Procedure
1N-Aqueous sodium hydroxide (195 ml.) was added dropwise to an aqueous suspension (190 ml.) of ethyl 2-(2-formamido-5-chlorothiazol-4-yl)-2-methoxyiminoacetate (18.9 g.) under ice-cooling and stirred for 4 hrs. The reaction mixture was washed with ethyl acetate, and ethyl acetate was added to the aqueous solution, adjusted to pH 1.0 with 6N-hydrochloric acid and then saturated with sodium chloride. The ethyl acetate layer was separated and the remaining aqueous layer was washed with ethyl acetate. The ethyl acetate layer obtained above and the washings were combined, washed with saturated aqueous sodium chloride, dried over magnesium sulfate and then evaporated in vacuo. The residue was pulverized with diisopropyl ether and the precipitates were collected by filtration and dried to give 2-(2-formamido-5-chlorothiazol-4-yl)-2-methoxyiminoacetic acid (syn isomer, 14.7 g.), m.p. 175° to 177° C.