反应详情

Ethyl (2-formamido-5-chlorothiazol-4-yl)glyoxylate (14.5 g) was added to a solution of 1N aqueous potassium hydroxide (110 ml) at ambient temperature, and the mixture was stirred for 10 minutes to prepare the solution of potassium (2-formamido-5-chlorothiazol-4-yl)glyoxylate. After this solution was adjusted to pH 2 with 10% hydrochloric acid under ice-cooling, thereto were added pyridine (20 ml) and a solution of tert-butyl 2-aminooxyacetate (10.3 g) in tetrahydrofuran (50 ml), followed by stirring at ambient temperature for 5 hours. After the reaction mixture was washed with ethyl acetate, the remaining aqueous solution was adjusted to pH 1.5 with 10% hydrochloric acid and extracted with ethyl acetate. The extract was washed with an aqueous sodium chloride and then dried over magnesium sulfate. Removal of the solvent gave 2-tert-butoxycarbonylmethoxyimino-2-(2-formamido-5-chlorothiazol-4-yl)acetic acid (syn isomer) (8.5 g).

1. temperaturecooling
2. stirringby stirring at ambient temperature for 5 hours
3. washAfter the reaction mixture was washed with ethyl acetate
4. extractionextracted with ethyl acetate
5. washThe extract was washed with an aqueous sodium chloride
6. dry with materialdried over magnesium sulfate
7. customRemoval of the solvent