反应详情

To a solution of 2-carboxymethoxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)acetic acid (syn isomer) (45.0 g) in N,N-dimethylacetamide (432 ml) was added methanesulfonyl chloride (29.8 g) under stirring and cooling in an ice bath. The mixture was stirred for 25 minutes at 4° to 6° C. and finely powdered potassium hydrogen carbonate (48.4 g) was added thereto. The reaction mixture was stirred for 2.5 hours at 4° to 6° C. and then poured into a cold mixture of ethyl acetate (1.2 l), 1N hydrochloric acid (484 ml) and water (500 ml) below 10° C. under stirring. The organic layer was separated out and the aqueous phase was extracted with ethyl acetate (300 ml). The combined extracts were washed with cold water (800 ml) and a saturated aqueous solution of sodium chloride (800 ml), dried over magnesium sulfate and evaporated. The residue was triturated in methylene chloride (200 ml) to give 2 -carboxymethoxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)acetic methanesulfonic anhydride (syn isomer) (28.0 g), mp. 143° to 146° C. (dec.).

1. temperaturecooling in an ice bath
2. stirringThe mixture was stirred for 25 minutes at 4° to 6° C.
3. stirringThe reaction mixture was stirred for 2.5 hours at 4° to 6° C.
4. stirringunder stirring
5. customThe organic layer was separated out
6. extractionthe aqueous phase was extracted with ethyl acetate (300 ml)
7. washThe combined extracts were washed with cold water (800 ml)
8. dry with materiala saturated aqueous solution of sodium chloride (800 ml), dried over magnesium sulfate
9. customevaporated
10. customThe residue was triturated in methylene chloride (200 ml)