Potassium Carbonate → 2,2-dimethylpropanoyloxymethyl (6R)-7-[[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-methoxyiminoacetyl]amino]-3-[(Z)-but-1-enyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

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Reaction Steps

Pivaloyloxymethyl iodide (162 mg, 0.67 mmole) was added at 0° C. to a mixture of 7-[(Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]-3-[(Z)-1-butenyl]-3-cephem-4-carboxylic acid (197 mg, 0.45 mmole) and K2CO3 (93 mg, 0.67 mmole) in DMF (4 ml). The mixture was stirred at 0°-5° C. for 1 hour and diluted with ethyl acetate (30 ml). The dilute was washed with water and a saturated NaCl solution, dried over anhydrous MgSO4 and evaporated in vacuo. The residue was chromatographed on a silica gel column (5 g) with 1% methanol in CHCl3. The desired fractions were combined and concentrated in vacuo. The residue was dissolved in dioxane and lyophilized to afford 242 mg (97%) of the dioxane solvate of the title compound. Silica gel TLC: Rf 0.25 (1:1 CHCl3 -ethyl acetate). Estimated purity 85% (by HPLC). Mp. 90°-95° C.

Provenance & Evidence