Methanesulfonic Acid → 7-Amino-2-benzhydryloxycarbonyl-3-(2-dimethylaminomethyleneamino-thiazol-5-yl)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene

Participants

Reaction Steps

Following the working method described in Example 15, 2-benzhydryloxycarbonyl-7-t-butoxycarbonylamino-3-(2-dimethylaminomethyleneamino-thiazol-5-yl)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene (E-form) (0.77 g) is treated with methanesulphonic acid (0.8 cc) in acetonitrile (8 cc). 7-Amino-2-benzhydryloxycarbonyl-3-(2-dimethylaminomethyleneamino-thiazol-5-yl)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene (E-form) (0.65 g) is obtained in the form of a crude brown froth (Rf=0.1, silica gel chromatographic plate; eluant: ethyl acetate), and this is redissolved in tetrahydrofuran (15 cc) and acylated, in accordance with the working method described in Example 1, with (thien-2-yl)acetyl chloride (0.15 cc) in the presence of triethylamine (0.17 cc). Chromatography is effected on a column (height: 28 cm; diameter: 2 cm) of silica gel (0.04-0.06 mm), elution being carried out under a pressure of 0.8 bar (80 kPa) by means of ethyl acetate, and 30 cc fractions being collected. Fractions 11 to 19, containing the pure product, are combined and concentrated to dryness under reduced pressure (30 mm Hg; 4 kPa) at 30° C. 2-Benzhydryloxycarbonyl-3-(2-dimethylaminomethyleneamino-thiazol-5-yl)-8-oxo-7-(thien-2-yl-acetamido)-5-thia-1-azabicyclo[4.2.0-oct-2-ene (E-form) (0.13 g) is obtained in the form of a yellow powder.

Provenance & Evidence