Methanesulfonic Acid → Diisopropyl Ether

Participants

Reaction Steps

3-(2-Anilino-thiazol-5-yl)-2-benzhydryloxycarbonyl-7-t-butoxycarbonylamino-8-oxo-5-thia-1-azabicyclo[4.2.0]-oct-2-ene (2.3 g) is treated with methanesulphonic acid (2.3 cc) in acetonitrile (23 cc) in accordance with the working method described in Example 2. Crude 7-amino-3-(2-anilino-thiazol-5-yl)-2-benzhydryloxycarbonyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene (1.85 g) is obtained and is acylated with (thien-2-yl)-acetyl chloride (0.445 cc) in tetrahydrofuran (25 cc) in the presence of triethylamine (0.505 cc), using the working method described in Example 1. The crude product obtained is chromatographed on a column (height: 30 cm; diameter: 2.5 cm) of silica gel (0.04-0.06 mm), elution being carried out under a pressure of 1.2 bar (120 kPa) with a 70:30 (by volume) mixture (3 liters) of cyclohexane and ethyl acetate, and 50 cc fractions being collected. Fractions 20 to 50 are combined and concentrated to dryness. After trituration with isopropyl ether, 3-(2-anilino-thiazol-5-yl)-2-benzhydryloxycarbonyl-8-oxo-7-(thien-2 -yl-acetamido)-5-thia-1-azabicyclo[4.2.0]oct-2-ene (0.9 g) is obtained in the form of a yellow solid.

Provenance & Evidence