2-Benzhydryloxycarbonyl-7-t-butoxycarbonylamino-8-oxo-3-(2-tosyloxyvinyl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-5-oxide → 7-Amino-2-benzhydryloxycarbonyl-8-oxo-3-(2-tosyloxyvinyl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-5-oxide

Participants

Reaction Steps

A solution of the E form of 2-benzhydryloxycarbonyl-7-t-butoxycarbonylamino-8-oxo-3-(2-tosyloxyvinyl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-5-oxide (54.3 g) and hydrated p-toluenesulphonic acid (30.4 g) in acetonitrile (1.4 liters) is stirred at 35° C. for 2 hours. The mixture is concentrated to dryness at 30° C. under 20 mm Hg (2.7 kPa), the residue is taken up in ethyl acetate (1 liter) and the mixture is washed with a semi-saturated solution of sodium bicarbonate (2×500 cc) and a semi-saturated solution of sodium chloride (2×500 cc), dried over sodium sulphate and concentrated to dryness at 20° C. under 20 mm Hg (2.7 kPa). The residue is triturated in ether (200 cc). This yields the E form of 7-amino-2-benzhydryloxycarbonyl-8-oxo-3-(2-tosyloxyvinyl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-5-oxide (28.13 g) in the form of a light brown powder.

Provenance & Evidence