which is administered once or twice a day at an interval of 6 to 12 hours wherein the suppositories are administered by insertion into the rectum to a solution of mercaptoethanol 1 46 g 18 7 mmol in thf 40 ml h 2 o 40 ml and 1n naoh 18 7 ml 3s 4s 3 2s 2 benzyloxycarbonylamino 2 phenylmethyl acetamido 4 acetoxy azetidin 2 one 3 98 g 9 365 mmol in acetone 50 ml and thf 50 ml was slowly added at 5 u00b0 c the mixture was stirred at 5 u00b0 c for 2 hrs after removal of solvent the residue was dissolved in ethyl acetate washed with water brine and dried over sodium sulfate after removal of solvent the solid was washed with chloroform and ether and 3 79 g of crude 3r 4sr 3 2s 2 benzyloxycarbonylamino 2 phenylmethyl acetamido 4 hydroxyethylthio azetidin 2 one was obtained to a solution of 3r 4sr 3 2s 2 benzyloxycarbonylamino 2 phenylmethyl acetamido 4 hydroxyethylthio azetidin 2 one 3 79 g 8 53 mmol in pyridine 30 ml p toluenesulfonyl chloride 3 26 g 17 mmol was added at u2212 15 u00b0 c the mixture was stirred at 5 u00b0 c for 6 hrs and then poured into 1n hcl 280 ml the resulting solution was adjusted to ph 2.