Reaction SMILES: P(Cl)(Cl)(Cl)(Cl)Cl.N1C=CC=CC=1.S1C=CC=C1CC([NH:21][C@@H:22]1[C:56](=[O:57])[N:24]2[C:25]([C:40]([O:42][CH:43]([C:50]3[CH:55]=[CH:54][CH:53]=[CH:52][CH:51]=3)[C:44]3[CH:49]=[CH:48][CH:47]=[CH:46][CH:45]=3)=[O:41])=[C:26]([CH2:29][O:30][C:31](=[O:39])[NH:32]C(=O)C(Cl)(Cl)Cl)[CH2:27][S:28][C@H:23]12)=O.C(O)CC(O)C.O.[C:65]1([CH3:75])[CH:70]=[CH:69][C:68]([S:71]([OH:74])(=[O:73])=[O:72])=[CH:67][CH:66]=1.C1(C)C=CC(S(O)(=O)=O)=CC=1>ClCCl.C(Cl)(Cl)Cl>[C:65]1([CH3:75])[CH:66]=[CH:67][C:68]([S:71]([OH:74])(=[O:72])=[O:73])=[CH:69][CH:70]=1.[NH2:21][C@@H:22]1[C:56](=[O:57])[N:24]2[C:25]([C:40]([O:42][CH:43]([C:50]3[CH:51]=[CH:52][CH:53]=[CH:54][CH:55]=3)[C:44]3[CH:49]=[CH:48][CH:47]=[CH:46][CH:45]=3)=[O:41])=[C:26]([CH2:29][O:30][C:31](=[O:39])[NH2:32])[CH2:27][S:28][C@H:23]12
Reactant: O=C(Cc1cccs1)N[C@@H]1C(=O)N2C(C(=O)OC(c3ccccc3)c3ccccc3)=C(COC(=O)NC(=O)C(Cl)(Cl)Cl)CS[C@H]12
Agent: CC(O)CCO
Agent: Cc1ccc(S(=O)(=O)O)cc1
Agent: ClP(Cl)(Cl)(Cl)Cl
Solvent: ClC(Cl)Cl
Solvent: ClCCl
Solvent: c1ccncc1
Product: NC(=O)OCC1=C(C(=O)OC(c2ccccc2)c2ccccc2)N2C(=O)[C@@H](N)[C@H]2SC1
Reaction time: 1 h
Yield: 91.5 %

Procedure:
A stirred suspension of phosphorus pentachloride (156 g, 0.75 mole) in dry dichloromethane (1.5 liters) was cooled in an ice-bath and treated with pyridine (60.5 ml, 0.75 mole) at such a rate that the temperature of the mixture remained at ca. 20° to 25°. The mixture was stirred and cooled to 8° and diphenylmethyl (6R,7R)-7-(thien-2-yl)acetamido-3-trichloroacetylcarbamoyloxymethylceph-3-em-4-carboxylate (354.5 g, 0.5 mole) was added in portions over 10 minutes. The mixture was stirred at ca. 8° for 1.75 hours and then added over 10 minutes to a stirred mixture of butane-1,3-diol (225 ml, 2.5 mole) and dichloromethane (500 ml) precooled to -20° so that the temperature of the mixture was kept in the range -15° to -20°. The cooling bath was removed and the mixture was stirred at ca. -10° for 20 minutes. Water (1 liter) was added and the two-phase mixture was stirred for 30 minutes. The aqueous phase was extracted with dichloromethane (2×500 ml), and the organic phases were washed sequentially with 2N hydrochloric acid (1 liter), combined and evaporated to a brown gum. The gum was dissolved in methanol (3.6 liters) and this solution was stirred and treated with saturated aqueous sodium hydrogen carbonate solution (1.2 liters) over a period of 10 minutes. The mixture was stirred at ca. 20° for 1.5 hours and a small quantity of brown solid was removed by filtration. The yellow filtrate was concentrated in vacuo (bath temp. not greater than 40°) to ca. 1.5 liters and water (1.5 liters) was added. The resulting suspension was refrigerated for 1 hour, and the yellow solid was filtered off, washed well with water, sucked as dry as possible and dried in vacuo at 40° for 24 hours. The greasy solid thus obtained, followed by toluene-p-sulphonic acid monohydrate (81 g, 0.425 mole), were added to stirred chloroform (2 liters). After several minutes the toluene-p-sulphonic acid salt began to crystallise. Stirring was continued for a further 30 minutes, after which the water was removed azeotropically in vacuo with continuous replacement of the chloroform so as to maintain a volume of 2 liters. The suspension was refrigerated overnight and the product was filtered off, slurry washed with chloroform (2×250 ml), refiltered, washed by displacement with chloroform (250 ml) and dried in vacuo at 40° to give the title compound as an off-white crystalline solid (237.8 g, 74.1%); λmax (EtOH) 262 nm (ε 7,250); the NMR spectrum (Me2SO-d6) indicated the presence of 0.25 mole of chloroform.