Reaction SMILES: [NH2:1][C:2]1[S:6][N:5]=[C:4](/[C:7](=[N:38]/[O:39][C:40]([C:43]([O:45]C(C)(C)C)=[O:44])([CH3:42])[CH3:41])/[C:8]([NH:10][C@@H:11]2[C:36](=[O:37])[N:13]3[C:14]([C:20]([O:22]C(C4C=CC=CC=4)C4C=CC=CC=4)=[O:21])=[C:15]([CH2:18]I)[CH2:16][S:17][C@H:12]23)=[O:9])[N:3]=1.C[Si](C)(C)NC(=O)C.[CH3:58][N:59]1[C:63]([NH:64]C(C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=[C:62]([NH:84][C:85]([N:87]2[CH2:91][CH2:90][C@H:89]([NH:92]C(=O)OC(C)(C)C)[CH2:88]2)=[O:86])[CH:61]=[N:60]1.C(OCC)(=O)C>CN(C)C=O.O>[NH2:64][C:63]1[N:59]([CH3:58])[N+:60]([CH2:18][C:15]2[CH2:16][S:17][C@@H:12]3[C@H:11]([NH:10][C:8](=[O:9])/[C:7](/[C:4]4[N:3]=[C:2]([NH2:1])[S:6][N:5]=4)=[N:38]\[O:39][C:40]([C:43]([OH:45])=[O:44])([CH3:42])[CH3:41])[C:36](=[O:37])[N:13]3[C:14]=2[C:20]([O-:22])=[O:21])=[CH:61][C:62]=1[NH:84][C:85]([N:87]1[CH2:91][CH2:90][C@H:89]([NH2:92])[CH2:88]1)=[O:86]
Reactant: CC(C)(C)OC(=O)C(C)(C)O/N=C(\C(=O)N[C@@H]1C(=O)N2C(C(=O)OC(c3ccccc3)c3ccccc3)=C(CI)CS[C@H]12)c1nsc(N)n1
Reactant: Cn1ncc(NC(=O)N2CC[C@H](NC(=O)OC(C)(C)C)C2)c1NC(c1ccccc1)(c1ccccc1)c1ccccc1
Agent: CC(=O)N[Si](C)(C)C
Solvent: O
Solvent: CCOC(C)=O
Solvent: CN(C)C=O
Product: Cn1c(N)c(NC(=O)N2CC[C@H](N)C2)c[n+]1CC1=C(C(=O)[O-])N2C(=O)[C@@H](NC(=O)/C(=N\OC(C)(C)C(=O)O)c3nsc(N)n3)[C@H]2SC1
Temperature: 25 °C
Reaction time: 0.5 h
Yield: 8.6 %

Procedure:
To a solution of benzhydryl 7β-[(Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(1-tert-butoxycarbonyl-1-methylethoxyimino)acetamido]-3-iodomethyl-3-cephem-4-carboxylate (820 mg) in N,N-dimethylformamide (2.4 ml) was added N-(trimethylsilyl)acetamide (656 mg), and the mixture was stirred at room temperature for 30 minutes. To the reaction mixture was added tert-butyl [(3S)-1-({[1-methyl-5-(tritylamino)-1H-pyrazol-4-yl]amino}carbonyl)-3-pyrrolidinyl]carbamate (680 mg). The whole mixture was stirred at room temperature for 3 hours. To the resulting reaction mixture were added ethyl acetate (80 ml) and water (50 ml). The aqueous layer was separated, and the organic layer was washed successively with 10% aqueous sodium trifluoroacetate solution, 10% aqueous sodium thiosulfate solution and brine, dried over sodium-sulfate and filtered. The filtrate was concentrated to about 5 ml in vacuo. The concentrate was poured into diisopropyl ether (120 ml), and the resulting precipitate was collected by filtration and dried in vacuo. To a solution of the resulting solid in methylene chloride (3.0 ml) were added anisole (1.0 ml) and trifluoroacetic acid (2.0 ml), and the mixture was stirred at room temperature for 4 hours. The reaction mixture was poured into diisopropyl ether (100 ml), and the resulting precipitate was collected by filtration and dried in vacuo to give a crude product (690 mg), which was purified by preparative HPLC utilizing ODS column. The eluate containing a desired product was concentrated to about 30 ml in vacuo. The concentrate was adjusted to about pH 3 with concentrated hydrochloric acid and chromatographed on Diaion® HP-20 (Mitsubishi Chemical Corporation) eluting with 30% aqueous 2-propanol. The eluate was concentrated to about 30 ml in vacuo and lyophilized to give 3-{[3-amino-4-({[(3S)-3-amino-1-pyrrolidinyl]carbonyl}amino)-2-methyl-1-pyrazolio]methyl}-7β-[(Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(1-carboxy-1-methylethoxyimino)acetamido]-3-cephem-4-carboxylate (60 mg) as an amorphous solid.