Reaction SMILES: [C:1]([NH:4][C@@H:5]1[C@@H:10]([O:11][CH2:12][C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=2)[C@H:9]([O:19][CH2:20][C:21]2[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=2)[C@@H:8]([CH2:27][O:28][CH2:29][C:30]2[CH:35]=[CH:34][CH:33]=[CH:32][CH:31]=2)[O:7][C@H:6]1[O:36][C@@H:37]1[C@@H:50]([CH2:51][O:52][CH2:53][C:54]2[CH:59]=[CH:58][CH:57]=[CH:56][CH:55]=2)[O:49][C@H:40]([O:41][CH2:42][C:43]2[CH:48]=[CH:47][CH:46]=[CH:45][CH:44]=2)[C@H:39]([NH:60][C:61](=[O:63])[CH3:62])[C@H:38]1[O:64][CH2:65][C:66]([OH:68])=[O:67])(=[O:3])[CH3:2].[N+](=[CH2:71])=[N-].C(O)(=O)C>ClCCl.CO.C(OCC)C>[C:1]([NH:4][C@@H:5]1[C@@H:10]([O:11][CH2:12][C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=2)[C@H:9]([O:19][CH2:20][C:21]2[CH:22]=[CH:23][CH:24]=[CH:25][CH:26]=2)[C@@H:8]([CH2:27][O:28][CH2:29][C:30]2[CH:35]=[CH:34][CH:33]=[CH:32][CH:31]=2)[O:7][C@H:6]1[O:36][C@@H:37]1[C@@H:50]([CH2:51][O:52][CH2:53][C:54]2[CH:55]=[CH:56][CH:57]=[CH:58][CH:59]=2)[O:49][C@H:40]([O:41][CH2:42][C:43]2[CH:48]=[CH:47][CH:46]=[CH:45][CH:44]=2)[C@H:39]([NH:60][C:61](=[O:63])[CH3:62])[C@H:38]1[O:64][CH2:65][C:66]([O:68][CH3:71])=[O:67])(=[O:3])[CH3:2]
Reactant: C=[N+]=[N-]
Reactant: CC(=O)N[C@H]1[C@H](O[C@H]2[C@H](OCC(=O)O)[C@@H](NC(C)=O)[C@@H](OCc3ccccc3)O[C@@H]2COCc2ccccc2)O[C@H](COCc2ccccc2)[C@@H](OCc2ccccc2)[C@@H]1OCc1ccccc1
Solvent: CCOCC
Solvent: CC(=O)O
Solvent: ClCCl
Product: COC(=O)CO[C@@H]1[C@@H](NC(C)=O)[C@@H](OCc2ccccc2)O[C@H](COCc2ccccc2)[C@H]1O[C@@H]1O[C@H](COCc2ccccc2)[C@@H](OCc2ccccc2)[C@H](OCc2ccccc2)[C@H]1NC(C)=O
Reaction time: 1 h
Yield: 93 %

Procedure:
To a stirred solution of 15 (933 mg, 1 mmol) in a mixture of dichloromethane-methanol (2:1, 75 ml) at 0° C. the solution of diazomethane in diethyl ether was added until a yellow coloration persisted. After standing at room temperature for 1 h, the excess diazomethane was decomposed with acetic acid and the mixture was evaporated. Chromatography of the residue on a silica gel C18 column in methanol-water (18:5) afforded 881 mg (93%) of 17 as a crystalline residue, which was crystallized from methanol; m.p. 221-223° C., [α]D+67° (c 0.5, chloroform); ref.25: m.p. 223° C. (methanol), [α]D +67° (c 0.5, chloroform). IR (chloroform): 3 404, 3 349 (N—H, NHAc); 3 090, 3 067, 3 032 (C—H, arom.); 1 738 (C═O, OCH2COOCH3); 1 675 (amide I); 1 607, 1 586, 1 497, 1 454 (arom. ring); 1 539, 1 520 (amide II); 1 441 (CH3, OCH2COOCH3). 1H NMR: 7.82 d, 2 H, J=4.5 (NHCOCH3, N′H′C′O′C′H′3); 7.21-7.39 m, 25 H (H-arom.,); 5.42 d, 1 H, J=3.4 (H-1); 4.82 d, 1 H, J=12.1 (CH2-Ph); 4.79 d, 1 H, J=12.1 (CH2-Ph); 4.76 d, 1 H, J=10.9 (CH2-Ph); 4.62 d, 1 H, J=12.0 (CH2-Ph); 4.58 d, 1 H, J=12.1 (CH2-Ph); 4.58 d, 1 H, J=11.9 (CH2-Ph); 4.58 d, 1 H, J=10.9 (CH2-Ph); 4.53 d, 1 H, J=18.5 (OCH2CO2CH3); 4.51 d, 1 H, J=12.0 (CH2-Ph); 4.49 d, 1 H, J=11.9 (CH2-Ph); 4.37 d, 1 H, J=9.4 (H-1′); 4.30 d, 1 H, J=12.1 (CH2-Ph); 4.28 d, 1 H, J=18.5 (OCH2CO2CH3); 3.88 dd, 1 H, J=8.8, 10.0 (H-1); 3.81 ddd, 1 H, J=3.4, 4.5, 11.0 (H-2); 3.77 dd, 1 H, J=2.9, 10.6 (H-6′a); 3.76 dd, 1 H, J=2.6, 10.6 (H-6′b); 3.75 ddd, 1 H, J=8.4, 9.4, 10.2 (H-2′); 3.75 dd, 1 H, J=8.9, 9.7 (H-4′), 3.66 dd, 1 H, J=8.8, 11.0 (H-3); 3.65 s, 3 H (OCH2CO2CH3); 3.60 dt, 1 H, J=2.5, 2.5, 10.0 (H-5); 3.54 dd, 1 H, J=2.6, 10.5 (H-6a); 3.36 dd, 1 H, J=2.5, 10.5 (H-6b); 3.34 ddd, 1 H, J=2.6, 2.9, 9.7 (H-5′); 3.34 dd, 1 H, J=8.9, 10.2 (H-3′); 2.00 s, 3 H (NHCOCH3); 1.66 s, 3 H (N′H′C′O′C′H′3). 13C NMR: 174.2 (OCH2CO2CH3), 170.8 (NHCOCH3, 169.7 (NHCOCH3), 138.4, 138.1, 138.1, 138.1, 137.8, 129.2 (2C), 128.8 (2C), 128.5 (3C), 128.4, 128.3 (2C), 128.3 (2C), 128.0 (2C), 127.9, 127.7, 127.7 (4C), 127.6, 127.5, 127.4 (3C) (C-arom.), 100.5 (C-1′), 96.7 (C-1), 82.2 (C-3′), 78.2 (C-4′), 78.0 (C-4), 77.2 (C-3), 74.8 (CH2-Ph), 74.6 (CH2-Ph), 74.4 (C-5′), 73.7 (CH2-Ph), 73.2 (CH2-Ph), 70.3 (CH2-Ph), 70.1 (C-5), 69.1 (OCH2CO2CH3), 68.7 (C-6′), 67.6 (C-6), 55.6 (C-2′), 54.2 (C-2), 51.7 (OCH2CO2CH3), 23.4 (N′H′C′O′C′H′3), 23.1 (NHCOCH3). For C54H62N2O13 calculated: relative molecular mass 947.1, monoisotopic mass 946.4. FAB MS, m/z: 947.4 [M+H]+, 969.4 [M+Na]+. For C54H62N2O13 (947.1) calculated: 68.48% C, 6.60% H, 2.96% N; found: 68.43% C, 6.62% H, 2.90% N.