[C:1]([CH2:6][CH2:7][N:8]([C:28]([O:30][C:31]([CH3:34])([CH3:33])[CH3:32])=[O:29])[CH2:9][CH2:10][CH2:11][CH2:12][N:13]([CH2:21][CH2:22][C:23]([O:25][CH2:26][CH3:27])=[O:24])[C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15])([O:3][CH2:4][CH3:5])=[O:2].CN([C:38]1[CH:43]=[CH:42][CH:41]=[CH:40]N=1)C.C(O)C[CH2:46][CH2:47][CH2:48][CH2:49][CH2:50][CH2:51]/[CH:52]=[CH:53]\[CH2:54][CH2:55][CH2:56][CH2:57][CH2:58][CH2:59][CH2:60][CH3:61].CCN=C=N[CH2:68][CH2:69][CH2:70]N(C)C>ClCCl>[CH2:26]([O:25][C:23](=[O:24])[CH2:22][CH2:21][N:13]([C:14]([O:16][C:17]([CH3:18])([CH3:19])[CH3:20])=[O:15])[CH2:12][CH2:11][CH2:10][CH2:9][N:8]([C:28]([O:30][C:31]([CH3:32])([CH3:33])[CH3:34])=[O:29])[CH2:7][CH2:6][C:1]([O:3][CH2:4][CH2:5][CH2:61][CH2:60][CH2:59][CH2:58][CH2:57][CH:56]=[CH:55][CH2:54][CH2:53][CH2:52][CH2:51][CH2:50][CH2:49][CH2:48][CH2:47][CH3:46])=[O:2])[CH2:27][CH2:38][CH2:43][CH2:42][CH2:41][CH2:40][CH:46]=[CH:47][CH2:48][CH2:49][CH2:50][CH2:51][CH2:52][CH2:53][CH2:70][CH2:69][CH3:68]To a solution of the N-protected amino acid 4 (n=4; 15.2 g, 35.1 mmol), dimethylaminopyridine (1.70 g, 14.0 mmol) and oleyl alcohol (18.4 g, 68.4 mmol) in dichloromethane (200 mL) was added a solution of EDCI (13.1 g, 68.4 mmol), in dichloromethane (50 mL) at 0° C. The resulting mixture was allowed to warm to room temperature and then stirred under N2 for 18 h. Dichloromethane (250 mL) was added and the mixture was washed with brine (4×200 mL), dried (Na2SO4) and concentrated in vacuo to leave an oil which was purified by column chromatography eluting with a solvent gradient of CH2Cl2 (50-90%) in hexane to afford the ester 5 as a colourless oil (13.0 g, 40%).
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