[Cl:1]C(Cl)(O[C:5](=[O:11])[O:6][C:7](Cl)(Cl)Cl)Cl.[Cl:13][C:14]1[CH:15]=[CH:16][C:17](CO)=[C:18]([NH:20][CH:21]2[CH2:26][CH2:25][N:24](C(OC(C)(C)C)=O)[CH2:23][CH2:22]2)[CH:19]=1.C(N(CC)C(C)C)(C)C>O1CCCC1>[ClH:1].[Cl:13][C:14]1[CH:15]=[CH:16][C:17]2[CH2:7][O:6][C:5](=[O:11])[N:20]([CH:21]3[CH2:26][CH2:25][NH:24][CH2:23][CH2:22]3)[C:18]=2[CH:19]=1Triphosgene (1.6 g) was added to a stirred solution of the product from step (i) (5 g), N,N-diisopropylethylamine (5.2 ml) in tetrahydrofuran (50 ml) at 0° C. The mixture was stirred at room temperature for 16 h, the precipitate filtered and the filtrate evaporated under reduced pressure. Purification was by chromatography eluting with 20% ethyl acetate/toluene. The product was dissolved in dichloromethane then a solution of hydrogen chloride in 1,4-dioxane added. After 2 h the solvent was removed under reduced pressure to yield a solid. Used directly.
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