[OH:1][N:2]1[C:6](=[O:7])[C:5]2=[CH:8][CH:9]=[CH:10][CH:11]=[C:4]2[C:3]1=[O:12].[CH2:13]1[CH2:23][CH2:22]N2[C:16](=NCCC2)[CH2:15][CH2:14]1.C1(Br)CCCCC1>CN(C=O)C>[CH:13]1([O:1][N:2]2[C:3](=[O:12])[C:4]3[C:5](=[CH:8][CH:9]=[CH:10][CH:11]=3)[C:6]2=[O:7])[CH2:14][CH2:15][CH2:16][CH2:22][CH2:23]1N-hydroxylphthalimide (61.3 mmol, 10.0 g) was dissolved in anhydrous DMF (60 mL) under nitrogen. To the stirring solution, DBU (92.0 mmol, 13.75 mL) was injected followed by cyclohexyl bromide (76.6 mmol, 9.43 mL) and the reaction was warmed to 55° C. After stirring for 15 hours, the reaction was warmed to 80° C. for 5 hours, then cooled to room temperature and concentrated to a red oil. The reaction was partitioned between ethyl acetate and 1N HCl. The organic layer was washed with 1N NaOH, brine and dried over magnesium sulfate. The solvent was removed under vacuum and the crude product was triturated with hexanes providing 2.89 g (19%) of a yellow solid. Rf: 0.7 (2:1 hexanes/ethyl acetate); H1-NMR (CDCl3): δ 7.80 (2H,m), 7.73(2H,m), 4.21 (1H,m), 2.02-1.98 (2H,m), 1.87-1.82 (2H,m), 1.59-1.53 (4H,m), 1.30-1.24 (2H,m).
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