Reaction Steps
To a suspension of 100 mg (0.41 mmol 1 equiv) of biotin in 3 mL of anhydrous DMF was added 66 mg (0.49 mmol, 1.2 equiv) of 1-hydroxybenzotriazole hydrate, 94 mg (0.49 mmol, 1.2 equiv) of N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride, and 79 mg (0.78 mmol, 1.9 equiv) of Et3N. The mixture was stirred for 10 min, and 95 mg (0.41 mmol) of 9 was added. The mixture was stirred for 24 h at 25° C. and poured into water. The precipitate was collected by filtration and chromatographed using 1:1 EtOAc-MeOH to give 120 mg (66%) of 11 as white crystals: mp 278-280° C. 1H NMR (DMSO-d6): δ 9.99 (s, 1H), 7.64 (d, 2H, J=8.8 Hz), 7.56 (d, 2H, J=8.8 Hz), 7.37-7.29 (m, 2H), 7.19-7.12 (m, 2H), 7.02 (d, 1H, J=16.4 Hz), 6.44 (s, 1H), 6.36 (s, 1H), 4.33-4.29 (m, 1H), 4.16-4.13 (m, 1H), 3.15-3.10 (m, 1H), 2.83 (dd, 1H, J1=12.8 Hz, J2=4.8 Hz), 2.58 (d, 1H, J=12.0 Hz), 2.33 (t, 2H, J=7.2 Hz), 1.70-1.33 (m, 6H). 13C NMR (DMSO-d6): δ 171.70, 163.13, 160.53 (dd, J1=247.8 Hz, J2=7.7 Hz, two C), 140.09, 135.28 (t, J=7.9 Hz), 131.77, 129.18 (t, J=10.7 Hz), 127.69 (two C), 119.54 (two C), 114.61 (t, J=15.5 Hz), 113.25, 112.45 (dd, J1=19.1 Hz, J2=6.3 Hz, two C), 61.48, 59.63, 55.82, 40.28, 36.70, 28.67, 28.53, 25.50. HRMS (EI) Calcd for C24H25F2N3O2S: 457.1636. Found: 457.1650. Anal. Calcd for C24H25F2N3O2S: C, 63.00; H, 5.51. Found: C, 62.82; H, 5.47.
