Reaction Steps
According to general procedure D, from #82 (670 mg, ≦0.818 mmol, 1 eq.), dichloromethane (5 mL, 0.16 M), N-[(9H-fluoren-9-ylmethoxy)carbonyl]-N,2-dimethylalanine (304 mg, 0.896 mmol, 1.1 eq.), HATU (372 mg, 0.978 mmol, 1.2 eq.) and diisopropylethylamine (440 μL, 2.53 mmol, 3.1 eq.) was synthesized the crude desired material, which was purified by silica gel chromatography (Gradient: 0% to 30% acetone in heptane) to give #83 (556 mg, 69% over two steps). LC-MS: m/z 994.7 [M+H+], retention time=0.69 minutes; HPLC (Protocol C): retention time=9.333 minutes (purity >98%); 1H NMR (400 MHz, DMSO-d6), presumed to be a mixture of rotamers, characteristic signals: δ [10.53 (br d, J=8 Hz) and 10.80 (br d, J=8 Hz), total 1H], 7.86-7.91 (m, 2H), [7.80 (d, J=3.3 Hz) and 7.82 (d, J=3.2 Hz), total 1H], [7.64 (d, J=3.2 Hz) and 7.68 (d, J=3.2 Hz), total 1H], 7.62-7.66 (m, 2H), 7.38-7.44 (m, 2H), 7.28-7.36 (m, 5H), 7.19-7.26 (m, 2H), 7.12-7.17 (m, 1H), [6.31 (ddd, J=11, 8, 4.5 Hz) and 6.44 (ddd, J=11, 8.5, 4.5 Hz), total 1H], [4.42 (dd, J=9, 8 Hz) and 4.48 (dd, J=8, 8 Hz), total 1H], 3.22 and 3.24 (2 s, total 3H), 3.13 and 3.17 (2 s, total 3H), 2.89 and 2.97 (2 br s, total 3H), 2.84 and 2.85 (2 s, total 3H), [1.13 (d, J=6.4 Hz) and 1.16 (d, J=6.4 Hz), total 3H].
