Diisopropylethylamine → N-[(9H-fluoren-9-ylmethoxy)carbonyl]-2-methylalanyl-N-[(3R,4S,5S)-3-methoxy-1-{(2S)-2-[(1R,2R)-1-methoxy-3-{[(2S)-1-methoxy-1-oxo-3-phenylpropan-2-yl]amino}-2-methyl-3-thioxopropyl]pyrrolidin-1-yl}-5-methyl-1-oxoheptan-4-yl]-N-methyl-L-valinamide

Participants

Reaction Steps

To a solution of #32 (321 mg, 0.881 mmol, 1 eq.) in dichloromethane (5 mL, 0.1 M) and N,N-dimethylformamide (1 mL) were added #39 (484 mg, ≦0.769 mmol, 0.9 eq.), HATU (353 mg, 0.881 mmol, 1 eq.) and diisopropylethylamine (463 μL, 2.64 mmol, 3 eq.). After stirring for 18 hours, the mixture was diluted with dichloromethane, washed with water and with brine, dried over magnesium sulfate, filtered, and concentrated onto silica in vacuo. The residue was purified by silica gel chromatography (Gradient: 0% to 30% acetone in heptane) to give #43 (574 mg, 68% over two steps) as a white solid. LC-MS: m/z 956.6 [M+H+], retention time=4.49 minutes; 1H NMR (400 MHz, CD3OD), presumed to be a mixture of rotamers, characteristic signals: δ 7.80 (d, J=7.5 Hz, 2H), 7.64-7.72 (m, 2H), 7.16-7.35 (m, 7H), [5.43 (dd, J=11, 4.5 Hz) and 5.58 (dd, J=11.5, 4 Hz), total 1H], 3.72 and 3.75 (2 s, total 3H), 3.34 and 3.35 (2 s, total 3H), 3.26 and 3.29 (2 s, total 3H), 3.05 and 3.11 (2 br s, total 3H), 1.39 and 1.40 (2 s, total 3H), [1.24 (d, J=6.7 Hz) and 1.29 (d, J=6.4 Hz), total 3H].

Provenance & Evidence