Diisopropylethylamine → N-(tert-butoxycarbonyl)-N,2-dimethylalanyl-N-[(3R,4S,5S)-3-methoxy-1-{(2S)-2-[(1R,2R)-1-methoxy-2-methyl-3-oxo-3-{[(1S)-2-phenyl-1-(1,3-thiazol-2-yl)ethyl]amino}propyl]pyrrolidin-1-yl}-5-methyl-1-oxoheptan-4-yl]-N-methyl-L-valinamide

Participants

Reaction Steps

To a mixture of #86 (80.3 mg, 0.122 mmol, 1 eq.) in dichloromethane (4 mL, 0.03 M) was added N-(tert-butoxycarbonyl)-N,2-dimethylalanine (29.1 mg, 0.134 mmol, 1.1 eq.) followed by diisopropylethylamine (64 μL, 0.365 mmol, 3 eq.) and HATU (71.7 mg, 0.183 mmol, 1.5 eq.) After stirring overnight, the reaction mixture was concentrated in vacuo. The residue was taken up in ethyl acetate (6 mL) and washed with 1 M aqueous hydrochloric acid solution (2×2 mL) and with brine. The organic solvent was dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was taken up in dichloromethane and filtered; the filtrate was concentrated in vacuo onto silica and purified by silica gel chromatography (Gradient: 0% to 50% acetone in heptane) to afford #87 (58 mg, 50%) as a white solid. LC-MS: m/z 857.7 [M+H+], 879.7 [M+Na+], retention time=0.99 minute; 1H NMR (400 MHz, DMSO-d6), presumed to be a mixture of rotamers, characteristic signals: δ [8.64 (br d, J=8 Hz) and 8.87 (br d, J=9 Hz), total 1H], [7.77 (d, J=3.3 Hz) and 7.80 (d, J=3.3 Hz), total 1H], [7.63 (d, J=3.2 Hz) and 7.66 (d, J=3.2 Hz), total 1H], 7.13-7.31 (m, 5H), [6.95 (br d, J=8 Hz) and 7.06 (br d, J=8 Hz), total 1H], 5.35-5.42 and 5.51-5.58 (2 m, total 1H), 3.15, 3.19, 3.20 and 3.26 (4 s, total 6H), 2.94 and 3.03 (2 br s, total 3H), 2.83 and 2.84 (2 s, total 3H), [1.05 (d, J=6.7 Hz) and 1.11 (d, J=6.7 Hz), total 3H].

Provenance & Evidence