Reaction Steps
A solution of 3-[(dipropylamino)carbonyl]-5-(1,3-thiazol-2-yl)benzoic acid (156 mg, 0.47 mmol), (2R,3S)-3-amino-4-(3,5-difluorophenyl)-1[(3-ethylbenzyl)amino]butan-2-ol dihydrochloride (191 mg, 0.47 mmol), HOBt (64 mg, 0.47 mmol), and N-methylmorpholine (200 μL, 1.5 mmol) was stirred in dimethylformamide (2 mL) for 15 min. EDC (145 mg, 0.84 mmol) was added and the reaction mixture was stirred overnight. The reaction mixture was diluted with water, and extracted with ethyl acetate (3×25 mL). The organic layer was washed with 1 N hydrochloric acid (25 mL), saturated sodium bicarbonate (25 mL), saturated sodium chloride, dried (sodium sulfate), and concentrated under reduced pressure. Purification by flash column chromatography (silica, 1:9 methanol/chloroform) provided N1-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(3-ethylbenzyl)amino]-2-hydroxypropyl}-N3,N3-dipropyl-5-(1,3-thiazol-2-yl)isophthalamide (33 mg): 1H NMR (500 MHz, CDCl3) δ 8.40 (br s, 1H, —NH), 8.15 (br s, 1H), 7.94 (br s, 1H), 7.80 (d, J=3 Hz, 1H), 7.51 (br s, 1H), 7.34 (d, J=3 Hz, 1H), 7.27–7.24 (m, 1H), 7.21–7.18 (m, 2H), 7.11–7.10 (m, 1H), 7.00 (br s, 1H), 6.62–6.58 (m, 1H), 4.23 (d, J=5 Hz, 1H), 3.91–3.85 (m, 3H), 3.57 (br s, 2H), 3.31 (br s, 2H), 3.05 (d, J=5 Hz, 4H), 2.83 (d, J=6 Hz, 2H), 2.64 (q, J=8 Hz, 2H), 1.75 (br s, 2H), 1.44 (t, J=7 Hz, 2H), 1.22 (t, J=8 Hz, 3H) 1.04 (t, J=7 Hz, 3H), 0.65 (t, J=7 Hz, 3H); ESI MS m/z 649 [M+H]+;
