Reaction Steps
[7-(Methanesulfonylamino-methyl)-1,1-dioxo-1,4-dihydro-1λ6-thieno[2,3-e][1,2,4]thiadiazin-3-yl]-acetic acid (prepared as described in Example 2c; 0.120 g, 0.340 mmol), O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (0.142 g, 0.373 mmol) and 4-methylmorpholine (0.075 mL, 0.682 mmol) were added sequentially to a solution of rac-2-cyclopentyl-3-(4-fluoro-benzylamino)-propionic acid ethyl ester (0.100 g, 0.341 mmol) in N,N-dimethylformamide (5 mL) at 25° C. The reaction mixture was stirred at 25° C. for 19 h, and then was concentrated in vacuo. The residue was partitioned between 1.0 M aqueous hydrochloric acid solution (100 mL) and ethyl acetate (2×100 mL). The organic layers were dried over sodium sulfate and were concentrated in vacuo. The residue was dissolved in ethanol (12 mL) at 25° C. A 21 wt. % solution of sodium ethoxide in ethanol (0.663 mL, 2.04 mmol) was added and the reaction mixture was heated to 70° C. for 66 h. After cooling to 25° C., the reaction mixture was partitioned between 1.0 M aqueous hydrochloric acid solution (100 mL) and ethyl acetate (2×100 mL). The organic layers were dried over sodium sulfate and were concentrated in vacuo. The residue was purified by flash chromatography (Teledyne Isco RediSep column; 50-100% ethyl acetate in hexanes) to afford (after trituration with diethylether) N-{3-[5-cyclopentyl-1-(4-fluoro-benzyl)-4-hydroxy-2-oxo-1,2,5,6-tetrahydro-pyridin-3-yl]-1,1-dioxo-1,4-dihydro-1λ6-thieno[2,3-e][1,2,4]thiadiazin-7-ylmethyl}-methanesulfonamide (0.036 g, 0.062 mmol, 18%) as a beige solid. 1H NMR (400 MHz, DMSO-d6) δ: 1.07-1.12 (1H, m), 1.16-1.62 (7H, m), 1.76-1.86 (1H, m), 2.28-2.35 (1H, m), 2.95 (3H, s), 3.21 (1H, d, J=14.9 Hz), 3.63 (1H, dd, J1=4.0 Hz, J2=14.0 Hz), 4.24 (2H, d, J=6.3 Hz), 4.34 (1H, d, J=14.6 Hz), 4.85 (1H, d, J=14.2 Hz), 7.15-7.19 (2H, m), 7.25 (1H, s), 7.37-7.40 (2H, m), 7.64 (1H, t, J=6.4 Hz). LC-MS (ESI) calculated for C24H27FN4O6S3 582.11. found 583.1 [M+H+].
