Diisopropylethylamine → (S)-2-[4-(2,3-dichloro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-4-methyl-pentanoic acid (1-methyl-1H-pyrazol-3-yl)-amide

Participants

Reaction Conditions

Reaction Steps

A solution of (S)-2-[4-(2,3-dichloro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-4-methy-1-pentanoic acid (prepared as in Example 77, 120 mg, 0.34 mmol) in N,N-dimethylformamide (4 mL) was treated with 1-methyl-1H-pyrazol-3-ylamine (50 mg, 0.51 mmol), benzotriazol-1-yl-oxy-tris(dimethylamino)phosphonium hexafluorophosphate (303 mg, 0.68 mmol) and N,N-diisopropylethylamine (110 mg, 0.85 mmol). The reaction mixture was stirred for 4 h at 25° C., under nitrogen. The reaction mixture was diluted with ethyl acetate, washed with saturated ammonium chloride, water, a saturated sodium chloride solution and dried over sodium sulfate. The organic layer was concentrated, and the crude product was purified by ISCO flash chromatography (Teledyne Isco RediSep Flash Column 12 g, 0% to 70% ethyl acetate/hexanes) to afford (S)-2-[4-(2,3-dichloro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-4-methyl-pentanoic acid (1-methyl-1H-pyrazol-3-yl)-amide as a waxy material. This material was dissolved in diethyl ether (4 mL) and treated with hydrogen chloride in diethyl ether (1 M, 2 mL). Solvents were evaporated and the residue was triturated with diethyl ether. The resulting mixture was filtered to give (S)-2-[4-(2,3-dichloro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-4-methyl-pentanoic acid (1-methyl-1H-pyrazol-3-yl)-amide hydrochloride (58 mg, 36%) as an orange solid: HR-ES-MS m/z calculated for C20H22Cl2N4O3 [M+Na]+ 459.0961, observed 459.0961; 1H NMR (300 MHz, DMSO-d6) δ ppm 0.88 (d, J=6.6 Hz, 3H) 0.92 (d, J=6.6 Hz, 3H) 1.31-1.64 (m, 2H) 1.64-1.82 (m, 1H) 3.71 (s, 3H) 4.21 (d, J=18.4 Hz, 1H) 4.59 (d, J=18.4 Hz, 1H) 4.82-4.89 (m, 1H) 4.90 (s, 1H) 6.38 (d, J=2.1 Hz, 1H) 7.40-7.57 (m, 3H) 7.62 (dd, J=7.8, 1.5 Hz, 1H) 10.73 (s, 1H).

Provenance & Evidence