1,1,1,3,3,3-Hexafluoro-2-propanol → 1,1,1,3,3,3-Hexafluoropropan-2-yl 4-[[4-(3-methylphenyl)-2-phenoxyphenyl]methyl]piperazine-1-carboxylate

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Reaction Steps

A 100 mL round-bottom flask, was charged with triphosgene (50.0 mg, 0.170 mmol, 0.30 equiv), dichloromethane (10 mL), 1,1,1,3,3,3-hexafluoropropan-2-ol (94.0 mg, 0.560 mmol, 1.00 equiv). N,N-Diisopropylethylamine (144 mg, 1.00 mmol, 2.00 equiv) was added dropwise. The resulting solution was stirred for 2 h at room temperature. 1-[[4-(3-Methylphenyl)-2-phenoxyphenyl]methyl]piperazine (200 mg, 0.560 mmol, 1.00 equiv) was added. The resulting solution was stirred overnight at room temperature and then diluted with water (5 mL). The resulting mixture was extracted with dichloromethane (2×10 mL) and the organic layers were combined, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product (230 mg) was purified by preparative HPLC using the following gradient conditions: 20% CH3CN/80% Phase A increasing to 80% CH3CN over 10 min, then to 100% CH3CN over 0.1 min, holding at 100% CH3CN for 1.9 min, then reducing to 20% CH3CN over 0.1 min, and holding at 20% for 1.9 min, on a Waters 2767-5 Chromatograph. Column: Xbridge Prep C18, 19*150 mm 5 um; Mobile phase: Phase A: aqueous NH4HCO3 (0.05%); Phase B: CH3CN; Detector, UV220 & 254 nm. Purification resulted in 173 mg (56% yield) of 1,1,1,3,3,3-hexafluoropropan-2-yl 4-[[4-(3-methylphenyl)-2-phenoxyphenyl]methyl]piperazine-1-carboxylate as yellow oil. 1H NMR 300 MHz (CDCl3) δ 7.51 (d, J=7.8 Hz, 1H), 7.27-7.39 (m, 5H), 7.21-7.248 (m, 1H), 7.18 (d, J=1.5 Hz, 1H), 7.12-7.14 (m, 1H), 7.02-7.07 (m, 1H), 6.92-6.96 (m, 2H), 5.71-5.79 (m, 1H), 3.62 (s, 2H), 3.50 (br, 4H), 2.50-2.51 (m, 4H), 2.37 (s, 3H). LCMS (ESI, m/z): 553 [M+H]+.

Provenance & Evidence