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

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Reaction Steps

A 100 mL round-bottom flask was charged with triphosgene (160 mg, 0.540 mmol, 0.30 equiv), dichloromethane (20 mL). 1,1,1,3,3,3-Hexafluoropropan-2-ol (302 mg, 1.80 mmol, 1.00 equiv) and N,N-diisopropylethylamine (441 mg, 3.41 mmol, 1.90 equiv) were added. The resulting solution was stirred for 2 h at room temperature. 1-[[2-methyl-4-(3-methylphenyl)phenyl]methyl]piperazine (500 mg, 1.78 mmol, 1.00 equiv) was added. The resulting solution was stirred overnight at room temperature, diluted with water (50 mL), extracted with dichloromethane (3×40 mL) and the organic layers were combined, dried over Na2SO4, filtered and concentrated under reduced pressure. The crude product (250 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 141 mg (16% yield) of 1,1,1,3,3,3-hexafluoropropan-2-yl 4-[[2-methyl-4-(3-methylphenyl)phenyl]methyl]piperazine-1-carboxylate as colorless oil. 1H NMR 400 MHz (CDCl3) δ 7.30-7.42 (m, 6H), 7.18 (d, J=7.2 Hz, 1H), 5.76-5.82 (m, 1H), 3.55-3.58 (m, 6H), 2.45-2.53 (m, 10H). LCMS (ESI, m/z): 475 [M+H]+.

Provenance & Evidence