2,5-Dichlorophenol → Tert-butyl 4-(2-(2,5-dichlorophenoxy)-5-nitrophenylsulfonyl)piperazine-1-carboxylate

참여 물질

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To a solution of 2,5-dichlorophenol (0.414 g, 2.54 mmol) in THF (20.00 mL) stirred in an ice bath was added NaH (0.101 g, 2.54 mmol) slowly. After addition, the mixture was stirred for 5 min. Compound 38 (0.790 g, 1.95 mmol) was then added and the resulting reaction mixture was heated to 75° C. overnight. The reaction was monitored by HPLC. However, the reaction was not complete after 16 hrs (HPLC), so THF was evaporated and 18-crown-6 (1.057 g, 4.00 mmol), DMF (15 mL), and K2CO3 (0.553 g, 4.00 mmol) were added. The reaction mixture was heated to 100° C. for another 16 hrs, at which time HPLC indicated that the reaction was complete by absence of starting material. The reaction mixture was cooled to room temperature, and water (0.250 mL) was added. The reaction mixture was extracted thrice with EtOAc. Combined extracts were washed sequentially with 1N NaOH, water, and brine, dried over MgSO4, filtered, and evaporated in vacuo. The residual was dissolved in a minimal amount of DCM and purified with chromatography using a gradient of 5 to 30% EtOAc in hexanes. Pure fractions were combined and evaporated in vacuo. The resulting solid was triturated with DCM and hexanes, and then filtered to afford compound 39 as a white/yellow powder (0.120 g, 100% HPLC purity, 10.0% yield). 1H NMR (500 MHz, DMSO-d6): δ 8.59 (d, J=2 Hz, 1H), 8.42 (dd, J1=2 Hz, J2=8 Hz, 1H), 7.76 (d, J=8 Hz, 1H), 7.66 (d, J=3 Hz, 1H), 7.50 (dd, J1=2 Hz, J2=8 Hz, 1H), 7.10 (d, J=8 Hz, 1H), 3.40 (m, 4H), 3.25 (m, 4H), 1.37 (s, 9H).

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