Triphosgene → 1-Isocyanato-4-(2,2,2-trifluoro-ethoxy)-benzene

関与物質

反応条件

反応手順

2,2,2-Trifluoro-ethanol (7.09 g, 70.09 mmol) and stirred for 30 min. A solution of 1-Fluoro-4-nitro-benzene (10 g, 70.09 mmol) in DMF (25 mL) was added at 5-15° C., allowed to rt, stirred for 2 h, quenched with ice-water, filtered, washed with water and dried under high vacuum to obtain 14 g (89%) 1-Nitro-4-(2,2,2-trifluoro-ethoxy)-benzene as yellow solid. Subsequently, a solution of 1-Nitro-4-(2,2,2-trifluoro-ethoxy)-benzene (50 g, 226.2 mmol) in methanol (400 mL) was purged with nitrogen and 10% Pd—C (4.6 g) was added under nitrogen. This was stirred at rt under hydrogen atmosphere (balloon pressure) for 24 h. The reaction mixture was filtered through a celite bed and washed with methanol and the filtrate was removed under reduced pressure and washed with hexane to get 37 g (87%) 4-(2,2,2-Trifluoro-ethoxy)-phenylamine as a brown liquid. LC-MS: 192.4 [M+1]+. To a solution of 4-(2,2,2-Trifluoro-ethoxy)-phenylamine (12 g, 62.82 mmol) in DCM (1000 mL) was added solid NaHCO3 (52.77 g, 628.2 mmol). After 10 min, triphosgene (27.96 g, 94.24 mmol) dissolved in toluene (30 mL) was added to the reaction mixture under cooling at 10° C. and stirred for 10 min. The reaction mixture was filtered and the filtrate was concentrated, azeotroped twice with dry toluene to give 10 g 1-Isocyanato-4-(2,2,2-trifluoro-ethoxy)-benzene as yellow oily liquid which was used in the next step without further purification.

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