General Procedure II: Synthesis of compounds of Formula II (Scheme 2a)
General procedure: General Procedure II: Synthesis of compounds of Formula II (Scheme 2a) l,l'-Carbonyldiimidazole (1.6 eq.) was added to a solution of the optionally substituted aminophenol V (1 eq.) in DMF (2.7 mL per mmol V), and the solution was heated to 60 °C for 2 hours. After cooling to room temperature, the reaction mixture was poured into water (15 mL per mmol V) and extracted with EtOAc (3 χ 15 mL per mmol V). The combined organic phases were washed with brine (15 mL per mmol V), dried over Na2S04, and evaporated on celite. The compound was purified by column chromatography using the Teledyne ISCO apparatus (cyclohexane:EtOAc).
With N-ethyl-N,N-diisopropylamine In tetrahydrofuran at 20℃; for 1h;
6.ii 5-chloro-6-methylbenzo [d] oxazol-2 (3H) -one
General procedure: mixture of compound 2 (0.050 g), 1,1'-carbonyldiimidazole (0.077 g), diisopropylethylamine (0.166 mL) and THF (1.5 mL) was stirred at room temperature for 1 hour .Water was added to the reaction mixture and extracted with ethyl acetate.The organic layer was dried over anhydrous sodium sulfate, concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 3/1) to give the title compound 3 (0.041 g).
ethyl [2-oxo-5-(trifluoromethyl)-1,3-benzoxazol-3(2H)-yl]acetate[ No CAS ]
Operation in experiment
With potassium carbonate In acetone for 4h; Reflux;
To a mixture of 5-trifluoromethyl-1,3-benzoxazol-2(3H)-one (999 mg) and acetone (25 mL) were added K2CO3 (1.02 g) and ethyl bromoacetate (708 μL) at room temperature, followed by heating to reflux for 4 hours. The reaction mixture was filtered while hot, and washed with acetone. The filtrate and the washed solution were combined and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: Hex/EtOAc=100/0-75/25) to obtain ethyl [2-oxo-5-(trifluoromethyl)-1,3-benzoxazol-3(2H)-yl]acetate (1.33 g).