One-pot synthesis of alkyl 3-cyclopropylamino-2-[2,4-dibromo-3-(difruoromethoxy) benzoyl]-2-propenoate as useful intermediate for antibacterial quinolone medicaments
A technology of difluoromethoxy, alkyl acrylate, applied to 3-cyclopropylamino-2-[2,4-dibromo-3-(difluoromethoxy base) benzoyl]-2-acrylic acid alkyl-pot synthesis field, which can solve problems such as unfavorable environment
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Embodiment 1
[0032] Preparation of 3-cyclopropylamino-2-[2,4-dibromo-3-(difluoromethoxy)benzoyl]-2-propenoic acid ethyl ester
[0033] Add toluene (15ml) and N,N-dimethylformamide (0.2 mL) of the mixture. The reaction mixture was slowly heated to reflux and stirred for about 2.5 hours. The reaction mixture was then cooled to 35 °C and a solution of ethyl 3,3-dimethylaminoacrylate (4.13 g) and triethylamine (3.79 g) in toluene (20 mL) was added dropwise while maintaining a temperature of 35-40 °C for about 1 hour. After the addition was complete, the reaction temperature was slowly increased to 60-65°C and the reaction mixture was stirred for 24 hours. Cool the reaction mixture to 30°C, add water (20 mL) and stir for about 10 minutes. The organic layer was separated, cooled to about 5°C, and cyclopropylamine (1.82 g) was added dropwise while maintaining the temperature at 8-10°C for 10 minutes. The reaction mixture was stirred for about 2 hours, the solvent was removed in vacuo (about ...
Embodiment 2
[0036] Preparation of 3-cyclopropylamino-2-[2,4-dibromo-3-(difluoromethoxy)benzoyl]-2-propenoic acid ethyl ester
[0037] To a mixture of 2,4-dibromo-3-(difluoromethoxy)benzoic acid (50 g) in ethyl acetate (175 mL) was added N,N-dimethylformamide (1 mL) and thionyl chloride ( 18.1 g). The reaction mixture was heated to reflux and stirred at reflux for 1 hour. After evaporating ethyl acetate (125 mL), triethylamine (16.1 g) and ethyl 3,3-dimethylaminoacrylate (20.7 g) were added at room temperature. The reaction mixture was heated to reflux and stirred at reflux for 3 hours. The reaction mixture was then cooled to 25°C, water (100 mL) was added, and the mixture was stirred for about 10 minutes. The organic layer was separated, cyclopropylamine (9.9 g) was added thereto, and the reaction mixture was stirred at 25° C. for 1 hour. The solvent of the reaction mixture was exchanged with isopropanol (200 mL), maintaining the temperature at about 68°C. The mixture crystallized on...
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