反応 #710490

反応方程式

potassium monophosphate

2-bromo-3,5-dichloropyridine

ethyl bromodifluoroacetate

→

brown oil

収率 86.7%

ethyl (3,5-dichloropyridin-2-yl)(difluoro)acetate

収率 86.7%

溶媒

water

dimethylsulfoxide

反応条件

後処理

1. 1
   温度After cooling of the reaction mixture
2. 2
   ろ過The black mixture was then filtered over a cake of Supercel™
3. 3
   洗浄the cake was washed three times by 200 mL of ethyl acetate
4. 4
   その他The organic phases were collected
5. 5
   洗浄washed with brine
6. 6
   乾燥dried over magnesium sulfate
7. 7
   その他Evaporation of the solvent under vacuum

実験手順

To a solution of 56 g (0.246 mol) of 2-bromo-3,5-dichloropyridine in 500 mL of dry dimethylsulfoxide, were added 53 g (0.261 mol) of ethyl bromodifluoroacetate followed by 94 g (0.518 mol) of copper bronze (200 mesh). The beige suspension was heated at 50° C. for 5 hours. After cooling of the reaction mixture, a solution of 44 g (0.328 mol) of potassium monophosphate in 280 mL of water was added and stirred for 1 hour. The black mixture was then filtered over a cake of Supercel™, and the cake was washed three times by 200 mL of ethyl acetate. The organic phases were collected, washed with brine and dried over magnesium sulfate. Evaporation of the solvent under vacuum gave 57.6 g of brown oil. After purification by column chromatography on silica gel (heptane/ethyl acetate 9/1) 40 g (57%) of ethyl (3,5-dichloropyridin-2-yl)(difluoro)acetate (Int-7) were obtained as a yellow oil, (M+1)=270, 19F-NMR (235 MHz, CDCl3) δ (ppm): −104.21 (CF2).

出典