反应详情

12.8 g of methyl 2-acetamido-5-chlorocinnamate are dissolved in 200 ml of dimethylformamide/toluene (1:1), and 1.6 g sodium hydride (80% in paraffin oil) are added. Stirring is effected for 30 minutes, and at 0° 7 g of dimethylsulphate are added drop by drop. After 2 hours additional stirring at room temperature, 500 ml of water and 50 ml of 2 N sodium hydroxide solution are added followed by washing with toluene. After acidification, extraction with methylene chloride, removing of the solvent and chromatografic purification one obtains 7.6 g of 5-chloro-2-(N-methyl-acetamido)-cinnamic acid as oil. This oil is stirred for 24 hours at 100° with 100 ml of 5 N hydrochloric acid; after cooling the pH is adjusted to 8.5 with dilute sodium hydroxide solution, and 10 g of sodium bicarbonate are added. 7.5 g of 3,4-dichlorobenzoyl chloride in 50 ml of toluene are added dropwise. Working up as in Example 1(a) yields 10.8 g of 5-chloro-2-(N-methyl-3,4-dichlorobenzamido)cinnamic acid, which are reacted without further purification for 2 days at room temperature with 200 ml of methanol under addition of 4 ml of concentrated sulphuric acid. Extraction with methylene chloride and working up yield 8.3 g of the corresponding methyl ester, which is reacted analogously to (a).

1. stirringAfter 2 hours additional stirring at room temperature
2. washby washing with toluene
3. extractionAfter acidification, extraction with methylene chloride
4. customremoving of the solvent and chromatografic purification one