反应详情

To 70 ml of ethanol, 10.7 g (70 mmol) of phenylthiourea and 11.6 g (70 mmol) of ethyl 2-chloro-3-oxobutanate were dissolved, followed by heating under refluxing for 8 hours. The reaction liquid was concentrated and dissolved in ethyl acetate and the organic layer was washed with an aqueous solution of sodium carbonate, water and a saturated saline solution in this order, followed by drying over anhydrous magnesium sulfate and concentrating under reduced pressure. Solid obtained was washed with diisopropyl ether to obtain 16.8 g (yield: 91%) of ethyl 4-methyl-2-(N-phenylamino)thiazole-5-carboxylate. (2) To 50 ml of ethanol, 12.8 g (49 mmol) of ethyl-4-methyl-2-(N-phenylamino)thiazole-5-carboxylate was dissolved, followed by adding 24 g (150 mmol) of 25% sodium hydroxide aqueous solution, and stirring at 80° C. for 15 hours. The reaction liquid was poured into ice water, and acetic acid was added to make acidic. Crystal precipitated was filtered, washed with water and a mixed solvent of hexane/ethyl acetate and dried to obtain 5.50 g (yield: 48%) of 4-methyl-2-(N-phenylamino)thiazole-5-carboxylic acid.

1. temperatureby heating
2. temperatureunder refluxing for 8 hours
3. customThe reaction liquid
4. concentrationwas concentrated
5. dissolutiondissolved in ethyl acetate
6. washthe organic layer was washed with an aqueous solution of sodium carbonate, water
7. dry with materialby drying over anhydrous magnesium sulfate
8. concentrationconcentrating under reduced pressure
9. customSolid obtained
10. washwas washed with diisopropyl ether