反应详情

To a solution of NaOEt (21% in EtOH, 215 ml, 584 mmol) were added ethyl formate (46.97 ml, 584 mmol) and then, with cooling (max. 28° C.), chloro acetic acid ethyl ester in Et2O (200 ml). The mixture was stirred at RT for 20 h and filtered after adding Et2O (200 ml). The resulting solid was dissolved in EtOH (400 ml) and after addition of 4-(trifluoromethyl)benzene-1-carbothioamide (11.98 g, 58.4 mmol) stirring to reflux was accomplished for 20 h. After filtration, the EtOH was removed under reduced pressure and extracted with CH2Cl2 (3×)/H2O. The organic phases were washed with H2O, dried (Na2SO4) and evaporated to give crude compound which was crystallized (Et2O/n-pentane) to give 12.43 g (71%) of 2-(4-trifluoromethyl-phenyl)-thiazole-5-carboxylic acid ethyl ester as off-white crystals, MS: 301 (M+), MP: 98-110° C.

1. filtrationfiltered
2. additionafter adding Et2O (200 ml)
3. dissolutionThe resulting solid was dissolved in EtOH (400 ml)
4. stirringstirring
5. temperatureto reflux
6. waitwas accomplished for 20 h
7. filtrationAfter filtration
8. customthe EtOH was removed under reduced pressure
9. extractionextracted with CH2Cl2 (3×)/H2O
10. washThe organic phases were washed with H2O
11. dry with materialdried (Na2SO4)
12. customevaporated
13. customto give crude compound which
14. customwas crystallized (Et2O/n-pentane)