反应详情

A mixture of ethyl 3-[(ethoxycarbonyl)amino]-4,4,4-trifluorocrotonate, (Z)-(2.04 g, 8 mmol), 5-amino-3-(6-methoxy-m-tolyl)-1,2-benzisothiazole (2.59 g, 9.6 mmol) and 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU, 1.46 g, 9.6 mmol) in xylene (15 mL) is heated at 110° C. for 6 hours, cooled, and quenched with ethyl acetate and water. The resultant mixture is extracted with ethyl acetate. The organic extracts are combined, washed with aqueous 2 N hydrochloric acid, dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo to obtain a foam. Flash chromatography of the foam using silica gel and a 3:7 ethyl acetate/hexanes solution gives the title product as a solid (2.5 g, 72% yield) which is identified by 1H and 19F NMR spectral analyses.

1. temperaturecooled
2. customquenched with ethyl acetate and water
3. extractionThe resultant mixture is extracted with ethyl acetate
4. washwashed with aqueous 2 N hydrochloric acid
5. dry with materialdried over anhydrous sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customto obtain a foam