反应详情

温度

145 °C

585 mg of preground maleic anhydride are added to 1 g of 6-chloro-1H-indazole-3-amine in 30 cm3 of ortho-xylene. The reaction medium is refluxed at 145° C. for ten minutes and then cooled in a water bath. The insoluble material is filtered off and washed successively with 2×25 cm3 of ethyl acetate and then with 2×25 cm3 of diisopropyl ether. The solid is then dried under reduced pressure (90 Pa; 50° C.) to give 1 g of 4-[(6-chloro-1H-indazol-3-yl)amino]-4-oxo-2-butenoic acid (Z form) in the form of yellow crystals melting at 230° C.

1. temperaturecooled in a water bath
2. filtrationThe insoluble material is filtered off
3. washwashed successively with 2×25 cm3 of ethyl acetate
4. customThe solid is then dried under reduced pressure (90 Pa; 50° C.)