Reaktion #53710

Reaktionsgleichung

methyl acrylate

tert-butyl 3-iodo-5-(2-methylsulfonylbenzenesulfonylamino)indazole-1-carboxylate

diisopropylethylamine

lithium chloride

→

methyl (E)-3-[5(2-methylsulfonylbenzenesulfonylamino)-1-tert-butoxycarbonylindazol-3-yl]acrylate

Lösungsmittel

water

dimethylformamide

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONare added
2. 2
   Extraktionthe reaction medium is extracted with ethyl acetate
3. 3
   WaschenThe pooled organic extracts are washed with distilled water
4. 4
   Trocknendried over magnesium sulfate
5. 5
   Filtrationfiltered
6. 6
   Einengenconcentrated to dryness under reduced pressure
7. 7
   SonstigeThe oil thus isolated
8. 8
   Sonstigeis purified by chromatography on a column of silica gel with a cyclohexane/ethyl acetate (80/20 by volume) mixture as eluent

Vorschrift

Methyl (E)-3-[5(2-methylsulfonylbenzenesulfonylamino)-1-tert-butoxycarbonylindazol-3-yl]acrylate can be obtained in the following way: 74 μL methyl acrylate are added dropwise to a solution, maintained under an atmosphere of argon and at a temperature in the region of 20° C., of 500 mg of tert-butyl 3-iodo-5-(2-methylsulfonylbenzenesulfonylamino)indazole-1-carboxylate, 1.2 ml of diisopropylethylamine, 121 mg of lithium chloride, 11.6 mg of palladium acetate in 15 ml of anhydrous dimethylformamide, and the reaction medium is then heated for 1 hour at 60° C. and then for 1 hour at 80° C. After returning to a temperature in the region of 20° C., 15 ml of distilled water are added and the reaction medium is extracted with ethyl acetate. The pooled organic extracts are washed with distilled water, dried over magnesium sulfate, filtered and concentrated to dryness under reduced pressure. The oil thus isolated is purified by chromatography on a column of silica gel with a cyclohexane/ethyl acetate (80/20 by volume) mixture as eluent. 90 mg of methyl (E)-3-[5(2-methylsulfonylbenzenesulfonylamino)-1-tert-butoxycarbonylindazol-3-yl]acrylate are thus obtained in the form of a white solid (Rf=0.90, silica gel thin layer chromatography, eluent: cyclohexane/ethyl acetate (50/50 by volume)).

Quelle