Piperidine → acetic acid 1-(5-fluoro-2-oxo-2,3-dihydro-1H-indol-6-ylcarbamoyl)-1-methyl-ethyl ester

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Reaction Steps

5-Fluoro-6-amino-1,3-dihydro-indol-2-one 3d (410 mg, 2.47 mmol) was dissolved in 10 ml of tetrahydrofuran under stirring at room temperature. The mixture was cooled down to −45° C. in a dry ice-acetone bath and added with piperidine (322 μl). A solution of acetic acid 1-chlorocarbonyl-1-methyl-ethyl ester (423 mg, 2.71 mmol) in tetrahydrofuran (10 ml) was added dropwise to the above reaction system. Upon completion of the addition, the ice-acetone bath was removed, and the reaction mixture was allowed to warm up to room temperature and stirred overnight. After thin lay chromatography showed the disappearance of starting materials, the reaction mixture was filtered. The filter cake was washed with water, and the resulting solid was dried to obtain acetic acid 1-(5-fluoro-2-oxo-2,3-dihydro-1H-indol-6-ylcarbamoyl)-1-methyl-ethyl ester 9a (792 mg) as a white solid to the next step.

Provenance & Evidence