Diethyl Ether → 2-[5-Chloro-3-(2-methoxyphenyl)-6-methyl-2-oxo-2,3-dihydro-1h-indol-3-yl]acetic acid

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Reaction Conditions

Reaction Steps

4-chloro-3-methylphenylcarbamate in 45 ml of ether is cooled to −70° C., under an argon atmosphere, 30 ml of 1.5M solution of tert-butyllithium in pentane are added dropwise, the mixture is stirred for 1 hour while allowing the temperature to rise to −10° C., and is stirred for 1 hour 45 minutes at −10° C. The reaction mixture is cooled to −70° C., a solution of 5 g of the compound obtained in step A in 25 ml of THF is added dropwise, the mixture is stirred for 1 hour and allowed to warm to −30° C., and is then stirred overnight while allowing the temperature to return to RT. Saturated NH4Cl solution is added to the reaction mixture, the THF is evaporated off, the resulting aqueous phase is extracted three times with EtOAc, the organic phase is washed with water, with saturated NaCl solution and dried over Na2SO4, the solvent is partially evaporated off and the crystalline product is filtered off by suction. 2.6 g of the expected product are obtained, m.p.=254–256° C.

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