Ammonium Chloride → 3,5-Dichloro-3-(2,3-dimethoxyphenyl)-1,3-dihydro-2h-indol-2-one

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Reaction Conditions

Reaction Steps

A mixture of 11.4 g of tert-butyl 4-chlorophenylcarbamate in 100 ml of ether is cooled to −40° C. under an atmosphere of dry nitrogen, 80 ml of a 1.5 M solution of tert-butyllithium in pentane are added dropwise and the mixture is left stirring at −20° C. for 3 hours. The reaction mixture is cooled to −40° C., a solution-of 14 g of the compound obtained in step A in 50 ml of THF is added over 1 hour and the mixture is left stirring for 4 days at RT. The reaction mixture is poured into saturated NH4Cl solution and the precipitate formed is spin-filtered off and dried. 10.2 g of the expected product are obtained and are used without further purification in the following step.

Provenance & Evidence