Carbon Dioxide → 4-Chloro-2-methylbenzoic acid

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Reaction Steps

Accordingly, the invention also provides a process for the preparation of N-diaminomethylene-2-methyl-4,5-di(methylsulfonyl)benzamine, characterized in that in the first stage a) according to the invention 2-bromo-5-chlorotoluene is reacted with a secondary or tertiary organolithium compound, particularly preferably sec-butyllithium, and CO2 to give the first intermediate 4-chloro-2-methylbenzoic acid, in stage b) a methylsulfonyl group is introduced by reacting 4-chloro-2-methylbenzoic acid with chlorosulfonic acid, sodium sulfite and methyl iodide to give the corresponding intermediate 2-methyl-4-chloro-5-methylsulfonylbenzoic acid,

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