Pyridine → Tert-butyl 4-chloro-2-nitrobenzoate

Beteiligte Stoffe

Reaktionsschritte

To 4-chloro-2-nitrobenzoic acid (262 g) in a pyridine (1.3 liter) solution, p-toluenesulfonyl chloride (272.6 g) was slowly added at room temperature, and the mixture was stirred at that temperature for 15 minutes. To the reaction solution, tert-butyl alcohol (249 ml) was added dropwise, then the mixture was stirred for 5 hours. To the reaction mixture toluene (1 liter) was added, and the mixture was stirred for 1.5 hours, then the precipitate were removed by filtration. The filtrate was concentrated, ethyl acetate (1.3 liter) was added to the residue, the mixture was successively washed with water, saturated aqueous potassium hydrogensulfate solution, aqueous saturated sodium hydrogencarbonate solution, and brine, then the organic layer was dried over anhydrous sodium sulfate, then concentrated. Methanol (470 ml) was added to the residue, and after the precipitation of the crystals was confirmed, water (142 ml) was added. The mixture was stirred under ice cooling for 1.5 hours, then the crystals were collected by filtration. The same recrystallization procedure as the above was performed again to obtain the title compound (297 g).

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