Trimethyl 2,4,6-triaminobenzene-1,3,5-tricarboxylate (1.00 g, 3.36 mmol, 1.00 equiv) was dissolved in dry acetonitrile and cooled to 0 °C. tert-butyl nitrite (3.12 g, 3.60 mL, 30.3 mmol, 9.00 equiv) and trimethylsilyl chloride (3.29 g, 3.84 mL, 30.3 mmol, 9.00 equiv) were added dropwise alternating. After complete addition, the mixture was slowly warmed up to 21 °C and stirred for 16 h. The resulting hydrochloric acid gas in the glassware was purged into a wash bottle that was filled with 1M sodium hydroxide solution. Then, water (30 mL) and DCM (30 mL) were added and the layers were separated. The aqueous layer was extracted with DCM (2x 30 mL). The combined organic layers were washed with water and brine and dried over sodium sulfate. The solvent was removed under reduced pressure and the residue was purified by column chromatography (cyclohexane/ethyl acetate 5:1) to give trimethyl-2,4,6-trichlorobenzene-1,3,5-tricarboxylate (69.0 mg, 194 μmol, 6% yield) as a light-yellow powder.
