Hydrochloric Acid → 2-Bromo-4-tert-butyl-5-nitro-phenol

Beteiligte Stoffe

Reaktionsschritte

(2-Bromo-4-tert-butyl-5-nitro-phenyl)methyl carbonate (72.9 g, 219.5 mmol) was charged to a reactor and DCM (291.6 mL) was added. The yellow reaction solution was cooled using an ice bath. Sodium methoxide (67.04 g, 69.11 mL of 5.4 M, 373.2 mmol) was added portion-wise at 2.2-6.9° C. After complete addition, the reaction was slowly warmed to ambient temperature. When complete, the reaction was cooled to 0° C. and quenched with 1M HCl (373.2 mL, 373.2 mmol). The biphasic mixture was stirred for 20 min and transferred to a seperatory funnel. The organic layer was separated and washed with water (300 mL) followed by brine (300 ml). The organic layer was concentrated and the crude product dried under high vacuum. The product was further purified using Supercritical Fluid Chromatography (SFC) separation on a Berger MultiGram III (Mettler Toledo AutoChem, Newark Del.). The method conditions were 20% methanol at 250 mL/min on a PPU column (30*150) from Princeton Chromatography, 100 bar, 35 C, 220 nm. An injection of 3.5 mL of a 55-70 mg/mL solution was injected. The data was collected using SFC ProNTo software. The purified product received from SFC purification was a methanol solvate. To remove the methanol, an azeotropic distillation was performed. The dark yellow solid, 2-bromo, 4-tertbuyl, 5-nitro phenol methanol solvate, (111.3 g, 0.59.9 mmol) was charged to a 1 L round bottom flask, followed by heptane (500 mL). The slurry is heated to 64° C. to obtain a clear solution. The solvent was distilled under reduced pressure (649 mbar) for 30 minutes and then stripped to dryness. This procedure was repeated three times until no MeOH was detected by 1H-NMR. The product was dried under high vacuum for 16 hours to give the product as a dark yellow semi solid. 1H-NMR (400 MHZ, DMSO-d6) δ 11.2 (bs, OH), 7.69 (s, 1H); 7.03 (s, 1H); 1.30 (s, 9H)

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