2-Hydroxy-4-nitro-benzoic acid tert-butyl ester synthesis

Yield:1356600-78-6 87%

Reaction Conditions:

with dmap;dicyclohexyl-carbodiimide in tetrahydrofuran at 20; for 20 h;Inert atmosphere;

Steps:

1 Preparation of tert-butyl 2-hydroxy-4-nitrobenzoate (41)

To a solution of benzoic acid 40 (2.07 g, 11.3 mmol) in THF (10 mL) were added tert-butanol (10 mL, 105.4 mmol), DMAP (1.2 g, 9.8 mmol), and DCC (2.5 g, 12.1 mmol). The resulting mixture was stirred for 20 h at room temperature. The mixture was diluted with EtOAc (200 mL) and washed with saturated aqueous NH₄Cl (100 mL), water (100 mL), saturated aqueous NaHCO₃ (100 mL), water (100 mL), and saturated aqueous NaCl (20 mL). The organic layer was dried with MgSO₄, filtered, and evaporated. The residue was purified by column chromatography (hexane/EtOAc, 1:9 to 9:1 v/v) to yield compound 41 (2.35 g, 87%) as a yellow oil. Calculated: [M + H]⁺ (C₁₁H₁₄NO₅) m/z = 240.1; Found ESI: [M + H]⁺(C₁₁H₁₄NO₅) m/z = 240.5.

References:

WO2020/154437,2020,A1 Location in patent:Paragraph 00400-00401; 00472-00474