Nitric Acid → 2-Bromo-3-fluoro-6-nitrobenzoic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

In a 1 L, three necked flask fitted with a dropping funnel and a thermometer were charged 2-bromo-3-fluorobenzoic acid (Example 134 g) (28.23 g, 0.13 mol) and concentrated H2SO4 (200 mL). After cooling to 0° C., HNO3 (70%, 16.0 mL) was added dropwise over 30 min, keeping the temperature between 0 to 10° C. After 1 h, the reaction mixture was poured into the crushed ice keeping the temperature below 20° C. The mixture was extracted with EtOAc (2×200 mL), the combined extract was washed with brine and dried with MgSO4. The filtrate was evaporated to give 27.27 g (77%) of a mixture of 2-bromo-3-fluoro-6-nitrobenzoic acid and 2-bromo-3-fluoro-5-nitrobenzoic acid (1:0.4) as a brown solid. 1H NMR (400 MHz, DMSO-d6) δ 8.33 (dd, J=9.6, 4.8 Hz, 1H), 7.21 (dd, J=10.0, 8.0 Hz, 1H).

Herkunft & Nachweise