反应 #470436

反应方程式

water

sulfuric acid

4-fluoro-2-nitrotoluene

NBS

→

1-bromo-5-fluoro-2-methyl-3-nitrobenzene

收率 100.0%

溶剂

trifluoroacetic acid

反应条件

后处理

1. 1
   workup.STIRRINGstirred for 15 min
2. 2
   萃取Extracted with ethyl acetate
3. 3
   洗涤the organic layer was washed with brine
4. 4
   其他dried
5. 5
   浓缩concentrated

实验过程

To a solution of 4-fluoro-2-nitrotoluene (10.0 g, 64.4 mmol) in trifluoroacetic acid (40 mL) was added con. sulfuric acid (12.5 mL) followed by NBS (17.2 g, 96.6 mmol) and the reaction mixture was stirred at room temperature for 16 h. Then the reaction mixture was poured into ice and water and stirred for 15 min. Extracted with ethyl acetate and the organic layer was washed with brine, dried, concentrated to get compound 1-bromo-5-fluoro-2-methyl-3-nitrobenzene (15.0 g, 100%) as a yellow oil. 1H NMR (400 MHz, DMSO-d6) δ 2.41 (s, 3H), 7.96 (dd, J=8.0, 2.4 Hz, 1H), 8.02 (dd, J=8.0, 2.4 Hz, 1H). A mixture of above prepared compound (15.0 g, 64.4 mmol), Fe (18.0 g, 0.32 mol), con. HCl (2 mL) in MeOH (150 mL) and water (30 mL) was stirred at reflux for 4 h. Then the mixture was adjusted to pH 12 with aqueous NaOH solution and filtered. The solvent was removed and diluted with water. Extracted with ethyl acetate, dried, concentrated. The residue was purified by column chromatograph (ethyl acetate in petroleum ether, 7%) to get compound 0104-69 (5.8 g, 44%) as yellow oil. LCMS: 204 [M+1]+, 1H NMR (400 MHz, DMSO-d6) δ 2.12 (s, 3H), 5.57 (s, 2H), 6.45 (dd, J=11.2, 2.4 Hz, 1H), 6.60 (dd, J=8.0, 2.4 Hz, 1H).

来源