反应详情

温度

2.5 °C

To a solution of commercially available 2-chloro-1,4-dimethylbenzene (5 mL, 37 mmol) in concentrated H2SO4 (5 mL) cooled to 0-5° C. was added dropwise concentrated HNO3 (4.7 mL, 74.6 mmol) over 20 min. After the addition, the reaction was stirred at 0-5° C. for 30 min, then poured carefully into a mixture of ice and saturated aqueous K2CO3 solution (40 mL), and extracted with EtOAc (3×). The combined EtOAc extracts were washed with brine, dried (Na2SO4), filtered and concentrated under reduced pressure. The residue was chromatographed (silica gel), eluting with 10-30% EtOAc/hexane to give a mixture of the title compound and its regioisomer (1-chloro-2,5-dimethyl-4-nitrobenzene) (3.0 g). The mixture was further chromatographed (silica gel) eluting with 10% CH2Cl2 in hexane to afford pure compound 19A (0.2 g).

1. additionAfter the addition
2. extractionextracted with EtOAc (3×)
3. washThe combined EtOAc extracts were washed with brine
4. dry with materialdried (Na2SO4)
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customThe residue was chromatographed (silica gel)
8. washeluting with 10-30% EtOAc/hexane
9. customto give