反应详情

4-Methyl-2'-nitrobiphenyl (from Step A) (2.173 g, 10.2 mmol) was dissolved in CCl4 (100 mL) and heated to reflux with stirring. To this was added a bromine solution [prepared by diluting 11.2 ml (11.2 mmole) of commercial 1.0M solution in CCl14 to a final volume of 40 mL with CCl4 ] dropwise while a 100 W lamp was used to irradiate the refluxing reaction mixture. After completion of addition, the solution was cooled to room temperature, volatiles were removed, and the residue was flash chromatographed over 700 mL SiO2, eluting with 1.5-4.0-10.0% EtOAc/hexane, to afford 2.68 g (90%) of the title compound, 85% pure as indicated by NMR (the remainder being the dibrominated material), but homogeneous on TLC (4/1 hex-EtOAc).

1. temperatureheated
2. temperatureto reflux
3. customprepared
4. customto irradiate
5. customthe refluxing reaction mixture
6. additionAfter completion of addition
7. customvolatiles were removed
8. customchromatographed over 700 mL SiO2
9. washeluting with 1.5-4.0-10.0% EtOAc/hexane