Finally, the title compound 4 was readily obtained in 96% yield in better than 98% purity by nitration of 3 with 1.0-1.05 equivalent of 95% fuming nitric acid in conc. sulfuric acid (98%) at 3540 C for 1 hour. This synthesis provided a higher yield and milder reaction conditions than chloro~ ulfonation~ of 4-chloro-2-fluoronitrobenzene which yielded only 78% of 4 and required the use of 5.4 equivalents of chlorosulfonic acid at 120-130 C for 3 hours.
