反应详情

Following the procedures outlined in Example 21, 10.7 g. (0.038 mol) of 2-iodo-4-chlorobenzoic acid, 4.3 g. (0.038 mol) of 4-fluorophenol 5.25 g. (0.038 mol) of potassium carbonate and 1.14 g. of cuprous chloride in 180 ml. of pyridine are heated under reflux overnight to give upon workup 4-chloro-2-(4-fluorophenoxy)-benzoic acid, 154°-173° C. Heating the acid (5.0 g., 0.019 mol) for one hour with 75 g. of sulfuric acid yields the corresponding 2-fluoro-6-chloro-9-xanthone, m.p. 210° C.

1. temperatureunder reflux overnight