Practical molar scale syntheses of the commercially unavailable dichloro-and dibromopyromellitic acid by a two-step oxidation of the corresponding dihalodurenes have been developed earlier in this laboratory.'Our interest in the preparation of hitherto unknown difluoropyromellitic acid (8), required significant quantities of difluorodurene (7). Stavber and Zupan2 had reported the isolation of small amounts (30 mg, 9% yield) of compound 7 from ...
