HETEROCYCLES hFUSED ONTO 4-OXOQUINOLINES.PART I.SYNTHESIS OF 6-OXO-6,9-DIHYDRO1,2,5OXADIAZOLO3,4-h-QUINOLINE-7-CARBOXYLIC ACID N-OXIDE

摘要

Ethyl 9-cyclopropyl-4-fluoro-6-oxo-6,9-dihydrof 1,2,5oxadiazolo3,4-hquinoline-7-carboxylate N(3)-oxide (3) is synthesized via pyrolysis of the 7-azido-8-nitroquinoline-3-carboxylate precursor (6).Acid-catalyzed hydrolysis of the product (3) afforded the corresponding carboxylic acid (4),of which structures are confirmed by spectroscopic means including X-Ray measurements.