Synthesis of fluorinated 2(3)-arylhydrazones of 1,2,3-tri(1,2,3,4-tetra)carbonyl compounds and their heterocyclization reactions

New fluorinated 2-arylhydrazones of 1,2,3-triketones, 2-arylhydrazone-1,2,3 -diketo esters and 3-arylhydrazone-1,2,3,4-triketo esters have been prepare d by the coupling of fluorine-containing 1,3-keto esters, 1,3-diketones, ac yl(aroyl)pyruvic eaters and their chelates with aryldiazonium chlorides. Th e arylhydrazones react with hydrazine hydrate, phenylhydrazine, thiosemicar bazide and hydroxylamine to form the corresponding pyrazole and isoxazole d erivatives. Interaction of 3-arylhydrazone-1,2,3,4-diketo eaters with o-phe nylenediamine results in quinoxaline products. Intramolecular cyclization o f the arylhydrazones with pentafluorophenyl substituents leads to cinnolone derivatives. (C) 1998 Published by Elsevier Science S.A.