SOME REACTIONS OF 3-HALOGENOCINNOLINES CATALYSED BY PALLADIUM COMPOUNDS

Article abstract of DOI:10.1016/0040-4020(82)80178-6

3-Bromo-or 3-iodo-cinnoline (and 4-substituted analogues ) are condensed with terminal alkynes in the presence of Pd and Cu compounds as catalysts to give the 3-alkynyl-derivatives.When 4-chloro- or 4-phenoxy-compounds are used, the products react with amines, in the presence of copper(I) iodide, to form pyrrolo<3,2-c>cinnolines and with hydrazines to give either the same ring system or a pyrazolo<4,3-c>cinnoline.Hydrolysis of 3-alkynyl-4phenoxycinnoline to 3-alkynyl-4(1H)-cinnolinone, followed by cyclisation, yields the furo<3,2-c>cinnoline.Attempts to condense 3-halogenocinnolines with alkenes gave variable results: 3-phenyl ethenyl- and 3(2-pyridylethenyl)-4-(1H)-cinnolinones were obtained but 3-bromocinnoline gave the 3,3'-bicinnolinyl.Action of palladium acetate in the presence of ethyl acrylate converted 3-bromo-4-phenoxycinnoline into benzofuro<3,2-c>cinnoline and 3-bromo-4-phenylaminocinnoline into indolo<3,2-c>cinnoline.