SYNTHETIC APPROACHES TO 5,7-DIMETHOXYQUINOLINE AND 5,8-DIMETHOXYQUINOLINE - SONOCHEMICAL DEHALOGENATION OF SUBSTITUTED 2,4-DICHLOROQUINOLINES - USE OF THE 2D COLOC SPECTRUM FOR THE NMR ASSIGNMENT OF 5,8-DIMETHOXYQUINOLINE

Sonochemical dehalogenation of 2,4-dichloroquinoline is very facile. H owever, with 5,7-dimethoxy-2,4-dichloroquinoline the reaction proceeds stepwise to provide the title dimethoxyquinolines which cannot be pre pared via the Skraup reaction. The C-13 NMR chemical shift assignments for 5,8-dimethoxyquinoline are presented. These were made by utilisin g the coupling connectivities from the bridgehead carbons in the 2D CO LOC spectrum.