Microwave Promoted One-Pot Synthesis of Some Novel N-Aryl Isoquinoline Derivatives

Homophthalic anhydride 1 reacts with different aromatic amines to produce N-substituted homophthalimides 2 under microwave irradiation. A rapid microwave-assisted chemical synthesis of condensed 4-substituted furo[2,3-c]isoquinoline-1,5(2H,4H)-diones 3 and 5-substituted-2,3-dihydro-1H-pyrano[2,3-c]isoquinoline-1,6(5H)-diones 4 involving the condensation of a variety of alkanoyl chlorides with 2-arylisoquinoline-1,3-diones 2 in the presence of base and aprotic solvent is described for the first time. By contrast, the facile ring opening reaction of furo[2,3-c]isoquinoline-1,5(2H,4H)-dione 3 with Vilsmeier-Haack reagent under microwave irradiation yielded the - unsaturated carboxyaldehyde 5. This novel and clean one-pot methodology, which is characterized by very short reaction time and easy workup procedure, can be exploited to generate some novel condensed isoquinoline derivatives.