Facile synthesis of spiro[indoline-3,3′-pyrrolo[1,2-a]quinolines] and spiro[indoline-3,1′-pyrrolo[2,1-a]isoquinolines] via 1,3-dipolar cycloaddition reactions of heteroaromatic ammonium salts with 3-phenacylideneoxindoles

Abstract

A series of complex spiro[indoline-3,3′-pyrrolo[1,2-a]quinolines] were efficiently synthesized by 1,3-dipolar cycloaddition reactions of N-phenacylquinolinium bromides with 3-phenacylideneoxindoles in ethanol with triethylamine as base. Under similar conditions the 1,3-cycloadditions of N-phenacylisoquinolinium and N-phenacyl-1,10-phenanthrolinium bromides with 3-phenacylideneoxindoles resulted in the corresponding spiro[indoline-3,1′-pyrrolo[2,1-a]isoquinoline] and spiro[benzo[h]pyrrolo[1,2-a]quinoline-3,3′-indoline] derivatives in good yields. The characterization data of spiro compounds and single crystal determination indicated that this 1,3-cycloaddition reaction is a regioselective and diastereoselective reaction and all prepared spiro compounds exist in the thermodynamically stable trans isomer.