SYNTHESIS OF [3,4-B]PYRROLO[1,2-A]QUINOLINE-6A(7H)-CARBONITRILE - A NOVEL TYPE OF INTRAMOLECULAR TETRAHYDROFURAN FORMATION

Approximately 4-substituted xahydro-3a-(methoxymethyl)pyrrolo[1,2-a]qu inolines 3 cyclize to [3,4-b]pyrrolo[1,2-a]quinoline-6a(7H)-carbonitri le (5) upon heating in polar solvents, the reaction being accelerated by lithium bromide. The formation of the annulated tetrahydrofuran rin g of 5 takes place via intramolecular attack of the oxygen atom of the methoxymethyl substituent at C-3a on the electrophilic carbon atom at C-4. The structure of 5 was confirmed by single-crystal X-ray structu re determination.