Reactions of heterocycles with thiophosgene. Part V. 7-Chloro-1,2-dihydro-4-methoxy-2-thioxoquinoline-3-carbaldehyde, a product from 7-chloro-4-methoxyquinoline

Abstract

7-Chloro-4-methoxyquinoline undergoes ring scission on treatment with thiophosgene and barium carbonate. The resulting 4-chloro-2-isothiocyanato-β-methoxycinnamaldehyde (3) undergoes ready ring closure to 7-chloro-1,2-dihydro-4-methoxy-2-thioxo-quinoline-3-carbaldehyde (4). Some reactions of the thioxoquinoline (4) and the corresponding ethylthio-(7) and sulphone (44) derivatives are described which give rise to other heterocyclic systems.