SYNTHESIS AND NMR ASSIGNMENT OF 1,4-OXATHIINO[3,2-C 5,6-C']DIQUINOLINE/

1,4-Oxathiinodiquinoline 3 was obtained in three ways from 1,4-dithiin odiquinolines 1 and 2 via ring opening-ring closure reactions with tot al yield of 19, 46 and 77%. Through-space interactions between the H-5 quinolinyl atoms and oxygen atom were discussed on the basis of H-1 nm r spectrum.