The title compounds 1-3 and their methyl derivatives 4-'I N-chlorosuccinimide gave the required precursors 11, 12, 14, were synthesized either by photolytic sulfur extrusion from 17, and 18. The results of the X-ray structure determinations the corresponding 2, 11-dithia [3.3] pyrazinophanes 24-26 or by for 1-4 and 7 which indicate an unequivocal isomer assign- Hofmann 1, 6-elimination of the appropriate [(5methyl-Zpyr-ment are discussed with ...
