The improved synthesis, Diels-Alder reactions, and desulfuration of trithio-1,8-naphthalic anhydride

In the presence of a strong Lewis base, such as Et3N, trithio-1,8-naphthali c anhydride (3) is easily oxidized. Two improved syntheses of trithio-1, 8- naphthalic anhydride (3) are described. Trithio-1, 8-naphthalic anhydride ( 3) undergoes Diels-Alder reactions with electron-deficient alkenes to give novel fused heterocyclic compounds (6-11) that then can undergo a novel, gr adual desulfuration dimerization with triethyl phosphite to afford 12 and i ts analogs 13 and 14. The structures of 6-14 are confirmed by microanalysis , IR, and NMR spectroscopy, and MS. (C) 1999 John Wiley & Sons, Inc.