CONDENSED HETEROCYCLES .24. SYNTHESIS OF NOVEL CONDENSED 1,2,3-SELENADIAZOLES

4,5,9,10-Tetrahydroacephenanthren-7(8H)-one (1), 2, 3-dihydro-2-methylnaphtho[1,2-b)pyran-4-one(V), 2,3-dihydro-2-methylnaphtho[1,2-b]thiopyran-4(H)-one (X), its 1,1-dioxide (XXII), 2,3-dihydro-2,2-dimethylnaphtho[1,2-b]thiopyran-4(H)-one(XIV),its 1,1-dioxide(XXV) and 2,3-dihydro-2,2-dimethylnaphtho[l, 2-b]selenin-4(H)-one (XIX) have been converted into 5,6,10,11-tetrahydroacephe-nanthro[7,8-d]-1,2,3-selenadiazole (III), 11-methyl-11H-naphtho[2',1':5,6]pyrano[4,3-d]-1,2,3-selenadiazole (VII), 11-methyl-11H-naphtho[2',1':5,6]thiopyrano[4,3-d]-1,2,3-selenadiazole (XII) its 10,10-dioxide (XXIV), 11,11-dimethyl-11H-naphtho[2',1':5,6]thiopyrano[4,3-d]-1,2,3-selenadiazole (XVI), its 10,10-dioxide (XXVII) and 11,11-dimethyl-IIH-naphtho[2',1':5,6]selenino[4,3-d]-1,2,3-selenadiazole (XXI), respectively via the corresponding semicarbazones followed by selenium dioxide oxidation in acetic acid. These compounds have been characterised through PMR spectral analysis.