Referring to Scheme II, a mixture of 2,8-dibromo-3,7-dinitrodibenzothiophene-5-oxide 3a and 2,8-dibromo-3-nitrodibenzothiophene-5-oxide 3b was treated in a heterogeneous solvent mixture which include but not limited to acetonitrile, carbon tetrachloride and water, p-dioxane and water, acetonitrile, tetrahydrofuran and water; with an oxidizing agent which include but not limited to sodium periodate and ruthenium(III) chloride; stirred at a temperature range from 15-75° C. until completion as indicated by TLC to yield 2,8-dibromo-3,7-dinitrodibenzothiophene-5,5-dioxide 9 as the isolated product. Treating 2,8-dibromo-3,7-dinitrodibenzothiophen-5,5-dioxide 9 with a reducing agent which include but are not limited to powdered iron, tin (II) chloride, zinc metal or palladium on charcoal with hydrogen in alcoholic solvents which include but are not limited to methyl alcohol, ethyl alcohol, propyl alcohol or 2-methoxy-ethanol and the like; and an organic acid which includes but is not limited to acetic acid; at a temperature range from 50-120° C. for about 2 hours or until completion to give 2,8-dibromo-5,5-dioxo-5H-5λ6 -dibenzothiophene-3,7-diamine 10.
