Synthesis of 6‐subsituted‐2,10‐dibromodibenzo[d,g][1,3,6,2]dioxathiaphosphocin 6‐sulfides ( 3a‐1 ) has been accomplished in a two‐step process. Reaction of 5,5′‐dibromo‐2,2′‐dihydroxydiphenyl sulfide 1 and thiophosphoryl chloride in equimolar quantities in the presence of triethylamine as a base and DMAP as a catalyst in anhydrous toluene afforded the intermediate 6‐chloro‐2,10‐dibromodibenzo[d,g][1,3,6,2]dioxathiaphosphocin 6‐sulfide 2 . Subsequent reaction of the monochloride 2 with sodium phenoxides/thiophenoxides afforded the title compounds. All the compounds showed moderate activity against bacteria and fungi.
