Reactions of Naphtho-1,2,3-trithiin 1,1,3,3-Tetraoxide (Naphthalene-1,8-disulfonothioic Acid Anhydrosulfide)

Article abstract of DOI:10.1021/jo00337a014

Attempts to oxidize naphtho<1,8-cd>-1,2,3-trithiin 1,1,3,3-tetraoxide (5) to the corresponding hexaoxide with oxidizing agents such as peracids, ozone, potassium permanganate, ruthenium tetraoxide, etc. were unsuccessful and led only to recovery of 5 unreacted.With the oxidizing agent HO2^-, however, 5 reacts rapidly; the trithiin ring is cleaved and naphthalene-1-sulfinate-8-sulfonate (6) and naphthalene-1,8-disulfinate (7) are formed in approximately equal amounts.Opening of the trithiin ring in 5 also occurs readily upon treatment with triphenylphosphine or cyanide ion.With the phosphine an interesting sequence of further reactions follows the opening of the ring and results in the eventual formation of the unusual zwitterionic phosphonium salt 15.This phosphonium salt undergoes thermal decomposition in boiling decalin to give triphenylphosphine oxide and cyclic thiosulfonate 1.Alkaline hydrolysis of 5 occurs easily and gives disulfinate 7 plus some sulfite.