Bunte salt

In organosulfur chemistry, a Bunte salt is an archaic name for salts with the formula R−S−SO−3Na⁺. They are also called S-alkylthiosulfates or S-arylthiosulfates.^[1] These compounds are typically derived from alkylation on the pendant sulfur of sodium thiosulfate:^[2][3]

RX + Na₂S₂O₃ → RS−SO−3Na⁺ + NaX

They have been used as intermediates in the synthesis of thiols.^[4] They are also used to generate unsymmetrical disulfides:

RS−SO−3Na⁺ + NaSR' → RS−SR' + Na₂SO₃

According to X-ray crystallography, they adopt the expected structure with tetrahedral sulfur(VI) atom, a sulfur-sulfur single bond, and three equivalent sulfur-oxygen bonds.^[5]