Synthesis and mass spectrum of 3,3′‐thiobispyridine and polarographic reduction of 1,1′‐dimethyl‐3,3′‐thiobispyridinediium diiodide

Abstract 3,3′‐Thiobispyridine is prepared by reaction of pyridine‐3‐thiol with 3‐bromopyridine. The base peak in the mass spectrum of 3,3′‐thiobispyridine is due to the molecular ion which fragments by loss of H, HCN and CS as well as by central bond rupture. The 1,1′‐dimethyl diquaternary salt of 3,3′‐thiobispyridine is reduced polarographically by a one electron transfer not involving hydrogen to an unstable radical cation at a potential (Eo) of −0.72 V in the pH range 7.4–11.2.