Dithietane

Dithietanes are saturated heterocyclic compounds that contain two divalent sulfur atoms and two sp3-hybridized carbon centers.

[1][2] Two isomers are possible for this class of organosulfur compounds: 1,2-dithietanes, 4-membered rings where the two sulfur atoms are adjacent, are very rare.

The first stable 1,2-dithietane to be reported was the dithiatopazine, formed by intramolecular photodimerization of a dithiocarbonyl compound.

A stable 1,2-dithietane derivative is trans-3,4-diethyl-1,2-dithietane 1,1-dioxide, formed by the spontaneous dimerization of the lachrymatory agent syn-propanethial-S-oxide, found in onion.

[5] 1,3-Dithietane itself, a colorless, easily sublimed, crystalline, unpleasant-smelling solid with melting point 105-106 °C, was first prepared in 1976 by reaction of bis(chloromethyl) sulfoxide with sodium sulfide followed by THF-borane reduction of the first formed 1,3-dithietane 1-oxide, as shown in the scheme below.

Structure of a 1,3-dithietane (left) and 1,2-dithietane (right), where R is an organic group
Structure of dithiatopazine
Structure of trans -3,4-diethyl-1,2-dithietane 1,1-dioxide, the dimer of the onion lachrymatory agent
Synthesis of 1,3-dithietane
Synthesis of 1,3-dithietane
Left: thiophosgene dimer, 2,2,4,4-tetrachloro-1,3-dithietane; center: a zwiebelane, found in onion volatiles; right: sulfene dimer