98203-29-3

Upstream product

• 17989-89-8 2,5-diamino-thiophene-3,4-dicarbonitrile 
• 16696-68-7 thioacetophenone 
• 670-54-2 ethenetetracarbonitrile 
• 1450-31-3 Thiobenzophenon 
• 98203-30-6 3,6-bis-<(diphenylmethylene)amino>-1,2-dithiin-4,5-dicarbonitrile 

Relevant academic research and scientific papers

Unusual formation of a thiacyclopent-2-ene by the reaction of 4,4′-dimethoxythiobenzophenone with tetracyanoethylene

The reaction of 4,4′-dimethoxythiobenzophenone (1a) with tetracyanoethylene (TCNE) afforded an unusual type of 2:1 adduct with the structure of thiacyclopent-2-ene (5a). On the other hand, the reaction of thiobenzophenone (1b) with TCNE afforded the corresponding thiophene, the normal 2:1 adduct (2b). The mechanism of the formation of 5a is discussed.

An unorthodox pathway to the 1,2-dithiin system

Tetracyanoethylene combines with two molecules of thiobenzophenone in refluxing benzene to give the tetrasubstituted 1,2-dithiin 8 (21-29%) besides the corresponding thiophene derivative 9 (40-52%). The X-ray analysis of the ruby-red 8 reveals a half-chair conformation with a torsion angle of 58.9° at the disulfide bond. The thermal desulfurization 8 → 9 (benzonitrile, 100°C) proceeds with t1/2 = 26.7 h, whereas the sulfur loss induced by triethyl phosphite is a billion times faster. The mechanisms of the formation of 8 and its sulfur extrusion are discussed in the light of recent literature. VCH Verlagsgesellschaft mbH, 1997.

THIOBENZOPHENONE AND TETRACYANOETHYLENE

The title reaction furnished the yellow 3,4-dicyano-2,5-bis(diphenylmethyleneamino)-thiophene and a red precursor which contains one more sulfur atom; structures and mechanism are discussed.