144847-57-4Relevant academic research and scientific papers
Heterocyclic fused 2,5-dihydrothiophene S,S-dioxides as precursors to heterocyclic o-quinodimethanes
Chaloner,Crew,O'Neill,Storr,Yelland
, p. 8101 - 8116 (2007/10/02)
2,5-Dihydrothiophene 5,5-dioxides 8 and 6 have been obtained by interception of flash-pyrolytically produced 2,3-dihydro-2,3-bis(methylene)thiophene with sulfur dioxide and from methyl 4,5-bischloromethylthiophene-2-carboxylate from 3-phenylsulfonyl-2,5-dihydrothiophene S,S-dioxide by cycloaddition of diazomethane, base induced aromatisation and N-substitution of the sulfone 14. Reaction of 3-acetyl-4-phenylthio-2,5-dihydrothiophene S,S-dioxide with hydrazine and interception of 1-methyl-4,5-dihydrobis(methylene)pyrazole also gave pyrazole fused sulfones. On heating at 200°C, the heterocyclic fused sulfones underwent extrusion of sulfur dioxide and the resulting heterocyclic o-quinodimethanes were trapped with a range of dienophiles.
The generation of 2,3-dihydro-2,3-bis-(methylene)thiophenes from 4,6-dihydrothieno[3,4-b]thiophene 5,5-dioxides
Crew,Jenkins,Storr,Yelland
, p. 1491 - 1494 (2007/10/02)
On heating in sulpholane 4,6-dihydrothieno[3,4-b]thiophene 5,5-dioxides give 2,3-dihydro-2,3-bis(methylene)thiophenes which can be intercepted in Diels-Alder reactions. Sulphur dioxide is a very efficient trap for these thiophene xylylenes giving the cycl
