91319-34-5

Upstream product

• 13979-15-2 ethyl (E)-3-(thiophen-2-yl)acrylate 
• 4233-33-4 4-Phenyl-1,2,4-triazolidine-3,5-dione 
• 91319-33-4 6a-(3,5-Dioxo-4-phenyl-[1,2,4]triazolidin-1-yl)-1,3-dioxo-2-phenyl-2,3,6a,9a-tetrahydro-1H-thieno[3,2-c][1,2,4]triazolo[1,2-a]pyridazine-5-carboxylic acid ethyl ester 
• 91319-32-3 ethyl 2,3,5,6-tetrahydro-1,3-dioxo-2-phenyl-6-(4-phenyl-3,5-dioxo-1,2,4-triazolin-1-yl)-1H-thieno<3,2-c><1,2,4>triazolo<1,2-a>pyridazine-5-carboxylate 

Relevant academic research and scientific papers

Ring Cleavage of a 3-Azidothiophene: Novel Extrusion of Acetylene

Mild thermal decomposition of ethyl 2-azido-3-(3-azido-2-thienyl)propenoate (8) results in the cleavage of the thiophene ring with extrusion of acetylene and formation of ethyl 5-cyanoisothiazole-3-carboxylate (10), together with ethyl thienopyridazine-3-carboxylate (9).The former reaction represents the first fragmentation of a five-membered heteroaromatic β-nitrene to extrude an acetylene, and the latter reaction is a rare example of formal intramolecular coupling of nitrenes in solution themolysis.This vinyl azide group is necessary for this cleavage of the thiophene ring and a mechanism is proposed in which the derived nitrene co-ordinates with the thiophene sulphur atom to facilitate ring fragmentation.The analogous furan does not fragment similarly.Diels-Alder cycloadditions of 4-phenyl-1,2,4-triazole-3,5-dione to 2-vinylthiophenes were investigated as an independent approach to the thienopyridazine system, but the fused 4-phenyl-1,2,4-triazoline-3,5-dione ring proved resistant to hydrolytic cleavage.