Vegar Stockmann, J. Bakke, P. Bruheim
May 2, 2009
Citations
0
Influential Citations
9
Citations
Journal
Tetrahedron
Abstract
Abstract A new thermal ring cleavage of 3-pyridyl nitrenes for the formation of 4-isocyanobut-2-enenitrile products is reported. Thermolysis of 4-(thien-3-yl)-3-pyridyl azide 1 and 3-azido-4-(1-TIPS-1 H -pyrrol-3-yl)pyridine 5 afforded two new isonitrile–nitrile products by ring cleavage; 4-isocyano-2-(thiophen-3-yl)but-2-enenitrile ( 3 , 27%) and 4-isocyano-2-(1-TIPS-1 H -pyrrol-3-yl)but-2-enenitrile ( 7 , 20%), in addition to our previously reported pyrido[3,4- b ]thienopyrrole ( 2 , 29%) and pyrido[3,4- b ]pyrrolo[3,2- d ]pyrrole ( 6 , 71%) products. Minor amounts of 2-(thien-3-yl)-1 H -pyrrole-3-carbonitrile ( 4 , 6%), formed by ring contraction, were also isolated after thermolysis of azide 1 . Isonitriles 3 and 7 underwent degradation into amine 3b and formamide 7a by acidic hydrolysis. The nature and chemistry of compounds 3 , 4 and 7 were investigated.