Pyrrole Ring Opening in 5-Nitroso- and 5-Phenylazo-1H-pyrrolotetrazoles --- An Unexpected Valence Isomerism
摘要:
1,6-Disubstituted 5-nitroso-1H-pyrrolotetrazoles ring open below 20-degrees-C to give the isomeric acrylonitrile oxides. The 5-phenylazo analogs as well as 5-nitroso derivatives having in addition an acceptor group at C-7 are stable at 20-degrees-C, but heating with the dipolarophile DMAD leads to pyrazoles and isoxazoles.