Urazole-Bridged Bicyclic Azoalkanes: Generation, Nitroxyl Trapping, and ESR Spectra of the Heterosubstituted 4,5-Diaza-1,3-cyclopentanediyl Diradicals through Direct and Benzephenone-Sensitized Photochemical Deazetation

Article abstract of DOI:10.1021/jo00107a007

The Diels-Alder reaction of isopyrazoles 3 with 4-methyl-1,2,4-triazoline-3,5-dione afforded the azoalkanes 4 in high yields.The stereochemistry of the syn- and anti-diastereomeric derivatives 4b was established on the basis of spectral data and an X-ray