4-NITROBENZENEDIAZONIUM SALT AND CYCLOPENTADIENE

Article abstract of DOI:10.1016/S0040-4039(01)91148-7

The title reaction, carried out without solvent at -50 deg C raised to room temperature, produces the hydrazonic 1:2 adduct 6 and the 1:3 adducts 9a and 9b whereas in methanol at -10 deg C the intermediate cyclopentadienone-4-nitrophenylhydrazone (5) adds a solvent molecule; the azo coupling does not require the cyclopentadienide anion, as demonstrated by the behavior of spiro<2.4>heptadiene (12).