Synthesis of 9-diazo-4-azafluorenes

Stable diazo compounds of the azafluorene series, viz., 9-diazo-4-azafluorenone and 1,3-diphenyl-4-azafluorene, were obtained from 4-azafluorenone and 1,3-diphenyl-4-azafluorene tosylhydrazones. 1′,2′-Dicarbomethoxyspiro(4-azafluorene-9,3′-cyclopropane) was obtained from 4-azafluorenone tosylhydrazone, and 4′,5′-dicarbomethoxyspiro(4-azafluorene-9,3′-pyrazolenine) was obtained from 9-diazo-4-azafluorene. It is assumed that the product in the latter case is obtained as a result of reaction of a carbene, viz., 4-azafluorenylidene carbene, which is formed from 9-diazo-4-fluorene, with dimethyl acetylenedicarboxylate. © 1980 Plenum Publishing Corporation.