Synthesis of frame pyrazolines based on azabicyclo[2.2.1]heptenes and nitrilimines

The stereo- and regiochemical features of the reaction of nitrilimines (generated in situ from N-hydrazonoyl chlorides) with derivatives of 2-aza-, 2-oxa-3-azanorbornenes, 7-azabenzonorbornadiene and 7-azanorbornadiene have been explored. The cycloaddition products contain pyrazoline moiety fused to bicyclic skeleton; in some cases the products undergo further retro-Diels–Alder fragmentation to form pyrazole derivatives.