83805-96-3

Downstream Products

• 83806-06-8 Acetic acid 3-cyano-2-(4-nitro-phenyl)-2,4-dihydro-chromeno[4,3-c]pyrazol-4-yl ester 
• 83805-89-4 2-(4-Nitro-phenyl)-2,4-dihydro-chromeno[4,3-c]pyrazole-3-carbonitrile 

Relevant academic research and scientific papers

Intramolecular 1,3-Dipolar Cycloaddition of Nitrilimines Bearing Alkenyl Groups

The reaction of the arylhydrazones of some 2-(alkenyloxy)benzaldehydes(or 1-naphthaldehydes) with Pb(OAc)4 leads, via the nitrilimine intermediates, to intramolecular 1,3-dipolar cycloadducts, 3-substituted 2-aryl-2,3,3a,4-tetrahydrobenzopyrano(or naphthopyrano)pyrazoles, in 10-80percent yields.In the presence of an excess of Pb(OAc)4, these cycloadducts were dehydrogenated to 3-substituted 2-aryl-2,4-dihydrobenzopyrano(or naphthopyrano)pyrazoles.In the presence of a large excess of Pb(OAc)4, some of the pyrazoles were acetoxylatedto give the corresponding 4-acetoxypyrazoles.The effect of substituents of the alkenyl group on reactivity of the reaction was interpreted in terms of the frontier molecular orbital (FMO) theory.