Pyridazine derivatives and related compounds, Part 15: Photochemical study of 3-azido-4,5-diphenyl-1H-pyrazolo[3,4-c]pyridazme

摘要

As an extension of our work in the photochemical study of nitrogen heterocyclic compounds such as 3-diazopyrazolopyridazine derivatives and [2+2] photocycloaddtion, in this paper we will studying the photolysis of 3-azidopyrazolopyridazine derivative in different solvents such as Methanol, Ethanol, Toluene, Benzene,.....etc. and reagent as diethyl malonate. The photochemistry of 3-azidopyrazolopyridazine has been investigated. The irradiation of 3-azido-4,5-diphenyl-1 H-pyrazolof 3,4-c]pyridazine I in various solvents brings to a photolytic nitrene intermediate, which involve into a ring-opening to give 3-substituted pyridazine derivatives. While the photolysis in toluene and/or anisole the photo attacks reaction of nitrene is faster than the ring opining to give the corresponding 3-anilinopyrazolopyridazine derivatives. The photolysis in the presence of diethyl malonate led to a mixture of three pyridazine derivatives.