Novel Synthesis of Dihydroquinoxalinylpyridazine Derivatives

Methylquinoxaline derivative 1 undergoes bromination to give bromomethyl quinoxaline 2, which could be transferred to cyanomethyl quinoxaline 3. The latter compound 3 readily coupled with arene diazonium salts to give hydrazone derivatives 5a‐c. Compounds 5a,b reacted with active methylene reagents to give the target ring system, quinoxalinylpyridazine derivatives 8a‐c. Compound 1 reacted with DMFDMA to give the enamine derivative 9, which coupled with arene diazonium salts to give the aldehydic hydrazone derivatives 10a‐c. Compound 10 reacted with active methylene compounds to give quinoxalinylpyridazine derivatives. UV characterization of some of the prepared compounds was reported.