Synthesis of pyrimido[5″,4″:5′,6′]pyrido[2′,3′:4,5]- thieno[2,3-c]pyridazine and pyridazino[4′3′:4,5]-thieno[3,2-b][1,8]naphthyridine, new tetrahete-rocyclic ring systems

Article abstract of DOI:10.3987/com-97-7865

Preparation of a number of pyrimido[5″,4″:5′,6′]pyrido-[2′,3′:4,5] thieno[2,3-c]pyridazine derivatives (4a-h) has been effected by reaction of appropriately heterocyclic aminonitrile precursor (1) and N,N-dimethyldichloromethyleniminium chloride. In addition, pyridazino[4′,3′:4,5]-thieno[3,2-b][1,8]naphthyridines (9a-i), were prepared via the Friedl?nder synthesis of the N-heteroaromatic carbaldehyde (8) with acyclic, cyclic, heterocyclic or α,β-unsaturated ketones and other active methylene compounds.