Synthesis of dihydrothiopyrano[3,4-c]pyridines and of fusion products thereof

Summary

Reaction of the 6-hydroxy-thiopyrano[3,4-c]pyridine-5-carbonitrile derivative2 with α-halogeno-carbonyl compounds gave the O-substituted intermediates3a–d which on treatment with base were converted into the furo[2,3-b]thiopyrano[4,3-d]pyridines4a–d by fusion of a furan moiety. Cyclization of the corresponding ester4d led to fusion of a pyrimidine ring, thus yielding the tetracyclic product8 as well as its N-substituted derivatives9a–e. Target compounds2–9 were derived from the three novel heterocyclic parent systemsA–C.

Zusammenfassung

Reaktion des 6-Hydroxy-thiopyrano[3,4-c]pyridin-5-carbonsäurenitril — Derivates2 mit α-Halogencarbonylverbindungen führte über die entsprechenden O-substituierten Zwischenprodukte3a–d durch Furan-Anellierungen zu den Furo[2,3-b]thiopyrano[4,3-d]pyridin — Derivaten4a–d. Cyclisierung des entsprechenden Esters4d gab unter Pyrimidin-Anellierung das tetracyclische Produkt8 sowie dessen N-Substitutionsprodukte9a–e. Die Zielverbindungen2–9 leiten sich von den drei neuen heterocyclischen GrundkörpernA–C ab.