New Azabenzoquinones by Ring‐Expansion Reactions.

Abstract

Pyridine derivatives Pyridine derivatives R 0380New Azabenzoquinones by Ring-Expansion Reactions. -Pyridinetriones (IV) are prepared form pyrrolidinediones (I) via ring-expansion reaction. In solution, two tautomeric forms of (IV) may exist, both of which represent hydroxy-azabenzoquinones. Azabenzoquinones (IV) react with phenylenediamine (V) furnishing violet quinoxalines (VI). Compounds such as (XII), another type of azaquinones, are generated in two steps from pyridones (IX) and transformed into the adduct (XIV) and the cycloadduct (XVII). -(POSCHENRIEDER, H.; STACHEL*, H.-D.; WIESEND, B.; POLBORN, K.; J. Heterocycl. Chem. 40 (2003) 1, 61-69; Inst. Pharm., Zent. Pharmaforsch.,