Piperazines as Model Substrate for Oxidations.

Abstract

Piperazines as Model Substrate for Oxidations. -A high tendency of polymerization is observed when piperazine derivatives are oxidized by mercury-EDTA. This unusual behavior is caused by means of the reactive cyclic enediamine intermediates as aza-analogous reductones and to the carbonyl compounds resulting from dehydrogenation in the side chain. Monosubstituted piperazines (I) give rise to the formation of piperazinediones (II) in medium yields. Surprisingly, benzhydryl derivative (IV) on oxidation yields a mixture of piperazinedione (V) and monolactam (VI) in addition to a small amount of benzophenone (VII). The bis-substituted piperazines (VIII) and (X) react more differently due to the symmetry and the preferred direction of the dehydrogenation into the cycle. -(MOEHRLE*, H.; AZODI, K.; Pharmazie 61 (2006) 10, 815-822; Inst. Pharm. Chem., Heinrich-Heine-Univ.,

Synthesis of Cu(II) complexes by N,O‐donor ligand transformation and their catalytic role in visible‐light‐driven alcohol oxidation

“…Literature reveals that piperazine ring tends to get oxidized to lactam in various oxidative conditions in presence and absence of metal catalysts. [74][75][76] It is assumed herein that the copper complex gets oxidized to mono keto form as depicted in Scheme S1 structure A. The keto form tautomerize into enol and forms an intermediate B (Scheme S1), identified by ESI-MS with simulated pattern peaks with as [M + H + ] ion at 881.0.…”