Mechanism of the oxidative degradation of dibenzoazepine derivatives via manganese(III) complexes in acidic phosphate media

作者：Wisniewska Joanna^*; Rzesnicki Pawel

来源：Reaction Kinetics, Mechanisms and Catalysis, 2013, 108(1): 1-16.

DOI：10.1007/s11144-012-0510-9

• Kinetics
• Mechanism
• Dibenzoazepine derivatives
• Manganese(III) complexes

The oxidative degradation of tricyclic antidepressants (TCA) was studied in the presence of a large excess of the oxidizing agents, manganese(III)-pyrophosphate (P2O7 (4-)), phosphate (PO4 (3-)), in acidic media. The products were detected and identified using UV-Vis, ESI-MS and IR methods. The reaction between dibenz[b,f]azepines and manganese(III) ions proceeded via two consecutive reactions: first, acridine analogues were formed, and then a dealkylation process resulted in the formation of unsubstituted acridine. The kinetics of the first degradation step of the TCAs was investigated independently of the slower dealkylation step. The pseudo-first order rate constants (k (obs)) were determined for the first degradation process. The reaction between 10,11-dihydro-5H-dibenz[b,f]azepines and the manganese(III) ion resulted in oxidative dehydrogenation, which proceeded via the formation of two intermediates: a free organic radical and a dimeric dication. Further oxidation of the second intermediate led to a positively charged radical dimer as a single final product. Simultaneously, two other substituent cleavage degradation processes occurred, which led to two dimeric derivatives. The kinetic traces were determined to be zeroth order.

• 出版日期2013-2