Ximenes Valdecir F
Departamento de Química, Faculdade de Ciências, Universidade Estadual Paulista Júlio de Mesquita Filho, Bauru, SP, Brazil.
J Pineal Res. 2008 Oct;45(3):297-301. doi: 10.1111/j.1600-079X.2008.00590.x. Epub 2008 Mar 26.
N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK) is the product of oxidative pyrrole ring cleavage of melatonin. AFMK and its deformylated derivative N(1)-acetyl-5-methoxykynuramine (AMK) are compounds for which there are increasing demands because of their antioxidant, immunomodulatory and anti-inflammatory properties. Here, we sought to determine the best reaction conditions for preparation of AFMK using chlorpromazine (CPZ) as a co-catalyst in the peroxidase-mediated oxidation of melatonin. The parameters studied were pH, identity and concentration of buffers, hydrogen peroxide (H(2)O(2)) and CPZ concentrations and the presence or absence of dissolved molecular oxygen in the reaction medium. The rate and efficiency of AFMK production were compared with a noncatalyzed method which uses a high concentration of H(2)O(2). We found that by using CPZ and bubbling molecular oxygen during the course of the reaction, the yield of AFMK was significantly increased (about 60%) and the reaction time decreased (about 30 min), as compared with the noncatalyzed reaction (yield 32% and reaction time 4 hr). Based on these data, we suggest that this could be a new, easily performed and efficient route for AFMK preparation. Additionally, we provide evidence that a radical chain reaction could be responsible for the formation of AFMK.
N(1)-乙酰基-N(2)-甲酰基-5-甲氧基犬尿胺（AFMK）是褪黑素氧化吡咯环裂解的产物。AFMK及其去甲酰化衍生物N(1)-乙酰基-5-甲氧基犬尿胺（AMK）因其抗氧化、免疫调节和抗炎特性而需求日益增加。在此，我们试图确定在过氧化物酶介导的褪黑素氧化反应中，使用氯丙嗪（CPZ）作为共催化剂制备AFMK的最佳反应条件。所研究的参数包括pH值、缓冲液的种类和浓度、过氧化氢（H₂O₂）和CPZ的浓度以及反应介质中是否存在溶解的分子氧。将AFMK的生成速率和效率与使用高浓度H₂O₂的非催化方法进行了比较。我们发现，与非催化反应（产率32%，反应时间4小时）相比，通过在反应过程中使用CPZ并鼓入分子氧，AFMK的产率显著提高（约60%），反应时间缩短（约30分钟）。基于这些数据，我们认为这可能是一种制备AFMK的新的、易于操作且高效的途径。此外，我们提供了证据表明自由基链反应可能是AFMK形成的原因。
