Adrover Miquel, Vilanova Bartolomé, Muñoz Francisco, Donoso Josefa
Institut Universitari d'Investigació en Ciències de la Salut, Departament de Química, Universitat de les Illes Balears, Palma de Mallorca, Spain.
Bioorg Chem. 2009 Feb;37(1):26-32. doi: 10.1016/j.bioorg.2008.11.002. Epub 2008 Dec 16.
Pyridoxamine is a vitamin B(6) derivative involved in biological reactions such as transamination, and can also act as inhibitor in protein glycation. In both cases, it has been reported that Schiff base formation between pyridoxamine and carbonyl compounds is the main step. Nevertheless, few studies on the Schiff base formation have been reported to date. In this work, we conduct a comparative study of the reaction of pyridoxamine and 4-picolylamin (a pyridoxamine analog) with various carbonyl compounds including propanal, formaldehyde and pyruvic acid. Based on the results, 4-picolylamin forms a Schiff base as end-product of its reactions with propanal and pyruvic acid, but a carbinolamine with formaldehyde. On the other hand, pyridoxamine forms a Schiff base with the three reagents, but the end-product is in equilibrium with its hemiaminal form, which results from the attack of the phenolate ion of the pyridine ring on the imine carbon. This isomeric equilibrium should be considered in studying reactions involving amine derivatives of vitamin B(6).
吡哆胺是一种参与转氨作用等生物反应的维生素B6衍生物，还可作为蛋白质糖基化的抑制剂。在这两种情况下，据报道吡哆胺与羰基化合物之间形成席夫碱是主要步骤。然而，迄今为止，关于席夫碱形成的研究报道很少。在这项工作中，我们对吡哆胺和4-吡啶甲胺（一种吡哆胺类似物）与包括丙醛、甲醛和丙酮酸在内的各种羰基化合物的反应进行了比较研究。根据结果，4-吡啶甲胺与丙醛和丙酮酸反应形成席夫碱作为最终产物，但与甲醛反应形成甲醇胺。另一方面，吡哆胺与这三种试剂都形成席夫碱，但最终产物与其半胺形式处于平衡状态，半胺形式是由吡啶环的酚盐离子对亚胺碳的进攻产生的。在研究涉及维生素B6胺衍生物的反应时，应考虑这种异构平衡。
