Tressl R, Wondrak GT, Krüger RP, Rewicki D
Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany.
J Agric Food Chem. 1998 Jan 19;46(1):104-110. doi: 10.1021/jf970657c.
In the 2-deoxy-D-ribose/methyl 4-aminobutyrate Maillard system a trapped N-substituted 2-(hydroxymethyl)pyrrole is one of the major products. However, nontrapped representatives of this type of compound were hitherto not found in other Maillard model systems, indicating their extraordinary reactivity. Model experiments with 2-deoxy-D-ribose/methylamine enabled the detection of N-methyl-2-(hydroxymethyl)pyrrole (1) and some derived linear oligomers (2, 3) as minor components. Consequently, 1 was synthesized and its oligomerization studied under very mild acidic conditions. The deformylated dimeric bis(N-methyl-2-pyrrolyl)methane (2) and trimeric N-methyl-2,5-bis(N-methyl-2-pyrrolylmethyl)pyrrole (3) were characterized by GC/MS and NMR. Higher regular oligomers up to 6 N-methyl-2-pyrrolylmethyl units as well as corresponding dehydro-oligomers up to 12 units were identified by MALDI-TOF-MS. A complementary experiment starting with N-methyl-2-hydroxy[(13)C]methylpyrrole ([(13)CH(2)OH]-1) confirmed the structure and the oligomerization pathway. The possible significance of this type of model oligomer for the melanoidin formation in Maillard reactions is discussed. The antioxidative activity of the isolated dimer and trimer was tested in Fe(III)-thiocyanate and DPPH assays.
在2-脱氧-D-核糖/4-氨基丁酸甲酯美拉德体系中，一种捕获的N-取代2-(羟甲基)吡咯是主要产物之一。然而，迄今为止在其他美拉德模型体系中尚未发现这类化合物的未捕获代表物，这表明它们具有非凡的反应活性。用2-脱氧-D-核糖/甲胺进行的模型实验能够检测到作为次要成分的N-甲基-2-(羟甲基)吡咯(1)和一些衍生的线性低聚物(2,3)。因此，合成了1并在非常温和的酸性条件下研究了其低聚反应。通过气相色谱/质谱联用仪（GC/MS）和核磁共振（NMR）对脱甲酰基二聚体双(N-甲基-2-吡咯基)甲烷(2)和三聚体N-甲基-2,5-双(N-甲基-2-吡咯基亚甲基)吡咯(3)进行了表征。通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF-MS）鉴定出了高达6个N-甲基-2-吡咯基亚甲基单元的更高规则低聚物以及高达12个单元的相应脱氢低聚物。以N-甲基-2-羟基[(13)C]甲基吡咯([(13)CH(2)OH]-1)开始的补充实验证实了结构和低聚反应途径。讨论了这类模型低聚物在美拉德反应中黑色素形成的可能意义。在铁(III)硫氰酸盐和二苯基苦味酰基自由基（DPPH）测定中测试了分离出的二聚体和三聚体的抗氧化活性。
