Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto, Kasugai, Aichi 487-8501, Japan.
San-Ei Gen F.F.I., Inc., 1-1-11 Miwa, Toyonaka, Osaka 561-8588, Japan.
J Agric Food Chem. 2021 Apr 7;69(13):3904-3911. doi: 10.1021/acs.jafc.0c07948. Epub 2021 Mar 24.
Genipin was reacted with benzylamine and several amino acids to prepare gardenia blue (GB). The time-course of GB formation with benzylamine was monitored by high-performance liquid chromatography (HPLC), liquid chromatography time-of-flight mass spectrometry (LC-TOFMS), and H and C NMR measurements. In this experiment, we determined the molecular structures of some intermediates using accurate masses and additional NMR techniques such as heteronuclear multiple bond correlation (HMBC). GBs with amino acids (GB-AAs) were characterized by both liquid and solid-state NMR measurements. Interestingly, many significant peaks appeared in the solid-state NMR spectra, although the C NMR spectra from solution samples did not show any distinct peaks. Therefore, we determined that GB-AAs had an alternating copolymer structure composed of methyne and 5-2-pyrindine, which was substituted by amino acids at N atom and linked with methyne at 5 and 7 positions. To confirm this molecular structure, the pyrolysis gas chromatography-mass spectrometry (GC-MS) measurement of GB-AAs was carried out, and 5-2-pyrindine and its methyl derivatives were formed as main pyrolysis products from the polymer chains.
京尼平与苄胺和几种氨基酸反应制备栀子蓝（GB）。通过高效液相色谱（HPLC）、液质联用飞行时间质谱（LC-TOFMS）和 H 和 C NMR 测量监测与苄胺的 GB 形成的时程。在该实验中，我们使用精确质量和其他 NMR 技术（如异核多键相关（HMBC））确定了一些中间体的分子结构。氨基酸的 GB（GB-AAs）通过液体和固体 NMR 测量进行了表征。有趣的是，尽管来自溶液样品的 C NMR 光谱没有显示任何明显的峰，但在固体 NMR 光谱中出现了许多显著的峰。因此，我们确定 GB-AAs 具有由亚甲基和 5-2-吡啶组成的交替共聚物结构，其在 N 原子处被氨基酸取代，并在 5 和 7 位与亚甲基相连。为了确认这种分子结构，对 GB-AAs 进行了热裂解气相色谱-质谱（GC-MS）测量，并且从聚合物链中形成了 5-2-吡啶及其甲基衍生物作为主要的热裂解产物。
