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Production of 3,4-cis- and 3,4-trans-Leucocyanidin and Their Distinct MS/MS Fragmentation Patterns
Journal of Agricultural and Food Chemistry ( IF 5.7 ) Pub Date : 2017-12-26 00:00:00 , DOI: 10.1021/acs.jafc.7b04380 Jia-Rong Zhang 1 , James Tolchard 1 , Katell Bathany 1 , Béatrice Langlois d’Estaintot 1 , Jean Chaudiere 1
Journal of Agricultural and Food Chemistry ( IF 5.7 ) Pub Date : 2017-12-26 00:00:00 , DOI: 10.1021/acs.jafc.7b04380 Jia-Rong Zhang 1 , James Tolchard 1 , Katell Bathany 1 , Béatrice Langlois d’Estaintot 1 , Jean Chaudiere 1
Affiliation
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(+)-2,3-trans-3,4-cis-Leucocyanidin was produced by acidic epimerization of (+)-2,3-trans-3,4-trans-leucocyanidin synthesized by reduction of (+)-dihydroquercetin with NaBH4, and structures of the two stereoisomers purified by C18- and phenyl-reverse-phase high-performance liquid chromatography (HPLC) were confirmed by NMR spectroscopy. We confirm that only 3,4-cis-leucocyanidin is used by leucoanthocyanidin reductase as substrate. The two stereoisomers are quite stable in aqueous solution at −20 °C. Characterization of the two stereoisomers was also performed using electrospray ionization tandem mass spectrometry (ESI-MS/MS), and we discuss here for the first time the corresponding MS/MS fragmentation pathways, which are clearly distinct. The main difference is that of the mode of dehydration of the 3,4-diol in positive ionization mode, which involves a loss of hydroxyl group at either C3 or C4 for the 3,4-cis isomer but only at C3 for the 3,4-trans isomer. Tandem mass spectrometry therefore proves useful as a complementary methodology to NMR to identify each of the two stereoisomers.
中文翻译：
3,4-顺式和3,4-反式-花青素的生产及其独特的MS / MS片段分析模式
（+）-2,3-反式-3,4-顺式-芥子苷是通过（+）-2,3-反式-3,4-反式-亮氨酸通过将（+）-二氢槲皮素还原而合成的NaBH 4，以及通过C18和苯基反相高效液相色谱（HPLC）纯化的两种立体异构体的结构均通过NMR光谱法确认。我们确认只有3,4-顺式-白花青素被白花青素还原酶用作底物。两种立体异构体在-20°C的水溶液中非常稳定。还使用电喷雾电离串联质谱（ESI-MS / MS）对这两种立体异构体进行了表征，并且我们在这里首次讨论了明显不同的相应MS / MS裂解途径。主要的区别是，在正离子化模式中，-3,4-二醇的脱水的模式，其涉及在无论是C羟基的损失的3或C 4的3,4-顺式异构体，但只有位于C 3为3，4-反式异构体。因此，串联质谱法被证明可作为NMR的互补方法来鉴定两种立体异构体中的每一种。
更新日期：2017-12-26
中文翻译：
3,4-顺式和3,4-反式-花青素的生产及其独特的MS / MS片段分析模式
（+）-2,3-反式-3,4-顺式-芥子苷是通过（+）-2,3-反式-3,4-反式-亮氨酸通过将（+）-二氢槲皮素还原而合成的NaBH 4，以及通过C18和苯基反相高效液相色谱（HPLC）纯化的两种立体异构体的结构均通过NMR光谱法确认。我们确认只有3,4-顺式-白花青素被白花青素还原酶用作底物。两种立体异构体在-20°C的水溶液中非常稳定。还使用电喷雾电离串联质谱（ESI-MS / MS）对这两种立体异构体进行了表征，并且我们在这里首次讨论了明显不同的相应MS / MS裂解途径。主要的区别是，在正离子化模式中，-3,4-二醇的脱水的模式，其涉及在无论是C羟基的损失的3或C 4的3,4-顺式异构体，但只有位于C 3为3，4-反式异构体。因此，串联质谱法被证明可作为NMR的互补方法来鉴定两种立体异构体中的每一种。
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