Équipe "Chimie des Substances Naturelles" BioCIS, CNRS, Université Paris-Saclay, 5 Rue J.-B. Clément, 92290 Châtenay-Malabry, France.
Institut de Chimie des Substances Naturelles, CNRS, ICSN UPR 2301, Université Paris-Saclay, 91198, Gif-sur-Yvette, France.
J Nat Prod. 2021 Sep 24;84(9):2617-2622. doi: 10.1021/acs.jnatprod.1c00572. Epub 2021 Sep 15.
Lyaline () is a monoterpene indole alkaloid that was isolated in 1974 from (Rubiaceae) in our laboratory and has not been reported elsewhere since then. Its structure was proposed on the basis of a very limited set of spectroscopic data (viz., H NMR and EIMS) as a structurally bizarre harman-1,4-dihydropyridine derivative. A total synthesis of this proposed structure 30 years later proved this product to be highly unstable, and inconsistencies with the original limited spectroscopic data indicated that the structure proposed for lyaline was incorrect. Having in our laboratory the initial and unique lyaline sample, we decided to reinvestigate it using modern spectroscopic techniques, 47 years after its isolation. Our new spectroscopic data confirmed that the initially assigned harman-1,4-dihydropyridine structure was incorrect, instead establishing lyaline as the first naturally occurring nacycline analogue. This structure revision substantiates a type of chemical reactivity of strictosidine first reported in 1975.
利阿灵碱（）是一种单萜吲哚生物碱，于 1974 年从我们实验室的（茜草科）中分离得到，此后再未在其他地方报道过。其结构是根据非常有限的光谱数据（即 1H NMR 和 EIMS）提出的，被认为是一种结构奇特的哈尔满-1,4-二氢吡啶衍生物。30 年后对该假定结构的全合成证明该产物极不稳定，与原始光谱数据的不一致表明最初提出的利阿灵碱结构是不正确的。由于我们实验室拥有最初的、独特的利阿灵碱样品，我们决定在分离 47 年后使用现代光谱技术对其进行重新研究。我们的新光谱数据证实，最初分配的哈尔满-1,4-二氢吡啶结构是不正确的，而将利阿灵碱确定为第一个天然存在的那克林类似物。这一结构修正证实了 1975 年首次报道的斯梯夫碱的一种化学反应类型。
