Onchidin B: A New Cyclodepsipeptide from the Mollusc <i>Onchidium</i> sp.
作者:Rogelio Fernández、Jaime Rodríguez、Emilio Quiñoá、Ricardo Riguera、Luis Muñoz、Miryam Fernández-Suárez、Cécile Debitus
DOI:10.1021/ja961314i
日期:1996.1.1
samples of the α-amino and α-hydroxy acids allowed us the assignment of the entire absolute stereochemistry of onchidin B. In this way, the α-hydroxy acids were found to be (S)-Hiv and (S,S)-Hmp, and the α-amino acids (R)-proline, (S)-proline, and (R)-MeVal. In order to establish the absolute configuration of the new β-hydroxy acid, Hymo, its four possible stereoisomers were stereoselectively synthesized
Onchidin B (4) 是一种从肺状软体动物 Onchidium sp. 中分离出来的环状缩酚肽。其结构由广泛的 2D-NMR、FABMS、串联 FAB MS/MS、选择性水解和合成确定。它含有四个α-氨基酸[两个单位的N-甲基缬氨酸(MeVal),两个单位的脯氨酸(Pro)],四个α-羟基酸[两个2-羟基异戊酸(Hiv),两个2-羟基-3-甲基戊酸部分 (Hmp)] 和新 β-羟基酸的两个单元:3-羟基-2-甲基辛酸-7-炔酸 (Hymo)]。选择性水解和手性 GC-MS 与 α-氨基和 α-羟基酸的真实样品的直接比较使我们能够确定 onchidin B 的整个绝对立体化学。通过这种方式,发现 α-羟基酸是( S)-Hiv 和 (S,S)-Hmp,以及 α-氨基酸 (R)-脯氨酸、(S)-脯氨酸和 (R)-MeVal。