Hubregtse Ton, Neeleman Ernst, Maschmeyer Thomas, Sheldon Roger A, Hanefeld Ulf, Arends Isabel W C E
Biocatalysis and Organic Chemistry, Delft University of Technology, Julianalaan 136, 2628 BL, Delft, The Netherlands.
J Inorg Biochem. 2005 May;99(5):1264-7. doi: 10.1016/j.jinorgbio.2005.02.004.
The ligand of the naturally occurring vanadium compound amavadin found in Amanita muscaria, (2S, 2'S)-N-hydroxyimino-2,2'-dipropionic acid (1), was synthesized stereoselectively in two steps with 43% overall yield. After complexation of this ligand to vanadyl acetate, amavadin was isolated in quantitative yield. Due to the chirality at vanadium amavadin consists of a mixture of delta and lambda diastereoisomers. Directly after its synthesis, the delta to lambda ratio of amavadin is 2.27 and it decreases to 0.80 after equilibrium has been reached. During this epimerization the optical rotation for V[(2S,2'S)-N-hydroxyimino-(2,2')-dipropionate]2 (=amavadin) changes from alpha25 = +36 degrees to +114.0 degrees (c = 0.5, H2O). For V[(2R,2'R)-N-hydroxyimino-(2,2')-dipropionate] the optical rotation changes from alpha25 = -36 degrees to -113.2 degrees (c = 0.5, H2O).
在毒蝇伞中发现的天然钒化合物阿玛瓦丁的配体，即(2S, 2'S)-N-羟基亚氨基-2,2'-二丙酸(1)，通过两步立体选择性合成，总产率为43%。该配体与乙酸氧钒络合后，以定量产率分离得到阿玛瓦丁。由于钒的手性，阿玛瓦丁由δ和λ非对映异构体的混合物组成。合成后，阿玛瓦丁的δ与λ比例为2.27，达到平衡后降至0.80。在这种差向异构化过程中，V[(2S,2'S)-N-羟基亚氨基-(2,2')-二丙酸酯]2（=阿玛瓦丁）的旋光率从α25 = +36°变为+114.0°（c = 0.5，H2O）。对于V[(2R,2'R)-N-羟基亚氨基-(2,2')-二丙酸酯]，旋光率从α25 = -36°变为-113.2°（c = 0.5，H2O）。
