A new pre-column derivatization for valienamine and beta-valienamine using o-phthalaldehyde to determine the epimeric purity by HPLC and application of this method to monitor enzymatic catalyzed synthesis of beta-valienamine
摘要:
Valienamine and -valienamine are representative C7N aminocyclitols with significant glycosidase inhibition activity that have been developed as important precursors of drugs for diabetes and lysosomal storage diseases, respectively. The quantitative analysis of these chiral compounds is crucial for asymmetric in vitro biosynthetic processes for converting valienone into valienamine epimers using aminotransferase. Here, we developed an efficient and sensitive method for separation and quantitative analysis of chiral valienamine using reversed-phase high-performance liquid chromatography (HPLC) through o-phthalaldehyde (OPA) pre-column derivatization of the analytes. The epimers were derivatized by OPA in borate buffer (pH 9.0) at room temperature for 30 s, separated on an Eclipse XDB-C18 (5m, 4.6x150mm) column, eluted with 22% acetonitrile at 30 degrees C for 18min, and detected by a fluorescence detector using 445nm emission and 340nm excitation wavelengths. The average resolution of the epimers is 3.86, and the concentration linearity is in the range of 0.02-20g/ml. The method proved to be effective, sensitive, and reliable with good intra- and inter-day precision and accuracy, and successfully evaluated the enantiopreference and catalytic capability of the potential aminotransferases on an unnatural prochiral substrate, facilitating the design of an asymmetric biosynthetic route for optically pure valienamine and -valienamine.[GRAPHICS].
Short Syntheses of Gabosine I and Gabosine G from δ-<scp>d</scp>-Gluconolactone
作者:Tony K. M. Shing、Hau M. Cheng
DOI:10.1021/jo0709697
日期:2007.8.1
A short synthesis of gabosine I (1) from δ-d-gluconolactone (3) in four steps, involving a one-pot TPAP oxidation−K2CO3-mediated intramolecular Horner−Wadsworth−Emmons (HWE) olefination as the key step, is described. Regioselective acetylation of the primary alcohol in gabosine I (1) then furnished gabosine G (2).
从δ-d-葡萄糖酸内酯(3)的四个步骤中短暂合成合成的Gabosine I(1),涉及一锅TPAP氧化-K 2 CO 3介导的分子内霍纳-沃兹沃思-埃蒙斯(HWE)烯化反应为关键步骤进行说明。然后在Gabosine I(1)中对伯醇进行区域选择性乙酰化,从而提供了Gabosine G(2)。
Total Syntheses of (+)-Gabosine P, (+)-Gabosine Q, (+)-Gabosine E, (−)-Gabosine G, (−)-Gabosine I, (−)-Gabosine K, (+)-Streptol, and (−)-Uvamalol A by a Diversity-Oriented Approach Featuring Tunable Deprotection Manipulation
A new diversity-oriented approach to C7-cyclitols, which possess a broad spectrum of biological activities, is developed. The key polyoxygenated intermediates with different O-protecting groups were accessed by an intramolecular aldol-cyclization of a diketone derived from δ-d-gluconolactone. The versatile intermediates can be easily transformed into structurally different carbasugars based on control
ValC, a New Type of C7-Cyclitol Kinase Involved in the Biosynthesis of the Antifungal Agent Validamycin A
作者:Kazuyuki Minagawa、Yirong Zhang、Takuya Ito、Linquan Bai、Zixin Deng、Taifo Mahmud
DOI:10.1002/cbic.200600528
日期:2007.4.16
thus suggesting a critical function of valC in validamycinbiosynthesis. In vitro characterization of ValC revealed a newtype of C7-cyclitolkinase, which phosphorylates valienone and validone--but not 2-epi-5-epi-valiolone, 5-epi-valiolone, or glucose--to afford their 7-phosphate derivatives. The results provide new insights into the activity of this enzyme and also confirm the existence of two
Carbocyclization of d-glucose: syntheses of gabosine I and streptol
作者:Tony K.M. Shing、Y. Chen、Wai-Lung Ng
DOI:10.1016/j.tet.2011.06.028
日期:2011.8
D-Glucose was differentially protected with a trans-diacetal at C-2,3, an ethoxymethyl ether at C-4, and a tert-butyldimethylsilyl ether at C-6, and then carbocyclized via a key Horner-Wadsworth-Emmons (HWE) olefination to give a versatile synthetic intermediate, enone 13, which was readily transformed into gabosine I and streptol. (C) 2011 Elsevier Ltd. All rights reserved.
New Access to Unsaturated Keto Carba Sugars (Gabosines) Using an Intramolecular Nozaki−Kishi Reaction as the Key Step