scholarly journals Isolation and characterization of ardicrenin from Ardisia crenata Sims

2009 ◽  
Vol 55 (No. 7) ◽  
pp. 305-310 ◽  
Author(s):  
Ma Yuan ◽  
Pu Shangrao ◽  
Cheng Qingsu ◽  
Ma Mingdong
Keyword(s):  
High Performance ◽  
Amorphous Powder ◽  
Gel Chromatography ◽  
Macroporous Resin ◽  
Resin Column ◽  
Isolation And Characterization ◽  
Natural Reserve ◽  
Silica Gel Chromatography ◽  
Counter Current

A new, effective and economical method to extract ardicrenin from <I>Ardisia crenata</I> Sims collected in the Wolong natural reserve, Sichuan, China, is established. <I>Ardisia crenata</I> Sims powder is counter-current extracted with 80% methanol reflux, decompressively enriched and centrifuged to defat. Supernatant is applied to macroporous resin column (AB-8) with 80% methanol, ardicrenin is isolated by silica gel chromatography with dichlormethane-acetoacetate-methanol (4:1.5:1) washing, and recrystallized in methanol. The final product which proved to be ardicrenin by analytic procedure including Furier transform infrared (FTIR) and ultraviolet spectrum (UV), mass spectroscopy (MS), nuclear magnetic resonance (NMR) and high performance liquid chromatography (HPLC) is white amorphous powder with yield of 1.59 ± 0.02%.

Preparation and Characterization of the High Molecular Weight [3H]Hyaluronic Acid

1992 ◽  
Vol 57 (10) ◽  
pp. 2151-2156 ◽  
Author(s):  
Peter Chabreček ◽  
Ladislav Šoltés ◽  
Hynek Hradec ◽  
Jiří Filip ◽  
Eduard Orviský
Keyword(s):  
Molecular Weight ◽  
Hyaluronic Acid ◽  
High Molecular Weight ◽  
Methyl Bromide ◽  
High Performance ◽  
Hydrogen Atoms ◽  
Isolation And Characterization ◽  
Labelling Procedure ◽  
Enzymatic Depolymerization

Two methods for the preparation of high molecular weight [3H]hyaluronic acid were investigated. In the first one, hydrogen atoms in the molecule were replaced by tritium. This isotopic substitution was performed in aqueous solution using Pd/CaCO3 as the catalyst. In the second method, the high molecular weight hyaluronic acid was alkylated with [3H]methyl bromide in liquid ammonia at a temperature of -33.5 °C. High-performance gel permeation chromatographic separation method was used for the isolation and characterization of the high molecular weight [3H]hyaluronic acid. Molecular weight parameters for the labelled biopolymers were Mw = 128 kDa, Mw/Mn = 1.88 (first method) and Mw = 268 kDa, Mw/Mn = 1.55 (second method). The high molecular weight [3H]hyaluronic acid having Mw = 268 kDa was degraded further by specific hyaluronidase. Products of the enzymatic depolymerization were observed to be identical for both, labelled and cold biopolymer. This finding indicates that the described labelling procedure using [3H]methyl bromide does not induce any major structural rearrangements in the molecule.

scholarly journals Synthesis, Isolation and Characterization of Process-Related Impurities in Oseltamivir Phosphate

2012 ◽  
Vol 9 (1) ◽  
pp. 113-120 ◽  
Author(s):  
Yogesh Kumar Sharma ◽  
Dau Dayal Agarwal ◽  
Sudesh Bhure ◽  
Sanjay Singh Rathore ◽  
Chakravir Rawat ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Mass Number ◽  
Reverse Phase ◽  
Related Impurities ◽  
Isolation And Characterization ◽  
Bulk Drug ◽  
Oseltamivir Phosphate

Three known impurities in oseltamivir phosphate bulk drug at level 0.1% (ranging from 0.05-0.1%) were detected by gradient reverse phase high performance liquid chromatography. These impurities were preliminarily identified by the mass number of the impurities. Different experiments were conducted and finally the known impurities were synthesized and characterized.

scholarly journals CAAC Boranes. Synthesis and characterization of cyclic (alkyl) (amino) carbene borane complexes from BF3 and BH3

2010 ◽  
Vol 6 ◽  
pp. 709-712 ◽  
Author(s):  
Julien Monot ◽  
Louis Fensterbank ◽  
Max Malacria ◽  
Emmanuel Lacôte ◽  
Steven J Geib ◽  
...  
Keyword(s):  
Silica Gel ◽  
Synthesis And Characterization ◽  
Gel Chromatography ◽  
Nmr Analysis ◽  
X Ray ◽  
X Ray Crystallography ◽  
In Situ Formation ◽  
Silica Gel Chromatography

In situ formation of two cyclic (alkyl) (amino) carbenes (CAACs) followed by addition of BF3•Et2O provided the first two examples of CAAC–BF3 complexes: 1-(2,6-diisopropylphenyl)-3,5,5-trimethyl-3-phenylpyrrolidin-2-ylidene trifluoroborane, and 2-(2,6-diisopropylphenyl)-3,3-dimethyl-2-azaspiro[4.5]decan-1-ylidene trifluoroborane. These CAAC–BF3 complexes are robust compounds that are stable to ambient laboratory conditions and silica gel chromatography. They were characterized by spectroscopy and X-ray crystallography. In contrast, a CAAC complex with borane (BH3) was readily formed in situ according to 1H and 11B NMR analysis, but did not survive the workup conditions. These results set the stage for further studies of the chemistry of CAAC boranes.

scholarly journals Efficient resolution of racemic crown-shaped cyclotriveratrylene derivatives and isolation and characterization of the intermediate saddle isomer

2019 ◽  
Vol 15 ◽  
pp. 1339-1346
Author(s):  
Sven Götz ◽  
Andreas Schneider ◽  
Arne Lützen
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Nmr Spectroscopy ◽  
High Performance ◽  
Chiral Stationary Phase ◽  
Hplc Separation ◽  
Promising Alternative ◽  
Isolation And Characterization ◽  
C Nmr

The preparative resolution of a trifunctionalized C 3-symmetrical chiral cyclotriveratrylene derivative was achieved via high-performance liquid chromatography (HPLC) on a chiral stationary phase. This approach is a promising alternative to the previously reported resolution through formation of diastereomeric esters because it involves fewer synthetic steps and is less prone to thermal (re)racemization. During these studies an intermediate saddle conformer could also be isolated and characterized by 1H and 13C NMR spectroscopy. The HPLC separation method was further developed in order to allow investigations on the racemization behavior of the cyclotriveratrylene derivative.

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