Isolation and Characterization of 1-Tigloyl-3-acetylazadirachtol from the Seed Kernels of the Thai Neem Azadirachta siamensis Valeton

1997 ◽  
Vol 52 (11) ◽  
pp. 1413-1417 ◽  
Author(s):  
H.-O. Kalinowski ◽  
C. Krack ◽  
K. Ermel ◽  
C. Chriathamjaree
Keyword(s):  
Large Scale ◽  
Botanical Insecticides ◽  
Preparative Hplc ◽  
Isolation And Characterization ◽  
Liquid Liquid Extraction ◽  
Related Compounds ◽  
Analytical Hplc ◽  
Azadirachtin A ◽  
C Nmr

Abstract The Thai neem A. siamensis (Valeton) is the main source for botanical insecticides in Thailand. Although azadirachtin A (aza A) is present in Thai neem, there are some other related compounds which may contribute to its bioefficiency. Analytical HPLC of Thai neem samples showed a peak closely eluted with azadirachtin. A large-scale cleanup involving two liquid/liquid extraction steps, silica filtration, and finally two successive preparative HPLC separations, resulted in the pure compound, which was identified as 1-tigloyl-3-acetylazadirachtol by 1D -and 2D -1H and 13C NMR spectroscopy.

Isolation and Characterization of Limonoids from Kigelia africana

2013 ◽  
Vol 68 (9) ◽  
pp. 1041-1048 ◽  
Author(s):  
Bushra Jabeen ◽  
Naheed Riaz
Keyword(s):  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
X Ray ◽  
X Ray Crystallography ◽  
Isolation And Characterization ◽  
Related Compounds ◽  
Absolute Stereochemistry ◽  
Cosy Nmr ◽  
C Nmr

Two new limonoids, 1-O-deacetyl-2a-methoxykhayanolide (1) and kigelianolide (2), together with deacetylkhayanolide E (3), 1-O-deacetyl-2α-hydroxykhayanolide E (4) and khayanolide B (5) were isolated from the ethyl acetate-soluble fraction of the methanolic extract of Kigelia africana. The structures of these limonoids (1-5) were elucidated by the combination of 1D (1H and 13C NMR) and 2D (HMQC, HMBC and COSY) NMR spectroscopy and mass spectrometry (EIMS, HREIMS), and in comparison with literature data of related compounds. The structure of compound 1 was further confirmed by X-ray crystallography, and the absolute stereochemistry of compounds 1 and 2 was determined by electronic circular dichroism (ECD) spectroscopy. Limonoids 1-5 showed weak inhibitory activities against the enzymes acetylcholinesterase (AChE), butyrycholinesterase (BChE) and lipoxygenase (LOX) in a concentration-dependent manner with IC50 values in the ranges 137.5 - 225.2 μM for AChE, 185.4 - 241.5 μM for BChE and 281.2 - 189.6 μM for LOX

Ryanoids and related compounds — Isolation and characterization of 11 new minor ryanoids from the plant Ryania Speciosa Vahl

2002 ◽  
Vol 80 (5) ◽  
pp. 483-488 ◽  
Author(s):  
Luc Ruest ◽  
Marco Dodier ◽  
Hélène De Sève ◽  
Christian Lessard ◽  
Pascal Mongrain
Keyword(s):  
Natural Compounds ◽  
New Members ◽  
Isolation And Characterization ◽  
Related Compounds

In a search for minor ryanoids from the plant Ryania Speciosa Vahl, we recently characterized 11 new members of that family of natural compounds. Most of them represent ryanodine (1) and dehydroryanodine (2) with a modified stage of oxidation in ring C. A second member of the new 4-deoxy series has been identified.Key words: minor natural ryanoids, ryanodine, dehydroryanodine, deoxyryanoids.

scholarly journals Isolation, Identification and Characterization of Degradation Impurity of Atorvastatin in Fixed Dose Combination of Atorvastatin and Ezetimibe

2019 ◽  
Vol 11 (05) ◽  
Author(s):  
Rajesh Desai ◽  
Suresh Koradia
Keyword(s):  
Reversed Phase ◽  
Fixed Dose Combination ◽  
Fixed Dose ◽  
Forced Degradation ◽  
Preparative Hplc ◽  
Atorvastatin Calcium ◽  
Isolation And Characterization ◽  
Dose Combination ◽  
Liquid Chromatographic

The objective of this study is to isolation and characterization of unknown degradation product of Atorvastatin calcium in combination formulation product with Ezetimibe by using modern techniques of separation and aracterization. An unknown impurity is generating during a forced degradation study of Atorvastatin and Ezetimibe fixed-dose combination tablets. By using the gradient reversed-phase high-pressure liquid chromatographic method, unknown degradation impurity was detected and quantified in the range of 0.05% to 0.2% of Atorvastatin. The impurity was enriched by extreme oxidation degradation of Atorvastatin and isolated through preparative HPLC. The structure of the impurity was characterized by mass and NMR spectrum.

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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