scholarly journals HYDROBORATION-OXIDATION OF GLYCIRRETHIC ACID’S DERIVATIVES

2020 ◽  
pp. 101-109
Author(s):  
Valentina Afanasievna Vydrina ◽  
Marina Petrovna Yakovleva ◽  
Aleksey Aleksandrovich Kravchenko ◽  
Rasul' Rustemovich Sayakhov ◽  
Gumer Yusupovich Ishmuratov
Keyword(s):  
Methyl Ester ◽  
Methylene Chloride ◽  
Raw Materials ◽  
Oxidation Reactions ◽  
Double Bonds ◽  
Pentacyclic Triterpenoid ◽  
Diene System ◽  
Subsequent Hydrolysis ◽  
Directed Synthesis ◽  
New Compounds

The hydroboration-oxidation reaction is widely used in the chemistry of terpenoids both for proving the structure of new compounds isolated from natural raw materials and for the directed synthesis of low molecular weight bioregulators. Moreover, most of the known examples affect mono- and sesquiterpenes, a much smaller number - for di- and triterpenoids: most are represented by hydroboration-oxidation of localized double bonds, examples for conjugated dienes are limited only by hydroboration-oxidation of cis-eudesma-6,11-diene, abietic acid and its methyl ester. We found that the reduction of the pentacyclic triterpenoid – glycyrrhetate methyl ester – diisobutylaluminium hydride in methylene chloride at -78 ° С and subsequent hydrolysis in the presence of ammonium chloride proceeds with the formation of 3β,30-dihydroxy-18βH-olean-9(11),12(13)-diene with a yield of 90%. It was shown that the hydroboration of the 1,3-diene system in it with a 3.3 molar excess of diborane in tetrahydrofuran is accompanied by the restoration of the carboxyl function, and after oxidation with the hydrogen peroxide-sodium acetate system of the organoboranes formed, three alcohols are mixed (2 : 1 : 1): 3β,11,30-trihydroxy-18βH-olean-12(13)-ene, 3β,12,30-trihydroxy-18βH-olean-9(11)-ene and 3β,9,30-trihydroxy-18βH-olean-12 (13)-ene, respectively. A similar mixture of triols was also obtained by hydroboration-oxidation of 3β-hydroxy-18βH-olean-9(11),12(13)-diene-30-oic acid. The hydroboration-oxidation reactions of 3β,30-dihydroxy-18βH-olean-9(11),12(13)-diene or the corresponding 30th acid proceed as monoprocesses predominantly at 9(11) double bonds.

scholarly journals Azukisapogenol Triterpene Glycosides from Oxytropis chiliophylla Royle

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2448
Author(s):  
Jun Wang ◽  
Hongshuai Yang ◽  
Yang Liu ◽  
Kelsang Norbo ◽  
Kewu Zeng ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Glucuronic Acid ◽  
Acid Methyl Ester ◽  
Triterpene Glycosides ◽  
Raw 264.7 Cells ◽  
No Production ◽  
Acid Methyl ◽  
Potent Inhibition ◽  
New Compounds ◽  
First Time

Eight azukisapogenol triterpene glycosides, including five new compounds, oxychiliotriterpenosides A–E (1–5), two new methyl glucuronide derivatives that proved to be artifacts, oxychiliotriterpenoside E-glucuronic acid methyl ester (6) and myrioside B-glucuronic acid methyl ester (7), and a known one, myrioside B (8), was isolated from the aerial part of Oxytropis chiliophylla Royle. Their structures were elucidated based on extensive spectroscopic analyses and chemical methods. Triterpene glycosides were first obtained from O. chiliophylla, and those containing a galactose unit (1, 2, 5 and 6) and diglucosidic or triglucosidic linkage at C-29 (1–4), were reported from Oxytropis species for the first time, which might be recognized as a chemotaxonomic feature of O. chiliophylla. All isolated compounds were evaluated for their anti-inflammatory activities against NO production using lipopolysaccharide (LPS)-induced RAW 264.7 cells, but no compounds showed potent inhibition on NO production.

Deposition of gold nanoparticles on organo-kaolinite — Application in electrocatalysis for carbon monoxide oxidation

2011 ◽  
Vol 89 (7) ◽  
pp. 845-853 ◽  
Author(s):  
Sadok Letaief ◽  
Wendy Pell ◽  
Christian Detellier
Keyword(s):  
Carbon Monoxide ◽  
Gold Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Fine Particles ◽  
Raw Materials ◽  
Carbon Monoxide Oxidation ◽  
Functional Materials ◽  
Metallic State ◽  
Oxidation Reactions ◽  
X Ray

The clay mineral kaolinite was used as support of gold nanoparticles for heterogeneous catalysis of oxidation reactions, particularly of carbon monoxide oxidation. The application of clay minerals in the preparation of new functional materials provides an alternative approach for the use of these abundant raw materials. To improve the physicochemical properties of kaolinite, as well as to ensure a strong immobilization of the adsorbed species, kaolinite was functionalized by grafting 2-amino-2-methyl-1,3-propanediol on the internal and external surfaces of the octahedral sheets by reaction with the aluminol groups. Gold nanoparticles were then deposited on the external surfaces of the fine particles of the functionalized kaolinite. The resulting gold kaolinite nanohybrid material was characterized by various physicochemical techniques. X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and energy-dispersive X-ray spectrometry confirmed that gold was effectively reduced to the metallic state during adsorption onto the external surfaces of the modified kaolinite. The gold nanoparticles have a narrow size distribution: more than 88% are less than 4 nm in diameter. Gold nanoparticles deposited on kaolinite catalyze the electro-oxidation of carbon monoxide in alkaline solution at room temperature.

scholarly journals Phenolation of vegetable oils

2011 ◽  
Vol 76 (4) ◽  
pp. 591-606 ◽  
Author(s):  
Mihail Ionescu ◽  
Zoran Petrovic
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Double Bond ◽  
Vegetable Oils ◽  
Raw Materials ◽  
Complex Mixture ◽  
Double Bonds ◽  
Triflic Acid ◽  
Model Compounds ◽  
Phenol Alkylation

Novel bio-based compounds containing phenols suitable for the synthesis of polyurethanes were prepared. The direct alkylation of phenols with different vegetable oils in the presence of superacids (HBF4, triflic acid) as catalysts was studied. The reaction kinetics was followed by monitoring the decrease of the double bond content (iodine value) with time. In order to understand the mechanism of the reaction, phenol was alkylated with model compounds. The model compounds containing one internal double bond were 9-octadecene and methyl oleate and those with three double bonds were triolein and high oleic safflower oil (82% oleic acid). It was shown that the best structures for phenol alkylation are fatty acids with only one double bond (oleic acid). Fatty acids with two double bonds (linoleic acid) and three double bonds (linolenic acid) lead to polymerized oils by a Diels Alder reaction, and to a lesser extent to phenol alkylated products. The reaction product of direct alkylation of phenol with vegetable oils is a complex mixture of phenol alkylated with polymerized oil (30-60%), phenyl esters formed by transesterification of phenol with triglyceride ester bonds (<10 %) and unreacted oil (30%). The phenolated vegetable oils are new aromatic-aliphatic bio-based raw materials suitable for the preparation of polyols (by propoxylation, ethoxylation, Mannich reactions) for the preparation of polyurethanes, as intermediates for phenolic resins or as bio-based antioxidants.

scholarly journals Exploring the In Vivo Existence Forms (23 Original Constituents and 147 Metabolites) of Astragali Radix Total Flavonoids and Their Distributions in Rats Using HPLC-DAD-ESI-IT-TOF-MSn

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5560
Author(s):  
Li-Jia Liu ◽  
Hong-Fu Li ◽  
Feng Xu ◽  
Hong-Yan Wang ◽  
Yi-Fan Zhang ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Total Flavonoids ◽  
Pharmacological Effects ◽  
Bioactive Components ◽  
Rat Urine ◽  
Astragali Radix ◽  
Material Basis ◽  
New Compounds ◽  
New Metabolites

Astragali Radix total flavonoids (ARTF) is one of the main bioactive components of Astragali Radix (AR), and has many pharmacological effects. However, its metabolism and effective forms remains unclear. The HPLC-DAD-ESI-IT-TOF-MSn technique was used to screen and tentatively identify the in vivo original constituents and metabolites of ARTF and to clarify their distribution in rats after oral administration. In addition, modern chromatographic methods were used to isolate the main metabolites from rat urine and NMR spectroscopy was used to elucidate their structures. As a result, 170 compounds (23 original constituents and 147 metabolites) were tentatively identified as forms existing in vivo, 13 of which have the same pharmacological effect with ARTF. Among 170 compounds, three were newly detected original constituents in vivo and 89 were new metabolites of ARTF, from which 12 metabolites were regarded as new compounds. Nineteen original constituents and 65 metabolites were detected in 10 organs. Four metabolites were isolated and identified from rat urine, including a new compound (calycoisn-3’-O-glucuronide methyl ester), a firstly-isolated metabolite (astraisoflavan-7-O-glucoside-2’-O-glucuronide), and two known metabolites (daidzein-7-O-sulfate and calycosin-3’-O-glucuronide). The original constituents and metabolites existing in vivo may be material basis for ARTF efficacy, and these findings are helpful for further clarifying the effective forms of ARTF.

scholarly journals Functionality changes of natural antioxidants during food processing and storage

2004 ◽  
Vol 22 (SI - Chem. Reactions in Foods V) ◽  
pp. S80-S83 ◽  
Author(s):  
J. Pokorný ◽  
Š. Schmidt ◽  
H. T T Nguyen
Keyword(s):  
Antioxidant Activity ◽  
Free Radicals ◽  
Food Processing ◽  
Degradation Products ◽  
Raw Materials ◽  
Natural Antioxidants ◽  
Phenolic Antioxidants ◽  
Oxidation Reactions ◽  
Processing And Storage ◽  
And Storage

Food raw materials and products contain inhibitors of oxidation reactions, both in the lipidic phase and the aqueous phase. The most important inhibitors are phenolic antioxidants. During food processing and storage, concentrations of antioxidants in the two phases reach an equilibrium. Phenolics react with lipidic free radicals, being converted into antioxidant free radicals, quinones, polymers and copolymers. Some degradation products possess an antioxidant activity, too. The relative antioxidant activity decreases with decreasing concentration of oxygen in the system and with increasing temperature. Antioxidants are more rapidly decomposed in surface layers. Health aspects of antioxidant degradation products are often neglected as the safety of antioxidant degradation products is mostly unknown.

Studies in Mass Spectrometry. VII. Triterpenoids: Ifflaionic Acid

1963 ◽  
Vol 16 (4) ◽  
pp. 683 ◽  
Author(s):  
JS Shannon
Keyword(s):  
Mass Spectrometry ◽  
Methyl Ester ◽  
Functional Groups ◽  
Mass Spectra ◽  
Molecular Ions ◽  
Keto Group ◽  
Chemical Derivatives ◽  
Pentacyclic Triterpenoid

The mass spectra of the methyl ester of the new unsaturated pentacyclic triterpenoid ifflaionic acid (urs-12-en-3-on-30-oic acid) and some of its chemical derivatives are presented. These may be used to assign position C-20 to the carbomethoxy and C-3 or C-7 to the keto group. Mechanistic proposals for, and the effect of functional groups on, the main fragmentation of the molecular ions (cleavage through ring C) are discussed.

THE REACTION OF CHLORAL WITH HALOBENZENES AND WITH 2,4-DICHLOROPHENOL: SYNTHESIS OF HALOGENATED ETHYLBENZENES AND OF α-METHOXYPHENYLACETIC ACIDS

1966 ◽  
Vol 44 (5) ◽  
pp. 575-582 ◽  
Author(s):  
Wilkins Reeve ◽  
John P. Mutchler ◽  
Charles L. Liotta
Keyword(s):  
Carbon Disulfide ◽  
Potassium Hydroxide ◽  
Methoxy Group ◽  
Methylene Chloride ◽  
Aluminium Chloride ◽  
Molar Ratio ◽  
Side Chain ◽  
New Compounds ◽  
Hydroxy Groups

The Friedel–Crafts reaction of chloral with aromatic compounds to form aryltrichloromethylcarbinols is reviewed. The molar ratio of aluminium chloride to chloral is critical and varies from 0.15 to 2.0 depending on the solvent, steric considerations, and the reactivity of the aromatic ring. The reaction has been used to prepare several new compounds with carbon disulfide or excess aromatic compound as the solvent. From 2,4-dichlorophenol, an o-hydroxy-α-trichloromethylbenzyl alcohol is obtained. Both the phenolic and side-chain hydroxy groups of this alcohol are methylated with equal ease by dimethyl sulfate.It has now been found that changing the solvent from carbon disulfide to methylene chloride results in the hydroxy group of the initial carbinol also being replaced by chlorine. This role of the solvent in controlling the course of the reaction has not been observed previously.The trichloromethylcarbinols are converted into α-methoxy acids by treatment with methanolic potassium hydroxide. Sodium in liquid ammonia removes the α-methoxy group, as well as the halogens, from 3,5-dichloro-α,2-dimethoxyphenylacetic acid.

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