The alkaloids of Echium plantagineum L

1956 ◽  
Vol 9 (4) ◽  
pp. 512 ◽  
Author(s):  
CCJ Culvenor
Keyword(s):  
Carboxylic Acid ◽  
Hydroxyl Group ◽  
Angelic Acid

Two new alkaloids, echiumine, C20H31O6N, and echimidine, C20H31O7N, have been isolated from Echium plantagineum L. Both have a retronecine nucleus esterified on the 7-hydroxyl group with angelic acid. The main esterifying acid of echiumine is trachelanthic acid and of echimidine is 2-methyl-2,3,4-trihydroxypentane-3-carboxylic acid, identical with the esterifying acid of heliosupine. The structure of heliosupine, a diastereoisomer of echimidine, has been confirmed.

scholarly journals N-(5′-Phosphopyridoxyl)glutamic acid and N-(5′-phosphopyridoxyl)-2-oxopyrrolidine-5-carboxylic acid and their action on the apoenzyme of aspartate aminotransferase

1971 ◽  
Vol 124 (1) ◽  
pp. 99-106 ◽  
Author(s):  
R M. Khomutov ◽  
H B. F. Dixon ◽  
L V. Vdovina ◽  
M P. Kirpichnikov ◽  
Y V. Morozov ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Glutamic Acid ◽  
Aspartate Aminotransferase ◽  
Fluorescence Spectra ◽  
Pyridoxal Phosphate ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Compound I ◽  
Compound Ii

1. N-(5′-Phosphopyridoxyl)-l-glutamic acid (P-Pxy-Glu, compound I) is readily converted at pH3 into a substance (P-Pxy-Glp, compound II) characterized as N-(5′-phosphopyridoxyl)-2-oxopyrrolidine-5-carboxylic acid. 2. The u.v., i.r. and fluorescence spectra of P-Pxy-Glu and P-Pxy-Glp have been determined; from the u.v. spectra their pK values have been found and compared. 3. The apoenzyme of aspartate aminotransferase is rapidly and irreversibly inactivated by P-Pxy-Glu, but is inactivated more slowly by P-Pxy-Glp. The complex with P-Pxy-Glp is stable enough to be isolated, but it is slowly reactivated in the presence of excess of pyridoxal phosphate. 4. The u.v. spectrum of the complex of apoenzyme and P-Pxy-Glp suggests that it contains a hydrogen bond between the phenolic hydroxyl group and the pyrrolidone nitrogen; this specifies the conformation of most of the molecule of P-Pxy-Glp. This conformation is similar to that previously postulated for the enzyme–glutamate complex except for the side chain of glutamate. Hence both the affinity of P-Pxy-Glp for the apoenzyme and the fact that it is more easily removed than P-Pxy-Glu are explicable.

scholarly journals Febuxostat ethanol monosolvate

2020 ◽  
Vol 76 (6) ◽  
pp. 816-819
Author(s):  
Thomas Gelbrich ◽  
Volker Kahlenberg ◽  
Verena Adamer ◽  
Sven Nerdinger ◽  
Ulrich J. Griesser
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Title Compound ◽  
Chain Structure ◽  
Hydroxyl Group ◽  
Carboxyl Group ◽  
Hydrogen Bond Donor ◽  
Ethanol Molecule ◽  
Hydrogen Bonded

The title compound, 2-(3-cyano-4-isobutoxyphenyl)-4-methyl-1,3-thiazole-5-carboxylic acid ethanol monosolvate, C16H16N2O3S·C2H6O, (I), displays intermolecular O—H...O and O—H...N bonds in which the carboxyl group of the febuxostat molecule and the hydroxyl group of the ethanol molecule serve as hydrogen-bond donor sites. These interactions result in a helical hydrogen-bonded chain structure. The title structure is isostructural with a previously reported methanol analogue.

Enhanced adsorption capacity of polypyrrole/TiO2 composite modified by carboxylic acid with hydroxyl group

RSC Advances ◽  
2016 ◽  
Vol 6 (48) ◽  
pp. 42572-42580 ◽  
Author(s):  
Jiangtao Feng ◽  
Jie Chen ◽  
Ning Wang ◽  
Jingjing Li ◽  
Jinwen Shi ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Adsorption Capacity ◽  
Hydroxyl Group ◽  
Enhanced Adsorption

Carboxylic acid with hydroxyl group enhanced the adsorption capacity of PPy/TiO2 composites.

Piptoside, a novel alkali-labile glucoside from Piptocalyx moorei Oliv.

1966 ◽  
Vol 19 (4) ◽  
pp. 683 ◽  
Author(s):  
NV Riggs ◽  
JD Stevens
Keyword(s):  
Periodate Oxidation ◽  
Aqueous Sodium Hydroxide ◽  
Carbon Chain ◽  
Hydroxyl Group ◽  
Reaction Products ◽  
Spectroscopic Information ◽  
Michael Type Addition ◽  
Angelic Acid ◽  
Methyl Derivatives ◽  
Fission Yields

The β-D-glucopyranoside, piptoside, is cleaved by hot dilute acid to glucose and aglucone, the latter being partly converted with loss of carbon dioxide into a furan keto acid. Glucose is also liberated by the action of bases. With sodium methoxide, the aglucone residue rearranges to a pair of isomeric dilactone esters, whereas, with aqueous sodium hydroxide, fission of the carbon chain to (-)-2,3-dimethylsuccinic acid occurs; with alkaline hydrogen peroxide, oxidative chain fission yields a buty- rolactone-4,4-dicarboxylic acid. The structure and partial stereochemistry of each of the products follows from chemical and spectroscopic information. These results, as also those of periodate oxidation, are accounted for by formulation of the aglucone as a system of two spiro-joined γ-lactone rings, one of which is fused to a ketofuranose ring. The reaction products are analogous to well-known products from simple sugars. The hemiacetal hydroxyl group of the ketofuranose remains free in the glucoside and is unusally acidic towards diazomethane, the methyl derivatives not being alkalilabile.��� Biogenesis of the aglucone may follow Michael-type addition of a 3-dehydrohexonic acid (of unknown stereochemistry) to angelic acid, or some variant.

Specific conjugate addition to α,β-acetylenic ketones

2011 ◽  
Vol 83 (3) ◽  
pp. 587-596 ◽  
Author(s):  
Myagmarsuren Sengee ◽  
Leiv K. Sydnes
Keyword(s):  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Sodium Hydroxide ◽  
Good Yield ◽  
Conjugate Addition ◽  
Hydroxyl Group ◽  
Terminal Alkyne ◽  
Reactive Group ◽  
Secondary Reactions ◽  
Nucleophilic Reagents

A variety of α,β-unsaturated acetylenic ketones, prepared in good yields from 3,3,4,4-tetraethoxybut-1-yne (TEB), have been reacted with selected mono- and bis-nucleophilic reagents. The mononucleophiles react in a Michael fashion and give in most cases the corresponding α,β-unsaturated alkenones in good yield. Many of the alkenes are formed as single stereoisomers, but the configuration depends on the nature of the nucleophile. If hydrogen bonds can be formed, the Z geometry is preferred, otherwise the E geometry is completely predominant. Experiments have also uncovered that α,β-unsaturated acetylenic ketones with a gem-diethoxy moiety in the α' position decompose when reacted with sodium hydroxide in aqueous tetrahydrofuran (THF); the carbonyl group is attacked and a carboxylic acid and a terminal alkyne are formed. If the nucleophiles contain two nucleophilic centers or if the α,β-unsaturated acetylenic ketones contain an additional reactive group, such as a hydroxyl group or an acyloxy moiety, useful secondary reactions may occur. By taking advantage of such secondary transformations, two completely regioselective syntheses of furans have so far been developed.

Potential antidepressants and inhibitors of 5-hydroxytryptamine and noradrenaline re-uptake in the brain: N,N-Dimethyl-(arylthio)thenylamines and N,N-dimethyl-2-(thienylthio)benzylamines

1991 ◽  
Vol 56 (2) ◽  
pp. 449-458 ◽  
Author(s):  
Karel Šindelář ◽  
Josef Pomykáček ◽  
Martin Valchář ◽  
Karel Dobrovský ◽  
Jiřina Metyšová ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Benzoic Acid ◽  
Potent Inhibitor ◽  
Brain Structures ◽  
Similar Type ◽  
Hydroxyl Group ◽  
Acid Chlorides ◽  
Selective Inhibitors ◽  
The Brain

3-(3-Methoxyphenylthio)thiophene-2-carboxylic acid (IV) and 2-(3-methoxyphenylthio)thiophene-3-carboxylic acid (VII) were transformed via acid chlorides and dimethylamides to the amines V and VIII which were demethylated to the phenolic amines VI and IX. N,N-Dimethyl-4-bromothiophene-3-carboxamide (XI) was reacted with 3-methoxythiophenol and the amide XII was reduced and demethylated to the amine XIV. 2-(2-Thienylthio)benzoic acid (XVa) and 2-(5-bromo-2-thienylthio)benzoic acid (XVb) were transformed via the isolated acid chlorides and N,N-dimethylamides to the amines XVIIIa and XVIIIb. The amines VI, IX, and XIV are thiophene isosters of moxifetin, the potent inhibitor of 5-hydroxytryptamine re-uptake in the brain structures. Out of the compounds prepared, only the methoxy amine VIII (VUFB-17697) showed a similar type of activity. The intermediate V, the phenolic amine VI, and the hydroxyl group lacking amine XVIIIa are selective inhibitors of noradrenaline re-uptake in the brain.

scholarly journals Neurosteroids: Structure-Uptake Relationships and Computational Modeling of Organic Anion Transporting Polypeptides (OATP)1A2

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5662
Author(s):  
Santosh Kumar Adla ◽  
Arun Kumar Tonduru ◽  
Thales Kronenberger ◽  
Eva Kudova ◽  
Antti Poso ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Organic Anion ◽  
Homology Model ◽  
Amide Bond ◽  
Hydroxyl Group ◽  
Breast Adenocarcinoma ◽  
Binding Modes ◽  
Brain Drug Delivery ◽  
Carboxylic Groups ◽  
Dynamics Simulations

In this study, we investigated the delivery of synthetic neurosteroids into MCF-7 human breast adenocarcinoma cells via Organic Anionic Transporting Polypeptides (OATPs) (pH 7.4 and 5.5) to identify the structural components required for OATP-mediated cellular uptake and to get insight into brain drug delivery. Then, we identified structure-uptake relationships using in-house developed OATP1A2 homology model to predict binding sites and modes for the ligands. These binding modes were studied by molecular dynamics simulations to rationalize the experimental results. Our results show that carboxylic acid needs to be at least at 3 carbon-carbon bonds distance from amide bond at the C-3 position of the androstane skeleton and have an amino group to avoid efflux transport. Replacement of hydroxyl group at C-3 with any of the 3, 4, and 5-carbon chained terminal carboxylic groups improved the affinity. We attribute this to polar interactions between carboxylic acid and side-chains of Lys33 and Arg556. The additional amine group showed interactions with Glu172 and Glu200. Based on transporter capacities and efficacies, it could be speculated that the functionalization of acetyl group at the C-17 position of the steroidal skeleton might be explored further to enable OAT1A2-mediated delivery of neurosteroids into the cells and also across the blood-brain barrier.

scholarly journals High molecular weight of polylactic acid (PLA): A Review on the effect of initiator

2021 ◽  
Vol 4 (1) ◽  
pp. 15
Author(s):  
Norliza Ibrahim ◽  
Anis Nuranisya Shamsuddin
Keyword(s):  
Molecular Weight ◽  
Carboxylic Acid ◽  
High Molecular Weight ◽  
Polylactic Acid ◽  
Ring Opening ◽  
Functional Group ◽  
Nitrogen Atmosphere ◽  
The Other ◽  
Hydroxyl Group ◽  
Aliphatic Polyester

This article reviews various initiator used to synthesize high molecular weight (MW >10,000 g/mol) of polylactic acid (PLA) through ring-opening polymerisation (ROP) of lactide. ROP has been chosen as the best method in producing PLA. On the other hand, stannous octoate (Sn(Oct)2) has been reported as the best catalyst used for ROP method. Many researchers have studied that polymerisation rate with the presence of only Sn(Oct)2 as catalyst is slow compared to polymerisation of lactide with the presence of initiator. An initiator is also favourable in producing high molecular weight of PLA as it can initiate the synthesis of PLA. Therefore, this review focus on ROP method catalysed by Sn(Oct)2 using different solvent as initiator. Among groups of initiators being reviewed are hydroxyl, carboxylic acid, aldehyde, aliphatic polyester and organophosphorus compound. Most of the studies applied in nitrogen atmosphere with a temperature range of 125 to 200 °C, while only one study in vacuum condition. Duration of the polymerisation time is between 1 to 24 hours. Based on the review, alcohol (hydroxyl group initiator) has been reported as the best initiator to produce high molecular weight of PLA. This functional group act as co-initiator molecule that reacts with Sn(Oct)2, forming the initiating stannous alkoxide linkage. The linkage is necessary to propagate monomer addition and hence increase the MW. 

scholarly journals Anthraquinones as Potential Antibiofilm Agents Against Methicillin-Resistant Staphylococcus aureus

2021 ◽  
Vol 12 ◽  
Author(s):  
Zhi-Man Song ◽  
Jun-Liang Zhang ◽  
Kun Zhou ◽  
Lu-Ming Yue ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Carboxylic Acid ◽  
Great Influence ◽  
Hydroxyl Group ◽  
Confocal Scanning Laser Microscopy ◽  
Microscopy Imaging ◽  
Methicillin Resistant ◽  
Treatment Groups ◽  
Relationship Analysis ◽  
Antibiofilm Agents

Biofilms formed by methicillin-resistant Staphylococcus aureus (MRSA) are one of the contributing factors to recurrent nosocomial infection in humans. There is currently no specific treatment targeting on biofilms in clinical trials approved by FDA, and antibiotics remain the primary therapeutic strategy. In this study, two anthraquinone compounds isolated from a rare actinobacterial strain Kitasatospora albolonga R62, 3,8-dihydroxy-l-methylanthraquinon-2-carboxylic acid (1) and 3,6,8-trihydroxy-1-methylanthraquinone-2-carboxylic acid (2), together with their 10 commercial analogs 3–12 were evaluated for antibacterial and antibiofilm activities against MRSA, which led to the discovery of two potential antibiofilm anthraquinone compounds anthraquinone-2-carboxlic acid (6) and rhein (12). The structure-activity relationship analysis of these anthraquinones indicated that the hydroxyl group at the C-2 position of the anthraquinone skeleton played an important role in inhibiting biofilm formation at high concentrations, while the carboxyl group at the same C-2 position had a great influence on the antibacterial activity and biofilm eradication activity. The results of crystal violet and methyl thiazolyl tetrazolium staining assays, as well as scanning electron microscope and confocal scanning laser microscopy imaging of compounds 6 and 12 treatment groups showed that both compounds could disrupt preformed MRSA biofilms possibly by killing or dispersing biofilm cells. RNA-Seq was subsequently used for the preliminary elucidation of the mechanism of biofilm eradication, and the results showed upregulation of phosphate transport-related genes in the overlapping differentially expressed genes of both compound treatment groups. Herein, we propose that anthraquinone compounds 6 and 12 could be considered promising candidates for the development of antibiofilm agents.

Sign in / Sign up

Export Citation Format

Share Document