One step introduction of the activated carboxyl groups with long aliphatic arm onto hydroxyl groups containing polymers

1990 ◽  
Vol 55 (5) ◽  
pp. 1321-1325
Author(s):  
Luboš Arnold ◽  
Jiří Smrt
Keyword(s):  
Carboxyl Groups ◽  
Hydroxyl Groups ◽  
Carboxyl Group ◽  
One Step ◽  
Nitrophenyl Ester

Bis-N-hydroxysuccinimide ester of 1,10-decanediol bis-succinate (Ia) reacts with hydroxyl groups bearing polymers (Spheron, cellulose, Sephacryl) affording activated carboxyl group containing derivatives IIa. Analogous 4-nitrophenyl group bearing Spheron derivative IIb was prepared starting from bis-4-nitrophenyl ester of 1,10-decanediol bis-succinate (Ib). 3'-O-(4,4'-Dimethoxytriphenylmethyl)-2'-deoxythymidine 5'-(6-amino-1-hexyl)-phosphate (V) was developed as reagent to determine the extent of activated carboxyl groups. Attachment ranging from 3.1-7.3 μmol/g was achieved.

TERPENOIDS: V. SENEGENIN: FUNCTIONAL GROUPS AND PART STRUCTURE

1964 ◽  
Vol 42 (3) ◽  
pp. 491-501 ◽  
Author(s):  
J. J. Dugan ◽  
P. De Mayo ◽  
A. N. Starratt
Keyword(s):  
Functional Groups ◽  
Empirical Formula ◽  
Carboxyl Groups ◽  
Hydroxyl Groups ◽  
Carboxyl Group ◽  
Secondary Hydroxyl ◽  
Part Structure ◽  
Oxygen Atoms

Senegenin, the sapogenin from Polygalasenega has been shown to contain chlorine; it has the empirical formula C30OH45O6Cl. The oxygen atoms, contrary to earlier work, are contained in two carboxyl groups and two secondary hydroxyl groups. There is one isolated ethylenic linkage. The environment of the hydroxylic functions and one carboxyl group has been shown to be as in (XI).

scholarly journals Hydrogenation of benzoic acid derivatives over Pt/TiO2 under mild conditions

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Miao Guo ◽  
Xiangtao Kong ◽  
Chunzhi Li ◽  
Qihua Yang
Keyword(s):  
Electron Transfer ◽  
Benzoic Acid ◽  
High Efficiency ◽  
Carboxyl Groups ◽  
Carboxyl Group ◽  
Benzoic Acids ◽  
Catalyst Poisoning ◽  
Benzoic Acid Derivatives ◽  
Mild Conditions ◽  
Transfer Direction

AbstractHydrogenation of benzoic acid (BA) to cyclohexanecarboxylic acid (CCA) has important industrial and academic significance, however, the electron deficient aromatic ring and catalyst poisoning by carboxyl groups make BA hydrogenation a challenging transformation. Herein, we report that Pt/TiO2 is very effective for BA hydrogenation with, to our knowledge, a record TOF of 4490 h−1 at 80 °C and 50 bar H2, one order higher than previously reported results. Pt/TiO2 catalysts with electron-deficient and electron-enriched Pt sites are obtained by modifying the electron transfer direction between Pt and TiO2. Electron-deficient Pt sites interact with BA more strongly than electron-rich Pt sites, helping the dissociated H of the carboxyl group to participate in BA hydrogenation, thus enhancing its activity. The wide substrate scope, including bi- and tri-benzoic acids, further demonstrates the high efficiency of Pt/TiO2 for hydrogenation of BA derivatives.

scholarly journals Structure and Antimicrobial Properties of Monensin A and Its Derivatives: Summary of the Achievements

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Daniel Łowicki ◽  
Adam Huczyński
Keyword(s):  
Antimicrobial Activity ◽  
Lipid Membranes ◽  
Antimicrobial Properties ◽  
Biological Properties ◽  
Sodium Cation ◽  
Hydroxyl Groups ◽  
Carboxyl Group ◽  
Growth Promoter ◽  
Monensin A

In this paper structural and microbiological studies on the ionophorous antibiotic monensin A and its derivatives have been collected. Monensin A is an ionophore which selectively complexes and transports sodium cation across lipid membranes, and therefore it shows a variety of biological properties. This antibiotic is commonly used as coccidiostat and nonhormonal growth promoter. The paper focuses on both the latest and earlier achievements concerning monensin A antimicrobial activity. The activities of monensin derivatives, including modifications of hydroxyl groups and carboxyl group, are also presented.

Succinate Functionalization of Hyperbranched Polyglycerol-Coated Magnetic Nanoparticles as a Draw Solute During Forward Osmosis

2015 ◽  
Vol 15 (10) ◽  
pp. 8279-8284 ◽  
Author(s):  
Hee-Man Yang ◽  
Hye Min Choi ◽  
Sung-Chan Jang ◽  
Myeong Jin Han ◽  
Bum-Kyoung Seo ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Succinic Anhydride ◽  
Water Flux ◽  
Forward Osmosis ◽  
Feed Solution ◽  
Carboxyl Groups ◽  
Solute Leakage ◽  
One Step ◽  
Hyperbranched Polyglycerol ◽  
The One

Hyperbranched polyglycerol-coated magnetic nanoparticles (SHPG-MNPs) were functionalized with succinate groups to form a draw solute for use in a forward osmosis (FO). After the one-step synthesis of hyperbranched polyglycerol-coated magnetic nanoparticles (HPG-MNPs), the polyglycerol groups on the surfaces of the HPG-MNPs were functionalized with succinic anhydride moieties. The resulting SHPG-MNPs showed no change of size and magnetic property compared with HPGMNPs and displayed excellent dispersibility in water up to the concentration of 400 g/L. SHPG-MNPs solution showed higher osmotic pressure than that of HPG-MNPs solution due to the presence of surface carboxyl groups in SHPG-MNPs and could draw water from a feed solution across an FO membrane without any reverse draw solute leakage during FO process. Moreover, the water flux remained nearly constant over several SHPG-MNP darw solute regeneration cycles applied to the ultrafiltration (UF) process. The SHPG-MNPs demonstrate strong potential for use as a draw solute in FO processes.

scholarly journals TEMPO-Functionalized Nanoporous Au Nanocomposite for the Electrochemical Detection of H2O2

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Dongxiao Wen ◽  
Qianrui Liu ◽  
Ying Cui ◽  
Huaixia Yang ◽  
Jinming Kong
Keyword(s):  
Electrochemical Detection ◽  
Nanoporous Gold ◽  
Carboxyl Groups ◽  
Time Interval ◽  
Optimal Conditions ◽  
Sem Images ◽  
One Step ◽  
Ph Range ◽  
Synthesis Approach ◽  
Higher Sensitivity

A novel nanocomposite of nanoporous gold nanoparticles (np-AuNPs) functionalized with 2,2,6,6-tetramethyl-1-piperidinyloxy radical (TEMPO) was prepared; assembled carboxyl groups on gold nanoporous nanoparticles surface were combined with TEMPO by the “bridge” of carboxylate-zirconium-carboxylate chemistry. SEM images and UV-Vis spectroscopies of np-AuNPs indicated that a safe, sustainable, and simplified one-step dealloying synthesis approach is successful. The TEMPO-np-AuNPs exhibited a good performance for the electrochemical detection of H2O2 due to its higher number of electrochemical activity sites and surface area of 7.49 m2g-1 for load bigger amount of TEMPO radicals. The TEMPO-functionalized np-AuNPs have a broad pH range and shorter response time for H2O2 catalysis verified by the response of amperometric signal under different pH and time interval. A wide linear range with a detection limit of 7.8 × 10-7 M and a higher sensitivity of 110.403 μA mM-1cm-2 were obtained for detecting H2O2 at optimal conditions.

Scorch Control of Carboxylic Elastomers

1973 ◽  
Vol 46 (1) ◽  
pp. 78-95 ◽  
Author(s):  
V. L. Hallenbeck
Keyword(s):  
Zinc Oxide ◽  
Physical Properties ◽  
Shelf Life ◽  
Zinc Sulfide ◽  
Zinc Phosphate ◽  
Carboxyl Groups ◽  
Carboxyl Group ◽  
Phosphate Coating ◽  
Ionic Bond ◽  
Cure Temperature

Abstract Carboxylic elastomers can be cured by standard compounding recipes utilizing sulfur and zinc oxide. The zinc oxide, besides aiding the sulfur cure, also gives a secondary cure through an ionic bond with the carboxyl groups. However, because of the affinity of the zinc oxide for the carboxyl group, the stocks tend to have an excessive scorch and a short shelf life. To prevent this excessive scorch the zinc oxide must be isolated from the carboxyl group until the desired cure temperature is reached. Three materials may be used to isolate the zinc oxide : 1) zinc sulfide coated zinc oxide, 2) zinc phosphate coated zinc oxide and 3) metallic alkoxide combined with the zinc oxide. The use of any of these gives scorch control without affecting final physical properties. The amount of zinc sulfide coating, zinc phosphate coating, and metallic alkoxide varies with the type of carboxylic elastomer.

scholarly journals Structure and Properties of Oxidized Chitosan Grafted Cashmere Fiber by Amide Covalent Modification

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3812
Author(s):  
Jifeng Li ◽  
Ting Fang ◽  
Wenjing Yan ◽  
Fei Zhang ◽  
Yunhui Xu ◽  
...  
Keyword(s):  
Magic Angle Spinning ◽  
Covalent Modification ◽  
Primary Amines ◽  
Carboxyl Groups ◽  
Hydroxyl Groups ◽  
Magic Angle ◽  
Structure And Properties ◽  
Carboxyl Content ◽  
Moisture Regain ◽  
Degree Structure

In this study, oxidized chitosan grafted cashmere fibers (OCGCFs) were obtained by crosslinking the oxidized chitosan onto cashmere fibers by amide covalent modification. A novel method was developed for the selective oxidation of the C6 primary hydroxyls into carboxyl groups for chitosan. The effect of oxidization reaction parameters of HNO3/H3PO4–NaNO2 mediated oxidation system on the oxidation degree, structure, and properties of chitosan were investigated. The chemical structure of the oxidized chitosan was characterized by solid-state cross-polarization magic angle spinning carbon-13 Nuclear Magnetic Resonance (CP/MAS 13C-NMR), Fourier transform infrared spectroscopy (FT-IR), and its morphology was investigated by scanning electron microscopy (SEM). Subsequently, the effect of the oxidized chitosan grafting on OCGCF was examined, and the physical properties, moisture regain, and antibacterial activity of OCGCFs were also evaluated. The results showed that oxidation of chitosan mostly occurred at the C6 primary hydroxyl groups. Moreover, an oxidized chitosan with 43.5–56.8% carboxyl content was realized by ranging the oxidation time from 30 to 180 min. The resulting OCGCF had a C–N amido bond, formed as a result of the reaction between the primary amines in the cashmere fibers and the carboxyl groups in the oxidized chitosan through the amide reaction. The OCGCF exhibited good moisture regain and remarkable bacteriostasis against both Staphylococcus aureus and Escherichia coli bacteria with its durability.

STRUCTURE ACTIVITY RELATIONSHIPS OF DERMATAN SULFATE : EFFECT OF MOLECULAR SIZE AND CARBOXYL GROUP ESTERIFICATION ON HEPARIN C0FACT0R-II ACTIVATION

1987 ◽  
Author(s):  
J Mardiguian ◽  
M Corgier ◽  
M Jouany
Keyword(s):  
Molecular Weight ◽  
Dermatan Sulfate ◽  
Methyl Esters ◽  
Molecular Size ◽  
Carboxyl Groups ◽  
Gel Chromatography ◽  
Carboxyl Group ◽  
Heparin Cofactor Ii ◽  
High Affinity

Dermatan is a high molecular weight glycosaminoglycan which has been shown to enhance the inhibition of thrombin by heparin-cofactor II. The aim of this study was to establish the influence of the molecular size and the role of the carboxyl group on the in vitro activity of Dermatan Sulfate. Pig skin Dermatan Sulfate was fractionated according to molecular size by gel-chromatography on Ultrogel Ac 44. Each fraction was characterized by its sulfur content and by its mean molecular weight measured on a TSK - 4000 column in reference to standard heparin fractions. Methyl esters of the unfractionated Dermatan Sulfate with varying degree of esterification, where prepared via activation of the carboxyl groups with a carbodiimide and reaction with methanol. The results of this study show that the heparin - cofactor II mediated anti-thrombin activity of Dermatan Sulfate is increasing with the molecular weight and is abolished by esterification of the carboxyl groups. Moreover, it can be speculated that each fraction contains the same amount of high affinity fraction and that, like heparin, the potency of the high affinity component is increasing with the molecular weight.

Conversion of hydroxyl groups into bromo groups in carbohydrates with inversion of configuration

1981 ◽  
Vol 59 (2) ◽  
pp. 339-343 ◽  
Author(s):  
Björn Classon ◽  
Per J. Garegg ◽  
Bertil Samuelsson
Keyword(s):  
Elevated Temperature ◽  
Hydroxyl Groups ◽  
Secondary Hydroxyl ◽  
Reaction Proceeds ◽  
One Step ◽  
High Yields

A novel reagent system is described for the efficient, one-step transformation of hydroxyl groups in carbohydrates to bromodeoxy groups. The reaction proceeds with inversion of configuration. The reagent system consists of triphenylphosphine, tribromoimidazole, and imidazole in toluene at elevated temperature. The carbohydrate need not be soluble in toluene. The examples given include substitution of isolated primary and secondary hydroxyl groups in otherwise protected carbohydrates as well as disubstitution involving one primary and one secondary position in hexopyranosides. High yields are obtained in the replacement of hydroxyl by bromine in the 2-position of 3,4,6-protected methyl α-D-gluco- and -mannopyranosides.

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