scholarly journals New bio-amphiphilic structures of sucrose via amides linkages

2019 ◽  
Vol 10 (4) ◽  
pp. 3143-3154
Author(s):  
Salih Mahdi Salman
Keyword(s):  
Chemical Structure ◽  
13C Nmr Spectroscopy ◽  
Alkyl Halides ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Staudinger Reaction ◽  
Target Structure ◽  
Leaving Group ◽  
Derivatives Of ◽  
Resolution Mass

A series of four new derivatives of sucrose have been synthesized using the straightforward methodology in order to give a mono substituted analogs of sucrose at C-6’ of fructose moiety. The synthesis was started from the reaction of sucrose with tert-butylchlorodiphenylsilane, which is able to react with an only less steric hindrance hydroxyl group at C-6’ due to its bulky structure. The other hydroxyl groups were acetylated by the reaction with acetic anhydride in pyridine. Then free the hydroxyl group at C-6’ again by the treatment with t-butylammonium fluoride in THF. The later was activated by conversion to a good leaving group via tosylation, followed by functionalized via azidation to give the precursor of the target series hepta-O-acetyl-6’-azido- sucrose. The precursor was coupled with four alkyl halides (C12, C8-4, C14, C10-8) via Staudinger reaction to produced the target structure after deacetylating. The purity and chemical structure of the synthesized compound was confirmed by CHN elemental analysis, high-resolution mass and 1H, 13C NMR spectroscopy. 

scholarly journals Reactivity of Aliphatic and Phenolic Hydroxyl Groups in Kraft Lignin towards 4,4′ MDI

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2131
Author(s):  
Leonardo Dalseno Antonino ◽  
Júlia Rocha Gouveia ◽  
Rogério Ramos de Sousa Júnior ◽  
Guilherme Elias Saltarelli Garcia ◽  
Luara Carneiro Gobbo ◽  
...  
Keyword(s):  
Experimental Work ◽  
Chemical Structure ◽  
31P Nmr ◽  
Kraft Lignin ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Diphenylmethane Diisocyanate ◽  
Complex Chemical ◽  
Heterogeneous Reactivity ◽  
Phenolic Hydroxyl Groups

Several efforts have been dedicated to the development of lignin-based polyurethanes (PU) in recent years. The low and heterogeneous reactivity of lignin hydroxyl groups towards diisocyanates, arising from their highly complex chemical structure, limits the application of this biopolymer in PU synthesis. Besides the well-known differences in the reactivity of aliphatic and aromatic hydroxyl groups, experimental work in which the reactivity of both types of hydroxyl, especially the aromatic ones present in syringyl (S-unit), guaiacyl (G-unit), and p-hydroxyphenyl (H-unit) building units are considered and compared, is still lacking in the literature. In this work, the hydroxyl reactivity of two kraft lignin grades towards 4,4′-diphenylmethane diisocyanate (MDI) was investigated. 31P NMR allowed the monitoring of the reactivity of each hydroxyl group in the lignin structure. FTIR spectra revealed the evolution of peaks related to hydroxyl consumption and urethane formation. These results might support new PU developments, including the use of unmodified lignin and the synthesis of MDI-functionalized biopolymers or prepolymers.

scholarly journals SYNTHESIS OF 1,2;3,4-DI-O-ISOPROPYLIDENE-6- O-[4-(1H-AZOL-1-YLMETHYL) PHENYL]- ¯-D-GALACTOPYRANOSE AND 1,2,3,4-TETRA-O-ACETYL-6- O-[4-(1H-AZOL-1- YLMETHYL)PHENYL]-¯-D-GLUCOPYRANOSE

2017 ◽  
Vol 17 (5) ◽  
pp. 122-128
Author(s):  
Z.P. Belousova ◽  
P.P. Purygin ◽  
A.P. Tyurin
Keyword(s):  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Secondary Hydroxyl ◽  
Primary Hydroxyl ◽  
Derivatives Of

Derivatives of D-galactose and D-glucose substituted for the primary hydroxyl group, which contain an aglycone azolylmethylphenyl fragments (for imidazole, 1,2,4-triazole, benzimidazole and benzotriazole) has been synthesized. Toprotect the secondary hydroxyl groups of monosaccharides acetyl and isopropylidene groups were used.

scholarly journals FACILE SYNTHESIS OF PHENOLIC DERIVATIVES, CONTAINIG LACTAMOMETHYL SUBSTITUENTS

2019 ◽  
Vol 62 (10) ◽  
pp. 40-48
Author(s):  
Stepan V. Vorobyev ◽  
Olga V. Primerova ◽  
Ludmila V. Ivanova ◽  
Vladimir D. Ryabov ◽  
Vladimir N. Koshelev
Keyword(s):  
13C Nmr Spectroscopy ◽  
Hydroxyl Group ◽  
1H And 13C Nmr ◽  
Mineral Oils ◽  
Ft Ir ◽  
Low Toxicity ◽  
Phenolic Derivatives ◽  
Intramolecular Hydrogen ◽  
Derivatives Of ◽  
Low Solubility

In this work we suggest the new method for the synthesis of novel phenolic derivatives, containing lactamomethyl substituents. Oxidation processes of fuels and mineral oils lead to losing of their properties, so the search for new and effective inhibitors of these processes is very actuel. We suggest a facile system for lactamomethylation reaction. Heating in the water some of phenols (resorcinol, phloroglucinol, methylphloroglucinol, pyrogallol, salicylic, resorcilic and gallic acids) with N-hydroxymethyl derivatives of pyrrolidone, valerolactam, caprolactam and 4-phenylpyrrolidone in the presence of catalytic amounts of acetic acid led to the target compounds with nearly quantitative yields. Time of the reaction ranged 1.5-2 h. As the products have low solubility in water, in contrast with the reagents, filtration was used for their extraction. The advantages of this method are also that it is eco-friendly because of small amounts of wastes and low toxicity of the reagents and solvent, and cheapness of starting compounds. Eighteen novel compounds were obtained. The composition of target substances was determined by elemental analysis whereas the structures of the synthesized compounds were confirmed by FT-IR spectroscopy methods, 1H- and 13C-NMR spectroscopy. In IR spectra there are carbonyl group stretching vibrations peaks in lower frequencies (about 1600 cm-1) than expected due to the formation of inter- and intramolecular hydrogen bonds between this group and phenolic hydroxyl group.

scholarly journals Antioxidant activity of some coumarins / Antioxidačná activita niektorých kumarínov

2015 ◽  
Vol 62 (s9) ◽  
pp. 41-45 ◽  
Author(s):  
F. Šeršeň ◽  
M. Lácová
Keyword(s):  
Antioxidant Activity ◽  
Acetic Acid ◽  
Superoxide Anion ◽  
The Other ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Coumarin Derivatives ◽  
Antioxidant Effectiveness ◽  
Derivatives Of ◽  
Superoxide Anion Radicals

AbstractNineteen derivatives of coumarin were tested on the scavenging of 2,2-diphenyl-1-picrylhydrazyl, hydroxyl and superoxide anion radicals. It was found that antioxidant activity exhibits only such coumarins that contain hydroxyl groups. The derivatives without hydroxyl group showed very low antioxidant effectiveness or they were ineffective. On the other hand, the greatest antioxidant effectiveness was exhibited by coumarin derivatives that contained hydroxyl groups in 6 or 8 position, whereas the effectiveness of derivatives with one hydroxyl group in 4, 5 or 7 position was very low. Based on scavenging of the above-mentioned radicals, it was found that the most effective scavengers were 7,8-dihydroxy-4-methylcoumarin (i.e. compound that contains two hydroxyl groups in 7 and 8 positions), (7,8-dihydroxy-2-oxo-2H-chromen-4-yl)acetic acid (this compound contains in addition to two hydroxyl groups in 7 and 8 positions also one hydroxyl group in the acidic residue), esculetin (6,7-dihydroxycoumarin) and 6,7-dihydroxy-4-methylcoumarin.

Glucuronidierung von Hydroxy-testosteron- und Hydroxy-androstendion-Verbindungen durch die mikrosomale UDP-Glucuronyl-Transferase der Rattenleber / Glucuronidation of Hydroxy-compounds of Testosterone and Androstenedione by the Microsomal UDP Glucuronyl Transferase of Rat Liver

1972 ◽  
Vol 27 (1) ◽  
pp. 49-52
Author(s):  
Herbert Schriefers ◽  
Rüdiger Ghraf ◽  
Birgit Lehnen
Keyword(s):  
High Specificity ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Testosterone Metabolism ◽  
Glucuronyl Transferase ◽  
Hydroxy Compounds ◽  
Derivatives Of ◽  
Special Case ◽  
Free Steroid ◽  
Very High

The microsomal UDP glucuronyl transferase exhibits activities against hydroxy derivatives of androstenedione (hydroxyl groups in the positions 2β, 6β or 16α) between 5% and 27% of the extent shown against testosterone. 2β-, 6β· and 16α-hydroxyl groups are much less efficient in accepting the glucuronic acid than the 17β-hydroxyl group.However, the acceptor function of the 17β-hydroxyl group is restricted by other hydroxy substituents in the testosterone molecule to an increasing extent represented by the following sequence: 2α, 6β, 6α, 16α, and 7α. A special case is represented by 2β-hydroxy-testosterone. The transferase displays a higher activity against this compound than against testosterone.Apparently the transferase approaches the steroid molecule from the α-side (with the β-side there is also contact at the C-6 atom) requires the 17β-hydroxyl group and the 3-oxo-4-ene system to display full activity.Thus the very high specificity of the transferase for testosterone explains the selective action of this enzyme on testosterone metabolism in the liver. This action is expressed by the fact, that in liver perfusates the percentage of testosterone in the glucuronide fraction is twice as large as the percentage of testosterone in the free steroid fraction.

The Advances in Research of Complexes of Chitosan and its Derivatives

2013 ◽  
Vol 456 ◽  
pp. 461-466
Author(s):  
Feng Ma ◽  
Feng Yan Lu
Keyword(s):  
Metal Ions ◽  
Chemical Structure ◽  
Antibacterial Effect ◽  
Degradation Products ◽  
Metal Recovery ◽  
Hydroxyl Groups ◽  
Adsorption Ability ◽  
Chitosan Derivatives ◽  
Functional Derivatives ◽  
Derivatives Of

Chitosan is a partially deacetylated polymer of acetyl glucosamine obtained byalkaline deacetylation of chitin. It displays interesting properties such as biocompatibility, biodegradability as its degradation products are non-toxic, non-immunogenic, and non-carcinogenic. It can be modified chemically for the presence of amino and hydroxyl groups to prepare functional derivatives of chitosan. Chitosan and its derivatives have good adsorption ability for metal ions due to theirs high percentage of nitrogen, amino and hydroxyl groups on their chemical structure act as chelation sites for metal ions. This article reviews the developments of the studies on coordination between chitosan, derivatives and metal ions, as well as the applications of chitosan-based complexes in many fields such as antibacterial effect, the catalysts, metal recovery and detection, and agriculture.

scholarly journals Identification of Novel Gymnodimines and Spirolides from the Marine Dinoflagellate Alexandrium ostenfeldii

Marine Drugs ◽  
2018 ◽  
Vol 16 (11) ◽  
pp. 446 ◽  
Author(s):  
Christian Zurhelle ◽  
Joyce Nieva ◽  
Urban Tillmann ◽  
Tilmann Harder ◽  
Bernd Krock ◽  
...  
Keyword(s):  
Chemical Diversity ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Alexandrium Ostenfeldii ◽  
Exocyclic Methylene ◽  
Polyketide Chain ◽  
Marine Dinoflagellates ◽  
Toxin Class ◽  
Derivatives Of

Cyclic imine toxins are neurotoxic, macrocyclic compounds produced by marine dinoflagellates. Mass spectrometric screenings of extracts from natural plankton assemblages revealed a high chemical diversity among this toxin class, yet only few toxins are structurally known. Here we report the structural characterization of four novel cyclic-imine toxins (two gymnodimines (GYMs) and two spirolides (SPXs)) from cultures of Alexandrium ostenfeldii. A GYM with m/z 510 (1) was identified as 16-desmethylGYM D. A GYM with m/z 526 was identified as the hydroxylated degradation product of (1) with an exocyclic methylene at C-17 and an allylic hydroxyl group at C-18. This compound was named GYM E (2). We further identified a SPX with m/z 694 as 20-hydroxy-13,19-didesmethylSPX C (10) and a SPX with m/z 696 as 20-hydroxy-13,19-didesmethylSPX D (11). This is the first report of GYMs without a methyl group at ring D and SPXs with hydroxyl groups at position C-20. These compounds can be conceived as derivatives of the same nascent polyketide chain, supporting the hypothesis that GYMs and SPXs are produced through common biosynthetic genes. Both novel GYMs 1 and 2 were detected in significant amounts in extracts from natural plankton assemblages (1: 447 pg; 2: 1250 pg; 11: 40 pg per mL filtered seawater respectively).

Selective Protection Strategies in the Synthesis of TRIS-Fatty Ester Derivatives

2002 ◽  
Vol 55 (10) ◽  
pp. 629 ◽  
Author(s):  
R. Adhikari ◽  
C. L. Francis ◽  
G. W. Simpson ◽  
Q. Yang
Keyword(s):  
Fatty Ester ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Selective Protection ◽  
Palmitoyl Chloride ◽  
Protection Strategies ◽  
Mild Hydrolysis ◽  
Derivatives Of ◽  
Trimethyl Orthoformate ◽  
Acyl Derivatives

A methodology for the selective synthesis of lipophilic acyl derivatives of the glycinamido triol (1) with either one, two, or three fatty ester groups has been established. Peracylation of (1), with palmitoyl chloride gave the triacylated derivative. Conversion of (1) into the acetonide, followed by acylation with either palmitoyl chloride or lauroyl chloride, and acetal hydrolysis provided the monoacylated derivatives. Treatment of (1) with trimethyl orthoacetate gave the orthoacetate derivative. Mild hydrolysis provided the monoacetate/diol. Acylation of the two hydroxyl groups with palmitoyl chloride gave the dipalmitate/acetate. Selective cleavage of the acetate group afforded the dipalmitate of (1). Analogous chemistry with trimethyl orthoformate provided the same dipalmitate via the orthoformate, monoformate/diol, and dipalmitate/formate. A more robust synthesis of the dipalmitate was achieved by converting the hydroxyl group of the acetonide of (1) into a tert-butyldiphenylsilyl ether, followed by acetal hydrolysis, palmitoylation of the liberated hydroxyl groups, and desilylation.

Derivatives of 2-Mercaptobenzothiazole and Dimethyldithiocarbamic Acid as Vulcanization Accelerators

1959 ◽  
Vol 32 (4) ◽  
pp. 983-991 ◽  
Author(s):  
M. S. Fel'dshteĭn ◽  
I. I. Eĭtingon ◽  
D. M. Pevzner ◽  
N. P. Strel'nikova ◽  
B. A. Dogadkin
Keyword(s):  
Functional Groups ◽  
Chemical Structure ◽  
Practical Interest ◽  
Hydroxyl Group ◽  
Carboxyl Group ◽  
Methyl Radical ◽  
Methyl Derivative ◽  
Great Practical Interest ◽  
Analogous Functional ◽  
Derivatives Of

Abstract 1. We have synthesized and investigated as vulcanization accelerators the derivatives of 2-mercaptobenzothiazole (MBT) in which the thiol hydrogen is replaced by the nonpolar methyl radical, as well as compounds in which methyl hydrogen of the methyl derivative is replaced by various functional groups. 2. It has been shown that methyl-2-thiolbenzothiazole is not an accelerator. The replacement in this compound of one of the methyl hydrogens by a polar hydroxyl group substantially enhances the activity (see, however, editors note in the text). The substitution of hydrogen by a carboxyl group does not increase vulcanizing activity. 3. We have determined that replacement of a methyl hydrogen by an amino radical increases sharply the accelerating activity. The structure obtained as a result of this reaction, benzothiazolyl-2-thiolmethyldiethylamine (BTMA), is of great practical interest as an accelerator. 4. The accelerator BTMA in stocks of natural and SKS rubber gives vulcanizates which are substantially superior in their properties to rubbers cured with MBT, and are practically equal to vulcanizates obtained with sulfenamide accelerators—sulfenamide BT and sulfenamide Z (Santocure). 5. The accelerator BTMA is much cheaper than sulfenamide BT since its production requires much less diethylamine. 6. It has been determined that, just as in the case of 2-mercaptobenzothiazole derivatives, for the derivatives of dimethyldithiocarbamic acid containing analogous functional groups the same results are obtained for the change in activity depending upon the chemical structure of the accelerator.

Studies on biliary excretion in the rabbit II. The relationship between the chemical structure of certain natural or synthetic pentacyclic triterpenes and their icterogenic activity. Part 1: The substituents on carbon atoms 3, 17, 22 and 24

1963 ◽  
Vol 157 (969) ◽  
pp. 473-491 ◽  
Keyword(s):  
Bile Flow ◽  
Chemical Structure ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Hydroxyl Groups ◽  
Pentacyclic Triterpene ◽  
Triterpene Acid ◽  
Pentacyclic Triterpenes ◽  
Bilirubin Excretion ◽  
The Relationship

Considerable interest has been aroused by the use of the pentacyclic triterpene acid, icterogenin, in studies associated with bilirubin excretion and the genesis of icterus of the intrahepatic cholestasis type. This compound, which produces within a few hours after administration to sheep and rabbits a very marked decline in bile flow and the amount of bilirubin excreted hourly without any histological damage to the liver parenchyma visible in the ordinary light microscope, has proved to be very useful in the study of the South African ovine photosensitization disease known as 'geeldikkop’ (‘yellow thick head’). In connexion with research on this disease, a study of the relationship between the chemical structure of the pentacyclic triterpenes and their icterogenic activity is in progress. The first part of this work dealing with certain structural variations in triterpenes of the oleanane and 24-noroleanane (hedragane) series is reported in this paper. Assays are recorded of sixteen of these compounds and some of their derivatives for such activity, using a modification of the rabbit test described in the first paper of this series (Heikel, Knight, Rimington, Ritchie & Williams 1960). Four new icterogenic agents are discussed, namely: 22 β -angeloyloxyoleanolic acid, 22 β -angeloyloxyhedragolic acid, 22 β -angeloyloxy-24-hydroxyoleanolic acid and 22 β -angeloyloxy-24-oxo-oleanonic acid. The first two mentioned compounds are extremely active, their potency far surpassing that of icterogenin. Icterogenic activity of these acids appears, so far, to be based upon the presence of a β -equatorially orientated hydroxyl group at C(3) or a hydroxyl at C(24) and a 22 β -angeloyl side-chain on the triterpene molecule. Stereoisomer specificity is shown in respect of icterogenicity by these compounds since the epimers of two of these substances carrying α -axially orientated hydroxyls at C(3) have been shown to have no such effect on bile flow or bilirubin excretion. Removal of the angelic acid side-chain, substitution of the hydroxyl groups or replacement of these with a ketone function, is followed by loss of activity.

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