scholarly journals The investigations of bioactive copper(II) complexes with reduced low-molar dextran

2008 ◽  
Vol 22 (2-3) ◽  
pp. 177-185 ◽  
Author(s):  
Milorad Cakić ◽  
Žarko Mitić ◽  
Goran S. Nikolić ◽  
Ljubomir Ilić ◽  
Goran M. Nikolić
Keyword(s):  
Fourier Transform ◽  
Complex Formation ◽  
Room Temperature ◽  
Molar Mass ◽  
Reaction Conditions ◽  
Average Molar Mass ◽  
Square Planar ◽  
Physicochemical Methods ◽  
Fourier Transform Ir ◽  
Aqueous Complexes

The optimization of the reaction conditions (pH,T,t) to obtain stable copper(II) ion complexes with dextran derivatives were investigated in this paper. A complete synthesis of stable aqueous complexes can be realized with reduced low-molar polysaccharides, at an average molar mass 5000 g mol–1and pH 7.5–8. Fourier-transform IR spectra of polysaccharide dextran and its compounds with copper(II) ion, recorded at room temperature, were analyzed in order to obtain the information about the structure and the conformation of these polymer compounds. The ESR parameters of the spectra indicate the square-planar coordination of Cu(II) ion with four O atoms. Copper(II) complex formation with dextran and its derivatives were analyzed by physicochemical methods. Synthesized complexes of Cu(II) ion with reduced low-molar dextran in comparison with commercial preparations showed the considerably lower acute toxicity (LD501705).

scholarly journals Influence of the average molar mass of poly(N-vinylpyrrolidone) on the dimensions and conductivity of silver nanowires

2019 ◽  
Vol 21 (18) ◽  
pp. 9036-9043 ◽  
Author(s):  
Luisa Sonntag ◽  
Franziska Eichler ◽  
Nelli Weiß ◽  
Ludwig Bormann ◽  
Dhriti S. Ghosh ◽  
...  
Keyword(s):  
Molar Mass ◽  
Silver Nanowires ◽  
Reaction Conditions ◽  
Average Molar Mass ◽  
Ag Nanowire

Improving the performance of Ag nanowire electrodes by adjusting the reaction conditions and the molar mass of PVP.

Fourier Transform IR Spectroscopy Study of the Degradation of Pyromellitic Acid Diester

1987 ◽  
Vol 41 (3) ◽  
pp. 479-482
Author(s):  
L. A. Sanchez ◽  
A. R. Wedgewood
Keyword(s):  
Fourier Transform ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Effect Of Temperature ◽  
Vibrational Modes ◽  
Spectroscopy Study ◽  
Pyromellitic Acid ◽  
Fourier Transform Ir Spectroscopy ◽  
Ft Ir ◽  
Fourier Transform Ir

The degradation of pyromellitic acid diester (PMDE) was studied by transmission Fourier transform IR spectroscopy (FT-IR). Reaction temperatures were varied from room temperature to 280°C, and the effect of temperature upon the observed vibrational modes of PMDE was monitored and analyzed. The formation of both a cyclic and a noncyclic anhydride was observed.

scholarly journals Hydrogel Synthesis Directed Toward Tissue Engineering: Impact of Reaction Condition on Structural Parameters and Macroscopic Properties of Xerogels

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Borivoj Adnadjević ◽  
Jelena Jovanović
Keyword(s):  
Tissue Engineering ◽  
Acrylic Acid ◽  
Molar Mass ◽  
Structural Parameters ◽  
Scaling Exponent ◽  
Reaction Conditions ◽  
Average Molar Mass ◽  
Functional Relationships ◽  
Macroscopic Properties ◽  
Poly Acrylic Acid

The existence of correlation and functional relationships between reaction conditions (concentrations of crosslinker, monomer and initiator, and neutralization degree of monomer), primary structural parameters (crosslinking density of network, average molar mass between crosslinks, and distance between macromolecular chains), and macroscopic properties (equilibrium swelling degree and xerogel density) of the synthesized xerogels which are important for application in tissue engineering is investigated. The structurally different xerogels samples of poly(acrylic acid), poly(methacrylic acid), and poly(acrylic acid-g-gelatin) were synthesized by applying different methods of polymerization: crosslinking polymerization, crosslinking polymerization in high concentrated aqueous solution, and crosslinking graft polymerization. The values of primary structural parameters and macroscopic properties were determined for the synthesized xerogels samples. For all of the investigated methods of polymerization, an existence of empirical power function of the dependence of primary structural parameters and macroscopic properties on the reaction conditions was established. The scaling laws between primary structural parameters and macroscopic properties on average molar mass between crosslinks were established. It is shown that scaling exponent is independent from the type of monomer and other reaction conditions within the same polymerization method. The physicochemical model that could be used for xerogel synthesis with predetermined macroscopic properties was suggested.

Sizing process of cotton yarn by size from a copolymer of methacrylic acid and hydrolyzed potato starch

2018 ◽  
Vol 89 (17) ◽  
pp. 3457-3465 ◽  
Author(s):  
Suzana Djordjevic ◽  
Stana Kovacevic ◽  
Dragan Djordjevic ◽  
Sandra Konstantinovic
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Methacrylic Acid ◽  
Molar Mass ◽  
Breaking Strength ◽  
Potato Starch ◽  
Cotton Yarn ◽  
Textile Processing ◽  
Average Molar Mass ◽  
Commercial Medium

In this paper, the synthesis, characterization and application of a copolymer as a sizing agent obtained by the grafting of methacrylic acid on hydrolyzed potato starch were investigated. Starch hydrolysis was performed in order to reduce the average molar mass (i.e. the size of the macromolecules). Grafting of methacrylic acid on hydrolyzed potato starch was performed to obtain a product that can be effective in textile processing, for example, for sizing yarn. The grafting of the monomer has been confirmed by Fourier transform infrared spectroscopy spectra of hydrolyzed and grafted potato starch. The distribution of molar masses was determined chromatographically. The results obtained by sizing of cotton yarn with the new starch agent confirmed its higher breaking strength, elongation, abrasion resistance, reduced hairiness, better evenness, etc. Grafted hydrolyzed potato starch (almost identical to the commercial medium) exhibits better performance as a potential agent for sizing cotton yarn than ungrafted hydrolyzed starch.

Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

Naturally Occurring Organic Acid-catalyzed Facile Diastereoselective Synthesis of Biologically Active (E)-3-(arylimino)indolin-2-one Derivatives in Water at Room Temperature

2019 ◽  
Vol 23 (16) ◽  
pp. 1778-1788 ◽  
Author(s):  
Gurpreet Kaur ◽  
Arvind Singh ◽  
Kiran Bala ◽  
Mamta Devi ◽  
Anjana Kumari ◽  
...  
Keyword(s):  
Room Temperature ◽  
Biologically Active ◽  
Environmentally Benign ◽  
Diastereoselective Synthesis ◽  
Substituted Anilines ◽  
Reaction Conditions ◽  
Naturally Occurring ◽  
Acid Catalyzed ◽  
Reaction Media ◽  
Column Chromatographic

A simple, straightforward and efficient method has been developed for the synthesis of (E)-3-(arylimino)indolin-2-one derivatives and (E)-2-((4-methoxyphenyl)imino)- acenaphthylen-1(2H)-one. The synthesis of these biologically-significant scaffolds was achieved from the reactions of various substituted anilines and isatins or acenaphthaquinone, respectively, using commercially available, environmentally benign and naturally occurring organic acids such as mandelic acid or itaconic acid as catalyst in aqueous medium at room temperature. Mild reaction conditions, energy efficiency, good to excellent yields, environmentally benign conditions, easy isolation of products, no need of column chromatographic separation and the reusability of reaction media are some of the significant features of the present protocol.

A Facile, Efficient and Selective Deprotection of P - Methoxy Benzyl Ethers Using Zinc (II) Trifluoromethanesulfonate

2019 ◽  
Vol 16 (12) ◽  
pp. 955-958
Author(s):  
Reddymasu Sireesha ◽  
Reddymasu Sreenivasulu ◽  
Choragudi Chandrasekhar ◽  
Mannam Subba Rao
Keyword(s):  
Room Temperature ◽  
Protecting Groups ◽  
Side Reactions ◽  
Reaction Conditions ◽  
Acid Sensitivity ◽  
Time Period ◽  
Protective Groups ◽  
Benzyl Ethers ◽  
Last Stage ◽  
Zinc Triflate

: Deprotection is significant and conducted over mild reaction conditions, in order to restrict any more side reactions with sensitive functional groups as well as racemization or epimerization of stereo center because the protective groups are often cleaved at last stage in the synthesis. P - Methoxy benzyl (PMB) ether appears unique due to its easy introduction and removal than the other benzyl ether protecting groups. A facile, efficient and highly selective cleavage of P - methoxy benzyl ethers was reported by using 20 mole% Zinc (II) Trifluoromethanesulfonate at room temperature in acetonitrile solvent over 15-120 min. time period. To study the generality of this methodology, several PMB ethers were prepared from a variety of substrates having different protecting groups and subjected to deprotection of PMB ethers using Zn(OTf)2 in acetonitrile. In this methodology, zinc triflate cleaves only PMB ethers without affecting acid sensitivity, base sensitivity and also chiral epoxide groups.

One-pot Synthesis of Pyrazolone Sulfones by Iodine-catalyzed Sulfenylation of Pyrazolones with Aryl Sulfonyl Hydrazides Followed by Oxidation in Water

2018 ◽  
Vol 15 (3) ◽  
pp. 380-387
Author(s):  
Xia Zhao ◽  
Xiaoyu Lu ◽  
Lipeng Zhang ◽  
Tianjiao Li ◽  
Kui Lu
Keyword(s):  
Double Bond ◽  
Efficient Method ◽  
Room Temperature ◽  
Sulfonyl Chloride ◽  
Antibacterial Activities ◽  
Oxidation Reactions ◽  
Reaction Conditions ◽  
One Pot ◽  
X Ray ◽  
Amide Form

Aim and Objective: Pyrazolone sulfones have been reported to exhibit herbicidal and antibacterial activities. In spite of their good bioactivities, only a few methods have been developed to prepare pyrazolone sulfones. However, the substrate scope of these methods is limited. Moreover, the direct sulfonylation of pyrazolone by aryl sulfonyl chloride failed to give pyrazolone sulfones. Thus, developing a more efficient method to synthesize pyrazolone sulfones is very important. Materials and Method: Pyrazolone, aryl sulphonyl hydrazide, iodine, p-toluenesulphonic acid and water were mixed in a sealed tube, which was heated to 100°C for 12 hours. The mixture was cooled to 0°C and m-CPBA was added in batches. The mixture was allowed to stir for 30 min at room temperature. The crude product was purified by silica gel column chromatography to afford sulfuryl pyrazolone. Results: In all cases, the sulfenylation products were formed smoothly under the optimized reaction conditions, and were then oxidized to the corresponding sulfones in good yields by 3-chloroperoxybenzoic acid (m-CPBA) in water. Single crystal X-ray analysis of pyrazolone sulfone 4aa showed that the major tautomer of pyrazolone sulfones was the amide form instead of the enol form observed for pyrazolone thioethers. Moreover, the C=N double bond isomerized to form an α,β-unsaturated C=C double bond. Conclusion: An efficient method to synthesize pyrazolone thioethers by iodine-catalyzed sulfenylation of pyrazolones with aryl sulfonyl hydrazides in water was developed. Moreover, this method was employed to synthesize pyrazolone sulfones in one-pot by subsequent sulfenylation and oxidation reactions.

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