Physico-chemical studies on the chelation behaviour of biologically active 2-hydroxy-1-naphthaldehyde semicarbazone (HNAS) with some lanthanons

1992 ◽  
Vol 123 (1-2) ◽  
pp. 25-33
Author(s):  
Sahadev R. K. Sharma ◽  
S. K. Sindhwani
Keyword(s):  
Biologically Active ◽  
Physico Chemical ◽  
Chemical Studies

Physico-Chemical Studies On Oligosaccharides From Procine Mucosal Heparin

1981 ◽  
Author(s):  
J Choay ◽  
J C Lormeau ◽  
M Petitou ◽  
G Torri ◽  
P Sinay
Keyword(s):  
Nitrous Acid ◽  
Additional Data ◽  
Gel Filtration ◽  
Biologically Active ◽  
Low Molecular Weight ◽  
Nmr Analysis ◽  
Structure Activity ◽  
Physico Chemical ◽  
Chemical Studies

Our recent studies have revealed that low molecular weight antithrombotic (in vivo) and anti Xa fractions and fragments can be obtained from porcine mucosal heparin (PMH) using three different processes: 1) Direct alcoholic fractionations, 2) depolymerization with nitrous acid and 3) by bacterial heparinase digestion. Ihe crude products are further fractionated by anti thrombin-III affinity chromatography and gel filtration. Physiocochemical studies were carried on each fragment employing nitrous acid degradation, colorimetric and NMR analysis. A potent antithrombotic octasaccharide (h-ULMF) is isolated from heparinase depolymerized fractions and in the NMR analysis gave some unexpected signals one of which was consistant to a 3-0-sulfated glucosamine unit (unsaturated sulfated uronic acid/N-Sulfo-Glucosamine/Iduronic acid/N- Acetyl-G1ucosamine/Glucouronic acid/N-Sulfoglucosami ne/Sulfated Idouronic acid/N-Sulfo-Glucosamine). ULMFs obtained by extraction and clemical degradation were also found to exhibit similar signals. Further degradation of h-ULMF-8 resulted in formation of smaller fragments with biological activity. Our results suggest that a smaller oligosaccharide fragment contained in the biologically active octasaccharide molecule is primarily responsible for the antithrombotic actions. Furthermore these studies provide additional data on the structure activity relationship for the antithrombotic actions of heparin, its fraction and fragments.

On the diagnostics of Adonis L. species (Ranunculaceae) of the Russian flora

2020 ◽  
pp. 3-14
Author(s):  
Aleksandr Luferov
Keyword(s):  
Raw Materials ◽  
Natural Populations ◽  
Structural Features ◽  
Biologically Active ◽  
Scientific Medicine ◽  
Diagnostic Features ◽  
Plant Raw Materials ◽  
Similar Chemical ◽  
Chemical Studies ◽  
Alternative Sources

The article provides brief information about cardiotonic, sedative, cytostatic, diuretic, and antibacterial effects of biologically active compounds of Adonis L. (Ranunculaceae) species. Chemical studies allowed to identify the cardiac glycosides, or cardenolides: or cardenolides: adontoxin, adonitol, adonitoxigenin, acetyldigitoxin and others. In scientific medicine, it is currently allowed to use Adonis vernalis L. Other types of Adonis have a similar chemical composition and are offered as substitutes for this official species, for example, Adonis apennina L. Many Adonis species have limited natural resources, and in some regions are rare, requiring conservation of their natural populations. The search for alternative sources of medicinal plant raw materials, based on this, is relevant. The experimental part of our research was carried out using the morphological and geographical method with the involvement of information on ecology and phenology. For the first time summarizes the diagnostic features of Adonis flora of Russian flora. Previously unknown structural features (shape and size of anthers) were identified that characterize the subgenera Adonanthe and Adonis. Taxonomic study of the genus Adonis of the Russian flora allowed us to determine its species composition, clarify its systematic affiliation, and nomenclature synonyms. 9 species were identified. Of these, 6 are perennials belonging to the subgenus Adonanthe, section Consiligo, which includes 2 subsections: Amurenses (2 species) and Vernales, which is differentiated into 2 rows: Apenninae (2 species) and Vernales (2 species). Subgenus Adonis is represented by 2 sections: Adonis (1 species) and Lophocarpa with sections Aestivales (1 species) and Dentatae (1 species). For all the considered species and varieties, the main distribution areas are given. A key has been compiled to determine the wild Adonis species distributed in Russia.

scholarly journals Quantum-Chemical Search for Keto Tautomers of Azulenols in Vacuo and Aqueous Solution

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 497
Author(s):  
Ewa D. Raczyńska
Keyword(s):  
Aqueous Solution ◽  
Quantum Chemical ◽  
Biologically Active ◽  
Deprotonation Reaction ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Scanty Information ◽  
Derivatives Of ◽  
Common Anion ◽  
Tautomeric Mixture

Keto-enol prototropic conversions for carbonyl compounds and phenols have been extensively studied, and many interesting review articles and even books appeared in the last 50 years. Quite a different situation takes place for derivatives of biologically active azulene, for which only scanty information on this phenomenon can be found in the literature. In this work, quantum-chemical studies have been undertaken for symmetrically and unsymmetrically substituted azulenols (constitutional isomers of naphthols). Stabilities of two enol (OH) rotamers and all possible keto (CH) tautomers have been analyzed in the gas phase {DFT(B3LYP)/6-311+G(d,p)} and also in aqueous solution {PCM(water)//DFT(B3LYP)/6-311+G(d,p)}. Contrary to naphthols, for which the keto forms can be neglected, at least one keto isomer (C1H, C2H, and/or C3H) contributes significantly to the tautomeric mixture of each azulenol to a higher degree in vacuo (non-polar environment) than in water (polar amphoteric solvent). The highest amounts of the CH forms have been found for 2- and 5-hydroxyazulenes, and the smallest ones for 1- and 6-hydroxy derivatives. The keto tautomer(s), together with the enol rotamers, can also participate in deprotonation reaction leading to a common anion and influence its acid-base properties. The strongest acidity in vacuo exhibits 6-hydroxyazulene, and the weakest one displays 1-hydroxyazulene, but all azulenols are stronger acids than phenol and naphthols. Bond length alternation in all DFT-optimized structures has been measured using the harmonic oscillator model of electron delocalization (HOMED) index. Generally, the HOMED values decrease for the keto tautomers, particularly for the ring containing the labile proton. Even for the keto tautomers possessing energetic parameters close to those of the enol isomers, the HOMED indices are low. However, some kind of parallelism exists for the keto forms between their relative energies and HOMEDs estimated for the entire molecules.

Design, synthesis and physico-chemical studies of a Co(II)/Co(III) mixed-valence complex: An experimental and DFT approach.

2021 ◽  
pp. 130384
Author(s):  
Intissar Hamdi ◽  
Noureddine Mhadhbi ◽  
Noureddine Issaoui ◽  
Andreas Roodt ◽  
Mark M. Turnbull ◽  
...  
Keyword(s):  
Mixed Valence ◽  
Design Synthesis ◽  
Physico Chemical ◽  
Chemical Studies ◽  
Mixed Valence Complex
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