scholarly journals Tannins of Tamarind Seed Husk: Preparation, Structural Characterization, and Antioxidant Activities

2011 ◽  
Vol 6 (6) ◽  
pp. 1934578X1100600 ◽  
Author(s):  
Puksiri Sinchaiyakit ◽  
Yohji Ezure ◽  
Sarin Sriprang ◽  
Supakorn Pongbangpho ◽  
Nasapon Povichit ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Antioxidant Activities ◽  
Uv Spectroscopy ◽  
Degree Of Polymerization ◽  
Dpph Assay ◽  
One Pot ◽  
Acetone Water ◽  
Seed Husk ◽  
C Nmr ◽  
Ir And Uv Spectroscopy

The high content (about 39%) of polymeric tannins in tamarind ( Tamarindus indica L.) seed husk (TSH) was demonstrated, and an extract (crude TSE) with a high content (about 94%) of polymeric tannins was prepared from TSH with a one pot extraction using ethanol/water (3:2, v/v). The crude TSE was further purified with Sephadex LH20 to give one fraction (metTSE) eluted with methanol/water (3:2, v/v) and another (acTSE) eluted with acetone/water (3:2, v/v). The tannins of acTSE were established as polymeric proanthocyanidins (PA) by 13C NMR spectroscopy; this was further confirmed by IR and UV spectroscopy, n-BuOH/HCl and vanillin assays, and from HPLC pattern. The ratio of procyanidins to prodelphinidins was 2:3, and the average degree of polymerization of acTSE was 7. Galloylated flavan-3-ols were not detected in acTSE. The main ingredients of metTSE were confirmed to be polymeric PA by 13C NMR spectroscopy. The antioxidant activities using DPPH and ABTS assays were investigated. The IC50 values of acTSE were 4.2±0.2 (DPPH assay) and 6.2±0.3 μg/mL (ABTS assay).

One-pot synthesis of the new Hydroxamic acid and its complexes with metals

2022 ◽  
Vol 19 ◽  
Author(s):  
Gulu Abbasova ◽  
Ajdar Medjidov
Keyword(s):  
Nmr Spectroscopy ◽  
Thermogravimetric Analysis ◽  
Hydroxamic Acid ◽  
Uv Spectroscopy ◽  
Molar Ratio ◽  
One Pot ◽  
Ethanol Medium ◽  
Physicochemical Methods ◽  
Colored Complexes ◽  
First Time

Abstract: A one-pot conversion of 2-hydroxy-1-naphthoic aldehyde to hydroxamic acid was described. An efficient photoorganocatalytic method of synthesis was developed. The obtained hydroxamic acid was identified by various physicochemical methods such as IR, UV- and NMR-spectroscopy. Solid colored complexes of copper (II) and iron (II), respectively, green and brown colours with the obtained hydroxamic acid were synthesized in ethanol medium for the first time. The molar ratio of ligand and metal in the complex was 2:1. Their structures were established using IR, UV- spectroscopy and thermogravimetric analysis.

Etude en rmn 13C de bicyclo[4,n,0]alcanones-3 trans α-substitués. Influence de la nature et de l'orientation du substituant sur le déplacement chimique du 13C du carbonyle

1980 ◽  
Vol 58 (15) ◽  
pp. 1503-1511 ◽  
Author(s):  
Pierre Metzger ◽  
Eliette Casadevall ◽  
André Casadevall ◽  
Marie-José Pouet
Keyword(s):  
Convenient Method ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Uv Spectroscopy ◽  
Substituent Effects ◽  
Fixed Ring ◽  
C Nmr ◽  
Ir And Uv Spectroscopy

The 13C nmr spectra of α, αα, and αα′ substituted trans-fused bicyclo [4,n,0]alkan-3 ones, are described. Substituent effects are discussed in terms of their electron withdrawing character, axial or equatorial configuration, and cyclohexane deformation. 13C=O chemical shifts are shown to be based on the polarization of π bond and on C=O/X non-bonded interactions. As in ir and uv spectroscopy, 13C nmr is a convenient method for detecting an a substituent configuration in fixed ring ketones.

Stereoselective Synthesis and Single Crystal X-Ray Structures of Some Sterically Congested Electron-poor N-Vinyl Pyrazole Derivatives

2008 ◽  
Vol 63 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Nader Noshiranzadeh ◽  
Ali Ramazani ◽  
Amir Tofangchi Mahyaria ◽  
Katarzyna Ślepokurab ◽  
Tadeusz Lisb
Keyword(s):  
Nmr Spectroscopy ◽  
Structural Analysis ◽  
Single Crystal ◽  
Structure Determination ◽  
Stereoselective Synthesis ◽  
Pyrazole Derivatives ◽  
One Pot ◽  
X Ray ◽  
One Pot Synthesis ◽  
C Nmr

A one-pot synthesis of sterically congested electron-poor N-vinyl pyrazoles in fairly good yields by the reaction of ethyl 3-phenyl-2-propynoate, pyrazoles and triphenylphosphine is reported. The structures of these compounds were confirmed by IR, 1H, and 13C NMR spectroscopy, and single crystal X-ray structure determination. The structural analysis of the products indicated that the reaction is completely regio- and stereoselective.

Regio- And Stereoselective Addition Of Imides To Ethyl 3-Phenyl-2- Propynoate In The Presence Of Triphenylphosphine. Single Crystal X-Ray Structure Of Ethyl (Z)-2-(1,3-Dioxo-1,3,3A,4,7,7A-Hexahydro-2H-Isoindol- 2-Yl)-3-Phenyl-2-Propenoate

2007 ◽  
Vol 62 (6) ◽  
pp. 829-834 ◽  
Author(s):  
Amir Tofangchi Mahyaria ◽  
Nahid Shajari ◽  
Ali Reza Kazemizadeh ◽  
Katarzyna Ślepokura ◽  
Tadeusz Lis ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Structural Analysis ◽  
Single Crystal ◽  
Structure Determination ◽  
One Pot ◽  
X Ray ◽  
One Pot Synthesis ◽  
Stereoselective Addition ◽  
High Yields ◽  
C Nmr

A one-pot synthesis of sterically congested N-vinyl imides in fairly high yields by the reaction of ethyl 3-phenyl-2-propynoate, imides and triphenylphosphine is reported. The structures of these compounds were confirmed by IR, 1H, and 13C NMR spectroscopy, and by a single crystal X-ray structure determination. The structural analysis of the products indicated that the reaction is regioand stereoselective

One-pot Multi-component Synthesis of Mono- and Bis-indolylimidazole Derivatives Using Zn2+@KSF and Their Antibacterial Activity

2014 ◽  
Vol 69 (6) ◽  
pp. 715-720 ◽  
Author(s):  
Nosrat O. Mahmoodi ◽  
Iraj Nikokar ◽  
Marzieh Farhadi ◽  
Atefeh Ghavidast
Keyword(s):  
Antibacterial Activity ◽  
Nmr Spectroscopy ◽  
Heterogeneous Catalyst ◽  
One Pot ◽  
H Nmr ◽  
C Nmr ◽  
Efficient Heterogeneous Catalyst

The preparation of mono- and bis-indolylimidazole derivatives using Zn2+ supported on montmorillonite KSF (Zn2+@KSF) as an efficient heterogeneous catalyst is described. The structures of these compounds were characterized by IR, 1H NMR and 13C NMR spectroscopy. The antibacterial activity of the selected products was examined. Some products exhibit promising activities.

scholarly journals Nucleobase-Based Barbiturates: Their Protective Effect against DNA Damage Induced by Bleomycin-Iron, Antioxidant, and Lymphocyte Transformation Assay

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Bhaveshkumar D. Dhorajiya ◽  
Bharatkumar Z. Dholakiya ◽  
Ahmed S. Ibrahim ◽  
Farid A. Badria
Keyword(s):  
Dna Damage ◽  
Protective Effect ◽  
Uv Spectroscopy ◽  
Lymphocyte Transformation ◽  
High Yield ◽  
One Pot ◽  
H Nmr ◽  
Transformation Assay ◽  
Ft Ir ◽  
C Nmr

A number of nucleobase-based barbiturates have been synthesized by combination of nucleic acid bases and heterocyclic amines and barbituric acid derivatives through green and efficient multicomponent route and one pot reaction. This approach was accomplished efficiently using aqueous medium to give the corresponding products in high yield. The newly synthesized compounds were characterized by spectral analysis (FT-IR,1H NMR,13C NMR, HMBC, and UV spectroscopy) and elemental analysis. Representative of all synthesized compounds was tested and evaluated for antioxidant, bleomycin-dependent DNA damage, and Lymphocyte Transformation studies. CompoundsTBC>TBA>TBGshowed highest lymphocyte transformation assay,TBC>TBA>BGshowed inhibitory antioxidant activity using ABTS methods, andTBC>BPA>BAMT>TBA>1,3-TBAmanifested the best protective effect against DNA damage induced by bleomycin.

scholarly journals An Efficient One Pot Synthesis of some New 1,4-Dihydropyridine Derivatives Using Multicomponent Reaction

2015 ◽  
Vol 57 ◽  
pp. 45-50
Author(s):  
Devang R. Prajapati ◽  
Hardik K. Senjani ◽  
Yogesh T. Naliapara
Keyword(s):  
Nmr Spectroscopy ◽  
Multicomponent Reaction ◽  
Elemental Analysis ◽  
One Pot ◽  
H Nmr ◽  
One Pot Synthesis ◽  
Target Molecules ◽  
Dihydropyridine Derivatives ◽  
C Nmr

Synthesize target molecules, multicomponent reaction of 4-(4-aminophenyl) morpholin-3-one with various pyrazole aldehydes and ethylacetoacetate or methylacetoacetate afforded various 1,4-dihydropyridines derivatives. The newly synthesized compounds were characterized by IR, Mass, 1H NMR, 13C NMR spectroscopy and elemental analysis.

Thermal Cyclocondensation of Ethyl (1-Methyl-5- and 6-Benzimidazolyl/benzotriazolyl)aminomethylenepropanedioates

1994 ◽  
Vol 59 (5) ◽  
pp. 1145-1152 ◽  
Author(s):  
Viktor Milata ◽  
Dušan Ilavský ◽  
Igor Goljer ◽  
Lubomír Zalibera
Keyword(s):  
Carboxylic Acid ◽  
Acid Medium ◽  
Uv Spectroscopy ◽  
Reaction Products ◽  
Aprotic Medium ◽  
C Nmr ◽  
Ir And Uv Spectroscopy

Thermal cyclocondensation of starting ethyl (1-methyl-5- and 6-benzimidazolyl/benzotriazolyl)aminomethylenepropanedioates (Ia - Ie) in aprotic medium gives angularly condensed ethyl azolo[4,5-f]quinolonecarboxylates IIa, IIc, IIe and azolo[5,4-f]quinolonecarboxylates IIb, IId, respectively, which are hydrolyzed to the corresponding carboxylic acid III in acid medium. The structure of reaction products has been confirmed by 1H and 13C NMR, IR, and UV spectroscopy.

scholarly journals Vanillin-Based Polymers—part II: Synthesis of Schiff Base Polymers of Divanillin and Their Chelation with Metal Ions

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Ananda S. Amarasekara ◽  
Ashfaqur Razzaq
Keyword(s):  
Schiff Base ◽  
Nmr Spectroscopy ◽  
Metal Ions ◽  
Renewable Resources ◽  
Model Compound ◽  
Degree Of Polymerization ◽  
Aqueous Methanol ◽  
Ft Ir ◽  
Schiff Base Polymers ◽  
C Nmr

Condensation of renewable resources-based monomer divanillin with alkyl diamines gives Schiff base polymers with degree of polymerization (DP) ~25–32 in 88–95% yield. These yellow polymers are insoluble in water and common organic solvents, slightly soluble in warm DMSO, DMF and dissolves in aqueous NaOH. The polymers were characterized using FT-IR, 1H, and 13C NMR spectroscopy and by comparison with the model compound N,N′-bis(vanillidene)-1,3-propanediamine. Polymer prepared by condensation of divanillin and 1,6-diaminohexane is shown to chelate with Cu(II), Fe(II), and Co(II) metal ions in basic aqueous methanol.

3,4-Disubstituted derivatives of 1,2,5-thiadiazole 1,1-dioxide. Ethanol addition reactions and electroreduction of 3-methyl-4-phenyl and 3,4-dimethyl derivatives in acetonitrile and ethanol solvents

1996 ◽  
Vol 74 (8) ◽  
pp. 1564-1571 ◽  
Author(s):  
José Alberto Caram ◽  
María Virginia Mirífico ◽  
Silvia Lucía Aimone ◽  
Enrique Julio Vasini
Keyword(s):  
Nmr Spectroscopy ◽  
Addition Reaction ◽  
Uv Spectroscopy ◽  
Equilibrium Constants ◽  
Addition Reactions ◽  
Solvent Mixtures ◽  
Second Order Reaction ◽  
Ethanol Addition ◽  
Derivatives Of ◽  
C Nmr

3-Methyl-4-phenyl-1,2,5-thiadiazole 1,1-dioxide (TMP), as well as 3,4-dimethyl-1,2,5-thiadiazole 1,1-dioxide (TMM), react with ethanol (EtOH), which adds to one of their C = N double bonds. The equilibrium constants for the addition reaction are measured in mixed acetonitrile (ACN) – EtOH solvents by means of UV spectroscopy in the case of TMP, and by 13C NMR spectroscopy in the case of TMM, since TMM presents only terminal UV absorption. Both equilibrium constants are also estimated through cyclic voltammetry (CV) experiments. In the case of TMP, the ethanol molecule adds to the C = N bond located on the methyl-substituted side of the substrate, according to 13C NMR spectroscopy and CV results. The electroreduction characteristics of the substrates and their ethanol addition products are studied using CV techniques in ACN, EtOH, and CAN–EtOH solvent mixtures. The radical anion formed by the first electron transfer to TMM is unstable and decomposes rapidly while that corresponding to TMP undergoes a relatively slow homogeneous second-order reaction with the substrate (k = 3 × 102 M−1 s−1). The equilibrium constant for EtOH addition and the voltammetric properties of the substrates are compared with those of the previously studied 3,4-diphenyl derivative (TPP). Key words: electrochemistry, thiadiazoles, structure–reactivity relations, kinetics.

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