scholarly journals Synthesis, Characterization, and Thermokinetic Analysis of New Epoxy Sugar Derivative

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Selinay Y. Erişkin ◽  
Fatma Ç. Telli ◽  
Yeliz Yıldırım ◽  
Yeşim Salman
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Thermogravimetric Analysis ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Epoxy Group ◽  
H Nmr ◽  
Thermokinetic Analysis ◽  
Sugar Derivative

The synthesis of 5,6-O-isopropylidene-1,2-O-(R)-trichloroethylidene-α-D-glucofuranose (compound1) and 5,6-O-isopropylidene-1,2-O-(R)-trichloroethylidene-3-O-(2′,3′-epoxypropan-1′-yl)-α-D-glucofuranose (compound2) was carried out. The synthesized compounds1and2were characterized by nuclear magnetic resonance (1H-NMR), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TG). The FTIR and1H NMR spectra showed that the epoxy group in compound2was attached by means of a nucleophilic substitution reaction. The activation energies for thermal degradation of compounds1and2were calculated from their TG data by using the Kissinger-Akahira-Sunose (KAS) and Tang methods.

scholarly journals Isolasi Senyawa Metabolit Sekunder dari Ekstrak Metanol Kulit Batang Bauhinia semibifida Roxb. dan Uji Aktivitas Antioksidan

2021 ◽  
Vol 17 (1) ◽  
pp. 132
Author(s):  
Haiyul Fadhli ◽  
Nur Fitria Rohmatul Ummah ◽  
Noveri Rahmawati
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Antioxidant Activity ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Magnetic Resonance ◽  
Vitamin C ◽  
Fourier Transform Infrared Spectroscopy ◽  
Fourier Transform Infrared ◽  
Proton Nuclear Magnetic Resonance ◽  
H Nmr

<p>Kulit batang <em>Bauhinia semibifida </em>Roxb. telah lama digunakan sebagai obat tradisional oleh masyarakat Melayu Lingga, Kepulauan Riau. Penelitian ini bertujuan untuk mengisolasi dan menguji aktivitas antioksidan senyawa metabolit sekunder dari ekstrak metanol kulit batang <em>B. semibifida </em>Roxb. Tiga isolat murni berupa satu senyawa alkaloid (BR1) dan dua senyawa flavonoid (BR2 dan BR3) telah berhasil diisolasi dengan cara ekstraksi menggunakan metode maserasi dan dilanjutkan fraksinasi dengan metode kromatografi kolom. Uji aktivitas antioksidan dilakukan terhadap isolat dengan metode 2,2 difenil-1-pikrilhidrazil (DPPH). Senyawa isolat BR1 menunjukan IC<sub>50 </sub>&gt;1000 µg/mL dikategorikan tidak aktif sebagai antioksidan, sedangkan senyawa isolat BR2 dan BR3 menunjukan IC<sub>50</sub> 2,92 µg/mL dan 4,39 µg/mL dikategorikan sangat kuat sebagai antioksidan jika dibandingkan dengan vitamin C sebagai kontrol. Berdasarkan evaluasi aktivitas antioksidan senyawa BR2 adalah senyawa pilihan yang dilanjutkan identifikasi dengan spektroskopi <em>Fourier-Transform Infrared Spectroscopy </em>(<em>FTIR</em>) dan <em>Proton Nuclear Magnetic Resonance</em> (<sup>1</sup>H-NMR) sehingga diduga senyawa isolat memiliki struktur dasar senyawa flavonoid.</p><p><strong>Isolation of Secondary Metabolite Compounds of Methanolic Extract of Steam Bark <em>Bauhinia semibifida</em> Roxb. and Their Antioxidant Activites</strong>. Stem bark of <em>Bauhinia semibifida</em> Roxb. has been long consumed as a medicinal herb by Lingga Malaya Ethnic. Therefore, this research aimed to isolate and examines the antioxidant activity of secondary metabolites from methanol extract of stembark of <em>Bauhinia semibifida</em> Roxb. Three pure compounds which are an alkaloid (BR1) and two flavonoids (BR2 and BR3) have been isolated by extraction using maceration method followed by fractionation using column chromatography method. Antioxidant activity assay was carried out by 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) method. Compound BR1 showed IC<sub>50</sub> &gt;1000 µg/mL categorized as inactive as an antioxidant, while compounds BR2 and BR3 showed IC<sub>50</sub> 2.92 µg/mL and 4.394 µg/mL, respectively, categorized as very strong as an antioxidant when compared to vitamin C as a control. Based on the evaluation of the antioxidant activity, the BR2 was selected compound and continued to identification by <em>Fourier-Transform Infrared Spectroscopy </em>(<em>FTIR</em>) and <em>Proton Nuclear Magnetic Resonance</em> (<sup>1</sup>H-NMR) spectroscopy so that the isolate has the basic structure of flavonoid compound.</p>

A 19F nuclear magnetic resonance study of the conjugate Brönsted-Lewis superacid HSO3F-SbF5. Part 1

1999 ◽  
Vol 77 (11) ◽  
pp. 1869-1886 ◽  
Author(s):  
Dingliang Zhang ◽  
Markus Heubes ◽  
Gerhard Hägele ◽  
Friedhelm Aubke
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Nuclear Magnetic Resonance Study ◽  
Magnetic Resonance Study ◽  
Formation Reaction ◽  
H Nmr ◽  
Acid Conjugate ◽  
Nmr Methods ◽  
Cis And Trans

The Brönsted-Lewis superacid HSO3F-SbF5 or "magic acid" is re-investigated by modern 19F NMR methods over a wide concentration range. The system is found to be considerably more complex than had been assumed previously. A total of 13 different anions are identified of which only five have previously been identified in magic acid. With increasing SbF5 contents the concentration of monomeric anions like [SbF6]-, [SbF5(SO3F)]-, cis- and trans-[SbF4(SO3F)2]-, and mer-[SbF3(SO3F)3]- gradually decreases. Except for [Sb2F11]-, which is present in very small concentrations only, the formation of oligomers involves exclusively μ-fluorosulfato bridges. In addition to donor (SO3F)- and acceptor (SbF5) complex formation to give [SbF5(SO3F)]- and possibly ligand redistribution, the solvolysis of SbF5 or SbF4(SO3F) in HSO3F appears to be the principal formation reaction for polyfluorosulfatofluoroantimonate(V) anions. In glass (NMR tubes) the solvolysis product HF is converted to the oxonium ion [H3O]+, which has previously been identified by 1H NMR and structurally characterized as [H3O][Sb2F11] by us.Key words: magic acid, conjugate superacid, fluorosulfuric acid, 19F NMR spectra.

scholarly journals Fourier Transform Infrared Spectral Analysis of Polyisoprene of a Different Microstructure

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Dongmei Chen ◽  
Huafeng Shao ◽  
Wei Yao ◽  
Baochen Huang
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Spectral Analysis ◽  
Fourier Transform ◽  
Magnetic Resonance ◽  
Detailed Analysis ◽  
Fourier Transform Infrared ◽  
Ftir Spectra ◽  
H Nmr ◽  
Infrared Spectral

Some polyisoprene samples of different microstructure contents were studied by Fourier transform infrared (FTIR) and1H Nuclear magnetic resonance (1H NMR). On the basis of detailed analysis of FTIR spectra of polyisoprene, the shift of absorption peaks caused by microstructure content’s variation was discussed. The contents of the polyisoprene samples’ microstructure which was determined by the1H NMR was used as the standard. Through the choice, calculation, and comparison with the corresponding absorption peaks of FTIR, a method based on the results of the analysis has been developed for the determination of the microstructure contents of polyisoprene by FTIR.

Aliphatic diazo compounds. XIV. The synthesis of 7-substituted 3-diazo-2-norbornanones and the infrared and proton and carbon-13 nuclear magnetic resonance spectra of these diazo ketones and their precursors

1984 ◽  
Vol 62 (9) ◽  
pp. 1751-1766 ◽  
Author(s):  
Peter Yates ◽  
John David Kronis
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Diazo Compounds ◽  
Lower Field ◽  
Tert Butyl ◽  
H Nmr ◽  
Nuclear Magnetic Resonance Spectra ◽  
C Nmr ◽  
Shielding Effects

syn- and anti-7-Isopropyl-2-norbornanone (5 and 6) were prepared by catalytic hydrogenation of 7-isopropylidene-2-norbornanone; syn- and anti-7-benzhydryl-2-norbornane (9 and 10) were prepared in analogous fashion. Ketones 5 and 6 and syn- and anti-7-tert-butyl-2-norbornanone (7 and 8) were converted to the corresponding 3-diazo-2-norbornanones 1–4 via the monotosylhydrazones 44–47 of the corresponding α-diketones 40–43. The 1H and 13C nmr spectra of 1–10, 40–47, and their precursors have been analyzed. The 1H nmr spectra of the diazo ketones 1–4 have their C-1 and C-4 bridgehead proton signals shifted to higher and lower field, respectively, relative to the bridgehead signals of the corresponding diketones. The 13C nmr spectra of all pairs of bicyclic epimers shown γ-gauche shielding effects by the 7-substituent at (sp3) C-3 in the syn compounds and at C-5 and C-6 in the anti compounds. A converse effect is found at (sp2) C-2 (and C-3 in the diketones). Comparison of the magnitude of the shielding effects of C-7 methyl, isopropyl, benzhydryl, and tert-butyl substituents gives evidence of δ deshielding effects at C-3 in the syn compounds and at C-5 and C-6 in the anti compounds by methyl substituents on C-8.

Study on Preparation and Properties of Starch and 4-Phenolsuflonate Graft Copolymer with HRP Catalysis

2010 ◽  
Vol 129-131 ◽  
pp. 837-841 ◽  
Author(s):  
Sheng Hua Lv ◽  
Yan Fen Ma ◽  
Rui Gong ◽  
Xiao Liang Yan ◽  
Ming Ming Hou
Keyword(s):  
Mechanical Properties ◽  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Magnetic Resonance ◽  
Horseradish Peroxidase ◽  
Fourier Transform Infrared Spectroscopy ◽  
Graft Copolymer ◽  
Fourier Transform Infrared ◽  
Structure And Properties

Degraded starch was reacted with 4-phenolsuflonate (PHS) in water in the presence of horseradish peroxidase (HRP) catalyst/H2O2/acetylacetone (ACAC) to give starch and PHS graft copolymers. The structure and properties of the graft copolymer are characterized by Fourier Transform Infrared spectroscopy (FTIR), Nuclear　Magnetic　Resonance (NMR). The retanned leather exhibits excellent increased thickness and softness, good dyeing ability and eligible mechanical properties.

Analysis of 1H and 13C{1H} NMR Spectral Parameters of Diphenylchloroarsine, Diphenylcyanoarsine, and 10-Chloro- 5,10-Dihydrophenarsazine: Identification of the Compounds through Reference to Simulated Spectra

1997 ◽  
Vol 51 (5) ◽  
pp. 733-737 ◽  
Author(s):  
Markku Mesilaakso ◽  
Eeva-Liisa Tolppa ◽  
Paula Nousiainen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Spectral Parameters ◽  
H Nmr ◽  
Iterative Analysis ◽  
Simulation Of Spectra ◽  
Nuclear Magnetic

The 1H and 13C{1H} nuclear magnetic resonance (NMR) spectra of diphenylchloroarsine, diphenylcyanoarsine, and 10-chloro-5,10-dihydrophenarsazine were recorded from samples prepared in CDCl3, CD2Cl2, and (CD3)2CO. Spectra were analyzed, and detailed 1H NMR spectral parameters were determined by iterative analysis. Simulation of spectra and their use as reference spectra for identification of the compounds under different conditions are discussed.

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