scholarly journals Preparation and Characterization of Urushiol Methylene Acetal Derivatives with Various Degrees of Unsaturation in Alkyl Side Chain

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Chengzhang Wang ◽  
Yuanfeng He ◽  
Hao Zhou ◽  
Ran Tao ◽  
Hongxia Chen ◽  
...  
Keyword(s):  
Anticancer Agents ◽  
Methylene Chloride ◽  
2D Nmr ◽  
Side Chain ◽  
Preparative Hplc ◽  
Increasing Demand ◽  
High Yields ◽  
Methylene Ether ◽  
C Nmr

Preparation of urushiol derivatives was carried out in response to the drug industry’s increasing demand for new synthetic anticancer agents. Urushiol methylene acetal derivatives were synthesized in high yields by reaction of urushiol with methylene chloride under the catalytic action of NaOH. Four kinds of urushiol methylene acetal monomers were separated by silica-gel column and preparative HPLC, and their structures were elucidated by extensive spectroscopic methods, including 1D-NMR and 2D-NMR (1H,13C-NMR,1H-1HCOSY, HSQC, and HMBC) as well as TOF-MS. They were identified as 3-[pentadecyl] benzene methylene ether (compound 1), 3-[8′-pentadecatrienyl] benzene methylene ether (compound 2), 3-[8′,11′-pentadecatrienyl] benzene methylene ether (compound 3), and 3-[8′,11′,14′-pentadecatrienyl] benzene methylene ether (compound 4). This research provides a theoretical reference for exploration of these interesting and potentially bioactive compounds.

E-Homolupane Derivatives Substituted in Position 17 and 22a. 1H NMR, 13C NMR and IR Spectra

1995 ◽  
Vol 60 (4) ◽  
pp. 619-635 ◽  
Author(s):  
Václav Křeček ◽  
Stanislav Hilgard ◽  
Miloš Buděšínský ◽  
Alois Vystrčil
Keyword(s):  
Nmr Spectra ◽  
2D Nmr ◽  
Coupling Constants ◽  
Side Chain ◽  
Oxidation Reactions ◽  
H Nmr ◽  
Complete Assignment ◽  
Nmr Techniques ◽  
Intramolecular Association ◽  
C Nmr

A series of derivatives with various oxygen functionalities in positions 17,22a or 19,20 was prepared from diene I and olefin XVI by addition and oxidation reactions. The structure of the obtained compounds was confirmed by 1H NMR, 13C NMR and IR spectroscopy. The kind of intramolecular association of the 17α-hydroxy group was studied in connection with modification of the side chain and substitution in position 22a. Complete assignment of the hydrogen signals and most of the coupling constants was accomplished using a combination of 1D and 2D NMR techniques. The 1H and 13C NMR spectra are discussed.

scholarly journals Isolation and Structural Characterization of Degradation Products of Aceclofenac by HPLC, HRMS and 2D NMR

2019 ◽  
Vol 31 (4) ◽  
pp. 851-854
Author(s):  
Santhosh Guduru ◽  
V.V.S.R.N. Anji Karun Mutha ◽  
B. Vijayabhaskar ◽  
Muralidharan Kaliyaperumal ◽  
Raghu Babu Korupolu ◽  
...  
Keyword(s):  
Degradation Product ◽  
Degradation Products ◽  
Acid Stress ◽  
2D Nmr ◽  
Stress Conditions ◽  
Preparative Hplc ◽  
Mass Spectral ◽  
2D Nmr Spectra ◽  
The Stability

The stability of aceclofenac under stress conditions was assessed to identify the degradation products. So, it was subjected to stress conditions like acid, base and oxidation, according to ICH guideline Q1A (R2). One degradation product formed when the drug was subjected to acid stress. Three degradation products were formed during the basic stress condition. The drug substance was found to be stable to oxidative stress. The degradants formed during the stress were separated on a C-18 column using gradient preparative HPLC elution. The only product (DP-2) formed during the acid stress and this one is same as of one of the three degradation products (DP-1, DP-2, DP-3) were formed during base stress. 1D and 2D NMR spectra and mass spectral analysis supported the proposed structures for the products. The products DP-2 and DP-3 have been reported earlier but this is the first report of product DP-1 as a degradation product of aceclofenac.

Synthesis and characterization of various unsubstituted and mono-N-substituted tetraazamacrocycles

1995 ◽  
Vol 73 (5) ◽  
pp. 685-695 ◽  
Author(s):  
I. Meunier ◽  
A.K. Mishra ◽  
B. Hanquet ◽  
R. Guilard ◽  
P. Cocolios
Keyword(s):  
Mass Spectrometry ◽  
Template Synthesis ◽  
2D Nmr ◽  
Spectral Studies ◽  
Synthesis And Characterization ◽  
Difference Spectroscopy ◽  
Protective Group ◽  
Noe Difference Spectroscopy ◽  
C Nmr

Syntheses of tetraazamacrocycles have been carried out by using p-toluenesulfonyl chloride as protective group. The [14(ane) N4] and [15(ane) N4] were also obtained by the template synthesis. Mono-N-functionalization of tetraazamacrocycles was accomplished by reaction of a fivefold excess of the free macrocycles with 1 equivalent of a suitable alkylating or arylating reagent. The key point of the synthesis lies in the use of an excess of the macrocycle over the substituting reactants to reduce the formation of polysubstituted derivatives, and in the easy separation of the excess of unreacted macrocycle. All the products were characterized on the basis of spectral studies (1H and l3C NMR, including 2D NMR and NOE difference studies) and mass spectrometry. Keywords: tetraazamacrocycles, improved synthesis, protective group, N-tosylation, template synthesis, NOE difference spectroscopy.

scholarly journals Synthesis and Spectroscopic Characterization of Some New Biological Active Azo–Pyrazoline Derivatives

2012 ◽  
Vol 9 (3) ◽  
pp. 1613-1622 ◽  
Author(s):  
Farouq E. Hawaiz ◽  
Mohammad K. Samad
Keyword(s):  
Addition Reaction ◽  
Coupling Reaction ◽  
Spectroscopic Characterization ◽  
Hydroxyl Group ◽  
Significant Activity ◽  
H Nmr ◽  
Ft Ir ◽  
High Yields ◽  
C Nmr

A number of 3-[4-(benzyloxy)-3-(2-Chlorophenylazo)-phenyl]-5-(substituted-phenyl)-1-substituted-2-pyrazolines( 4a-j) and (5a-j) have been synthesized by diazotization of 2-chloroaniline and its coupling reaction with 4-hydroxy acetophenone, followed by benzyloxation of the hydroxyl group to give the substrate [4-benzyloxy-3-(2-chlorophenylazo)-acetophenone (1)].The prepared starting material (1) has been reacted with different substituted benzaldehydes to give a new series of chalcone derivatives 1-[(4-benzyloxy)-3-(2-chloro-phenylazo)-phenyl]-3-(substituted phenyl)-2-propen-1-one (3a-j), in high yields and in a few minutes, and the later compounds were treated with hydrazine hydrate according to Michael addition reaction to afford a new biolological active target compounds (4a-j) and (5a-j). Furthermore, The structures of the newly synthesized compounds were confirmed by FT-IR,13C-NMR,13C-DEPT &1H-NMR spectral data. The chalcone and pyrazoline derivatives were evaluated for their anti bacterial activity againstEscherichia colias gram negative andStaphylococcus aureusas gram positive, the results showed significant activity against both types of bacteria.

scholarly journals Synthesis and Characterization of Novel 1,3-Thiazole and 2-Amino-1,3,4-Thiadiazole Derivatives

2014 ◽  
Vol 33 (2) ◽  
pp. 189 ◽  
Author(s):  
Mustafa Er ◽  
Ayşe Şahin ◽  
Hakan Tahtacı
Keyword(s):  
Biological Activities ◽  
High Yield ◽  
Synthesis And Characterization ◽  
Hantzsch Reaction ◽  
H Nmr ◽  
Thiadiazole Derivatives ◽  
High Yields ◽  
Mass Spectrometric Techniques ◽  
C Nmr

<p>Thiosemicarbazone derivatives <strong>3a–e</strong> were synthesized by the reaction of various aldehydes<strong> 1a–e</strong> with 4-methyl thiosemicarbazide <strong>2</strong> in 78% to 90% yield. Then, the thiazole moieties of the target materials <strong>5a–e</strong> were obtained in high yields (71–93%) using the Hantzsch reaction utilizing thiosemicarbazone derivatives <strong>3a–e</strong> with ethyl-2-chloroacetoacetic ester. The substituted nitrile derivatives <strong>7a–e</strong> were obtained in moderate to high yield (58–84%) from the reaction of compounds <strong>5a–e</strong> with chloroacetonitrile by the nucleophilic aliphatic substitution reaction in the presence of anhydrous potassium carbonate. Finally, substituted 2-amino-1,3,4-thiadiazole compounds <strong>9a–e</strong> were obtained in moderate to good yields (51–62%) from the reaction of thiosemicarbazide with substituted nitrile derivatives <strong>7a–e</strong>. As a result, compounds that all share a high disposition for biological activities were obtained. The structures of the newly synthesized compounds were confirmed by IR, <sup>1</sup>H NMR, <sup>13</sup>C NMR, elemental analysis, and mass spectrometric techniques.</p>

Synthesis, Characterization of 2',7'-dibromo-2,3,6,7-tetraethoxy-9,9'-spirobifluorene

2013 ◽  
Vol 781-784 ◽  
pp. 499-502
Author(s):  
Chun Hua Qi ◽  
Xiao Long Lei ◽  
Xiao Xia Sun ◽  
Yu Hu
Keyword(s):  
Ethyl Acetate ◽  
Organic Solvents ◽  
Methylene Chloride ◽  
Good Solubility ◽  
Synthetic Procedure ◽  
High Yields

A simple and efficient synthetic procedure of 2',7'-dibromo-2,3,6,7-tetraethoxy-9,9'-spirobi [fluoren has been developed. The new monomer of 2',7'-dibromo-2,3,6,7-tetraethoxy-9,9'-spirobi [fluoren has been synthesized in high yields over five steps from readily available starting materials. The new monomer has good solubility in organic solvents such as chloroform, methylene chloride, tetrahydrofuran, ethyl acetate and so on.

MWL fraction with a high concentration of lignin-carbohydrate linkages: Isolation and 2D NMR spectroscopic analysis

Holzforschung ◽  
2007 ◽  
Vol 61 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Mikhail Yu. Balakshin ◽  
Ewellyn A. Capanema ◽  
Hou-min Chang
Keyword(s):  
Loblolly Pine ◽  
Spectroscopic Analysis ◽  
Direct Detection ◽  
2D Nmr ◽  
Side Chain ◽  
High Concentration ◽  
Hmbc Correlation ◽  
Nmr Techniques ◽  
C Nmr ◽  
Hmbc Technique

Abstract A preparation enriched in lignin-carbohydrate fragments (LCC-AcOH) was isolated in the course of purification of loblolly pine crude milled wood lignin (MWL). The preparation contained approximately equal amounts of lignin and carbohydrates, with high amounts of arabinose and galactose compared to their levels in wood. LCC-AcOH was investigated by 2D 1H-13C (HMQC and HMBC) correlation NMR techniques and quantitative 13C NMR. The HMQC spectra allowed direct detection of phenyl glycoside, ester and benzyl ether lignin-carbohydrates linkages in high amounts. The assignment of these structures was supported by the HMBC technique. It is noteworthy that in the ester lignin-carbohydrate linkages, a uronic acid residue was attached not to the benzylic position of lignin, as commonly believed, but to the γ-position of the side chain.

Synthesis and characterization of a series of 4-methyl-1-[2-aryl-1-diazenyl]-1,4-diazepanes and 1,4-di-[2-aryl-1-diazenyl]-1,4-diazepanes

2004 ◽  
Vol 82 (12) ◽  
pp. 1725-1735 ◽  
Author(s):  
Shasta Lee Moser ◽  
Keith Vaughan
Keyword(s):  
Nmr Assignments ◽  
Diazonium Salt ◽  
Variable Temperature ◽  
2D Nmr ◽  
Diazonium Salts ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Compounds ◽  
C Nmr

1-Methylhomopiperazine was coupled with a series of diazonium salts to afford the 4-methyl-1-[2-aryl-1-diazenyl]-1,4-diazepanes (6), a new series of triazenes. These compounds are, in the main, stable crystalline solids (some of the series are stable oils), and they have been characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, and mass spectrometry. NMR assignments were determined by 2D NMR and variable-temperature NMR experiments and by comparison with model compounds. A second series of new compounds, namely, 1,4-di-[2-aryl-1-diazenyl]-1,4-diazepanes (5), were prepared by coupling unsubstituted homopiperazine (1,4-diazepane) with 2 molar equivalents of the diazonium salt and were similarly characterized. The crystal and molecular structure of the parent member of this bis-triazene series (5, X = H) has been determined by single-crystal X-ray diffraction analysis.Key words: triazene, bis-triazene, diazenyl, bis-diazenyl, diazonium salt, NMR, diazepane.

Isolation and Characterization of 1-Tigloyl-3-acetylazadirachtol from the Seed Kernels of the Thai Neem Azadirachta siamensis Valeton

1997 ◽  
Vol 52 (11) ◽  
pp. 1413-1417 ◽  
Author(s):  
H.-O. Kalinowski ◽  
C. Krack ◽  
K. Ermel ◽  
C. Chriathamjaree
Keyword(s):  
Large Scale ◽  
Botanical Insecticides ◽  
Preparative Hplc ◽  
Isolation And Characterization ◽  
Liquid Liquid Extraction ◽  
Related Compounds ◽  
Analytical Hplc ◽  
Azadirachtin A ◽  
C Nmr

Abstract The Thai neem A. siamensis (Valeton) is the main source for botanical insecticides in Thailand. Although azadirachtin A (aza A) is present in Thai neem, there are some other related compounds which may contribute to its bioefficiency. Analytical HPLC of Thai neem samples showed a peak closely eluted with azadirachtin. A large-scale cleanup involving two liquid/liquid extraction steps, silica filtration, and finally two successive preparative HPLC separations, resulted in the pure compound, which was identified as 1-tigloyl-3-acetylazadirachtol by 1D -and 2D -1H and 13C NMR spectroscopy.

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