Sequence distribution of poly(ether-sulfone)/poly(ether-ketone) copolymers by mass spectrometry and 13C NMR

1995 ◽  
Vol 196 (2) ◽  
pp. 499-511 ◽  
Author(s):  
Giorgio Montaudo ◽  
Maurizio S. Montaudo ◽  
Concetto Puglisi ◽  
Filippo Samperi
Keyword(s):  
Mass Spectrometry ◽  
13C Nmr ◽  
Sequence Distribution ◽  
Ether Ketone

Synthesis and Spectral Characterization of New S-Alkylated 1,2,4-Triazoles as Potential Biological Agents

2017 ◽  
Vol 68 (10) ◽  
pp. 2436-2439
Author(s):  
Stefania Felicia Barbuceanu ◽  
Laura Ileana Socea ◽  
Constantin Draghici ◽  
Elena Mihaela Pahontu ◽  
Theodora Venera Apostol ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Spectral Data ◽  
1H Nmr ◽  
Elemental Analysis ◽  
13C Nmr ◽  
Ethyl Bromide ◽  
Spectral Characterization ◽  
Basic Medium ◽  
Phenacyl Bromide

In the work we presented the behavior of 5-(4-(4-X-phenylsulfonyl)phenyl)-4-(n-propyl)-2H-1,2,4-triazole-3(4H)-thiones (X= Cl or Br) with some alkylation agents. Thus, new S-alkylated 1,2,4-triazole derivatives were synthesized by reaction of the corresponding 1,2,4-triazole-3-thione derivatives with different �-halogenated compounds (ethyl bromide, ethyl chloroacetate or phenacyl bromide), in basic medium. The structures of synthesized compounds were elucidated by spectral data (1H-NMR, 13C-NMR, mass spectrometry) and elemental analysis.

scholarly journals (2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol

Molbank ◽  
10.3390/m1140 ◽  
2020 ◽  
Vol 2020 (2) ◽  
pp. M1140
Author(s):  
Jack Bennett ◽  
Paul Murphy
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
13C Nmr ◽  
Conjugate Addition ◽  
13C Nmr Spectroscopy ◽  
One Pot ◽  
1H And 13C Nmr ◽  
Esi Mass Spectrometry ◽  
The One

(2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol was isolated in 18% after treating the glucose derived (5R,6S,7R)-5,6,7-tris[(triethylsilyl)oxy]nona-1,8-dien-4-one with (1S)-(+)-10-camphorsulfonic acid (CSA). The one-pot formation of the title compound involved triethylsilyl (TES) removal, alkene isomerization, intramolecular conjugate addition and ketal formation. The compound was characterized by 1H and 13C NMR spectroscopy, ESI mass spectrometry and IR spectroscopy. NMR spectroscopy was used to establish the product structure, including the conformation of its tetrahydropyran ring.

scholarly journals 13C-NMR of Polyisoprenes: Sequence Distribution of cis-1,4 and trans-1,4 Units

1975 ◽  
Vol 7 (2) ◽  
pp. 264-266 ◽  
Author(s):  
Yasuyuki Tanaka ◽  
Hisaya Sato ◽  
Takeshi Seimiya
Keyword(s):  
13C Nmr ◽  
Sequence Distribution

scholarly journals Rearrangement of spiroderivatives of 1,3-benzo(naphtho)dioxin-4(1)-ones as a new method of synthesis of xanthene bromo derivatives

2021 ◽  
pp. 73-77
Author(s):  
A.V. Kovtun ◽  
◽  
S.A. Varenichenko ◽  
E.V. Zaliznaya ◽  
A.V. Mazepa ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
13C Nmr ◽  
Bromine Atom ◽  
Sodium Perchlorate ◽  
Building Blocks ◽  
Dimethylamino Group ◽  
1H And 13C Nmr ◽  
Molecular Building Blocks ◽  
Derivatives Of ◽  
Fold Excess

We have proposed a method for the synthesis of previously unknown bromo xanthenes using the reagent PBr3/DMF as a rearrangement initiator. Bromo derivatives of xanthenes in the form of organic perchlorates were prepared by reacting the corresponding benzo(naphtho)dioxin-4(1)-ones with a three-fold excess of Vilsmeier-Haack PBr3/DMF reagent at 1100C for 2 hours, followed by the addition of sodium perchlorate. The conditions for the synthesis of formyl derivatives of xanthenes under conditions of acid hydrolysis were selected. The structure of the compounds was confirmed by 1H and 13C NMR spectral data and mass spectrometry. Preliminary studies showed that it is possible to selectively replace the dimethylamino group and the bromine atom with various nucleophiles in bromo derivatives of xanthenes, which opens up wide possibilities for the synthesis of low-molecular building blocks and dyes.

scholarly journals Design of Pure Heterodinuclear Lanthanoid Cryptate Complexes

2021 ◽  
Author(s):  
Christian Dirk Buch ◽  
Steen Hansen ◽  
Dmitri Mitcov ◽  
Camilla Mia Tram ◽  
Gary Nichol ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Magnetic Properties ◽  
13C Nmr ◽  
Exchange Coupling ◽  
Lanthanide Ions ◽  
Squid Magnetometry ◽  
Counter Ion ◽  
Synthetic Procedure ◽  
Optical And Magnetic Properties ◽  
Fine Tune

Heterolanthanide complexes are difficult to synthesize owing to the similar chemistry of the lanthanide ions. Conse-quently, very few purely heterolanthanide complexes have been synthesized. This is despite the fact that such complexes hold inter-esting optical and magnetic properties. To fine-tune these properties, it is important that one can choose complexes with any given combination of lanthanides. Herein we report a synthetic procedure which yields pure heterodinuclear lanthanide cryptates LnLn*LX3 (X = NO3- or OTf-) based on the cryptand H3L = N[(CH2)2N=CH-R-CH=N-(CH2)2]3N (R = m-C6H2OH-2-Me-5). In the synthesis the choice of counter ion and solvent prove crucial in controlling the Ln-Ln*composition. Choosing the optimal solvent and counter ion affords pure heterodinuclear complexes with any given combination of Gd(III)-Lu(III) including Y(III). To demon-strate the versatility of the synthesis all dinuclear combinations of Y(III), Gd(III), Yb(III) and Lu(III) were synthesized resulting in 10 novel complexes of the form LnLn*L(OTf)3 with LnLn* = YbGd 1, YbY 2, YbLu 3, YbYb 4, LuGd 5, LuY 6, LuLu 7, YGd 8, YY 9 and GdGd 10. Through the use of 1H, 13C NMR and mass spectrometry the heterodinuclear nature of YbGd, YbY, YbLu, LuGd, LuY and YGd was confirmed. Crystal structures of LnLn*L(NO3)3 reveal short Ln-Ln distances of ~3.5 Å. Using SQUID magnetometry the exchange coupling between the lanthanide ions was found to be anti-ferromagnetic for GdGd and YbYb while ferromagnetic for YbGd.

Synthesis of urease inhibitory 2, 4-bis (4-cyanobenzyl)glycoluril using sandmeyer reaction and density functional theory investigation

2021 ◽  
Vol 18 ◽  
Author(s):  
Mirza Arfan Yawer ◽  
Shehar Bano ◽  
Muhammad Saleem ◽  
Affiefa Yawer ◽  
Riaz Hussain ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Density Functional Theory ◽  
1H Nmr ◽  
13C Nmr ◽  
Density Functional ◽  
Spectroscopic Techniques ◽  
Pure Compound ◽  
Functional Theory ◽  
Sandmeyer Reaction ◽  
Urease Enzyme

Aims: The aim of present research was to synthesize glycoluril derivative 2,4-Bis(4-cyanobenzyl)glycoluril through convergent scheme. Background: For this purpose Sandmeyer reaction procedure was employed for the synthesis of said compound. The structure of the pure compound was confirmed by using different spectroscopic techniques such as 1H-NMR, 13C-NMR and (HR-MS) Mass spectrometry. Objective: Convergent synthesis of 2,4-BIS (4-CYANOBENZYL)GLYCOLURIL USING SANDMEYER REACTION and urease inhibition study. Methods: The structure of the pure compound was confirmed by using different spectroscopic techniques such as 1H-NMR, 13C-NMR and (HR-MS) Mass spectrometry. The electronic properties of newly synthesized compound and thiourea were determined by using density functional theory. Results: Furthermore compound was evaluated against urease enzyme and was found to be potent inhibitors with IC50 value of 11.5 ± 1.50 µM when compared with standard inhibitor thiourea (IC50 = 21.0 ± 1.90 µM). Compound may serve as lead compound for the synthesis of new cyano based bambusuril in future with enhanced biological properties. Conclusion: We have synthesized a new glycoluril derivative 2,4-Bis(4-cyanobenzyl)glycoluril by the sandmeyer reaction. It has obtained in the form of light yellowish powder in good yield (96%). Glycoluril based macrocycles have been used in various fields. Starting from the 2,4-Bis(4-nitrobenzyl)glycoluril (already reported compound) which has undergone reduction (CH3OH,Pt/C) , diazotization (NaNO2/HCl), cyanation (CuCl/KCN) respectively in order to synthesize the desired new glycoluril derivative. The obtained product will be used as a building block for the synthesis of the cyano based bambusuril marcocycle in future. The yield of the obtained product has been monitored by using different amount of cyanating reagent but the best results shown by the use of 4 mmol of CuCl/KCN. KCN with CuCl assisted the conversion of diazo group into cyano group with enhanced yield when used in excess amount. It act as a catalyst. Solubility characteristic of 2,4-Bis(4-cyanobenzyl)glycoluril has determined also in different organic solvents. 1H NMR technique proved to be very helpful for the structure determination of our desired product. Benzylic protons give signals at 7.5 ppm and 7.8 ppm respectively. The downfield peaks confirm about the presence of CN group near the benzylic protons. Methine protons show signal at 5.2 ppm which ensures about the basic skeleton of glycoluril. Ureidyl protons also confirm the synthesis of the heterocyclic 2,4-Bis(4-cyanobenzyl)glycoluril compound. The negative and positive electrostatic potential sites, molecular descriptors, and charge density distribution of frontier molecular orbitals are revealing that 4a with promising sites for electrophilic and nucleophilic attacks would result to enhance the urease inhbition which is in good agreement with the experimental data.

scholarly journals Reducing-End Functionalization of 2,5-Anhydro-d-mannofuranose-Linked Chitooligosaccharides by Dioxyamine: Synthesis and Characterization

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1143 ◽  
Author(s):  
Maxence Coudurier ◽  
Jimmy Faivre ◽  
Agnès Crépet ◽  
Catherine Ladavière ◽  
Thierry Delair ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
13C Nmr ◽  
Nitrous Acid ◽  
Chemical Structure ◽  
Chemical Method ◽  
Reductive Amination ◽  
High Mass ◽  
Synthesis And Characterization ◽  
1H And 13C Nmr ◽  
Chitosan Oligosaccharides

The nitrous acid depolymerization of chitosan enables the synthesis of singular chitosan oligosaccharides (COS) since their reducing-end unit is composed of 2,5-anhydro-d-mannofuranose (amf). In the present study, we describe a chemical method for the reducing-end conjugation of COS-amf by the commercially available dioxyamine O,O′-1,3-propanediylbishydroxylamine in high mass yields. The chemical structure of resulting dioxyamine-linked COS-amf synthesized by both oximation and reductive amination ways were fully characterized by 1H- and 13C-NMR spectroscopies and MALDI-TOF mass spectrometry. The coupling of chemically attractive linkers such as dioxyamines at the reducing end of COS-amf forms a relevant strategy for the development of advanced functional COS-based conjugates.

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