Absorption-Mode Phase-Sensitive Zero-Quantum-Coherence Correlation Spectroscopy

1993 ◽  
Vol 105 (2) ◽  
pp. 193-203 ◽  
Author(s):  
T.J. Norwood
Keyword(s):  
Quantum Coherence ◽  
Correlation Spectroscopy ◽  
Phase Sensitive ◽  
Absorption Mode

Two-dimensional NMR studies of acrylate copolymers

2009 ◽  
Vol 81 (3) ◽  
pp. 389-415 ◽  
Author(s):  
A. S. Brar ◽  
Ashok Kumar Goyal ◽  
Sunita Hooda
Keyword(s):  
Methyl Methacrylate ◽  
Methyl Acrylate ◽  
Quantum Coherence ◽  
Multiple Bond ◽  
Microstructural Analysis ◽  
2D Nmr ◽  
Correlation Spectroscopy ◽  
Nmr Studies ◽  
Poly Methyl Methacrylate ◽  
Nmr Study

High-resolution NMR spectroscopy is the most versatile, reliable, and generally acceptable technique for the determination of the microstructure of polymers. 2D NMR techniques, along with 1D NMR, have more potential to study absolute configurational assignments and sequence distribution of copolymers. Physical and chemical properties of polymers are influenced fundamentally by their microstructure. We discuss the detailed microstructure analysis of a large number of homopolymers, copolymers, and terpolymers. 2D NMR study of poly(methyl methacrylate) (PMMA), poly(methyl acrylate) (PMA), and poly(methacrylonitrile) (PMAN) is discussed in this article. In addition to homopolymers, 2D heteronuclear single-quantum coherence (HSQC), total correlation spectroscopy (TOCSY), and heteronuclear multiple-bond correlation (HMBC) study of different copolymers such as poly(methyl methacrylate-co-methyl acrylate), poly(styrene-co-methyl methacrylate), and poly(methyl methacrylate-co-methacrylonitrile) have also been reported here. This in turn helps in microstructural analysis of terpolymers such as poly(methacrylonitrile-co-styrene-co-methyl methacrylate), poly(acrylonitrile-co-methyl methacrylate-co-methyl acrylate), and poly(ethylene-co-vinyl acetate-co-carbon monoxide).

scholarly journals Boosting the resolution of multidimensional NMR spectra by complete removal of proton spin multiplicities

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Peyman Sakhaii ◽  
Bojan Bohorc ◽  
Uwe Schliedermann ◽  
Wolfgang Bermel
Keyword(s):  
Quantum Coherence ◽  
Structural Connectivity ◽  
Complete Removal ◽  
Proton Spin ◽  
Multidimensional Nmr ◽  
Random Delay ◽  
Multiplet Structure ◽  
Phase Sensitive ◽  
Indispensable Tool ◽  
Doublet Splitting

AbstractOver decades multidimensional NMR spectroscopy has become an indispensable tool for structure elucidation of natural products, peptides and medium sized to large proteins. Heteronuclear single quantum coherence (HSQC) spectroscopy is one of the work horses in that field often used to map structural connectivity between protons and carbons or other hetero nuclei. In overcrowded HSQC spectra, proton multiplet structures of cross peaks set a limit to the power of resolution and make a straightforward assignment difficult. In this work, we provide a solution to improve these penalties by completely removing the proton spin multiplet structure of HSQC cross peaks. Previously reported sideband artefacts are diminished leading to HSQC spectra with singlet responses for all types of proton multiplicities. For sideband suppression, the idea of restricted random delay (RRD) in chunk interrupted data acquisition is introduced and exemplified. The problem of irreducible residual doublet splitting of diastereotopic CH2 groups is simply solved by using a phase sensitive JRES approach in conjunction with echo processing and real time broadband homodecoupling (BBHD) HSQC, applied as a 3D experiment. Advantages and limitations of the method is presented and discussed.

A norterpenoid and tripenoids from Commiphora mukul: isolation and biological activity

2017 ◽  
Vol 72 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Najeeb Ur Rehman ◽  
Hidayat Hussain ◽  
Husain Yar Khan ◽  
René Csuk ◽  
Ghulam Abbas ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Quantum Coherence ◽  
Nuclear Overhauser Effect ◽  
Multiple Bond ◽  
Cancer Cell Line ◽  
Inhibitory Effect ◽  
Correlation Spectroscopy ◽  
Ionization Mass ◽  
Commiphora Mukul ◽  
Substantial Decline

AbstractBio-guided fractionation of the guggul gum resin of Commiphora mukul HOOK using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay for the breast cancer cell line MDA-MB-231 led to the isolation of a new C17 norditerpene named myrrhanone C (1) along with two known polypodane-type triterpenes, namely, myrrhanone B (2) and myrrhanol B (3). The structures of the isolated compounds were elucidated by means of 1D (1H and 13C) and 2D (correlation spectroscopy, heteronuclear single-quantum coherence, heteronuclear multiple-bond correlation, and nuclear Overhauser effect spectroscopy) NMR spectroscopy as well as mass (electrospray ionization-mass spectroscopy) spectral analyses. Interestingly myrrhanone C (1) was able to induce a substantial decline in cell proliferation. It reduced the viability of cancer cells by almost 81% and 87% at concentrations of 50 and 100 μg mL−1, respectively. Myrrhanone B (2) and myrrhanol B (3) showed a concentration-dependent growth inhibitory effect on cancer cells, with the latter being slightly more cytotoxic than the former at both the concentrations tested. Furthermore, myrrhanone C (1) and myrrhanone B (2) showed good α-glucosidase and urease inhibition.

The isolation and structural elucidation of a new iridoid glycoside from Cymbaria dahurica L.

2018 ◽  
Vol 73 (6) ◽  
pp. 377-379 ◽  
Author(s):  
Cui-Lan Bai ◽  
Qing-Hu Wang ◽  
Yan-Hua Xu ◽  
Jun-Sheng Han ◽  
Yin-Ping Bao
Keyword(s):  
Quantum Coherence ◽  
Nuclear Overhauser Effect ◽  
Multiple Bond ◽  
2D Nmr ◽  
Iridoid Glycoside ◽  
Correlation Spectroscopy ◽  
Etoac Extract ◽  
Overhauser Effect ◽  
Nuclear Overhauser ◽  
C Nmr

AbstractA new iridoid glycoside, namely, cymdahoside A (1), together with two known ones, 2 and 3, were isolated from the EtOAc extract of Cymbaria dahurica. The structure elucidation of 1 was carried out by one-dimensional (1D) NMR (1H and 13C NMR) and 2D NMR (correlation spectroscopy, heteronuclear single-quantum coherence, heteronuclear multiple-bond correlation and nuclear Overhauser effect spectroscopy) spectral analyses.

scholarly journals 6-Nitro-7-tosylquinazolin-4(3H)-one

Molbank ◽  
10.3390/m1168 ◽  
2020 ◽  
Vol 2020 (4) ◽  
pp. M1168
Author(s):  
Thi Ngoc Nguyen ◽  
Thi Phuong Thuy Tran ◽  
Thi Hoang Mai Vu ◽  
Hoa Binh Nguyen ◽  
Nguyet Suong Huyen Dao ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Quantum Coherence ◽  
Multiple Bond ◽  
Growth Factor Receptor ◽  
Functional Materials ◽  
Building Blocks ◽  
Correlation Spectroscopy ◽  
Biologically Active ◽  
Ft Ir ◽  
Epidermal Growth

Sulfones are important building blocks in the construction of biologically active molecules or functional materials. The sulfonyl functional group in sulfones is so versatile that it can act as either a nucleophile, an electrophile, or a radical in different organic reactions. Recently, quinazoline sulfones have been used to build asymmetrical ether derivatives as inhibitors of signaling pathways governed by tyrosine kinases and the epidermal growth factor-receptor. In this paper, we report a facile synthesis of a novel quinazoline sulfone, 6-nitro-7-tosylquinazolin-4(3H)-one (III), using the modified protocol from 7-chloro-6-nitroquinazolin-4(3H)-one (I) and sodium p-toluenesulfinate (II). The structure of the title compound III was determined using mass-spectrometry, FT-IR, 1H-NMR, 13C-NMR, DEPT, HSQC (Heteronuclear single quantum coherence), HMBC (Heteronuclear Multiple Bond Correlation Spectroscopy) spectroscopies, and PXRD analysis.

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