A carbon-13 CP/MAS nuclear magnetic resonance study of several 1,4-disubstituted benzenes in the solid state

Penner, Glenn H.; Wasylishen, Roderick E.

doi:10.1139/v89-080

Cited by 20 publications

(6 citation statements)

References 36 publications

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“…C-2 is greatly shielded compared with C-6" and its signal comes beneath the C-3,5 signal. 16 The assignments of C-1 and C-4 differ from the previous studyI6 but are consistent with those of Gowenlock and co-workers,zO*zl where C-1-N-0 carbons always occur at 8 2 162. On warming the sample of 1 the C-6 signal broadens considerably and a broad, low-frequency shoulder appears on the C-3,5 signal which is attributed to C-2.…”

Section: Compoundsupporting

confidence: 87%

Dynamic NMR study of the factors governing nitroso group rotation in p‐nitrosoanilines in the solution and solid states

Fletcher

Gowenlock

Orrell

et al. 1995

Magnetic Reson in Chemistry

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The energy barriers associated with N=O rotation in a series of p-nitrosoanilines were measured by the total bandshape NMR method. Energies [AG (298.15 K)] are in the range 38-57 kJ mol-', the magnitudes being lowered appreciably by the presence of methyl substituents flanking the nitroso group on either side. In the case of pnitrost+N,N-dimethylaniline, N=O rotation has been shown to occur also in the solid state with a slightly higher energy barrier to that in the dissolved state. For p-nitroso-N-methylaniline, a combination of 2D-exchange spectroscopy (EXSY) and 1D-bandshape analysis NMR methods enabled the barriers to N -0 rotation and NHMe rotation to be measured separately.

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Section: Compoundsupporting

confidence: 87%

Dynamic NMR study of the factors governing nitroso group rotation in p‐nitrosoanilines in the solution and solid states

Fletcher

Gowenlock

Orrell

et al. 1995

Magnetic Reson in Chemistry

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“…The solvent was removed and the residue was purified by column chromatography. The analytical properties of the corresponding sulfides are in agreement with literature[63][64][65][66][67][68][69][70][71].Diphenylsulfide (1a): R f = 0.75 (n-hexane:ethyl acetate 1:5); 1 H NMR (CDCl 3 , 200 MHz): d = 7.26-7.47 ppm (m, 10H); 13 C NMR (CDCl 3 , 50 MHz): d = 135.8, 131.0, 129.2, 127.0 ppm; MS (ESI) m/z = 186 (100, M ? ), 152 (11), 92 (19), 77 (27), 65 (20), 51 (43).…”

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confidence: 88%

Reduction of Sulfoxides to Sulfides in the Presence of Copper Catalysts

Enthaler

Weidauer

2011

Catal Lett

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Copper complexes catalyze the reduction of aliphatic and aromatic sulfoxides in the presence of silanes as reducing reagent. The influence of different reaction parameters on the catalytic activity is investigated in detail. The scope and limitations of the described catalyst is demonstrated in the reduction of various sulfoxides. In most cases, high conversion and excellent chemoselectivity are obtained.

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“…Flash column separation of this layer over silica gel afforded three previously unreported chemical entities (1-3) along with twentyfour known compounds. The known compounds were identified to be methyl 4-hydroxybenzoate (4) [18], β-sitosterol (5) [19], (Z)-2-methyl-6-oxo-2-hepten-1-ol (6) [20], gallic acid (7) [21], 4-hydroxyphenyl-2-ethyl β-D-glucopyranoside (8) [22], tyrosol (9) [23], methyl gallate (10) [24], p-coumaric acid (11) [25], caffeic acid (12) [25], aspergillol B (13) [26], 2R,3R-dihydrokaempferol (14) [27], (E)-2-methyl-6-oxo-2-hepten-1-ol (15) [33], creoside III (25) [33], salidroside (26) [34], and icariside D2 (27) [35] based on spectroscopic data analysis and comparison to the literature. Compound 1, obtained as amorphous white powder, had a formula of C 41 H 32 O 24 , as determined using 13 (C-5), δ H 2.12 (H 3 -7)/δ C 211.4 (C-6) and 43.7 (C-5) and δ H 4.22 (H-1′)/δ C 75.6 (C-1) indicated that the aglycone of 2 was connected with the C-1′ of β-D-glucopyranoside via an ether linkage to form creoside I.…”

mentioning

confidence: 99%

Anti-MMP-2 Activity and Skin-Penetrating Capability of the Chemical Constituents from Rhodiola rosea

et al. 2016

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Introduction !Matrix metalloproteinases (MMPs) are a family of zinc-and calcium-dependent endopeptidases, which are grouped into the metzincin clan of metallopeptidases (MPs) together with other families such as ADAMs/adamalysins, astacins, fragilysins, and serralysins. MMPs are found throughout the animal and plant kingdoms, where their distribution is consistent with a Darwinian tree-based pathway [1]. Furthermore, polyplication has led to the presence of several paralogous MMP genes in the same organism: 24 in humans, 26 in sea urchins, 26 in zebrafish, 7 in sea squirts, and 2 in fruit flies. Overexpression of MMPs may cause various inflammatory, malignant, and degenerative symptoms [2]. Among the MMPs studied, gelatinase-A (MMP-2), gelatinase-B (MMP-9), and collagenase-1 (MMP-1) were reported to be responsible for the signal transduction of dermal photoaging [3], and inhibition of the activities of these two enzymes could potentially slow down skin aging. Thus, the search for bioactive compounds that can regulate the activities of MMP-1, -2, and -9 from natural resources is one of the key steps in delaying skin aging. [16]. In a preliminary biological evaluation, crude extracts of R. rosea roots exhibited inhibitory activities toward MMP-2 and collagenase at a concentration of 100 µg/mL [17]. An investigation of the active principles of this plant was thus undertaken by using a bioassayguided method. Of the tested water, n-butanol, and ethyl acetate layers, the ethyl acetate layer Abstract ! Based on the significant inhibitory activity toward matrix metalloproteinase-2 and collagenase noticed in preliminary studies, crude extracts of Rhodiola rosea were partitioned and chromatographed sequentially to afford three new compounds, 1,2,3,6-tetra-O-galloyl-4-O-p-hydroxybenzoyl-β-D-glucopyranoside (1), (E)-creoside I (2), and (R,Z)-2-methylhept-2-ene-1,6-diol (3), along with twenty-four known compounds (4-27). Their structures were determined by spectroscopic data analyses. All isolated compounds were subjected to bioactivity assays. In these, 1 specifically inhibited matrix metalloproteinase-2 activity with an IC 50 value of 16.3 ± 1.6 µM, while its analogue 1,2,3,6-tetra-O-galloyl-β-D-glucopyranonoside (17) inhibited matrix metalloproteinase-2 with an IC 50 value of 23.0 ± 4.8 µM. In the collagenase activity assay, the inhibitory effects of 1 and 17 at concentrations of both 20 and 40 µM were more potent than those of the positive control, 1,10-phenanthroline. In order to realize whether 17 could penetrate from the epidermal layer into the basal and dermal layers of the human skin to inhibit the activity of matrix metalloproteinase-2 and collagenase or not, a transdermal penetration test in nude and white mice skins was performed. Penetration percentages of 17 quantified by LC-MS were 27.8 % and 74.8 % in 24 hours, respectively. Supporting information available online at

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A carbon-13 CP/MAS nuclear magnetic resonance study of several 1,4-disubstituted benzenes in the solid state

Cited by 20 publications

References 36 publications

Dynamic NMR study of the factors governing nitroso group rotation in p‐nitrosoanilines in the solution and solid states

Dynamic NMR study of the factors governing nitroso group rotation in p‐nitrosoanilines in the solution and solid states

Reduction of Sulfoxides to Sulfides in the Presence of Copper Catalysts

Anti-MMP-2 Activity and Skin-Penetrating Capability of the Chemical Constituents from Rhodiola rosea

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