keyword
MENU ▼
Read by QxMD icon Read
search

Ortho

keyword
https://www.readbyqxmd.com/read/29351263/twenty-nine-new-limonoids-with-skeletal-diversity-from-the-mangrove-plant-xylocarpus-moluccensis
#1
Jianzhi Zhang, Wanshan Li, Yiguo Dai, Li Shen, Jun Wu
Twenty-nine new limonoids-named xylomolins A₁-A₇, B₁-B₂, C₁-C₂, D-F, G₁-G₅, H-I, J₁-J₂, K₁-K₂, L₁-L₂, and M-N, were isolated from the seeds of the mangrove plant, Xylocarpus moluccensis. Compounds 1-13 are mexicanolides with one double bond or two conjugated double bonds, while 14 belongs to a small group of mexicanolides with an oxygen bridge between C1 and C8. Compounds 15-19 are khayanolides containing a Δ8,14 double bond, whereas 20 and 21 are rare khayanolides containing a Δ14,15 double bond and Δ8,9, Δ14,15 conjugated double bonds, respectively...
January 19, 2018: Marine Drugs
https://www.readbyqxmd.com/read/29351200/comparing-nutrient-removal-from-membrane-filtered-and-unfiltered-domestic-wastewater-using-chlorella-vulgaris
#2
Elyssia Mayhead, Alla Silkina, Carole A Llewellyn, Claudio Fuentes-Grünewald
The nutrient removal efficiency of Chlorella vulgaris cultivated in domestic wastewater was investigated, along with the potential to use membrane filtration as a pre-treatment tool during the wastewater treatment process. Chlorella vulgaris was batch cultivated for 12 days in a bubble column system with two different wastewater treatments. Maximum uptake of 94.18% ammonium (NH₄-N) and 97.69% ortho-phosphate (PO₄-P) occurred in 0.2 μm membrane filtered primary wastewater. Membrane filtration enhanced the nutrient uptake performance of C...
January 19, 2018: Biology
https://www.readbyqxmd.com/read/29350934/a-molecular-electron-density-theory-study-of-the-reactivity-and-selectivities-in-3-2-cycloaddition-reactions-of-c-n-dialkyl-nitrones-with-ethylene-derivatives
#3
Luis R Domingo, Mar Ríos-Gutiérrez, Patricia Pérez
The zw-type [3+2] cycloaddition (32CA) reactions of C,N-dialkyl nitrones with a series of ethylenes of increased electrophilic character have been studied within the Molecular Electron Density Theory (MEDT) at the MPWB1K/6-311G(d,p) computational level. Both, reactivity and selectivities are rationalised depending on the polar character of the reaction. Due to the strong nucleophilic character of C,N-dialkyl nitrones, the corresponding zw-type 32CA reactions are accelerated with the increased electrophilic character of the ethylene, which also plays a crucial role in the reaction mechanism, thus determining the regio- and stereoselectivities experimentally observed...
January 19, 2018: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29350226/the-ortho-benzyne-cation-is-not-planar
#4
D Kaiser, E Reusch, P Hemberger, A Bodi, E Welz, B Engels, I Fischer
A recent review on the photoionisation of the C6H4 isomer ortho-benzyne suggests that bands reported in earlier photoelectron spectra might be due to side products or contaminations, while computations raise doubts, whether the cation has a planar geometry. We therefore reinvestigate the photoionisation of ortho-benzyne, generated by pyrolysis from benzocyclobutenedione, by photoion mass-selected threshold photoelectron (ms-TPE) spectroscopy using synchrotron radiation. The experiments are accompanied by a theoretical study that investigates the structure of the ortho-benzyne cation systematically as a function of the computational method, up to CASPT2(11,14) ab initio computations...
January 19, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29350042/application-of-sulfur-ylides-in-1-2-difunctionalization-of-arynes-via-insertion-into-a-c-s-%C3%AF-bond
#5
Milind M Ahire, Mahesh B Thoke, Santosh B Mhaske
A novel reactivity of sulfur ylides has been demonstrated in a transition-metal-free protocol to access ortho-substituted thioanisole derivatives by insertion of arynes into a C-S σ-bond in moderate to good yields. The reaction involves the formation of C-C and C-S bonds and consecutive breaking of two C-S bonds under operationally mild reaction conditions.
January 19, 2018: Organic Letters
https://www.readbyqxmd.com/read/29348095/estimation-of-simvastatin-and-cetirizine-by-rp-lc-method-application-to-freeze-and-thaw-ft-stability-studies
#6
Safila Naveed, Khan Usmanghani, Aisha Sana, Huma Ali, Farya Zafar, Fatima Qamar, Ghulam Sarwer, Sarah Abbas, M Tanweer Alam, Muhammad Ibrar Shinwari
Sensitive, simple, reliable and rapid HPLC technique for the estimation of simvastatin (SMV) and cetirizine has been designed in this study. The chromatographic conditions were set using Shimadzu LC-10 AT VP pump, with UV detector (SPD-10 AV-VP). System integration was performed with CBM-102 (Bus Module). Partitioning of components was attained with pre-packed C-18 column of Purospher Star (5 μm, 250 x 4.6 mm) at ambient conditions. Injected volume of sample was 10 μl. Mobile phase was composed of 50:50 v/v ratio of Acetonitrile/water (pH 3...
January 2018: Pakistan Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/29345936/copper-catalyzed-one-pot-cross-dehydrogenative-thienannulation-chemoselective-access-to-naphtho-2-1-b-thiophene-4-5-diones-and-subsequent-transformation-to-benzo-a-thieno-3-2-c-phenazines
#7
Gaurav Shukla, Abhijeet Srivastava, Dhananjay Yadav, Maya Shankar Singh
A facile, cost-effective and highly efficient copper-catalyzed, TEMPO-mediated straightforward synthesis of 2,3-disubstituted naphtho[2,1-b]thiophene-4,5-diones has been achieved via Cross-Dehydrogenative Thienannulation (CDT). The reaction proceeded via in situ generated naphthalene-1,2-diones by dearomatization of β-naphthols, followed by oxidative heteroannulation with α-enolic dithioesters chemoselectively in an open-flask. Further, the naphtho[2,1-b]thiophene-4,5-diones undergo L-Proline-catalyzed cross-dehydrative coupling with ortho-phenylenediamine enabling pentacyclic benzo[a]thieno[3,2-c]phenazines in good yields under solvent-free conditions...
January 18, 2018: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29345002/remote-c-h-activation-of-various-n-heterocycles-using-a-single-template
#8
Guoqiang Yang, Dajian Zhu, Peng Wang, Ri-Yuan Tang, Jin-Quan Yu
A single simple ortho-sulfonyl benzonitrile template was developed to achieve remote C-H olefination of six different classes of N-heterocycles. We demonstrate that, by varying precatalysts and conditions, the same template can be applied to the remote C-H activation of six structurally distinct heterocyclic scaffolds, and the site-selectivity can be predicted based on distance and geometry. Furthermore, this new development shows that template-directed remote C-H activation are possible via macrocyclopalladation processes with smaller ring sizes...
January 18, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29344916/the-acute-effects-of-erythromycin-and-oxytetracycline-on-enhanced-biological-phosphorus-removal-system-shift-in-bacterial-community-structure
#9
Zhetai Hu, Peide Sun, Jingyi Han, Ruyi Wang, Liang Jiao, Pengfei Yang, Jing Cai
Since extensive application, an increasing amount of antibiotics has been released into wastewater treatment plants. In this study, the enhanced biological phosphorus removal (EBPR) system was fed with synthetic wastewater containing erythromycin (ERY) and oxytetracycline (OTC) for 7 days to evaluate the variations of solution ortho-P (SOP), volatile fatty acid (VFA), poly-bhydroxyalkanoates (PHAs), specific oxygen uptake rater (SOUR), and microbial community in the EBPR system. The obtained results showed that the P-removal efficiency decreased to 0...
January 18, 2018: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29344439/regiochemical-control-in-triptycene-formation-an-exercise-in-subtle-balancing-multiple-factors
#10
Jan-Hendrik Lamm, Yury V Vishnevskiy, Eric Ziemann, Beate Neumann, Hans-Georg Stammler, Norbert W Mitzel
Reactions between 1,8-dichloroanthracenes with substituents in position 10 and ortho-chloroaryne afford mixtures of 1,8,13- (syn) and 1,8,16-trichlorotriptycenes (anti). The syn/anti ratio is dependent on these substituents. Electropositive substituents like SiMe3 and GeMe3 lead to preferred formation of the syn-isomer, whereas CMe3 groups exclusively afford the anti-isomer. Different quantum chemical calculations including location of transition states give conflicting results, but indicate the importance of dispersion forces for an at least qualitative prediction of results...
January 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29341302/twisted-charge-transfer-antennas-for-ultra-bright-terbium-iii-and-dysprosium-iii-bioprobes
#11
Anh Thy Bui, Amandine Roux, Alexei Grichine, Alain Duperray, Chantal Andraud, Olivier Maury
The design of original twisted charge transfer antennas where a non planar geometry is enforced thanks to one or two bulky ortho-Me substituents allows us to prepare the corresponding ultra-bright Tb(III) and Dy(III) bioprobes. The brightness of the Tb(III) derivative compares well with that of the benchmark Tb-Lumi4 complex. The first bio-imaging experiments with a Dy(III) luminescent bioprobe are also reported.
January 17, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29338244/synthesis-and-reaction-of-ortho-benzoquinone-monohemiaminals
#12
Emi Saito, Yuri Matsumoto, Akihiko Nakamura, Yuki Namera, Masahisa Nakada
The preparation and reactions of ortho-benzoquinone monohemiaminals are described. The oxidative dearomatization of phenols bearing amino alcohol groups induced N-cyclization to afford ortho-benzoquinone monohemiaminals. The N-cyclization stereoselectively affords the product when a chiral amino alcohol is used as the substituent. The chiral ortho-benzoquinone monohemiaminal undergoes stereoselective Diels-Alder reactions with electron-deficient alkenes, as expected, confirming the promising utility of ortho-benzoquinone monohemiaminals...
January 17, 2018: Organic Letters
https://www.readbyqxmd.com/read/29337346/effective-role-of-medium-supplementation-in-microalgal-lipid-accumulation
#13
Azadeh Fazeli Danesh, Peter Mooij, Sirous Ebrahimi, Robbert Kleerebezem, Mark van Loosdrecht
The present study investigated the interaction between starch and lipid accumulation was in a green microalgae enrichment culture. The objective was to optimize the lipid content by manipulation of the medium in regular batch culture. Two medium designs were evaluated: first a high ortho-P concentration with vitamin supplement (Pi-vitamins supplemented medium), second normal growth medium (control). Both media contained a low amount of nitrogen which was consumed during batch growth in three days. The batch experiments were prolonged continued for another four days with the absence of soluble nitrogen in the medium...
January 16, 2018: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/29336509/the-investigation-of-substituent-effects-on-the-fragmentation-pathways-of-pentacoordinated-phenoxyspirophosphoranes-by-esi-msn
#14
Xiaoyan Cui, Can Sun, Pei Zhao, Yanyan Wang, Yanchun Guo, Yufen Zhao, Shuxia Cao
The fragmentation pathways of pentacoordinated phenoxyspirophosphoranes were investigated in the positive mode by electrospray ionization multistage mass spectrometry (ESI-MSn ). The results demonstrate that the sodium adducts of the title compounds undergo two competitive fragmentation pathways, and the fragmentation patterns are heavily dependent on the various substituent patterns at the phenolic group. An electron-withdrawing substituent at the ortho-position always results in the removal of a corresponding phenol analogue, while cleavage by spiroring opening becomes the predominant fragmentation pathway if an electron-donating substituent is at the phenolic group...
January 16, 2018: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/29335845/carnosic-acid-as-a-promising-agent-in-protecting-mitochondria-of-brain-cells
#15
REVIEW
Marcos Roberto de Oliveira
Carnosic acid (CA; C20H28O4), a phenolic diterpene characterized as an ortho-dihydroquinone-type molecule, is a pro-electrophile agent that becomes an electrophile after reacting with free radicals. The electrophile generated from CA interacts with and activates the nuclear factor erythroid 2-related factor 2 (Nrf2) transcription factor, which is a major modulator of redox biology in mammalian cells. CA induces antioxidant and anti-inflammatory effects in several cell types, as observed in both in vitro and in vivo experimental models...
January 15, 2018: Molecular Neurobiology
https://www.readbyqxmd.com/read/29335207/synthesis-and-biological-evaluation-of-3-2-aminoethyl-uracil-derivatives-as-gonadotropin-releasing-hormone-gnrh-receptor-antagonists
#16
Seon-Mi Kim, Minhee Lee, So Young Lee, Soo-Min Lee, Eun Jeong Kim, Jae Sun Kim, Jihyae Ann, Jiyoun Lee, Jeewoo Lee
We investigated a series of uracil analogues by introducing various substituents on the phenyl ring of the N-3 aminoethyl side chain and evaluated their antagonistic activity against human gonadotropin-releasing hormone (GnRH) receptors. Analogues with substituents at the ortho or meta position demonstrated potent in vitro antagonistic activity. Specifically, the introduction of a 2-OMe group enhanced nuclear factor of activated T-cells (NFAT) inhibition up to 6-fold compared to the unsubstituted analogue...
January 2, 2018: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29334464/asymmetric-synthesis-of-secondary-and-tertiary-propargylic-alcohols-by-umpolung-of-acetylenic-sulfones-and-ortho-sulfinyl-carbanions
#17
Ricardo I Rodriguez, Elsie Ramírez, Francisco Yuste, Ruben Sanchez-Obregon, José Alemán
The generation of diasteromerically enriched secondary benzyl propargyl alcohols by the asymmetric addition of ortho-sulfinylbenzyl carbanions to sulfonylacetylene derivatives via formation of Csp-Csp3 bond is described. This reaction proceeds through an unusual α-attack (anti-Michael addition) of the ortho-sulfinylbenzyl carbanions, followed by elimination of the arylsulfonyl moiety. The scope of this alkynylation reaction is also discussed. Moreover, the development of a new approach for the synthesis of optically active tertiary benzylpropargyl alcohols is described, discussing the possible stereocourse of the reaction so as the influence of the ether 18-crown-6 and steric importance of acetylenic substituent...
January 15, 2018: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29333860/copper-ii-mediated-ortho-selective-c-sp2-h-tandem-alkynylation-annulation-and-ortho-hydroxylation-of-anilides-with-2-aminophenyl-1h-pyrazole-as-a-directing-group
#18
Wan-Chen Cindy Lee, Wei Wang, Jie Jack Li
2-Aminophenyl-1H-pyrazole has been identified as a viable directing group to promote copper(II)-mediated ortho-selective sp2 C-H bond tandem alkynylation/annulation of anilides with terminal alkynes to offer arylmethylene isoindolinones. Meanwhile, copper(II)-mediated ortho-selective sp2 C-H hydroxylation of anilides has also been optimized as the major reaction pathway by using Cu(OAc)2 as the promoter and 1,1,3,3-tetramethylguanidine as an organic base. Recovery of the directing group was achieved by hydrazinolysis for arylmethylene isoindolinones and basic hydrolysis for the hydroxylation products, respectively...
January 15, 2018: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29329901/effects-of-orthokeratology-on-axial-length-growth-in-myopic-anisometropes
#19
Zhi Chen, Jiaqi Zhou, Xiaomei Qu, Xingtao Zhou, Feng Xue
PURPOSE: To investigate the effect of orthokeratology (ortho-k) lens wear on axial length (AL) growth in juvenile myopic anisometropes. METHODS: This retrospective study consisted of two parts. In Part One, 25 anisometropic participants (mean age, 11.2 ± 1.9 years; 11 females and 14 males) were fitted with ortho-k lenses in the more myopic eye only, and the rate of AL growth was compared between the ortho-k lens wearing eye and the untreated contralateral eye over an average period of 23...
January 10, 2018: Contact Lens & Anterior Eye: the Journal of the British Contact Lens Association
https://www.readbyqxmd.com/read/29328991/comparison-of-effects-of-charge-delocalization-and-%C3%AF-electron-delocalization-on-the-stability-of-monocyclic-compounds
#20
Younes Valadbeigi
Aromaticities and stabilities of ortho, meta, and para isomers of some derivatives of benzene, C5H5- and C7H7+ were studied and compared basis on the NICS index and their relative energies. For the benzene and C7H7+ derivatives, the ortho isomers with less stability were more aromatic. This discrepancy was also observed for the molecules with conjugated and non-conjugated π-electrons. However, for the charged conjugated systems, the structures with delocalized charge were more stable. Effect of electron withdrawing (EWGs) and electron donating groups (EDGs) on the electron delocalization and stability of the neutral and charged molecules was investigated...
January 5, 2018: Journal of Molecular Graphics & Modelling
keyword
keyword
2761
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"