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1.
A cobalt-catalyzed reductive coupling of terminal alkynes, RC?CH, with activated alkenes, R'CH?CH(2) , in the presence of zinc and water to give functionalized trans-disubstituted alkenes, RCH?CHCH(2) CH(2) R', is described. A variety of aromatic terminal alkynes underwent reductive coupling with activated alkenes including enones, acrylates, acrylonitrile, and vinyl sulfones in the presence of a CoCl(2) /P(OMe)(3) /Zn catalyst system to afford 1,2-trans-disubstituted alkenes with high regio- and stereoselectivity. Similarly, aliphatic terminal alkynes also efficiently participated in the coupling reaction with acrylates, enones, and vinyl sulfone, in the presence of the CoCl(2) /P(OPh)(3) /Zn system providing a mixture of 1,2-trans- and 1,1-disubstituted functionalized terminal alkene products in high yields. The scope of the reaction was also extended by the coupling of 1,3-enynes and acetylene gas with alkenes. Furthermore, a phosphine-free cobalt-catalyzed reductive coupling of terminal alkynes with enones, affording 1,2-trans-disubstituted alkenes as the major products in a high regioisomeric ratio, is demonstrated. In the reactions, less expensive and air-stable cobalt complexes, a mild reducing agent (Zn) and a simple hydrogen source (water) were used. A possible reaction mechanism involving a cobaltacyclopentene as the key intermediate is proposed. 相似文献
2.
Vasudevan Subramaniyan Ashok Kumar Anbarasu Govindaraj Ganesan Mani 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(6):734-739
The reaction of NiCl2 with 1,3‐bis[(diphenylphosphanyl)methyl]hexahydropyrimidine in the presence of 2,6‐dimethylphenyl isocyanide and KPF6 afforded a new pentacoordinated PCP pincer NiII complex, namely {1,3‐bis[(diphenylphosphanyl)methyl]hexahydropyrimidin‐2‐yl‐κN2}(2,6‐dimethylphenyl isocyanide‐κC)nickel(II) hexafluoridophosphate 0.70‐hydrate, [Ni(C9H9N)(C30H30ClN2P2)]PF6·0.7H2O or [NiCl{C(NCH2PPh2)2(CH2)3‐κ3P,C,P′}(Xylyl‐NC)]PF6·0.7H2O, in very good yield. Its X‐ray structure showed a distorted square‐pyramidal geometry and the compound does not undergo dissociation in solution, as shown by variable‐temperature NMR and UV–Vis studies. Density functional theory (DFT) calculations provided an insight into the bonding; the nickel dsp2‐hybridized orbitals form the basal plane and the nearly pure p orbital forms the axial bond. This is consistent with the NBO (natural bond orbital) analysis of analogous nickel(II) complexes. 相似文献
3.
Thin-layer chromatography (TLC)-densitometry was used to separate, identify, and quantitate chlorpheniramine maleate (CPM) and pheniramine maleate (PM) when present in combination with other drugs in pharmaceutical preparations of tablets, syrups, eye and ear drops, etc. CPM or PM was extracted (tablets, capsules, etc.) or diluted (liquid preparations, if needed) with 80% ethanol and isolated from other ingredients by TLC on silica gel G using cyclohexane-chloroform-methanol-diethylamine (4.5 + 4.0 + 0.5 + 1.0, v/v) as the mobile phase. Separated CPM and PM were detected under shortwave ultraviolet light and quantitated by scanning densitometry at 260 nm. Recoveries of CPM and PM were 100.09+/-0.77% and 100.09+/-0.87%, respectively. 相似文献
4.
Govindasamy Rajarajan Natesan Jayachandramani Subramaniyan Manivarman Jayaraman Jayabharathi Venugopal Thanikachalam 《Transition Metal Chemistry》2008,33(3):393-397
The kinetics of oxidation of aldonitrones by 4-(dimethylamino)pyridinium chlorochromate (DMAPCC) has been studied in aqueous
N,N-dimethylformamide in the presence of perchloric acid. The reaction follows first-order kinetics with respect to each of DMAPCC
and nitrone. The order with respect to [H+] was found to be close to zero. The rate of oxidation was unaltered by the variation of [NaClO4] but addition of MnSO4 decreased the rate. The reaction rate was found to decrease with a decrease in dielectric constant of the medium. Electron-releasing
and electron-withdrawing groups perturb the reaction rate with a good Hammett correlation. The oxidation products were found
to be benzaldehyde and nitrosobenzene. The reaction was carried out at four different temperatures and the activation parameters
have been calculated. On the basis of the experimental findings, a suitable mechanism has been proposed. 相似文献
5.
A series of novel N‐methyl spiropyrrolidines have been synthesized in good yield by the cycloaddition reaction of azomethine ylides generated by a decarboxylative route from sarcosine and paraformaldehyde with conformationally locked s‐trans enone functionality present in the (E)‐3‐arylidene‐4‐chromanone as dipolarophiles. The structure of the title compound was established by spectroscopic techniques. 相似文献
6.
Venkatadri Babu Selvaraj Arokiyaraj Swathi Pon Sakthi Sri Mary George Rameshkumar Marimuthu Ragavan Dinesh Dharmalingam Taehwan Oh Subramaniyan Ramasundaram Paul Agastian 《Molecules (Basel, Switzerland)》2022,27(22)
The present study aimed to analyze the in vitro antibacterial, antioxidant, larvicidal and cytotoxicity properties of green synthesized silver nanoparticles (Ag NPs) using aqueous extracts from fruits of Lagerstroemia speciosa and flowers of Couropita guinensis. Synthesized Ag NPs were characterized using UV-DRS, FTIR, XRD, DLS, and High-Resolution SEM and TEM analyses. Absorption wavelength was observed at 386 nm by UV-DRS analysis and energy band gap was calculated as 3.24 eV. FTIR analysis showed the existence of various functional groups in the aqueous extract and in the NPs. DLS analysis showed the stability and particle size of the synthesized Ag NPs. SEM analysis revealed that Ag NPs are in a face centered cubic symmetry and spherical shape with a size of 23.9 nm. TEM analysis showed particle size as 29.90 nm. Ag NPs showed antibacterial activity against both Gram-positive and Gram-negative bacteria. DPPH scavenging trait of Ag NPs was ranging from 20.0 ± 0.2% to 62.4 ± 0.3% and observed significant larvicidal activity (LC50 at 0.742 ppm and LC90 at 6.061 ppm) against Culex quinquefasciatus. In vitro cytotoxicity activity of Ag NPs was also tested against human breast cancer (MCF-7) and fibroblast cells (L-929) and found that cells viabilities are ranging (500 to 25 µg/mL) from 52.5 ± 0.4 to 94.0 ± 0.7% and 53.6 ± 0.5 to 90.1 ± 0.8%, respectively. The synthesized Ag NPs have the potential to be used in the various biomedical applications. 相似文献
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8.
Subasri R. Reddy D. S. Soma Raju K. R. C. Rao K. S. Kholov P. Gaponenko N. 《Research on Chemical Intermediates》2019,45(8):4179-4191
Research on Chemical Intermediates - Fully dielectric solar control coatings based on alternating layers of Ba (or Sr)TiO3 and MgF2 were deposited on soda lime glass substrates. Three-layered... 相似文献
9.
Heat treatment of sodium silicate water glass of the nominal composition Na2O/SiO2 = 1:3 was carried out from 100 °C up to 800 °C and the advancement of the resulting phases was followed up by powder X-ray diffraction, scanning electron microscopy and thermogravimetry along with differential thermal analysis. The water glass, initially being an amorphous solid, starts to form crystals of β-Na2Si2O5 at about 400 °C and crystallizes the SiO2 modification cristobalite at about 600 °C that coexists along with β-Na2Si2O5 up to 700 °C. At 750 °C Na6Si8O19 appears as a separate phase and beyond 800 °C, the system turns into a liquid. 相似文献
10.
Sivakumar Allur Subramaniyan Da Rae Kang Shah Ahmed Belal Ho Sung Choe Kwan Seob Shim 《Journal of Cluster Science》2018,29(1):129-139
The present study examined the characterization and concentration of Brassica oleracea L. var. capitata f. rubra (BOL, commonly known as red cabbage) extracted AgNPs (BOL-AgNPs) and chemically (CHE) synthesized AgNPs (CHE-AgNPs) in chicken embryos through in ovo injections. We investigated the effects of both AgNPs on the survival, hatchability, body weight, and expressions of heat-shock proteins (HSPs). The BOL-AgNPs and CHE-AgNPs at (T1) amounted 100, at (T2) 1000, at (T3) 2500, and at (T4) 5000 µg/100 µl/egg, respectively through in ovo injections. At the end of the experimental period, the body and liver weights of the chicks were altered between the groups and among the concentrations. The serum levels of SGOT and SGPT were significantly increased at BOL-T3 and -T4. Survival and hatching rates were more reduced in the BOL-T3- and -T4-treated groups than at BOL-T1 and -T2. Nevertheless, they were more diminished in the CHE-AgNPs than in the BOL-AgNPs. The CHE-AgNPs revealed the presence of micronuclei and nuclear abnormalities, in contrast to BOL-T4. The mRNA and protein expressions of HSP-60 and 70 in the liver were higher in CHE-AgNPs than in BOL-AgNPs. Hence, plant-synthesized AgNPs are superior in ovo nano-nutrition carriers of nutrients without toxicity than CHE-AgNPs. 相似文献