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101.
Dinesh Singh Moirangthem Surbala Laishram Virendra Singh Rana Jagat Chandra Borah 《Natural product research》2015,29(12):1161-1165
This study was conducted to determine the effect of Cephalotaxus griffithii needle essential oil (CGNO) on proliferation and migration of human cervical cancer (HCC) cells. CGNO treatment decreased the viability of all the tested HCC (HeLa, ME-180 and SiHa) cells. Morphological and DNA fragmentation analysis of CGNO-treated HeLa cells indicated the involvement of apoptosis in inducing HCC cell death. CGNO increased mitochondrial membrane depolarisation and upregulated the expression of caspase-9, caspase-8, caspase-3 and cleaved-PARP. The activity of caspase-8 and caspase-9 was also significantly increased. Wound healing and transwell migration assay demonstrated that CGNO significantly inhibited the migration of HeLa cells to close a scratched wound and also inhibited their migration through filter towards a chemotactic stimulus. Taken together, these results indicated that CGNO inhibited the proliferation and migration of HCC cells. Of note, CGNO induced HeLa cell death through mitochondria-initiated and death receptor-mediated apoptosis pathway. 相似文献
102.
Abir Das Rajib Mandal Harihara Subramanian Ravi Sankar Dr. Subramani Kumaran Dr. J. Richard Premkumar Dipanti Borah Prof. Dr. Basker Sundararaju 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(6):e202315005
Metal-catalyzed asymmetric C−H bond annulation strategy offers a versatile platform, allowing the construction of complex P-chiral molecules through atom- and step-economical fashion. However, regioselective insertion of π-coupling partner between M−C bond with high enantio-induction remain elusive. Using commercially available Co(II) salt and chiral-Salox ligands, we demonstrate an unusual protocol for the regio-reversal, enantioselective C−H bond annulation of phosphinamide with bromoalkyne through desymmetrization. The reaction proceeds through ligand-assisted enantiodetermining cyclocobaltation followed by regioselective insertion of bromoalkyne between Co−C, subsequent reductive elimination, and halogen exchange with carboxylate resulted in P-stereogenic compounds in excellent ee (up to >99 %). The isolation of cobaltacycle involved in the catalytic cycle and the outcome of control experiments provide support for a plausible mechanism. 相似文献
103.
Samim Sultana Shreemoyee Bordoloi Surajit Konwer Geetika Borah Pradip K. Gogoi 《应用有机金属化学》2020,34(5):e5582
Reduced graphene oxide was synthesized and functionalized with FeSO4⋅7H2O to form a reduced graphene oxide/iron oxide hybrid composite. The hybrid composite was extensively characterized using various techniques. Its application for transfer hydrogenation of various ketones was studied. The investigation showed that it serves as a good catalyst for transfer hydrogenation of aromatic and some aliphatic ketones resulting in excellent isolated yields (97–99%) of products. It is magnetically separable showing good reusability. The products were characterized and compared with authentic ones. 相似文献
104.
Nirmalendu Das Debasish Borah Himadri Acharya Sudip Choudhury S. Krishna Prasad D.S. Shankar Rao 《Liquid crystals》2019,46(4):609-617
Liquid crystal-gold nanoparticle (GNP-LC) composite were accessed via covalent coupling of 4-mercaptophenol capped gold nanoparticles (GNP) and a carboxylic acid functionalised rod shaped mesomorphic Schiff base (LC). The Schiff base ligand and the composite both showed schlieren texture with distinct difference in phase transition temperature. The X-ray diffraction study suggested a smectic C mesophase for the compounds. The LC and GNP-LC, both exhibited room temperature photoluminescence when excited at 264nm.The transmission electron micrography revealed the composite to be nearly monodisphersed having almost spherical shape of ~ 2nm size. The composite material in addition to being mesomorphic exhibited pronounced AC conductivity in the semiconductor domain and antioxidant activity. 相似文献
105.
Ionic liquid‐derived polyoxometalate salts [mdsim]3[PM12O40] (where M = W and Mo) of two heteropolyacids H3PW12O40.nH2O and H3PMo12O40.nH2O were synthesized using 2‐methyl‐1,3‐disulfoimidazolium chloride ([mdsim][Cl]) ionic liquid and the corresponding heteropolyacids. Three equivalents of [mdsim][Cl] were treated with the respective Keggin‐structured heteropolyacids (one equivalent) in aqueous medium at room temperature to afford the water‐stable ionic polyoxometalates as acidic solids. They were completely characterized using spectroscopic and other analytical techniques including thermal analysis and Hammett acidity studies. The inherent Brønsted acidic properties of ─SO3H group of these polyoxometalate salts were studied for the nitration of aromatic compounds with 69% HNO3 at normal temperature and 80°C without use of any external concentrated sulfuric acid. These strongly acidic polyoxometalates display good recyclability and efficient reusability. 相似文献
106.
Podma Pollov Sarmah Bibek Jyoti Borah Alexandra M.Z. Slawin Dipak Kumar Dutta 《Journal of organometallic chemistry》2010,695(24):2603-2608
The dimeric rhodium precursor [Rh(CO)2Cl]2 reacts with quinoline (a) and its three isomeric carboxaldehyde ligands [quinoline-2-carboxaldehyde (b), quinoline-3-carboxaldehyde (c), and quinoline-4-carboxaldehyde (d)] in 1:2 mole ratio to afford complexes of the type cis-[Rh(CO)2Cl(L)] (1a-1d), where L = a-d. The complexes 1a-1d have been characterised by elemental analyses, mass spectrometry, IR and NMR (1H, 13C) spectroscopy together with a single crystal X-ray structure determination of 1c. The X-ray crystal structure of 1c reveals square planar geometry with a weak intermolecular pseudo dimeric structure (Rh?Rh = 3.573 Å). 1a-1d undergo oxidative addition (OA) with different electrophiles such as CH3I, C2H5I and I2 to give Rh(III) complexes of the type [Rh(CO)(COR)Cl(L)I] {R = -CH3 (2a-2d), R = -C2H5 (3a-3d)} and [Rh(CO)Cl(L)I2] (4a-4d) respectively. 1b exhibits facile reactivity with different electrophiles at room temperature (25 °C), while 1a, 1c and 1d show very slow reactivity under similar condition, however, significant reactivity was observed at a temperature ∼40 °C. The complexes 1a-1d show higher catalytic activity for carbonylation of methanol to acetic acid and methyl acetate [Turn Over Frequency (TOF) = 1551-1735 h−1] compared to that of the well known Monsanto’s species [Rh(CO)2I2]− (TOF = 1000 h−1) under the reaction conditions: temperature 130 ± 2 °C, pressure 33 ± 2 bar, 450 rpm and time 1 h. The organometallic residue of 1a-1d was also isolated after the catalytic reaction and found to be active for further run without significant loss of activity. 相似文献
107.
Kushal C. Lekhok Dipak Prajapati Ramesh C. Boruah Sharbani Mazumder Tarun C. Borah 《Monatshefte für Chemie / Chemical Monthly》2009,18(4):1183-1187
Abstract
3-Aryl-2,1-benzisoxazoles and its salts underwent reductive cleavage of the N–O bond leading to 2-aminobenzophenones with bakers’ yeast under non-fermenting conditions in aqueous media. The procedure gives excellent yields of 2-alkylamino- and 2-aminobenzophenones. 相似文献108.
Taking oxygen ion conductor La2Mo2O9, as a base compound, a series of Sn-doped La2Mo2−x
Sn
x
O9−δ, x = 0, 0.01, 0.02, 0.03, 0.05, 0.1, 0.15, 0.2 specimens were prepared and characterized by XRD for phase and crystal structure
determination and ac impedance spectroscopy for ac and dc conductivity measurement. We have found that there is slight improvement
in overall conductivity of the specimen with x = 0.03 at 800°C compared to the undoped compound at the same temperature. The value of conductivity when extrapolated to
800°C is found to be 0.055 S cm-1 for the specimen with x = 0.03, whereas conductivity of undoped specimen at the same temperature is found to be 0.033 Scm−1. 相似文献
109.
The present paper deals with the room temperature conductivity study of some polymer electrolytes based on polyacrylonitrile,
ammonium tetraflouroborate as dopant, and propylene carbonate (PC) and polyethylene glycols (PEG300 and PEG600) as plasticizers.
The additions of plasticizers having different dielectric constant have been found to modify the conductivity of polymer electrolytes.
The increase in room temperature conductivity with plasticizer addition has been found to depend upon (1) the amount of salt
present and (2) amount of plasticizers added. The polymer electrolytes prepared were characterized by X-ray diffraction, scanning
electron micrographs, infrared, thermogravimetric, and AC impedance measurements. The highest room temperature conductivity
observed in case of these polymer electrolytes was ∼10–13 s/cm. 相似文献
110.