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981.
Graphene Oxide Supported Molybdenum Cluster: First Heterogenized Homogeneous Catalyst for the Synthesis of Dimethylcarbonate from CO2 and Methanol 下载免费PDF全文
Subodh Kumar Dr. Om P. Khatri Dr. Stéphane Cordier Prof. Rabah Boukherroub Dr. Suman L. Jain 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3488-3494
The octahedral molybdenum cluster‐based compound, Cs2Mo6Bri8Bra6 was immobilized on graphene oxide (GO) by using a facile approach. High resolution transmission electron microscopy results revealed that molybdenum clusters were uniformly distributed on the GO nanosheets. Cs2Mo6Bri8Bra6 was attached to the GO support via chemical interaction between apical ligands of Mo6Bri8Bra6 cluster units and oxygen functionalities of GO, as revealed by XPS studies. The developed material was used for the synthesis of dimethyl carbonate by reduction of carbon dioxide. The synthesized catalyst, that is, GO–Cs2Mo6Bri8Brax, exhibited higher catalytic efficiency than its homogeneous analogue without using dehydrating agent. The catalyst was found to be efficiently recyclable without significant loss of catalytic activity. 相似文献
982.
The bisthiadiazolines ( 4a , 4b , 4c , 4d , 4e , 4f , 4g ) were synthesized from the cyclization of bisthiosemicarbazones ( 3a , 3b , 3c , 3d , 3e , 3f , 3g ) by refluxing under Ac2O medium. The intermediates were obtained from the reactions of dibenzaldehydes ( 2a , 2b , 2c , 2d , 2e , 2f , 2g ) with thiosemicarbazide by refluxing in the presence of dry EtOH/HCl. The latter were prepared in good yields from the O‐alkylation of 3‐hydroxybenzaldehyde with suitable dibromo derivatives under the alkaline conditions. The structures of prepared compounds were determined from rigorous analysis of their spectral parameters (UV–vis, IR, 1H NMR, 13C NMR and ESI‐MS). The newly prepared compounds were screened for their antimicrobial activity against seven bacterial and five fungi strains using serial tube dilution method. 相似文献
983.
All Solid State Chromium(III) Selective Potentiometric Sensor Based on 2‐(1‐(2‐((3‐(2‐Hydroxyphenyl)‐1H‐pyrozol‐1‐yl)methyl)benzyl)‐1H‐pyrazol‐3‐yl)phenol 下载免费PDF全文
Pankaj Kumar Sanjeev Kumar Sapna Jain Bhawna Y. Lamba Girdhar Joshi Shefali Arora 《Electroanalysis》2014,26(10):2161-2167
Highly selective all solid state electrochemical sensor based on a synthesized compound i.e. 2‐(1‐(2‐((3‐(2‐hydroxyphenyl)‐1H‐pyrozol‐1‐yl)methyl)benzyl)‐1H‐pyrazol‐3‐yl)phenol (I) as an ionophore has been prepared and investigated for the selective quantification of chromium(III) ions. The effect of various plasticizers, viz. dibutyl phosphonate (DBP), dibutyl(butyl) phosphonate (DBBP), nitrophenyl octyl ether (NPOE), tris‐(2‐ethylhexyl)phosphonate (TEP), tri‐butyl phosphonate (TBP), dioctyl phthalate (DOP), dioctyl sebacate (DOS), benzyl acetate (BA) and acetophenone (AP) along with anion excluders NaTPB (sodium tetraphenyl borate) and KClTPB (potassium(tetrakis‐4‐chlorophenyl)borate was also studied. The optimum composition of the best performing membrane contained (I):KClTPB:NPOE:PVC in the ratio 15 : 3 : 40 : 42 w/w. The sensor exhibited near Nernstian slope of 20.1±0.2 mV/decade of activity in the working concentration range of 1.2×10?7–1.0×10?1 M, and in a pH range of 3.8–4.5. The sensor exhibited a fast response time of 10 s and could be used for about 5 months without any considerable divergence in potentials. The proposed sensor showed very good selectivity over most of the common cations including Na+, Li+, K+, Cu2+, Sr2+, Ni2+, Co2+, Ba2+, Hg2+, Pb2+, Zn2+, Cs+, Mg2+, Cd2+, Al3+, Fe3+and La3+. The activity of Cr(III) ions was successfully determined in the industrial waste samples by using this sensor. 相似文献
984.
Cyclization reactions of lapachol (1) isolated from Heterophragma adenophyllum have been studied under microwave irradiation under different conditions using alumina (acidic, basic and neutral)/silica gel/montmorillonite (KSF and K-10) as solid support along with neat reaction using 2-3 drops of DMF giving naturally occurring dehydro-alpha-lapachone (2), alpha-lapachone (3), beta-lapachone (4) depending upon the nature of support and irradiation time. A novel naphthoquinone derivative adenophyllone (5) can be synthesized from lapachol using DMF under microwaves. 相似文献
985.
Rakesh K. Singh Sanjay Jain Neelima Sinha Anita Mehta Nitya Anand 《Tetrahedron》2006,62(17):4011-4017
A convenient and efficient synthesis of N6-substituted 3,6-diazabicyclo[3.2.1]octanes (6a-c) has been achieved starting from suitably substituted lactams, which were converted to nitroenamines followed by reductive cyclization to afford 3,6-diazabicyclo[3.2.1]octane-2-ones in good yields. These bicyclic lactams were then reduced to the corresponding 3,6-diazabicyclo[3.2.1]octanes and converted to the required N3,N6-disubstituted 3,6-diazabicyclo[3.2.1]octanes (7a-h), which were screened for α1-adrenoceptors antagonistic activities. 相似文献
986.
Veerasamy Ravichandran Abhishek Jain Vishnukanth Mourya Ram K. Agrawal 《Chemical Papers》2008,62(6):596-602
A QSAR study on a series of pyrimidinyl and triazinyl amines was performed to explore the physico-chemical parameters responsible
for their anti-HIV activity and cytotoxicity. Physico-chemical parameters were calculated using WIN CAChe 6.1. Stepwise multiple
linear regression analysis was carried out to derive QSAR models which were further evaluated for statistical significance
and predictive power by internal and external validation. The selected best QSAR models showed correlation coefficient R of 0.914 and 0.901, and cross-validated squared correlation coefficient Q
2 of 0.685 and 0.691 for anti-HIV activity and cytotoxicity, respectively. The developed significant QSAR model indicates that
hydrophobicity of the whole molecule plays an important role in the anti-HIV activity and cytotoxicity of pyrimidinyl and
triazinyl amine derivatives. When hydrophobicity is increased, anti-HIV activity of the present series of compounds is decreased
leading to high cytotoxicity. 相似文献
987.
988.
Souradeep Roy Shalini Nagabooshanam Kushagra Krishna Shikha Wadhwa Nidhi Chauhan Utkarsh Jain Ranjit Kumar Ashish Mathur James Davis 《Electroanalysis》2020,32(9):2082-2089
L‐tyrosine is an amino acid, the concentration of which is found to be highly elevated in patients suffering from diabetic foot ulcer (DFU). The latter proves to be fatal when it turns out chronic and may lead to amputation. The conventional clinical diagnostic methods are costly and time consuming, in which case, the condition of patient(s) may deteriorate long before proper treatment commences. Herein, we report the development of smart band‐aid for real time monitoring of L‐tyrosine by employing enzymatic bio‐sensor using α‐MnO2/tyrosinase. The smart band‐aid was further integrated with portable electronics capable of wireless data transmission to a personal digital assistant, and its tyrosine sensing performance was evaluated. Anodic current was found to vary linearly with the concentrations of L‐tyrosine in the range of 5 nM–500 μM. The developed sensor displayed a limit of detection and sensitivity of 0.71 nM and 0.67 μA/nM/mm2 respectively, with a stability of 25 days. The developed sensor was validated using a commercial impedance analyzer. The impedance response was found to be consistent with the cyclic voltammogram obtained and demonstrated to be a linear function of tyrosine concentration. The developed sensing platform combines early diagnosis with connected health technologies, thus, fitting well into modern healthcare needs. 相似文献
989.
Viktor Kelemen Magdolna Csvs Judit Hotzi Mihly Herczeg Poonam Brijesh Rathi Pl Herczegh Nidhi Jain Anik Borbs 《化学:亚洲杂志》2020,15(6):876-891
The photoinitiated thiol?ene addition reaction is a highly stereo‐ and regioselective, and environmentally friendly reaction proceeding under mild conditions, hence it is ideally suited for the synthesis of carbohydrate mimetics. A comprehensive study on UV‐light‐induced reactions of 2,3‐unsaturated O‐, C‐, S‐ and N‐glycosides with various thiols was performed. The effect of experimental parameters and structural variations of the alkenes and thiols on the efficacy and regio‐ and stereoselectivity of the reactions was systematically studied and optimized. The type of anomeric heteroatom was found to profoundly affect the reactivity of 2,3‐unsaturated sugars in the thiol?ene couplings. Hydrothiolation of 2,3‐dideoxy O‐glycosyl enosides efficiently produced the axially C2‐S‐substituted addition products with high to complete regioselectivity. Moderate efficacy and varying regio‐ and stereoselectivity were observed with 2,3‐unsaturated N‐glycosides and no addition occurred onto the endocyclic double bond of C‐glycosides. Upon hydrothiolation of 2,3‐unsaturated S‐glycosides, the addition of thiyl radicals was followed by elimination of the thiyl aglycone resulting in 3‐S‐substituted glycals. 相似文献
990.
Evin AHN SADIK Hamdi Melih SARAOLU lke GÜROL Mehmet Ali EBEOLU Fatma Emel KOAK 《Turkish Journal of Chemistry》2020,44(5):1293
Determining the blood glucose level is important for the prevention and treatment of diabetes mellitus. We developed a sensor system using Quartz Crystal Microbalance (QCM) to determine the blood glucose level from human blood serum. This study consists of two experimental stages: artificial glucose/pure water solution tests and human blood serum tests. In the first stage of the study, the QCM sensor with the highest performance was identified using artificial glucose solution concentrations. In the second stage of the study, human blood serum measurements were performed using QCM to determine blood glucose levels. QCM sensors were coated with phthalocyanines (Pcs) by jet spray method. The blood glucose values of 96 volunteers, which ranged from 71 mg/dL to 329 mg/dL, were recorded. As a result of the study, human glucose values were determined with an average error of 3.25%. 相似文献