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51.
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Pyrazolopyrimidine and pyrimidopyrimidine derivatives have shown a wide range of biological activities such as acting as A1 adenosine receptors, kinase insert domain receptor (KDR), Rous sarcoma oncogene (Src), epidermal growth factor receptor (EGFR), antiproliferative, dihydrofolate reductase (DHFR), antimicrobial, antifungal, and lipid peroxidation. Because of this wide range of activities, we have synthesized pyrazolo[3,4‐d]pyrimidines and pyrimido[4,5‐d]pyrimidin‐4‐one derivatives.  相似文献   
53.
In this study, n-type 95 %Bi2Te3-5 %Bi2Se3 thermoelectric materials have been produced by a combined process of gas atomization with subsequent magnetic pulsed compaction and spark plasma sintering, and then we investigated the behavior of transport properties with sintering temperature. The microstructural observation was performed by optical microscopy and scanning electron microscopy. The crystal structures were analyzed by X-ray diffractometer. The mechanical properties were calculated by measuring the density and micro-Vickers hardness of the samples. It was found that with increasing sintering temperature the gaps between powder particles decreases and the grain sizes were coarsened. The mechanical properties shows higher values along the parallel direction compared to the perpendicular direction to the pressing. The transport properties of the thermoelectric material were investigated with variation of the sintering temperatures. The maximum power factor 1.7 × 10?3 Wm?1 K?2 was measured at the sintering temperature of 450 °C.  相似文献   
54.
A simple, sensitive and specific high‐performance liquid chromatography mass spectrometry (LC‐MS/MS) method was developed and validated for the quantification of β‐hydroxy‐β‐methyl butyrate (HMB) in small volumes of rat plasma using warfarin as an internal standard (IS). The API‐4000 LC‐MS/MS was operated under the multiple reaction‐monitoring mode using the electrospray ionization technique. A simple liquid–liquid extraction process was used to extract HMB and IS from rat plasma. The total run time was 3 min and the elution of HMB and IS occurred at 1.48 and 1.75 min respectively; this was achieved with a mobile phase consisting of 0.1% formic acid in a water–acetonitrile mixture (15:85, v/v) at a flow rate of 1.0 mL/min on a Agilent Eclipse XDB C8 (150 × 4.6, 5 µm) column. The developed method was validated in rat plasma with a lower limit of quantitation of 30.0 ng/mL for HMB. A linear response function was established for the range of concentrations 30–4600 ng/mL (r > 0.998) for HMB. The intra‐ and inter‐day precision values for HMB were acceptable as per Food and Drug Administration guidelines. HMB was stable in the battery of stability studies, viz. bench‐top, autosampler freeze–thaw cycles and long‐term stability for 30 days in plasma. The developed assay method was applied to a bioavailability study in rats. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
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Clay catalyzed Friedländer condensation of 2-amino arylaldehyde or ketone with carbonyl compounds containing α-methylene group has been achieved in solvent free condition under microwave irradiation to give polycyclic quinoline derivatives.  相似文献   
57.
The composite hydrogel of a nanoscale metal–organic framework (NMOF) and nanoclay has emerged as a new soft-material with advanced properties and applications. Herein, we report a facile synthesis of a hydrogel nanocomposite by charge-assisted self-assembly of Pd@ZIF-8 nanoparticles with Laponite® nanoclay which coat the surface of Pd@ZIF-8 nanoparticles. Such surface coating significantly enhanced the thermal stability of the ZIF-8 compared to the pristine framework. Further, the Pd@ZIF-8+LP hydrogel nanocomposite shows better size-selective catalytic hydrogenation of olefins than Pd@ZIF-8 nanoparticles based on selective diffusion of the substrate.  相似文献   
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Thermolysis of [Cp*Ru(PPh2(CH2)PPh2)BH2(L2)] 1 (Cp*=η5‐C5Me5; L=C7H4NS2), with terminal alkynes led to the formation of η4‐σ,π‐borataallyl complexes [Cp*Ru(μ‐H)B{R‐C=CH2}(L)2] ( 2 a – c ) and η2‐vinylborane complexes [Cp*Ru(R‐C=CH2)BH(L)2] ( 3 a – c ) ( 2 a , 3 a : R=Ph; 2 b , 3 b : R=COOCH3; 2 c , 3 c : R=p‐CH3‐C6H4; L=C7H4NS2) through hydroboration reaction. Ruthenium and the HBCC unit of the vinylborane moiety in 2 a – c are linked by a unique η4‐interaction. Conversions of 1 into 3 a – c proceed through the formation of intermediates 2 a – c . Furthermore, in an attempt to expand the library of these novel complexes, chemistry of σ‐borane complex [Cp*RuCO(μ‐H)BH2L] 4 (L=C7H4NS2) was investigated with both internal and terminal alkynes. Interestingly, under photolytic conditions, 4 reacts with methyl propiolate to generate the η4‐σ,π‐borataallyl complexes [Cp*Ru(μ‐H)BH{R‐C=CH2}(L)] 5 and [Cp*Ru(μ‐H)BH{HC=CH‐R}(L)] 6 (R=COOCH3; L=C7H4NS2) by Markovnikov and anti‐Markovnikov hydroboration. In an extension, photolysis of 4 in the presence of dimethyl acetylenedicarboxylate yielded η4‐σ,π‐borataallyl complex [Cp*Ru(μ‐H)BH{R‐C=CH‐R}(L)] 7 (R=COOCH3; L=C7H4NS2). An agostic interaction was also found to be present in 2 a – c and 5 – 7 , which is rare among the borataallyl complexes. All the new compounds have been characterized in solution by IR, 1H, 11B, 13C NMR spectroscopy, mass spectrometry and the structural types were unequivocally established by crystallographic analysis of 2 b , 3 a – c and 5 – 7 . DFT calculations were performed to evaluate possible bonding and electronic structures of the new compounds.  相似文献   
60.
The chemoselective reaction of hydrazine on the ketone rather than the ester in a gem diester system with a γ‐keto group by hydrazinium sulfate and a tandem deesterification of one of the esters in this system by N,N‐dimethylformamide are reported.  相似文献   
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