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61.
Oindrila Das Tanmay Malakar Arghya Mandal Dr. Ankan Paul Dr. Tapan Kanti Paine 《化学:亚洲杂志》2013,8(3):623-629
The synthesis and characterization of two pyrazolate‐bridged dicopper(II) complexes, [Cu2(L1)2(H2O)2](ClO4)2 ( 1 , HL1=3,5‐dipyridyl‐4‐(2‐keto‐pyridyl)pyrazole) and [Cu2(L2)2(H2O)2](ClO4)2 ( 2 , HL2=3,5‐dipyridyl‐4‐benzoylpyrazole), are discussed. These copper(II) complexes are formed from the reactions between pyridine‐2‐aldehyde, 2‐acetylpyridine (for compound 1 ) or acetophenone (for compound 2 ), and hydrazine hydrate with copper(II) perchlorate hydrate under ambient conditions. The single‐crystal X‐ray structure of compound 1? 2 H2O establishes the formation of a pyrazole ring from three different carbon centers through C? C bond‐forming reactions, mediated by copper(II) ions. The free pyrazoles (HL1 and HL2) are isolated from their corresponding copper(II) complexes and are characterized by using various analytical and spectroscopic techniques. A mechanism for the pyrazole‐ring synthesis that proceeds through C? C bond‐forming reactions is proposed and supported by theoretical calculations. 相似文献
62.
A facile one‐pot, three‐component protocol for the synthesis of novel spiro[3H‐indole‐3,2′‐thiazolidine]‐2,4′(1H)‐diones by condensing 1H‐indole‐2,3‐diones, 4H‐1,2,4‐triazol‐4‐amine and 2‐sulfanylpropanoic acid in [bmim]PF6 (1‐butyl‐3‐methyl‐1H‐imidazolium hexafluorophosphate) as a recyclable ionic‐liquid solvent gave good to excellent yields in the absence of any catalyst (Scheme 1 and Table 2). The advantages of this protocol over conventional methods are the mild reaction conditions, the high product yields, a shorter reaction time, as well as the eco‐friendly conditions. 相似文献
63.
A recent report by El Feraly et. al 3 describing the direct conversion of 5, 7-dimethoxy - 2, 3 - dihydro - 1H-benzcyclopenten- 1 -one(1) to the homologated aldehyde (3) by dimethyl sulfonium 4 methylide4 (2), prompted us to present results obtained from our investigation of the reaction of various aromatic aldehydes and ketones, possessing electron releasing p-substituent, with (2). Our interest in examining this particular reaction arose from a need to prepare the oxirane (5) and the aldehyde (6), required in connection with the synthesis and biological evaluation of semi-rigid analogues of catecholamines as probes for the study 5 of adrenergic and dopaminergic receptors.5 相似文献
64.
Acid catalysed epoxy ring opening of several lupane type triterpenoids leads to unusual allylic hydroxylation. The reaction involves the formation of epoxide by m‐chloroperbenzoic acid followed by the treatment of mineral acid. The simple methodology finds utility to introduce a hydroxyl function at the allylic position in these triterpenoids, which is otherwise quite difficult. 相似文献
65.
One-pot oxidation of alanine and its ethyl ester with a mild oxidant 4′-methylazobenzene-2-sulfenyl bromide is described. Using a nonreactively water-soluble electrophilic species, 4′-methylazobenzene-2-sulfenyl bromide, with L-alanine and its ethyl ester (in 3:1 molar proportions) in aqueous solution at room temperature, the corresponding sulfenimines are prepared. On hydrolysis in acidic medium at room temperature, these sulfenimines give ethanal and pyruvic acid respectively.
66.
Parnajyoti Karmakar Sumon Ray Debabrata Nandi Arup Mandal Subala Mondal Subhasis Mallick Biplab K. Bera Alak K. Ghosh 《Journal of solution chemistry》2013,42(2):441-458
The kinetics of the substitution reactions of [Pt(dach)(H2O)2]2+ and [Pt(en)(H2O)2]2+ (where ‘dach’ and ‘en’ are cis-1,2-diaminocyclohexane and ethylenediamine, respectively) with excess N,N′-diethylthiourea have been studied in aqueous solution by UV–Vis spectrophotometry. The effect of different N–N spectator ligands on the reactivity of platinum(II) complexes was investigated by studying the water lability of the reactant complexes. The kinetic study has been substantiated by product isolation, IR, NMR and ESI-MS spectral analysis and DFT calculations. The reactions follow normal square-planar substitution mainly in an associative way. Rate parameters have been evaluated under different conditions. The substitution rates of the complexes studied can be tuned through the nature of the N–N chelates, which is important in the development of new active compounds for cancer therapy. 相似文献
67.
Karthikeyan Rajendran Surianarayanan Mahadevan Rajendhran Jeyaprakash Gunasekaran Paramasamy Asit Baran Mandal 《Applied biochemistry and biotechnology》2013,171(6):1328-1338
Bacillus badius isolated from soil has been identified as potential producer of penicillin G acylase (PGA). In the present study, batch experiments performed at optimized inoculum size, temperature, pH, and agitation yielded a maximum PGA of 9.5 U/ml in shake flask. The experiments conducted in bioreactor with different oxygen flow rates revealed that 0.66 vvm oxygen flow rate could be sufficient for the maximum PGA activity of 12.7 U/ml. From a detailed investigation on the strategies of the addition of phenyl acetic acid (PAA) for increasing the production of PGA, it was found that the controlled addition of 10 ml of 0.1 % (w/v) PAA once in every 2 h from 6th hour of growth showed the maximum PGA activity of 32 U/ml. Thus, our studies for the first time showed that at concentration above 0.1 % (w/v) PAA, the PGA production decreased. This selective condition paves the way for less costly bioprocess for the production of PGA. 相似文献
68.
69.
K. D. Mandal Laxman Singh Sunita Sharma U. S. Rai M. M. Singh 《Journal of Sol-Gel Science and Technology》2013,66(1):50-58
Effect of doping at Ti4+ site by Ce3+ has been examined in CaCu3Ti3.90Ce0.10O12 synthesized by citrate-gel route. DTA/TG analysis of dry powder gives pre-information about formation of final product around 850 °C. X ray diffraction analysis confirmed the formation of CaCu3Ti3.90Ce0.10O12 phase of the ceramic sintered at 950 °C for 12 h. Microstructure has been studied using scanning electron microscopy and confirmed the average grain size found in nano range 200–400 nm in system CaCu3Ti3.90Ce0.10O12.The nature of relaxation behavior of ceramic was also rationalized by using the impedance and modulus spectroscopy. The bulk conductivity indicates an Arrhenius-type thermally activated process. The ac conductivity spectrum obeyed the Jonscher power law. The complex impedance diagrams of the ceramic exhibited a significant contribution from the grains, grain boundaries and electrode. The activation energies calculated from the grain-boundary relaxation time constant was found to be 0.49 eV which confirmed the Maxwell–Wagner type of relaxation present in the ceramic. 相似文献
70.
Sisir Lohar Arnab Banerjee Animesh Sahana Sukanya Panja Ipsit Hauli Subhra Kanti Mukhopadhyay Debasis Das 《Tetrahedron letters》2014
Visible light excitable rhodamine B derivative (TARDHD) has been developed for fluorescence and naked eye detection of histidine in aqueous medium. TARDHD shows 45 fold fluorescence enhancement in the presence of histidine. It forms Schiff base with histidine and stabilizes via intra-molecular H-bonding. TARDHD can efficiently detect intracellular histidine. 相似文献