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41.
A Facile Diversity‐Oriented Multicomponent One‐Pot Synthesis of 3‐Amino‐6,7‐dihydrobenzo[c]thiophen‐4(5H)‐one Derivatives from α‐Oxo‐N,S‐ketene Acetal 下载免费PDF全文
Swapnil G. Yerande Sunil D. More Mayur Bhandari Kiran M. Newase Kareem Khoury Kan Wang Alexander Dömling 《Journal of heterocyclic chemistry》2014,51(Z1):E358-E363
A convenient one‐pot multicomponent method for the preparation of 3‐amino‐6,7‐dihydrobenzo[c]thiophen‐4(5H)‐one derivative has been developed. Reaction of 1,3‐cyclohexanedione and phenyl isothiocynate gave α‐oxo‐N,S‐ketene acetal that were reacted in situ with 2‐chloromethylquniazoline‐4‐one derivatives, in the presence of sodium hydride to afford the target compound in reasonable overall yields. 相似文献
42.
Cho DS Gibson SC Bhandari D McNally ME Hoffman RM Cook KD Song L 《Rapid communications in mass spectrometry : RCM》2011,25(23):3575-3580
Batch slurry reactions are widely used in the industrial manufacturing of chemicals, pharmaceuticals, petrochemicals and polymers. However, onsite monitoring of batch slurry reactions is still not feasible in production plants due to the challenge in analyzing heterogeneous samples without complicated sample preparation procedures. In this study, direct analysis in real time mass spectrometry (DART-MS) has been evaluated for the onsite monitoring of a model batch slurry reaction. The results suggested that automation of the sampling process of DART-MS is important to achieve quantitative results. With a sampling technique of manual sample deposition on melting point capillaries followed by automatic sample introduction across the helium beam, relative standard deviation (RSD) of the protonated molecule signals from the reaction product of the model batch slurry reaction ranged from 6 to 30%. This RSD range is improved greatly over a sampling technique of manual sample deposition followed by manual sample introduction where the RSDs are up to 110%. Furthermore, with the semi-automated sampling approach, semi-quantitative analysis of slurry samples has been achieved. Better quantification is expected with a fully automated sampling approach. 相似文献
43.
An exploration of imidazolylpropargyl amides as linchpin synthons for the construction of a diverse array of heterocyclic frameworks, many of which are related to those found in the oroidin derived alkaloids, is described. One such intermediate has been used in a formal total synthesis of cyclooroidin. 相似文献
44.
Manohar Aggrawal Poonam SinghMahesh Kumar Panda 《Statistics & probability letters》2011,81(2):259-266
Chan et al. (1998a) obtained A-optimal designs for an additive quadratic mixture model for q≥3 mixture components. In this paper, we obtain the A-optimal designs for an additive cubic model for q≥3 mixture components using the class of symmetric weighted centroid designs based on barycentres of various depths. We observe that barycentres of depths 0 and 2 are possible support points for an A-optimal design. We have also given the optimal weights of A-optimal designs for 3≤q≤17. 相似文献
45.
The 6.4 GHz ECR ion source that was indigenously developed a few years ago has been operating continuously for injecting oxygen
and neon beams to the cyclotron since 1997. VEC-ECR is a single stage high magnetic field ion source provided with a negatively
biased electron repeller placed on the axis, near the injection mirror point. The supply of cold electrons and use of low
mass mixing gas improve the stability of ECR plasma. Very recently, the effect of aluminum oxide coating on the copper plasma
chamber wall has been studied. The plasma chamber wall was coated with aluminum by vacuum evaporation method and then exposed
to oxygen gas to form aluminum oxide. It was noticed that the process substantially shifts the charge state distribution to
the higher charge state with an enhancement of ion current by an order of magnitude. With the aluminized plasma chamber, the
VEC-ECR can now produce 12 μA of O7+, 6.5 μA of Ar12+, 1.5 μA of Kr20+ and 1.0 μA of Xe31+. 相似文献
46.
47.
M. D. Agrawal C. S. Bhandari M. K. Dixit N. C. Sogani 《Monatshefte für Chemie / Chemical Monthly》1976,107(1):75-82
Stability constants of praseodymium chelates of 3,4,5-trihydroxy sodium benzoate are determined by using Bjerrum-Calvin pH titration technique at constant ionic strength 0.1M-sodium perchlorate and at 28±0.1°C. Values calculated by different methods are in good agreement. The study reveals that during complexation only one proton of the ligand molecule is replaced by the metal and oxygen of adjacent phenolic group acts as a coordinating atom. IR and NMR spectral studies of the ligand reveal that one of the OH groups (in meta position to carboxylic group) remains free while two other phenolic groups are involved in intramolecular hydrogen bonding. One water molecule is found attached in crystalline gallic acid.
Mit 2 Abbildungen 相似文献
Mit 2 Abbildungen 相似文献
48.
Ln(R)3, Ln(R)2(OPri), and Ln(R)(OPri)2 (where Ln = La, Pr, Nd, and Sm; R = deprotonated furfuryl alcohol, RH) were prepared from lanthanide isopropoxide and furfuryl alcohol in 1:3, 1:2 and 1:1 stoichiometric ratios respectively in anhydrous benzene under reflux. Ln(R)2-(OPri) and Ln(R)(OPri)2 were also obtained at room temperature. The isopropoxy group(s) of these derivatives were replaced by tertiary butoxy group(s) during the alcohol exchange reactions with tertiary butanol. All these derivatives are soluble in benzene except the tertiary butoxy derivatives which are only sparingly soluble. However, they become insoluble on standing. These furfuroxides did not distil at ~300°C/102 torr but decomposed. Isopropoxy/butoxy furfuroxides were characterized by the elemental analysis and also by estimating the liberated isopropanol. The i.r. spectra of Ln(R)3 clearly supports the presence of furfuroxide groups in these derivatives. 相似文献
49.
N. Bhandari J. N. Goswami D. Lal D. Macdougall A. S. Tamhane 《Proceedings Mathematical Sciences》1972,76(1):27-50
An experimental technique has been developed for systematic measurements of fossil tracks along selected planes cut from grains and rocks. With controlled etching, the technique allows successive revelation of tracks in different minerals in the same section, a typical sequence being olivine, anorthite, clinopyroxene. It thus becomes possible to study precisely the cosmic ray track density variations over dimensions much greater than those of individual crystals. The technique also provides accurate information on the relative recording characteristics of different minerals present in a rock and cosmic ray tracks can be studied with a minimum interference of tracks due to spontaneous fission of uranium and transuranic elements. Continuous chains of sections, each section measuring approximately 1 cm., have been cut along several different planes in fifteen rocks from Mare Tranquillitatis, Oceanus Procellarum and Fra Mauro region. The cosmic ray track measurements from these sections have provided dramatic evidence for a number of processes affecting lunar rocks. The statistical, and non-uniform nature of erosion by micrometeorite bombardment can be seen in sections intersecting exposed surface which show regions of very steep track density gradients interspersed with eroded regions having lower track densities. The thick section technique permits determination of the energy spectrum of VH nuclei from track density gradients that extend over distances limited only by the dimensions of the rock, and, more important, in samples of identical orientation. The latter is particularly important in higher energy regions (deeper within the rock) where variations in crystal orientation cause track density differences of the same order as real changes in the gradient. Also in the near surface regions of rocks where low energy particles produce steep track density gradient, the thick section method has proved indispensable since it permits accurate depth determinations not possible in the spot sampling procedure. In this paper the technique of studying track profiles in thick sections is described. Although developed primarily for studying lunar samples, the thick section technique is also useful for similar studies in meteorites, particularly for gas-rich meteorites containing irradiated grains. In contrast to single grain studies, thick sections preserve the grain boundaries and permit accurate depth—density measurements. In addition thick section studies have revealed occasional large uniformly irradiated lithic fragments which would not have been possible to discover by spot sampling methods. 相似文献
50.
Subash Khushu Poonam Rana Tarun Sekhri Gopalakrishnan Sripathy Rajendra Prasad Tripathi 《Magnetic resonance imaging》2010
Mitochondrial metabolism particularly oxidative phosphorylation is greatly influenced by thyroid hormones. Earlier studies have described neuromuscular symptoms as well as impaired muscle metabolism in hypothyroid and hyperthyroid patients. In this study, we intend to look in to the muscle bioenergetics including phosphocreatine recovery kinetics based oxidative metabolism in thyroid dysfunction using in vivo 31P nuclear magnetic resonance spectroscopy (MRS). 31P MRS was carried out at resting state on 32 hypothyroid, 10 hyperthyroid patients and 25 control subjects. Nine out of 32 hypothyroid patients and 17 out of 25 control subjects under went exercise protocol for oxidative metabolism study and performed plantar flexion exercise while lying supine in 1.5 T magnetic resonance scanner using custom built exercise device. MRS measurements of inorganic phosphate (Pi), phosphocreatine (PCr), phosphodiesters (PDE) and adenosine triphosphate (ATP) of the calf muscle were acquired during rest, exercise and recovery phase. PCr recovery rate constant (kPCr) and oxidative capacity were calculated by monoexponential fit of PCr versus time (t) at the beginning of recovery. During resting condition in hypothyroid patients, PCr/Pi ratio was reduced whereas PDE/ATP and Pi/ATP were increased. However, in case of hyperthyroidism, an increased PCr/Pi ratio and reduced PDE/ATP and Pi/ATP were observed. The results confirmed differential energy status of the muscle due to increased or decreased levels of thyroid hormone. Our results also demonstrate reduced oxidative metabolism in hypothyroid patients based on PCr recovery kinetics. PCr recovery kinetics study after exercise revealed decreased PCr recovery rate constant (kPCr) in hypothyroid patients compared to controls that resulted in decrease in oxidative capacity of muscle by 50% in hypothyroids. These findings are consistent with a defect of high energy phosphate mitochondrial metabolism in thyroid dysfunction. 相似文献