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The stereoselective total synthesis of decytospolides A and B, two naturally occurring pyran derivatives, has been achieved using D ‐mannitol as the starting material. The intramolecular oxa‐Michael reaction has been employed to construct the tetrahydropyran ring of the molecules and Weinreb amide formation to generate their side chain with a keto function. 相似文献
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Stereoselective total synthesis of ophiocerin C has been accomplished through two different approaches starting separately from acetaldehyde and from (R)‐propylene oxide, and Sharpless asymmetric dihydroxylation has been employed as the key step in both approaches. 相似文献
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Srilatha Avuluri Sheshurao Bujaranipalli Saibal Das J.S. Yadav 《Tetrahedron letters》2018,59(39):3547-3549
A first stereoselective total synthesis of 14-memebered β-resorcylic macrolactone 5′-hydroxyzearalenone (1) has been achieved. The key steps are Jocobsen hydrolytic kinetic resolution, Sharpless asymmetric dihydroxylation, Vilsmeier-Haack reaction, Mitsunobu esterification and ring-closing metathesis. 相似文献
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Hemoglobin-based oxygen carriers (HBOCs) are blood substitutes, synthesized by polymerizing hemoglobin, which are being developed and investigated as alternatives to blood for medical purposes. However, due to their ability to increase the oxygen carrying capacity when taken by healthy individuals, HBOCs have been used as a doping agent among endurance athletes and are included in the World Anti-Doping Agency's Prohibited List. To maintain the fairness of competitions and continue the battle against doping, it is essential to be able to detect HBOCs if present in an athlete's blood. To achieve this goal, it is necessary to differentiate HBOCs from the native hemoglobin and to do so in a cost and time effective manner. We have developed a rapid capillary zone electrophoresis (CZE), UV absorbance, method capable of detecting HBOCs, in whole blood samples, at levels below those considered necessary to provide a performance enhancement. Our approach to the analysis for HBOCs utilizes the whole blood sample, not just the plasma, and does not require the use of immunoprecipitants to ensure accurate analysis. By lysing the red blood cells and using centrifugal filtration, followed by our CZE separation, we are able to effectively distinguish between native hemoglobin and HBOCs. Through this method, we have been able to reliably detect concentrations of HBOCs at the equivalent of 5.5 g/L, the equivalent to a 3.5% increase in blood hemoglobin concentration for an athlete. 相似文献
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K. Srilatha L. Pavić A. Moguš-Milanković Ch. Srinivasa Rao G. Little Flower V. Ravi Kumar N. Veeraiah 《Journal of Non》2011,357(19-20):3538-3547
LiI–AgI–B2O3 glasses mixed with different concentrations of V2O5 (ranging from 0 to 1.0 mol%) were prepared. Electrical and dielectric properties over wide ranges of frequency (10?2–107 Hz) and temperature (173–523 K) have been studied. Additionally spectroscopic properties viz., optical absorption and ESR spectra have been investigated. The optical absorption and ESR studies have revealed that vanadium ions do exist in both V4+ and V5+ states and the redox ratio is the highest in the glasses containing 0.8 mol% of V2O5. The results of conductivity measurements have indicated that there is a mixed conduction (both ionic and electronic). The ionic conduction seems to be dominant over polaron hopping only in the glasses containing V2O5 more than 0.8 mol% of V2O5. The impedance spectra have also indicated that the conduction is predominantly polaronic in nature. The frequency and temperature dependence of the electrical moduli as well as dielectric loss parameters have exhibited relaxation character attributed to the vanadyl complexes. The relaxation effects have been analyzed by the graphical method and from this analysis it has been established that there is a spreading of relaxation times. The results have been further discussed quantitatively in the light of different valance states of vanadium ions with the aid of the data on spectroscopic properties. 相似文献
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Biswanath Das Boyapati Veeranjaneyulu Penagaluri Balasubramanyam Malampati Srilatha 《Tetrahedron: Asymmetry》2010,21(23):2762-2767
The stereoselective total synthesis of two naturally occurring α-pyrone derivatives, (+)-strictifolione and (6R)-6[(E,4R,6R)-4,6-dihydroxy-10-phenyl-1-decanyl]-5,6-dihydro-2H-2-pyrone has been accomplished involving the Sharpless kinetic resolution and olefin cross-metathesis as the key reactions. 相似文献
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Guijie Zhu Liangliang Sun Jennifer Heidbrink‐Thompson Srilatha Kuntumalla Hung‐yu Lin Christopher J. Larkin James B. McGivney IV Norman J. Dovichi 《Electrophoresis》2016,37(4):616-622
We have evaluated CZE‐ESI‐MS/MS for detection of trace amounts of host cell protein impurities in recombinant therapeutics. Compared to previously published procedures, we have optimized the buffer pH used in the formation of a pH junction to increase injection volume. We also prepared a 5‐point calibration curve by spiking 12 standard proteins into a solution of a human mAb. A custom CZE‐MS/MS system was used to analyze the tryptic digest of this mixture without depletion of the antibody. CZE generated a ~70‐min separation window (~90‐min total analysis duration) and ~300‐peak capacity. We also analyzed the sample using ultra‐performance LC‐MS/MS. CZE‐MS/MS generated approximately five times higher base peak intensity and more peptide identifications for low‐level spiked proteins. Both methods detected all proteins spiked at ~100 ppm level with respect to the antibody. 相似文献
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Boyapati Veeranjaneyulu Malampati Srilatha Gandolla Chinna Reddy Biswanath Das 《Helvetica chimica acta》2012,95(7):1152-1157
The stereoselective total synthesis of the naturally occurring γ‐lactone derivative botryolide E ( 1 ) was accomplished with acetaldehyde as the starting material (Scheme 2). The asymmetric allyl boration, asymmetric dihydroxylation, chelation‐mediated diastereoselective vinylation, and ring‐closing metathesis reaction are the key steps. The method can conveniently be utilized for the preparation of other related γ‐lactone derivatives. 相似文献