Enantioselective Synthesis of (−)-Acetylapoaranotin

The first enantioselective total synthesis of the epipolythiodiketopiperazine (ETP) natural product (−)-acetylapoaranotin (3) is reported. The concise synthesis was enabled by an eight-step synthesis of a key cyclohexadienol-containing amino ester building block. The absolute stereochemistry of both amino ester building blocks used in the synthesis is set through catalytic asymmetric (1,3)-dipolar cycloaddition reactions. The formal syntheses of (−)-emethallicin E and (−)-haemotocin are also achieved through the preparation of a symmetric cyclohexadienol-containing diketopiperazine

Production Of Ag/zno Nanocomposite Particles Via Ultrasonic Spray Pyrolysis (usp) Method And Their Application In Textile Industry Wastewater Treatment

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2012Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2012Bu çalışmada, sıklıkla tercih edilen nano yapılı yarıiletken ZnO ile soy metal Ag kompoziti üretilmiş ve model olarak seçilen metilen mavisi çözeltisinin UV-A altında renk giderimi incelenmiştir. Ag/ZnO nanokompozit katalizörlerinin üretimi ultrasonik sprey piroliz tekniği kullanılarak 0,05; 0,1 ve 0,2M Ag+ ve Zn2+ iyonları içeren sulu çözeltileri ile gerçekleşmiştir. Hava aerosolü fırın ortamına taşıyan gaz olarak seçilmiş ve tüm deneylerde, 500 mL/dak. akış debisinde tutulmuştur. Reaksiyonlar 700-900°C arasında gerçekleştirilmiştir. Kristalografik yapısı XRD ve TEM ile belirlenenmiştir. Kristal boyutu, Scherrer formülü yardımıyla Ag ve ZnO için ayrı hesaplanmıştır. Partikül morfolojisi SEM kullanılarak belirlenmiştir. Sözkonusu yöntemle, küresel morfolojide mikronaltı partiküller elde edilmiştir. TEM görüntüleri, artan başlangıç konsantrasyonu ile boşluklu yapının yerini yoğun ikincil partiküllere bıraktığını göstermiştir. Fotokatalitik oksidasyon deneyleri için seçilen model kirletici metilen mavisinden renk giderimi, sabit konsantrasyon (0,2M) ve üç farklı sıcaklıkta (700, 800 ve 900°C) üretilen partiküller kullanılarak UV-Vis spektroskopisi ile hesaplanmıştır. Deney sonuçlarında, UV-A ışığı altında her 15 dakika aralıkla alınan numunelerde metilen mavisi çözeltisi için tüm deney setlerde renk gideriminin görüldüğü, en fazla giderimin ise 900°C setinde üretilen partiküllerle gerçekleştiği hesaplanmıştır. Ayrıca adsorpsiyon reaksiyonu hız sabitleri her 3 set için hesaplanmıştır.In this study, one of the widely used nanostructured metal oxide semiconductors ZnO were made composite with one of the noble metals Ag. Ultrasonic Spray Pyrolysis method was used to produce Ag/ZnO nanocomposites starting from 0.05; 0.1; 0.2M silver and zinc ion containing aqueous solutions. Air was selected as a carrier gas into the reaction furnace and flow rate was kept constant for all experiments. Reactions were taken place at the temperature between 700-900°C. XRD, SEM, TEM were used to determine the crystallographic structure, morphology of the produced particles. The morphology for the particles produced via USP method was spherical as proven by SEM and TEM pictures. Crystallite size was determined using Debye-Scherrer equation. Methylene Blue was selected as a model dye for photocatalytic oxidation experiments. Catalysts are produced in the constant concentration of 0.2M at 700, 800 and 900°C reaction temperature. Decoloration was calculated for each experimental set. After irradiation to UV-A, at every 15 minutes, samples were collected and their final concentrations were calculated from UV-Vis spectroscopy. Decolorization and 1st order reaction kinetics were discussed in the photocatalytic characterization. 0.2M-900°C set showed the highest decolorization and highest reaction rate constant.Yüksek LisansM.Sc

A case of thrombocytopenia associated with the use of hydroxychloroquine following open heart surgery

INTRODUCTION: Thrombocytopenia is a common problem occurring in patients and drug-induced thrombocytopenia is a significant cause of thrombocytopenia. PRESENTATION OF CASE: We present an unusual case of thrombocytopenia that was considered to be associated with the use of hydroxychloroquine in the late term following open heart surgery. DISCUSSION: The drug-induced thrombocytopenia, mechanical destruction of the platelets, and hemodilution are common causes of low platelet count. Although drug-induced immune thrombocytopenia has a mild clinical course in most cases (in this case it has severe clinical course), some patients may experience life-threatening hemorrhages. The decision to discontinue the drug that is deemed to be responsible from the drug-induced thrombocytopenia (DITP) relies on the clinical condition of the patient. The diagnosis is mostly established by discontinuation, exclusion, and correlation because the tests performed to detect drug-dependent antibodies (DDAbs) for the diagnosis of DITP are time-consuming, and these tests are also not commonly available. The authors of the current study diagnosed DITP by discontinuation of the drug. We suggest that the use of hydroxychloroquine could be severe thrombocytopenia occurring after open heart surgery. CONCLUSION: The medication history must be carefully reviewed in patients presenting with thrombocytopenia, and if the medications could cause thrombocytopenia must be discontinued

Rh(I)-Catalyzed Decarbonylation of Diynones via C–C Activation: Orthogonal Synthesis of Conjugated Diynes

Utilization of C–C bond activation as a unique mode of reactivity for constructing C–C bonds provides new strategies for preparing important organic molecules. Development of a Rh(I)-catalyzed C–C activation of diynones to synthesize symmetrical and unsymmetrical conjugated diynes through decarbonylation is reported. This C–C cleavage strategy takes advantage of the innate reactivity of conjugated ynones without relying on any ring strain or auxiliary directing group. This alkynation method also has orthogonal properties compared to typical cross-coupling reactions

Rh(I)-Catalyzed Decarbonylation of Diynones via C–C Activation: Orthogonal Synthesis of Conjugated Diynes

Utilization of C–C bond activation as a unique mode of reactivity for constructing C–C bonds provides new strategies for preparing important organic molecules. Development of a Rh(I)-catalyzed C–C activation of diynones to synthesize symmetrical and unsymmetrical conjugated diynes through decarbonylation is reported. This C–C cleavage strategy takes advantage of the innate reactivity of conjugated ynones without relying on any ring strain or auxiliary directing group. This alkynation method also has orthogonal properties compared to typical cross-coupling reactions

A novel green and one-step electrochemical method for production of sulfur-doped graphene powders and their performance as an anode in Li-ion battery

Graphene-based negative electrodes in lithium-ion batteries have recently been the focus of interest. In this study, sulfur (S)–doped graphene powders in different functionality have been prepared in one step by using Yucel’s method for the first time in the literature and they have been used as anode materials of Li-ion batteries. By changing the scanned potential during the preparation of S-doped graphene powders, the graphenic surface is covalently doped by –C-S-C- and –C-SOx-C- (x:2, 3) groups at different amount. When the potential has been scanned in wider potential range (− 1.0 and 2.5 V), 48 sp2-hybridized carbon rings have been determined on the powders by using Raman analysis. It is the lowest as 16 for graphenic powder prepared at narrower potential range (1.5 and 2.5 V) and chronoamperometric method. S-doped graphene powders have been investigated by microscopic methods. Electrochemical properties of the prepared S-doped graphene powders and their potential use in Li-ion batteries have been assessed. At a 50-mA/g current density, the 915-mAh/g specific capacity has been determined as the highest discharge capacity in the powder which was prepared by the chronoamperometric method. Specific capacities of 710 mAh/g, 594 mAh/g, and 642 mAh/g have been observed in the powders prepared between − 1.0–(+ 2.5 V), 0.6–(+ 2.5 V), and 1.5–(+ 2.5 V) samples, respectively. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature