Bulunan: 17 Adet 0.001 sn
Araştırmacılar Nermin Şimşek Kuş
Nermin Şimşek KuşFEN FAKÜLTESİ KİMYA BÖLÜMÜ ORGANİK KİMYA ANABİLİM DALI
167251

Some synthetic cyclitol derivatives alleviate the effect of water deficit in cultivated and wild-type chickpea species

Yıldızlı Aytunç, Güzel Değer Ayşin

Cyclitols were prepared from corresponding allylic hydroperoxides, synthesized by photooxygenation of the appropriate cyclic alkenes. These hydroperoxides were then separately treated with a catalytic amount of OsO4. Synthesized dl-cyclopentane-1,2,3-triol 9 (A), dl-cyclohexane-1,2,3-triol 12 (B), and dl-cycloheptane-1,2,3-triol 15 (C) were used in the investigation of plant stress. Antioxidants, lipid peroxidation, and water status of chickpea species exposed to synthetic cyclitols under water deficit were examined. Cyclitol derivatives significantly decreased leaf water potential, lipid peroxidation and H2O2 levels of wild and cultivated species under water deficit. Cyclitol treatments affected antioxidant enzyme activities differently in both species under water deficit. The highest SOD...

167243

Oxidation of Alchols to Carbonyl Compounds Benzylic Carbons to their Ketones and Arenes to their Quinones with Molecular Oxygen in Subcritical Water

Özen Recep, Şimşek Kuş Nermin

Molecular oxygen is used as an efficient oxidant for the conversion of alcohols into carbonyl compounds, benzylic carbons to their ketones, and arenes to their quinones in subcritical water in the absence of catalysts. The procedure utilizes water and does not require support materials and metal salts.

167242

OXIDATION OF TOLUENES TO AROMATIC ALDEHYDES WITH MOLECULAR OXYGEN IN SUBCRITICAL WATER

Recep Özen, Ahmet M. Gizir & N. Simsek Kus

Oxidations are important transformations in organic synthesis. In general, many oxidations are carried out with a large excess of chromium or manganese reagents. The metal residues are environmentally undesirable and often cause problems during work-up.2 In addition organic oxidations in the chemical industry have traditionally been performed in either aromatic or halogenated solvents.' One of the most attractive oxidants is molecular oxygen? since oxygen is highly soluble in subcritical water. Molecular oxygen has been used as the reagent for the oxidation of alkyl aromatic compounds in the presence of different catalysts, such as MnBr.

167244

A Mild and Effective Method for the Conversion of Alkenes into Alcohols in Subcritical Water

Özen Recep, Şimşek Kuş Nermin

lkenes were oxidized to alcohols in subcritical water. A number of alkenes were oxidized directly to their alcohols in excellent yields. The syntheses were performed in 215 cm3 stainless steel high pressure reactor at 120 ºC in 150 cm3 water. The yields of alcohols increased with the nitrogen pressure.

167252

Diels Alder reactions The effects of catalyst on the addition reaction

Yılmaz Özgür, Şimşek Kuş Nermin

The reaction between 2,3-dimethyl-1,3-butadiene and dimethyl 7-oxabicyclo[2.2.1]hepta-2,5-diene-2,3dicarboxylate is efficiently achieved with small amounts of catalyst, i.e. phenol, AcOH, nafion, and b cyclodextrin. Exo-diastereoselective cycloaddition reactions were observed both without catalyst and different catalysts for 48 days. As a result, different products (tricyclicmolecule 5, retro-DielseAlder product 6, and oxidation product 7) were obtained with different catalysts. In addition, we synthesized DielseAlders product 8 and tricyclocyclitol 10 via DielseAlder reaction. The structures of these products were characterized by 1H NMR, 13C NMR, MS and IR spectroscopy.

167250

Simple and convenient preparation of some bicyclic alcohols and epoxide derivatives promising antibiotic activities of rac dimethyl 3 8 dioxatricyclo 3 2 1 02 4 oct 6 ene 6 7 dicarboxylate

Yılmaz Özgür, Şimşek Kuş Nermin

The biological activity of alcohol and epoxide groups containing bicyclic skeletal structures was investi- gated in terms of antibiotic and toxic effects at cellular level. The present protocol, which utilizes readily available starting materials and mild reaction conditions, provides an attractive approach to a series of functionalized bicyclic alcohol and epoxide derivatives with promising biological applications. In this protocol, while some of the bicyclic compounds were synthesized as in the literature, the other bicyclic compounds were synthesized by new synthetic methods. The antibiotic and toxic properties of the syn- thesized bicyclic compounds were investigated, and some of their biological activities were tested in prokaryotic and eukaryotic systems. (rac)-Dimethyl 3,8-dioxatric...

167240

High temperature bromination XIII Bromination of dimethyl 7 oxabicyclo 2 2 1 hepta 2 5 diene 2 3 dicarboxylate

Kuş, Nermin Şimşek

The electrophilic addition of bromine to dimethyl 7-oxabicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylate 10 at 0 and −60°C led in high yield to the formation of dibromide 11. However, high-temperature bromination of 10 in carbon tetrachloride at 77°C gave four products 12–15, three of them with nonrearranged skeleton. Similarly, bromination of the dibromides 14 and 15 at 77°C yielded the nonrearranged tetrabromides 13 and 16, respectively. The structure of the tetrabromide 13 was solved by single-crystal X-ray analysis. The formation mechanism is discussed and supported by calculations

170692

Aquatic toxic effect of epoxide derivatives on model organism Dapnia magna

Doğan, Ahmet | Özdemir, Birgül | Şimşek Kuş, Nermin

Since epoxides, which are found as natural products, show a wide range of biological activities, scientists have always been interested in studies on this subject. There are epoxides with very different substituents in the literature. For example, epoxides with lactone as paniculide A, amino as anticapsin, hydroxide as Eutypoxide B and Eutypoxide C are used as drugs by showing biological activity. Based on the studies in the literature, we planned to study the biological activity of molecules that do not contain amino, lactone and hydroxyl groups. For this purpose, we first performed the Diels-Alder reaction of 2,3-dimethyl-1,3-butadiene (1) with benzoquinone (2), in the next step, epoxidation reaction was targeted. Our research group previously showed that epoxide derivatives with ...

167249

One-step synthesis of substituted isobenzofuran-1(3H)-ones and isobenzofuran-1,3-diones from indane derivatives in subcritical media

Kuş, Nermin Şimşek

Molecular oxygen is one of the most attractive oxidants in organic synthesis because it is highly soluble in subcritical water. In this study, indane derivatives were oxidized to the corresponding isobenzofuran-1(3H)-one with molecular oxygen and isobenzofuran-1,3-dione with a mixture of molecular oxygen and H2O2 in subcritical water. This paper describes a simple, economic, environmentally benign,and general procedure that can be used for the synthesis of substituted isobenzofuran-1(3H)-ones and isobenzofuran-1,3-diones in only one step and without catalyst.

167276

28. Ulusal kimya Kongresi özet kitabı

Şimşek Kuş Nermin,

28. Ulusal kimya Kongresi özet kitabı

167275

ORGANİK KİMYA "YAŞAMIN KALBİ"

Kuş, Prof. Dr. Nermin Şimşek

KARBOKSİLİK ASİTLER

167247

Concise preparation of azenes by oxidation of aromatic amines with molecular oxygen in subcritical water

Nermin, Şimşek Kuş

Reaction of organic substrates with molecular oxygen, the most abundant and accessible oxidant, has always been an attractive method for preparation of target molecules. In terms of green chemistry, non-metal-catalyzed oxidation of organic substrates is very attractive. This paper describes a general procedure for synthesis of azenes by oxidation of primary aromatic amines with molecular oxygen (3O2) in subcritical water. The reactions afforded the corresponding azenes in moderate to good yield.

167266

Oxidation of Toluenes to Aromatic Aldehydes With Molecular Oxygen in Subcritical Water

Özen Recep, Gizir Ahmet Murat

Oxidation of Toluenes to Aromatic Aldehydes With Molecular Oxygen in Subcritical Water

167274

Chemistry and Alternative Usage of Missile Propellants Stored in Azerbaijan

Zir Ahmet Murat, Şimşek Kuş Nermin

Chemistry and Alternative Usage of Missile Propellants Stored in Azerbaijan

167246

Photochemical Bromination of Substitued Indan 1 one Derivatives Synthesis of New Polybromoindan 1 one Derivatives

Nermin, Şimşek Kuş

he photobromination of substituted indan derivatives was studied. Four products, 2,3-dibromo-inden1-one (5), trans-2,3-dibromoindan-1-one (6), 2,2-dibromoindan-1,3-dione (7) and 2,2-dibromoindan-1-one (8), were obtained by the bromination of indan-1-one (4). The bromination of 2-methyl indanone (9) and 3- methyl-indanone (13) gave the corresponding monobromo, dibromo, and tribromo compounds in high yield. 4-Nitro indan (16) was tribrominated under same condition reaction. The structures of these products were determined from 1 H-NMR, 13 C-NMR, MS, and IR data.

167241

An Unprecedented CoII-Tetraphenylporphyrin-Catalyzed Decomposition of Bicyclic Endoperoxides: A New Approach to Substituted Furofuran Systems

Kuş, Nermin Şimşek

CoII-tetraphenylporphyrin-catalyzed decomposition of bicyclic endoperoxides 4 and 5 with a strained double bond moiety has been studied. Compounds 4 and 5 have been synthesized by photooxygenation of 3 which itself was obtained by dichloroketene addition to cycloheptatriene, followed by removal of the chlorine atoms. An unusual decomposition mode of 4 promoted by CoII-TPP resulted in the formation of 8 and 9 which are important building blocks in furofuran systems.

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