Organic Chemistry Commons^™

Synthetic Studies On Angucycline C104, Rui Zheng

Legacy Theses & Dissertations (2009 - 2024)

The Hauser's annulation and Hauser and Xu's route for C-aryl glycoside synthesis were successfully employed to prepare the linear tetracyclic anthraquinone substituted C-aryl glycoside, galtamycin as well as bis C-aryl glycosides. Synthetic studies on angucycline C104 extended the utility of both methods to structures with angular tetracyclic framework.

A Mild And Chemoselective Method For The Deprotection Of Tert-Butyldimethylsilyl (Tbdms) Ethers Using Iron(Iii) Tosylate As A Catalyst, Ram Mohan, Jason Bothwell, Veronica Angeles, James Carolan, Margaret Olson

Scholarship

The most common method for the deprotection ofTBDMS ethers utilizes stoichiometric amounts of tetrabutylammonium fluoride, n-Bu₄N⁺F(TBAF), which is highly corrosive and toxic. We have developed a mild and chemoselective method for the deprotection ofTBDMS, TES, and TIPS ethers using iron(III) tosylate as a catalyst. Phenolic TBDMS ethers, TBDPS ethers and the BOC group are not affected under these conditions. Iron(III) tosylate is an inexpensive, commercially available, and non-corrosive reagent.

Bismuth(Iii) Bromide In Organic Synthesis. A Catalytic Method For The Allylation Of Tetrahydrofuranyl And Tetrahydropyranyl Ethers, Ram Mohan, Scott Krabbe, Veronica Angeles

Scholarship

A bismuth bromide-catalyzed (10.0 mol %) multicomponent reaction involving the allylation of THF- and THP-ethers, followed by in situ derivatization with acetic anhydride to generate highly functionalized esters has been developed under solvent-free conditions. To the best of our knowledge, this is the first report of a catalytic procedure for the allylation of THF- and THP-ethers to yield ring-opened products.

Iron(Iii) Tosylate-Catalyzed Deprotection Of Aromatic Acetals In Water, Ram Mohan, Margaret Olson, James Carolan, Michael Chiodo, Phillip Lazzara

Scholarship

The deprotection of aromatic as well as conjugated acetals and ketals in water is catalyzed by iron(III) tosylate (1.0–5.0 mol %). Iron(III) tosylate is an inexpensive and readily available catalyst. The use of water, the most environmentally benign solvent, makes this procedure especially attractive for acetal deprotection.

In Your Element: Green Bismuth, Ram Mohan

Scholarship

No abstract provided.

Approaches Towards The Synthesis Of Bradyoxetin, Vanildo Martins Lima Braga

Electronic Theses and Dissertations

Quorum sensing bacteria produce and release chemical signal molecules (like N-acyl homoserine lactones, AHL) that increase in concentration as a function of cell density. The responses cover a large spectrum of process such as the virulence in Staphylococcus aureus, competence for DNA-uptake in Bacillus subtilis and Streptococcus pneumoniae, sporulation in Bacillus subtilis, conjugal plasmid transfer in Enterococcus faecalis, and bacteriocin production in lactic acid bacteria. The collapse of (AHL) signaling system in bacteria represents an attractive therapeutic approach towards the development of new antibiotics. Recently, a new extracellular modulator was isolated from a symbiotic bacterium (Bradyrhizobium japonicum) that nodulates soybean. …

Microporous Organic Polymers: Synthesis And Post Synthetic Modifications, Phillip Andrew Kerneghan

Theses and Dissertations (Comprehensive)

Microporous solids are an important class of materials that have been studied extensively. Newer to this field are Microporous Organic Polymers (MOPs) which are networks constructed from smaller organic building blocks and exhibit large surface areas, small pore sizes and low densities. It is due to these characteristics that MOPs have attracted attention because of their potential use in applications such as catalysis, chemical separations and gas storage.

In this thesis is described the synthesis of two novel MOPs, the first of which being a network based on benzenediboronic acid and triptycene building blocks linked together by boronate esters. This …

Supramolecular Self-Assembly Strategies Involving Water Soluble Calixarenes., Irene Ling

Student Works (2010-2019)

Fundamental investigations of host-guest interactions on the supramolecular self-assembly involving water-soluble p-sulfonatocalix[4]arene, with a series of imidazolium-based cations and pyrrolidinium cation with variable alkyl chain lengths, which featured extensively in ionic liquids have been established. Combinatorial studies incorporating multiple components concerning p-sulfonatocalix[4]arene, imidazolium cations or pyrrolidinium cation, phosphonium cations and lanthanide ions have been developed, which yielded diverse solid state motifs with a common structural characteristic that the imidazolium or pyrrolidinium cation resides in the cavity of the calixarene. Shorter terminal alkyl chain of mono-imidazolium molecules, i.e. n-ethyl and n-butyl imidazoliums are confined in the „molecular capsule‟, being encapsulated by …

Oxidation Of Dibenzothiophene To Dibenzothiophene Using Metal Nanoparticles Supported On Silica, Karina Castillo

Open Access Theses & Dissertations

Silica and nanoparticles of Pt, Au, and Ag supported on silica were tested for the ability to oxidize dibenzothiophene (DBT) to sulfone. High performance liquid chromatography was used to study the removal of DBT from solution. In addition, X- ray diffraction, infrared spectroscopy and Raman Spectroscopy were used to characterize the product of the oxidation reaction. Further studies involved the use X-ray absorption spectroscopy to characterize the nanoparticle catalysts before and after the oxidation reaction.

To better understand the reaction, silica was synthesized at different pHs using three different acids. The acids used to synthesize the silica were HCl, HNO3, …

A New Photochemical Method For The Preparation Of Amino Acid-α-Phenylthioesters And Peptide-α-Phenylthioesters, Tyrone Hogenauer

Open Access Theses & Dissertations

We describe the development of a novel resin with a photoreactive N-acylnitroindoline linker that allows for the synthesis of amino acid- (in solution) or peptide-α-thioesters using standard Fmoc/t-Bu standard solid phase peptide synthesis (SPPS). Recent advances have shown that the yields of this thioesterification reaction have dramatically increased due to a simple change in the order of addition of reagents. Upon illumination with UV-light, in the presence of N-hydroxybenzotriazole (HOBt), the amino acid- or peptide-α-OBt ester is generated by direct photo-release from the nitroindoline linker with minimal epimerization, followed by reaction with thiophenol in the dark to produce amino acid-α-phenylthioesters …

I-Kinetic And Mechanistic Investigations Of Amino Acid Substrates Reactivities With Ferryl Species, Ahmed Ibrahim Youssef Abouelatta

Wayne State University Dissertations

ABSTRACT

I-KINETIC AND MECHANISTIC INVESTIGATIONS OF AMINO ACID SUBSTRATES REACTIVITIES WITH FERRYL SPECIES

II-SYNTHESIS AND CHARACTERIZATION OF DERIVATIVES OF THE BN-TPEN LIGAND AND THEIR METAL COMPLEXES

by

AHMED IBRAHIM YOUSSEF ABOUELATTA

MAY 2011

Advisor: Dr. Jeremy Jacob Kodanko

Major: Chemistry (Organic)

Degree: Doctor of philosophy

The reactivity of tryptophan, methionine, aspartic acid, glutamic acid, histidine and hydrochloride salt of lysine amino acid substrates with the N4Py ferryl species was studied by UV-vis spectroscopy and product characterization. Based on kinetic isotope effect studies and product analysis, an ET-PT mechanism was proposed for the reaction of tryptophan substrate with N4Py ferryl and …

Conversion Of Racemic Ibuprofen To (S)-Ibuprofen, David Chavez-Flores

Open Access Theses & Dissertations

Ibuprofen is a common Non-Steroidal Anti-Inflammatory Drug (NSAID) sold as a racemic or equal mixture of (R) and (S) mirror-image enantiomers. Without patent protection, ibuprofen is an orphan drug even though one enantiomer, (S)-ibuprofen, provides relief three times faster than its racemic mixture with fewer side effects. The goal of this research was to develop a facile, environmentally benign (no waste of ibuprofen or catalysts), and inexpensive process to convert a commercially available racemic mixture of ibuprofen to the therapeutically active (S)-ibuprofen.

After many attempts, the most successful conversion of racemic ibuprofen to (S)-ibuprofen was the in situ racemization and …

Chemical Constituents Of Aglaia Lanuginose. King, Fadzly Adzhar Kamarulzaman

Student Works (2010-2019)

Aglaia is a small genus of trees that belong to the family Meliaceae. They are widely distributed in India, Malay Peninsula and throughout Indomalesia. The chemistry of Aglaia has been extensively investigated and most of the researches done on these plants focused on their effect as insecticides, antifeedant, growth inhibitors, cytotoxicity and others. The dichloromethane extract from the bark of Aglaia lanuginose were studied. The chromatographic separation on both of the extracts gave ten compounds. The compounds isolated were identified as eichlerialactone 102, methyl eichlerianate 103, cabraleone 104, ocotillone 105, 4-hydroxycinnamyl acetate 106, cabralealactone 107, eichlerianic acid 108, shoreic acid …

Synthesis, Characterization And Biological Activity Of Copper (Ii) And Zinc (Ii) Complexes Of Thiosemicarbazones And Their N(4)-Substituted Derivatives Derived From 2,4-Dihydroxybenzaldehyde., Tan Kong Wai

Student Works (2010-2019)

Four thiosemicarbazones ligands (1-4) have been prepared with good yield by refluxing 2,4-dihydroxybenzaldehyde with thiosemicarbazide or N(4)-substituted thiosemicarbazide in ethanol or methanol. From these four ligands, 16 new ternary metal complexes (5-20) with the general formulation of M(B)L have been prepared from the reactions of metal acetates with 2,4-dihydroxybenzaldehyde N(4)-substituted thiosemicarbazone in the presence of N,N-heterocyclic base (M2+ = Zn2+ or Cu2+; B = 2,2'-bipyridine, (bpy); 1,10-phenanthroline, (phen); L2- = doubly deprotonated thiosemicarbazones = 2,4-dihydroxybenzaldehyde thiosemicarbazonato, (HT); 2,4-dihydroxybenzaldehyde 4-methylthiosemicarbazonato, (HM); 2,4-dihydroxybenzaldehyde 4-ethylthiosemicarbazonato, (HE) and 2,4-dihydroxybenzaldehyde 4-phenylthiosemicarbazonato, (HP)) These compounds have been characterized by elemental analyses, IR, UV-Vis, NMR and magnetic …

Synthesis, Characterization And Biological Activities Of Some Indole Derivatives And Their Metal Complexes., Mohamed Mustafa Mohamed Ibrahim

Student Works (2010-2019)

Tryptamine (1H-indole-3-ethyleneamine) Schiff bases were prepared by the condensation reaction of ethanolic solution of tryptamine with: salicylaldehyde (TS), 5 chlorosalicylaldehyde (TCS), 5-nitrosalicylaldehyde (TNS), 3,5-di-tert-butyl-2-hydroxy benzaldehyde (TTET) and the ketones: 2-hydroxyacetophenone (THAP), 5-methyl-2- hydroxyacetophenone (TMeHAP), 5-methoxy-2 hydroxyacetophenone (TOMeHAP), 5- chloro-2-hydroxyacetophenone (TClHAP) and 5-bromo-2 hydroxyacetophenone (TBrHAP). The ligands were coordinated to Zn(II), Cu(II) and Ni(II) by the reaction of metal acetates with the corresponding ligand in a 1 : 2 metal to ligand ratio. The solid products formed were collected, washed with ethanol and recrystallized from a suitable solvent. All the ligands and complexes prepared have been characterized by spectroscopic methods using …

Synthesis, Characterization And Electrochemical Studies Of Cu(Ii), Fe(Ii), Fe(Iii) And Ni(Ii) Complexes Of Someo-Phenylenediamine Schiff Bases., Abdulaziz Ali Alomari

Student Works (2010-2019)

Four Schiff base ligands, N,N’-1,2-benzene-1,2-diyl-bis(5-chlorosalicylideneimine) (H2L1), N,N’-1,2-benzene-1,2-diyl-bis(4-bromosalicylideneimine) (H2L2), N,N’-1,2- benzene-1,2-diyl-bis(4-hydroxysalicylideneimine) (H2L3), and N,N’-1,2-benzene-1,2-diyl-bis(3-bromo-5-chlorosalicylideneimine) (H2L4) were obtained in good yields from the condensation reaction of o-phenylenediamine with 5-chlorosalicylaldehyde, 5-bromosalicylaldehyde, 4-hydroxysalicylaldehyde and 3-bromo-5-chlorosalicylaldehyde respectively. These Schiff bases formed complexes with copper(II), iron(II) and nickel(II) ions in good yields. The structures of these complexes are mainly square planar, which is confirmed by the crystal structure of nickel(II) complex of bis-N,N’-3-chloro-5-bromosalicylideneamine-,2-diaminobenzene. Attempts to prepare the corresponding iron(III) complexes were unsuccessful. The ligands were characterized by Fourier transform infrared spectroscopy, elemental analysis, 1H-Nuclear magnetic resonance spectroscopy and UV-vis spectroscopy, while the complexes were characterized by …

New Palm Oil Products By Enzymatic Interesterification And Dry Fractionation., Saw Mei Huey

Student Works (2010-2019)

Palm olein is one of the major palm oil products that domestically and industrially used as cooking or frying oil. Palm olein tends to crystallize at low temperature that limits its usage in temperate countries. In spite of various nutritional studies, palm olein is also not well considered as recommended choice due to its higher saturation content. Against these factors, there is a need to reduce its saturation content. In this study, the saturation content in palm olein was reduced through the combination of enzymatic interesterification and dry fractionation. Enzymatic interesterification allows interchanging of acyl groups between and within triacylglycerols …

Chemical Constituents Of Cryptocarya Densiflora., Nurul Nazneem Wan Othman

Student Works (2010-2019)

The extraction of alkaloids from the Malaysian Cryptocarya densiflora has been carried out in this study. The alkaloids were extracted from the bark and leaves of this species using acid base extraction and the crude alkaloids obtained were subjected to extensive chromatographic techniques such as thin layer and column chromatography. The structural elucidation of the purified alkaloids were performed with the aid of spectroscopic methods i.e. 1H NMR, 13C NMR, 2D NMR, IR, UV and LCMS. Investigation of the alkaloidal content from the bark of Cryptocarya densiflora afforded six alkaloids and their structures were elucidated as laurotetanine 63, isocaryachine 64, …

Synthesis Of Novel Glycosylidene-Based Quinolines, Peter H. Dobbelaar

Seton Hall University Dissertations and Theses (ETDs)

.

Development Of Novel Ahr Antagonists, Hyosung Lee

University of Kentucky Doctoral Dissertations

Aryl hydrocarbon receptor (AHR) is a sensor protein, activated by aromatic chemical species for transcriptionally regulating xenobiotic metabolizing enzymes. AHR is also known to be involved in a variety of pathogenesis such as cancer, diabetes mellitus, cirrhosis, asthma, etc. The AHR signaling induced by xenobiotics has been intensively studied whereas its physiological role in the absence of xenobiotics is poorly understood. Despite a number of ligands of AHR have been reported thus far, further applications are still hampered by the lack of specificity and/or the partially agonistic activity. Thus, a pure AHR antagonist is needed for deciphering the AHR cryptic …