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Full-Text Articles in Physical Sciences and Mathematics

Effect Of A Strategically Positioned Methoxy Substituent On The Photochemistry Of 3-Aryl-3h-1-Oxacyclopenta[L]Phenanthren-2-Ones, Roshini Thumpakara, Binoy Jose, Perupparampil Unnikrishnan, Sreedharan Prathapan, Nigam Rath Dec 2010

Effect Of A Strategically Positioned Methoxy Substituent On The Photochemistry Of 3-Aryl-3h-1-Oxacyclopenta[L]Phenanthren-2-Ones, Roshini Thumpakara, Binoy Jose, Perupparampil Unnikrishnan, Sreedharan Prathapan, Nigam Rath

Chemistry & Biochemistry Faculty Works

Irradiation of 3-methoxy-3-aryl-3H-1-oxacyclopenta[l]phenanthren-2-one derivatives 5a–d resulted in singlet-mediated decarbonylation reaction leading to the formation of phenanthrene derivatives 9a–d. The structure of the photoproduct was unequivocally established on the basis of X-ray crystallographic analysis.


Role Of Amyloid Beta Assembly State In The Human Immune Response, Deepa Viswanathan Dec 2010

Role Of Amyloid Beta Assembly State In The Human Immune Response, Deepa Viswanathan

Dissertations

Alzheimer’s disease (AD) is a slowly progressing neurodegenerative disease that leads to dementia. Histopathological hallmarks that characterize AD are senile plaques formed by extracellular deposition of Amyloid beta (Aβ) peptide and intracellular aggregates of hyperphosphorylated tau protein. The plaques, which are found in the brain parenchyma, comprise both 40 and 42 residue Aβ. Aggregation of Aβ is an established pathogenic mechanism in AD, but little is known about the initiation of this process in vivo. Several studies have revealed significant inflammatory markers such as activated microglia and cytokines surrounding the plaques. Plaques are a hallmark of AD, but they are …


Activation Of Propargylic Alcohols By Piano-Stool Ruthenium Complexes Bearing Phosphoramidite Ligands, Stephen Andrew Costin Dec 2010

Activation Of Propargylic Alcohols By Piano-Stool Ruthenium Complexes Bearing Phosphoramidite Ligands, Stephen Andrew Costin

Dissertations

Various piano-stool ruthenium complexes bearing phosphoramidite ligands have been synthesized and characterized spectroscopically and in some cases structurally. Reaction of phosphoramidite ligands with an appropriate metal precursor gives new piano-stool ruthenium complexes [RuCl(L)(arene)(phosphoramidite)], where L = Cl, PPh3, or others. The novel complexes are tested for their ability to activate propargylic alcohols catalytically as well as stoichiometrically. Specifically, catalytic substitution of propargylic alcohols via allenylidene intermediates is envisioned. Stoichiometric reactions designed to form stable, isolable allenylidenes are sought as well. h6-p-cymene complexes of the type [RuCl2(h6-p-cymene)(phosphoramidite)] activate propargylic alcohols in the reaction with carboxylic acids to form b-oxo esters. The …


The Molecular Transport And Intercalation Of Guest Molecules Into Hydrogen–Bonded Metal-Organic Frameworks (Hmofs), Greg Anthony Hogan Nov 2010

The Molecular Transport And Intercalation Of Guest Molecules Into Hydrogen–Bonded Metal-Organic Frameworks (Hmofs), Greg Anthony Hogan

Dissertations

The process of molecular transport and intercalation has been widely studied for many years, resulting in the discovery of molecular frameworks that are capable of hosting guest molecules or ions. Layered and porous metal-organic frameworks (MOFs) have been found to have applications in the field of catalysis, storage, separations, and ion-exchange. While MOFs are perhaps stronger materials, HMOFs have the advantage of being easily modifiable and more flexible. Because HMOFs have not been extensively studied for their ability to host molecules, and because their ability to withstand guest loss and guest exchange is essentially unknown, here we report the synthesis …


Activation Of The Innate Immune Response By The Alzheimer's Amyloid Beta Protein Via Toll-Like Receptors, Udan Lourdes Maria Oct 2010

Activation Of The Innate Immune Response By The Alzheimer's Amyloid Beta Protein Via Toll-Like Receptors, Udan Lourdes Maria

Dissertations

Alzheimer’s Disease (AD) is the most common form of neurodegenerative disease characterized by the generation and deposition of amyloid beta plaques and the formation of neurofibrillary tangles. A wealth of data now demonstrate that inflammation is a prominent feature in AD pathology and a potential therapeutic target for the treatment and prevention of the disease. The emergence of evidence linking amyloid beta protein (Aβ), the primary component of senile plaques, to inflammation has led to new insights into understanding AD pathology. Aβ, a protein fragment resulting from cleavage of human amyloid precursor protein (APP), primarily exists in two forms: a …


(1e,3e)-1,4-Bis(4-Methoxyphenyl)Buta1,3-Diene, Gopinathan Narayan, Nigam Rath, Suresh Das Oct 2010

(1e,3e)-1,4-Bis(4-Methoxyphenyl)Buta1,3-Diene, Gopinathan Narayan, Nigam Rath, Suresh Das

Chemistry & Biochemistry Faculty Works

The title compound, C18H18O2, which exhibits blue emission in the solid state, is an inter­mediate in the preparation of liquid crystals and polymers. The mol­ecule is located on an inversion centre. In the crystal, mol­ecules are arranged in a herringbone motif.


2,2′,5,5′-Tetra­Chloro­Benzidine, Onome Ugono, Marcel Douglas, Nigam Rath, Alicia Beatty Sep 2010

2,2′,5,5′-Tetra­Chloro­Benzidine, Onome Ugono, Marcel Douglas, Nigam Rath, Alicia Beatty

Chemistry & Biochemistry Faculty Works

In the crystal structure of the title compound, C12H8Cl4N2, mol­ecules lie on crystallographic twofold axes at the centre of the C-C bonds linking the benzene rings, such that the asymmetric unit consists of a half-mol­ecule. The individual mol­ecules participate in inter­molecular N-H...N, N-H...Cl, C-H...Cl and Cl...Cl [3.4503 (3) Å] inter­actions.


Inhibition Studies Of Serine Hydrolases By Cyclic Phosphates And Phosphonates, Supratik Dutta Jul 2010

Inhibition Studies Of Serine Hydrolases By Cyclic Phosphates And Phosphonates, Supratik Dutta

Dissertations

The serine hydrolase superfamily is one of the largest known enzyme families comprising approximately 1% of the predicted protein product in human genome. This family of enzymes contains a catalytic triad that is mainly consists of serine, aspartic acid/glutamic acid and histidine residues in their active sites. It has been proposed that the potential drug targets for Alzheimer’s disease and diabetes type 2 are enzymes that belong to this enzyme family. Acetylcholinesterase is an enzyme that catalyses the breakdown of acetylcholine, a neurotransmitter that helps transport information from one nerve cell to another. Breakdown of acetylcholine in Alzheimer’s disease patients …


2,4,6-Triphenyl­Aniline, Onome Ugono, Stephanie Cowin, Alicia Beatty Jul 2010

2,4,6-Triphenyl­Aniline, Onome Ugono, Stephanie Cowin, Alicia Beatty

Chemistry & Biochemistry Faculty Works

Individual mol­ecules of the title compound, C24H19N, do not participate in hydrogen-bonding inter­actions due to the steric bulk of the phenyl rings ortho to the amine. The dihedral angles between the central ring and the pendant rings are 68.26 (10), 55.28 (10) and 30.61 (11)°.


The Nature Of The O-2/O-5 Cooperative Effect And Its Role In Chemical Glycosylation, Laurel Kathryn Mydock Jul 2010

The Nature Of The O-2/O-5 Cooperative Effect And Its Role In Chemical Glycosylation, Laurel Kathryn Mydock

Dissertations

Since carbohydrates were first discovered, understanding the structure, reactivity, and function of these bioorganic compounds has remained of great priority. However, as the appreciation for the biological roles of carbohydrates intensifies, a growing demand for efficient and scalable methods towards the synthesis of these challenging molecules has become even more imperative. While modern synthetic techniques have allowed us to readily achieve most glycosidic linkages, it is the inability to effectively predict and control the stereoselectivity of the glycosylation reaction that has remained the synthetic hurdle. Herein, much effort has been placed in the investigation of “mixed-patterned” glycosyl donors as they …


Effect Of Anions On The Iron Release Pathways Of Human Serum Transferrin, Rashmi Subhash Chander Sharma May 2010

Effect Of Anions On The Iron Release Pathways Of Human Serum Transferrin, Rashmi Subhash Chander Sharma

Dissertations

Transferrin, the serum iron transport protein in humans, is used to transport 30-40 mg of iron per day through blood. The accessibility of transferrin makes it an attractive target for iron cheating therapeutic agents used in the treatment of iron overload. There is an ongoing search for ligands which can accelerate the rate of iron release, as the currently approved drug DFO has a very slow rate for iron removal. Previous studies have shown that anions can accelerate the rate of iron release. Studies on the effect of anions on the rates of iron release from C-terminal monoferric transferrin at …


New Chiral Phosphoramidite Complexes Of Iron As Catalytic Precursors In The Oxidation Of Activated Methylene Groups, Pushkar Shejwalkar, Nigam Rath, Eike Bauer Apr 2010

New Chiral Phosphoramidite Complexes Of Iron As Catalytic Precursors In The Oxidation Of Activated Methylene Groups, Pushkar Shejwalkar, Nigam Rath, Eike Bauer

Chemistry & Biochemistry Faculty Works

New phosphoramidite complexes of iron were synthesized and structurally characterized. Reaction of the known chiral phosphoramidites (RO)2PNR’2 (R = binaphthyl, R’ = CH3, 1a; R = binaphthyl, R’ = benzyl, 1b) with [FeBr(Cp)(CO)2] afforded the title compounds [FeBr(Cp)(CO)(1a,b)] (4a,b) in 34 and 65 % isolated yields as mixtures of diastereomers, since both the metal and the ligand are stereogenic. Similarly, reaction of 1b with [Fe(Cp)I(CO)2] in the presence of catalytic [Fe(Cp)(CO)2]2 afforded [Fe(Cp)I(CO)(1b)] (5b) in 81% yield as a mixture of diastereomers. The molecular structures of 4a, 4b and 5 were determined, revealing a pseudo octahedral coordination geometry about the …


Phase Transition Enthalpy Measurements Of Organic And Organometallic Compounds. Sublimation, Vaporization And Fusion Enthalpies From 1880 To 2010, William Acree, James Chickos Jan 2010

Phase Transition Enthalpy Measurements Of Organic And Organometallic Compounds. Sublimation, Vaporization And Fusion Enthalpies From 1880 To 2010, William Acree, James Chickos

Chemistry & Biochemistry Faculty Works

No abstract provided.