Open Access. Powered by Scholars. Published by Universities.®

Medicinal-Pharmaceutical Chemistry Commons

Open Access. Powered by Scholars. Published by Universities.®

Medical Sciences

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1 - 30 of 82

Full-Text Articles in Medicinal-Pharmaceutical Chemistry

Integration Of Random Forest Classifiers And Deep Convolutional Neural Networks For Classification And Biomolecular Modeling Of Cancer Driver Mutations, Steve Agajanian, Odeyemi Oluyemi, Gennady M. Verkhivker Jun 2019

Integration Of Random Forest Classifiers And Deep Convolutional Neural Networks For Classification And Biomolecular Modeling Of Cancer Driver Mutations, Steve Agajanian, Odeyemi Oluyemi, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

Development of machine learning solutions for prediction of functional and clinical significance of cancer driver genes and mutations are paramount in modern biomedical research and have gained a significant momentum in a recent decade. In this work, we integrate different machine learning approaches, including tree based methods, random forest and gradient boosted tree (GBT) classifiers along with deep convolutional neural networks (CNN) for prediction of cancer driver mutations in the genomic datasets. The feasibility of CNN in using raw nucleotide sequences for classification of cancer driver mutations was initially explored by employing label encoding, one hot encoding, and embedding to ...


Purification And Characterization Of A Nonspecific Lipid Transfer Protein 1 (Nsltp1) From Ajwain (Trachyspermum Ammi) Seeds, Meshal Nazeer, Humera Waheed, Maria Saeed, Saman Yousuf Ali, M. Iqbal Choudhary, Zaheer Ul-Haq, Aftab Ahmed Mar 2019

Purification And Characterization Of A Nonspecific Lipid Transfer Protein 1 (Nsltp1) From Ajwain (Trachyspermum Ammi) Seeds, Meshal Nazeer, Humera Waheed, Maria Saeed, Saman Yousuf Ali, M. Iqbal Choudhary, Zaheer Ul-Haq, Aftab Ahmed

Pharmacy Faculty Articles and Research

Ajwain (Trachyspermum ammi) belongs to the family Umbelliferae, is commonly used in traditional, and folk medicine due to its carminative, stimulant, antiseptic, diuretic, antihypertensive, and hepatoprotective activities. Non-specific lipid transfer proteins (nsLTPs) reported from various plants are known to be involved in transferring lipids between membranes and in plants defense response. Here, we describe the complete primary structure of a monomeric non-specific lipid transfer protein 1 (nsLTP1), with molecular weight of 9.66 kDa, from ajwain seeds. The nsLTP1 has been purified by combination of chromatographic techniques, and further characterized by mass spectrometry, and Edman degradation. The ajwain nsLTP1 is ...


Thioredoxin Modulates Protein Arginine Deiminase 4 (Pad4)-Catalyzed Citrullination, Mitesh Nagar, Ronak Tilvawala, Paul R. Thompson Feb 2019

Thioredoxin Modulates Protein Arginine Deiminase 4 (Pad4)-Catalyzed Citrullination, Mitesh Nagar, Ronak Tilvawala, Paul R. Thompson

Open Access Articles

Protein citrullination is a post-translational modification catalyzed by the protein arginine deiminases (PADs). This modification plays a crucial role in the pathophysiology of numerous autoimmune disorders including RA. Recently, there has been a growing interest in investigating physiological regulators of PAD activity to understand the primary cause of the associated disorders. Apart from calcium, it is well-documented that a reducing environment activates the PADs. Although the concentration of thioredoxin (hTRX), an oxidoreductase that maintains the cellular reducing environment, is elevated in RA patients, its contribution toward RA progression or PAD activity has not been explored. Herein, we demonstrate that hTRX ...


Synthesis, Biological Evaluation And Molecular Modeling Studies Of Novel Chromone/Aza-Chromone Fused Α-Aminophosphonates As Src Kinase Inhibitors, S. Bapat, N. Viswanadh, M. Mujahid, Amir Nasrolahi Shirazi, Rakesh Tiwari, Keykavous Parang, M. Karthikeyan, M. Muthukrishnan, Renu Vyas Feb 2019

Synthesis, Biological Evaluation And Molecular Modeling Studies Of Novel Chromone/Aza-Chromone Fused Α-Aminophosphonates As Src Kinase Inhibitors, S. Bapat, N. Viswanadh, M. Mujahid, Amir Nasrolahi Shirazi, Rakesh Tiwari, Keykavous Parang, M. Karthikeyan, M. Muthukrishnan, Renu Vyas

Pharmacy Faculty Articles and Research

A series of novel chromone/aza-chromone fused α-aminophosphonate derivatives were synthesized in good yields using silica chloride as the catalyst. All the synthesized compounds were tested for their c-Src kinase inhibitory activity. Aza-chromone compound showed Src kinase inhibition with an IC50 value of 15.8 µM. The compounds were subjected to molecular docking and dynamics simulations to study the atomic level interactions with an unphosphorylated proto-oncogenic tyrosine protein kinase Src (PDB code 1Y57) as well as phosphorylated tyrosine protein kinase Src (PDB code 2H8H). Docking and molecular dynamic results revealed phosphorylated Src tyrosine kinase protein better results than unphosphorylated tyrosine ...


Donated Chemical Probes For Open Science, Susanne Muller, Paul R. Thompson, Anke Mueller-Fahrnow Apr 2018

Donated Chemical Probes For Open Science, Susanne Muller, Paul R. Thompson, Anke Mueller-Fahrnow

Open Access Articles

Potent, selective and broadly characterized small molecule modulators of protein function (chemical probes) are powerful research reagents. The pharmaceutical industry has generated many high-quality chemical probes and several of these have been made available to academia. However, probe-associated data and control compounds, such as inactive structurally related molecules and their associated data, are generally not accessible. The lack of data and guidance makes it difficult for researchers to decide which chemical tools to choose. Several pharmaceutical companies (AbbVie, Bayer, Boehringer Ingelheim, Janssen, MSD, Pfizer, and Takeda) have therefore entered into a pre-competitive collaboration to make available a large number of ...


Ferrocenylchalcone-Uracil Conjugates: Synthesis And Cytotoxic Evaluation, Amandeep Singh, Vishu Mehra, Neda Sadeghiani, Saghar Mozaffari, Keykavous Parang, Vipan Kumar Feb 2018

Ferrocenylchalcone-Uracil Conjugates: Synthesis And Cytotoxic Evaluation, Amandeep Singh, Vishu Mehra, Neda Sadeghiani, Saghar Mozaffari, Keykavous Parang, Vipan Kumar

Pharmacy Faculty Articles and Research

Huisgen’s azide-alkyne cycloaddition reaction was employed to synthesize a series of 1H-1,2,3-triazole-tethered uracil-ferrocenyl chalcone conjugates with the aim of evaluating their in vitro anti-proliferative efficacy on human leukemia (CCRF-CEM) and human breast adenocarcinoma (MDA-MB-468) cell lines. Cytotoxic evaluation studies identified a number of synthesized conjugates that inhibited the proliferation of leukemia cancer cells by ~70% after 72 h. The selected synthesized conjugates were found to be significantly less cytotoxic against normal kidney cell line (LLC-PK1) when compared with CCRF-CEM cancer cells.


Traceable Peo-Poly(Ester) Micelles For Breast Cancer Targeting: The Effect Of Core Structure And Targeting Peptide On Micellar Tumor Accumulation, Shyam M. Garg, Igor M. Paiva, Mohammad R. Vakili, Rania Soudy, Kate Agopsowicz, Amir H. Soleimani, Mary Hitt, Kamaljit Kaur, Afsaneh Lavasanifar Aug 2017

Traceable Peo-Poly(Ester) Micelles For Breast Cancer Targeting: The Effect Of Core Structure And Targeting Peptide On Micellar Tumor Accumulation, Shyam M. Garg, Igor M. Paiva, Mohammad R. Vakili, Rania Soudy, Kate Agopsowicz, Amir H. Soleimani, Mary Hitt, Kamaljit Kaur, Afsaneh Lavasanifar

Pharmacy Faculty Articles and Research

Traceable poly(ethylene oxide)-poly(ester) micelles were developed through chemical conjugation of a near-infrared (NIR) dye to the poly(ester) end by click chemistry. This strategy was tried for micelles with poly(ε-caprolactone) (PCL) or poly(α-benzyl carboxylate-ε-caprolactone) (PBCL) cores. The surface of both micelles was also modified with the breast cancer targeting peptide, P18-4. The results showed the positive contribution of PBCL over PCL core on micellar thermodynamic and kinetic stability as well as accumulation in primary orthotopic MDA-MB-231 tumors within 4–96 h following intravenous administration in mice. This was in contrast to in vitro studies where ...


Cytotoxicity Of Platinum Anticancer Drugs In Mammalian Cell Lines Of Metastatic Cancer, Hosannah Evie Jun 2017

Cytotoxicity Of Platinum Anticancer Drugs In Mammalian Cell Lines Of Metastatic Cancer, Hosannah Evie

Honors College Capstone Experience/Thesis Projects

With the invention of advanced technology, focus has been put on understanding and looking for potential cures for many diseases, one of which is cancer. The difference in the leaving and non-leaving ligands of the FDA approved cancer drugs contributes to the differential cell specific cytotoxic effects. These drugs such as oxaliplatin approved for colorectal cancer, cisplatin approved for testicular cancer, and their analogs were used to treat different cancer cell lines in an MTT assay. This project aims to determine how changing the molecular shape of these compounds affects their uptake and toxicity into different cell lines. The assay ...


Synthesis, Self-Assembly, And Immunological Activity Of Α-Galactose-Functionalized Dendron–Lipid Amphiphiles, John Trant, Namrata Jain, D. M. Mazzuca, J Trevor Mcintosh, Bo Fan, S M Mansour Haeryfar, Sebastien Lecommandoux, Elizabeth Gillies Sep 2016

Synthesis, Self-Assembly, And Immunological Activity Of Α-Galactose-Functionalized Dendron–Lipid Amphiphiles, John Trant, Namrata Jain, D. M. Mazzuca, J Trevor Mcintosh, Bo Fan, S M Mansour Haeryfar, Sebastien Lecommandoux, Elizabeth Gillies

Chemistry Publications

Nanoassemblies presenting multivalent displays of biologically active carbohydrates are of significant interest for a wide array of biomedical applications ranging from drug delivery to immunotherapy. In this study, glycodendronlipid hybrids were developed as a new and tunable class of dendritic amphiphiles. A modular synthesis was used to prepare dendronlipid hybrids comprising distearylglycerol and 0 through 4th generation polyester dendrons with peripheral protected amines. Following deprotection of the amines, an isothiocyanate derivative of C-linked α-galactose (α-Gal) was conjugated to the dendron peripheries, affording amphiphiles with 1 to 16 α-Gal moieties. Self-assembly in water through a ...


Peroxiredoxin Catalysis At Atomic Resolution, Arden Perkins, Derek Parsonage, Kimberly J. Nelson, O. Maduka Ogba, Paul Ha-Yeon Cheong, Leslie B. Poole, P. Andrew Karplus Sep 2016

Peroxiredoxin Catalysis At Atomic Resolution, Arden Perkins, Derek Parsonage, Kimberly J. Nelson, O. Maduka Ogba, Paul Ha-Yeon Cheong, Leslie B. Poole, P. Andrew Karplus

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Peroxiredoxins (Prxs) are ubiquitous cysteine-based peroxidases that guard cells against oxidative damage, are virulence factors for pathogens, and are involved in eukaryotic redox regulatory pathways. We have analyzed catalytically active crystals to capture atomic resolution snapshots of a PrxQ-subfamily enzyme (from Xanthomonas campestris) proceeding through thiolate, sulfenate, and sulfinate species. These analyses provide structures of unprecedented accuracy for seeding theoretical studies, and show novel conformational intermediates giving insight into the reaction pathway. Based on a highly non-standard geometry seen for the sulfenate intermediate, we infer that the sulfenate formation itself can strongly promote local unfolding of the active site to ...


Terpenes As ‘Resistance-Busting” Anthelmintic Drug, Zeynep Mirza, David Koch, Thanh-Thanh Nguyen, Yan Hu, Raffi V. Aroian, Gary R. Ostroff May 2016

Terpenes As ‘Resistance-Busting” Anthelmintic Drug, Zeynep Mirza, David Koch, Thanh-Thanh Nguyen, Yan Hu, Raffi V. Aroian, Gary R. Ostroff

UMass Center for Clinical and Translational Science Research Retreat

There is an urgent need for new therapies for parasitic helminthic diseases affecting 1.5-2 billion people worldwide due to the threat of wide-spread resistance development to existing treatments and due to problems of incomplete efficacies.

Terpenes are plant secondary metabolites and major essential oil constituents. Historically, the terpene thymol was successfully used to cure hookworm infections in the 1900’s. Although effective, large doses were needed and thymol treatment had significant side effects. Because free terpenes are absorbed in the stomach, less than 10% of oral terpenes entered the site where the parasites live. To overcome these problems we ...


Zn(Ii), Cu(Ii), Sn(Ii), And Ni(Ii) And Other Metal Cations Do Not Prevent The Aggregation Of Hiapp, Charles Hoying May 2016

Zn(Ii), Cu(Ii), Sn(Ii), And Ni(Ii) And Other Metal Cations Do Not Prevent The Aggregation Of Hiapp, Charles Hoying

Honors Thesis

The Zn(II) metal ion has been shown to interact with Islet Amyloid Polypeptide (IAPP), a protein implicated in the progression of Type II Diabetes Mellitus, in such a way as to prevent the protein from aggregating into toxic fibers. We set out to find whether other metal ions might similarly prevent IAPP aggregation. Using Thioflavin T (ThT) spectroscopic assays, which measure fluorescence of ThT upon binding to aggregated IAPP, we observed a decrease in aggregation when incubated with Zn(II), Cu(II), Ni(II), and Sn(II). Atomic Force Microscopy (AFM), which can visualize fibril formation, revealed that the ...


Analysis Of New Hiv-1 Inhibitors As Potential Antiviral Agents For Hiv-2, Rowan Brothers Apr 2016

Analysis Of New Hiv-1 Inhibitors As Potential Antiviral Agents For Hiv-2, Rowan Brothers

Georgia State Undergraduate Research Conference

No abstract provided.


A Sodium Salt Of The Dimer Of Boronoterephthalic Acid Anhydride, Scott Simmons, Albert Fratini, Vladimir Benin Mar 2016

A Sodium Salt Of The Dimer Of Boronoterephthalic Acid Anhydride, Scott Simmons, Albert Fratini, Vladimir Benin

Albert Fratini

The title compound, sodium bis­(6-carb­oxy-1-hy­droxy-3-oxo-1,3-dihydro-2,1-benzoxaborol-1-yl)oxidanium, Na+·C16H15B2O13-, was prepared in two steps from 2-bromo-p-xylene. Its crystal structure was determined at 140 K and has triclinic (P) symmetry. The compound presents a unique structural motif, including two units of the cyclic anhydride of boronoterephthalic acid, joined by a protonated, and thereby trivalent, oxonium center. Association in the crystal is realized by complementary hydrogen bonding of the carboxyl groups, as well as by coordination of the sodium cations to the oxygen centers on the five-membered rings.


Interrogating Metabolism In Brain Cancer, Travis Salzillo, Jingzhe Hu, Linda Nguyen, Nicholas Whiting, Jaehyuk Lee, Joseph Weygand, Prasanta Dutta, Shivanand Pudakalakatti, Niki Zacharias Millward, Seth Gammon, Frederick F. Lang, Amy B. Heimberger, Pratip Bhattacharya Dec 2015

Interrogating Metabolism In Brain Cancer, Travis Salzillo, Jingzhe Hu, Linda Nguyen, Nicholas Whiting, Jaehyuk Lee, Joseph Weygand, Prasanta Dutta, Shivanand Pudakalakatti, Niki Zacharias Millward, Seth Gammon, Frederick F. Lang, Amy B. Heimberger, Pratip Bhattacharya

Nicholas Whiting

Many existing and emerging techniques of interrogating metabolism in brain cancer are at an early stage of development. A few clinical trials that employ these techniques are in progress in patients with brain cancer to establish the clinical efficacy of these techniques. It is likely that in vivo metabolomics and metabolic imaging is the next frontier in brain cancer diagnosis and assessing therapeutic efficacy.


C–N Bond Rotation And E–Z Isomerism In Some N-Benzyl-N-Methylcarbamoyl Chlorides: A Dft Study, Michael Horwath, Vladimir Benin Nov 2015

C–N Bond Rotation And E–Z Isomerism In Some N-Benzyl-N-Methylcarbamoyl Chlorides: A Dft Study, Michael Horwath, Vladimir Benin

Vladimir Benin

The current report presents the first theoretical study of the restricted CN bond rotation in carbamoyl chlorides. Several N-benzyl-N-methylcarbamoyl chlorides were investigated, with varying pattern of substitution in the aromatic ring. Optimizations and frequency calculations were conducted employing DFT at the B3LYP/6-31+G(d) level of theory. Each of the studied structures exhibits a pair of rotamers (s-Z and s-E), generated upon rotation around the C(O)N bond. The s-E isomer is the global minimum in every case, but the preference for it is usually less than 1 kcal/mol. Two possible transition state structures were identified for ...


Preparation And Characterization Of Some Substituted Benzyl N-Nitrosocarbamates Containing An N-2-(Methylthio)Ethyl Or A Bis(2-Aminoethyl)Sulfide Functionality, Satya Venkata, Eric Shamo, Vladimir Benin Nov 2015

Preparation And Characterization Of Some Substituted Benzyl N-Nitrosocarbamates Containing An N-2-(Methylthio)Ethyl Or A Bis(2-Aminoethyl)Sulfide Functionality, Satya Venkata, Eric Shamo, Vladimir Benin

Vladimir Benin

The synthesis and characterization of some substituted benzyl N-nitrosocarbamates with an N-2-(methylthio)ethyl or a bis(2-aminoethyl)sulfide functionality is reported, as a part of a long-term goal to design and prepare novel photolabile structures that could be used as substances for controlled release of alkylating and/or crosslinking agents. The synthesis was accomplished by reaction of benzyl chloroformates with the corresponding amines, resulting in the preparation of carbamates. The latter were subsequently nitrosated, utilizing two different N-nitrosation methods, to yield the target structures.


The Tetrafluoroborate Salt Of 4-Methoxybenzyl N-2-(Dimethylamino)Ethyl-N-Nitrosocarbamate: Synthesis, Crystal Structure And Dft Calculations, Helene Hedian, Vladimir Benin Nov 2015

The Tetrafluoroborate Salt Of 4-Methoxybenzyl N-2-(Dimethylamino)Ethyl-N-Nitrosocarbamate: Synthesis, Crystal Structure And Dft Calculations, Helene Hedian, Vladimir Benin

Vladimir Benin

The tetrafluoroborate salt of 4-methoxybenzyl N-2-(dimethylamino)ethyl-N-nitrosocarbamate was prepared in two steps, via the corresponding carbamate. Its crystal structure is monoclinic, space group P21/c. The unit cell dimensions are: a = 19.499(8) Å, b = 5.877(3) Å, c = 15.757(7) Å, α = 90°, β = 110.019(7)°, γ = 90°, V = 1696.5(12) Å3, Z = 4. The structure exhibits an unexpected, pseudo-gauche conformation with respect to the C2–C3 bond, due to a stabilizing hydrogen bond between the carbonyl oxygen (O1) and the hydrogen atom at the trialkylammonium center (H3n), with a distance between them ...


A Sodium Salt Of The Dimer Of Boronoterephthalic Acid Anhydride, Scott Simmons, Albert Fratini, Vladimir Benin Nov 2015

A Sodium Salt Of The Dimer Of Boronoterephthalic Acid Anhydride, Scott Simmons, Albert Fratini, Vladimir Benin

Vladimir Benin

The title compound, sodium bis­(6-carb­oxy-1-hy­droxy-3-oxo-1,3-dihydro-2,1-benzoxaborol-1-yl)oxidanium, Na+·C16H15B2O13-, was prepared in two steps from 2-bromo-p-xylene. Its crystal structure was determined at 140 K and has triclinic (P) symmetry. The compound presents a unique structural motif, including two units of the cyclic anhydride of boronoterephthalic acid, joined by a protonated, and thereby trivalent, oxonium center. Association in the crystal is realized by complementary hydrogen bonding of the carboxyl groups, as well as by coordination of the sodium cations to the oxygen centers on the five-membered rings.


Secondary N-Nitrosocarbamate Anions: Structure And Alkylation Reactions. A Dft Study, Vladimir Benin Nov 2015

Secondary N-Nitrosocarbamate Anions: Structure And Alkylation Reactions. A Dft Study, Vladimir Benin

Vladimir Benin

The current article reports theoretical studies (DFT: B3LYP/6-31+G(d)) on the structure and alkylation reactions of the anions of some secondary N-nitrosocarbamates, a class of ambident nucleophiles whose chemistry has been little explored. Several anions (1–4), with an increasing size of the carbamate alkyl (aryl) group were investigated, in an attempt to establish the influence of the size of that group on the thermal stability and regioselectivity of alkylation of the title anions. The conclusion is that thermal stability and the mode of reaction are affected significantly only in the presence of very large and branched carbamate ...


Preparation Of Phosphonoterephthalic Acids Via Palladium-Catalyzed Coupling Of Aromatic Iodoesters, Nathaniel Ivan, Vladimir Benin, Alexander Morgan Nov 2015

Preparation Of Phosphonoterephthalic Acids Via Palladium-Catalyzed Coupling Of Aromatic Iodoesters, Nathaniel Ivan, Vladimir Benin, Alexander Morgan

Vladimir Benin

The current article reports in detail the preparation of two phosphonoterephthalic acids: 2-phosphonoterephthalic acid (1) and 2,5-diphosphonoterephthalic acid (2). Efficient, scalable syntheses have been developed for both compounds based on Pd-catalyzed coupling reactions of iodinated terephthalate esters. Phosphonoterephthalic acids are potentially useful as flame-retardant additives or as monomers for the construction of acid-pendant polymer chains.


Preparation Of Some Substituted Terephthalic Acids, Susanna Branion, Vladimir Benin Nov 2015

Preparation Of Some Substituted Terephthalic Acids, Susanna Branion, Vladimir Benin

Vladimir Benin

We report in detail the preparation of two substituted terephthalic acids: 2‐sulfomethylterephthalic acid (1) and 2‐phosphonoterephthalic acid (2). Efficient, short syntheses have been developed for both compounds. They are potentially useful monomers for construction of acid‐pendant polymer chains.


Theoretical Investigation Of A Reported Antibiotic From The 'Miracle Tree' Moringa Oleifera, Michael Horwath, Vladimir Benin Nov 2015

Theoretical Investigation Of A Reported Antibiotic From The 'Miracle Tree' Moringa Oleifera, Michael Horwath, Vladimir Benin

Vladimir Benin

Moringa oleifera, sometimes called the “Miracle Tree,” has received international attention for its potential to improve health in impoverished tropical areas. In addition to high vitamin content in the leaves and pods, the tree contains compounds with antioxidant and antibacterial properties. This study focused on the theoretical investigation of the suggested structure of one antibacterial compound, “pterygospermin,” whose existence was proposed after some studies of the roots of M. oleifera. The structure of pterygospermin was first proposed by a research group working in the 1950s, but later studies have not found evidence of this compound and have instead attributed the ...


Synthesis And Flammability Testing Of Epoxy Functionalized Phosphorous-Based Flame Retardants, Vladimir Benin, Xuemei Cui, Alexander Morgan, Karl Seiwert Nov 2015

Synthesis And Flammability Testing Of Epoxy Functionalized Phosphorous-Based Flame Retardants, Vladimir Benin, Xuemei Cui, Alexander Morgan, Karl Seiwert

Vladimir Benin

Several potential new phosphorus-containing flame retardant molecules were evaluated for heat release reduction potential by incorporation of the molecules into a polyurethane, generated from methylene diphenyl diisocyanate and 1,3-propane diol. The heat release reduction potential of these substances was evaluated using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods to qualitatively evaluate their potential reactivity into the polyurethane prior to heat release testing. The functionality of the flame retardants was epoxide based that would potentially react with the diol during polyurethane synthesis. Flammability ...


Synthesis And Flame Retardant Testing Of New Boronated And Phosphonated Aromatic Compounds, Vladimir Benin, Sravanthi Durganala, Alexander Morgan Nov 2015

Synthesis And Flame Retardant Testing Of New Boronated And Phosphonated Aromatic Compounds, Vladimir Benin, Sravanthi Durganala, Alexander Morgan

Vladimir Benin

The present report describes the preparation and use of some dimethyl terephthalate derivatives in transition metal-catalyzed coupling reactions to produce new reactive flame retardants. Dimethyl iodoterephthalate and dimethyl 2,5-diiodoterephthalate were successfully employed in the preparation of phosphonic and boronic esters and acids. The latter were tested for heat release with a microcombustion calorimeter (ASTM D7309) to determine the potential for heat release reduction of these flame retardant molecules. The results showed that the addition of boronic or phosphonic acids greatly lowered the heat release, due to a condensed phase (char formation) mechanism. Adding ester groups to the boronic acids ...


Heat Release Of Polyurethanes Containing Potential Flame Retardants Based On Boron And Phosphorus Chemistries, Vladimir Benin, Bastien Gardelle, Alexander Morgan Nov 2015

Heat Release Of Polyurethanes Containing Potential Flame Retardants Based On Boron And Phosphorus Chemistries, Vladimir Benin, Bastien Gardelle, Alexander Morgan

Vladimir Benin

Using a polyurethane of methylene diphenyl isocyanate and 1,3-propane diol, several new non-halogenated aromatic boron and phosphorus flame retardants were evaluated for heat release reduction potential using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods, and were then analyzed via spectroscopic methods to determine if the flame retardant was still present in the final product. PCFC testing on the resulting products showed that the flame retardant molecule can have different effects on heat release depending upon how it is mixed into the polyurethane ...


Preparation, Characterization And Dft Studies Of Some New N-Nitrosocarbamates And N-Nitrosoureas, Ragavan Narayanan, Helene Hedian, Eric Shamo, Vladimir Benin Nov 2015

Preparation, Characterization And Dft Studies Of Some New N-Nitrosocarbamates And N-Nitrosoureas, Ragavan Narayanan, Helene Hedian, Eric Shamo, Vladimir Benin

Vladimir Benin

We are presenting the preparation, characterization and density functional theory (DFT) studies {B3LYP/6-31+G(d)) of several reiated classes of N-nitrosocarbamates and N-nitrosoureas. The iong-range goal is the design and preparation of compounds, which would undergo photochemical or hydrolytic decomposition, to yield stabilized cyclic cations that can serve as alkylating agents at various nucleophilic centers, including DNA bases.


Synthesis, Structural Studies And Desilylation Reactions Of Some N-2-(Trimethylsilyl)Ethyl-N-Nitrosocarbamates, Arpitha Thakkalapally, Vladimir Benin Nov 2015

Synthesis, Structural Studies And Desilylation Reactions Of Some N-2-(Trimethylsilyl)Ethyl-N-Nitrosocarbamates, Arpitha Thakkalapally, Vladimir Benin

Vladimir Benin

The present report describes the preparation and characterization of several N-2-(trimethylsilyl)ethyl-N-nitrosocarbamates, designed as precursors to thermally unstable secondary N-nitrosocarbamate anions via fluoride-assisted cleavage. X-ray structural studies demonstrate that the core N-nitrosocarbamate moiety has a nearly planar geometry, with an s-E orientation at the N–N bond. DFT calculations (B3LYP/6-31+G(d)) reproduce accurately the structural features of the title compounds and detailed conformational analysis at the same level of theory addresses the long-standing issue of preferred geometries for three classes of related structures: N-nitrosocarbamates, N-nitrosoureas and N-nitrosoamides. Desilylation ...


Reactions Of Methyl Perfluoroalkyl Ethers With Isopropyl Alcohol: Experimental And Theoretical Studies, Howard Knachel, Vladimir Benin, Chadwick Barklay, Janine C. Birkbeck, Billy D. Faubion, William E. Moddeman Nov 2015

Reactions Of Methyl Perfluoroalkyl Ethers With Isopropyl Alcohol: Experimental And Theoretical Studies, Howard Knachel, Vladimir Benin, Chadwick Barklay, Janine C. Birkbeck, Billy D. Faubion, William E. Moddeman

Vladimir Benin

The reaction of an isomeric mixture of the methyl perfluoroalkyl ether, C4F9OCH3 (Novec-7100), in the presence of isopropyl alcohol (IPA) and/or water has been studied by measuring the rate of product formation using an ion-selective electrode (ISE) for fluoride ion, Karl Fisher coulometric titrations for water, and 1H and 19F NMR spectroscopy for product identification and rate studies. The results showed the methyl perfluoroalkyl ether to be very stable with products forming at the rate of ∼1 ppm per year at a laboratory temperature of 20 °C. Measurements over the temperature range of 6° to 100 °C were made ...


Preparation Of Halogenated Derivatives Of Thiazolo[5,4-D]Thiazole Via Direct Electrophilic Aromatic Substitution, Vladimir Benin, Alan T. Yeates, Douglas Dudis Nov 2015

Preparation Of Halogenated Derivatives Of Thiazolo[5,4-D]Thiazole Via Direct Electrophilic Aromatic Substitution, Vladimir Benin, Alan T. Yeates, Douglas Dudis

Vladimir Benin

Chlorination and bromination reactions of thiazolo[5,4-d]thiazole led to the generation of its mono- and dihalogenated derivatives. These are the first instances of successful direct electrophilic aromatic substitution in the thiazolo[5,4-d]thiazole ring system. X-ray analysis demonstrates that both 2-bromothiazolo[5,4-d]-thiazole and 2,5-dibromothiazolo[5,4-d]thiazole are planar structures, with strongly manifested π-stacking in the solid state. Theoretical analysis of the pyridine-catalyzed halogenation (MP2/6-31+G(d) and B3LYP/6-31+G(d)calculations) reveals that introduction of one halogen actually leads to a slightly enhanced reactivity towards further halogenation. Several halogenation mechanisms have ...