Seminar Speakers 2013 - Chemistry Department
Department Seminar Speakers
- Dr. Michael De Castro (Farmingdale State College, SUNY)
- November 7, 2013 (The LI-ACS Seminar)
- Title: "A Facile Synthesis of N-Glycooxazolines, N-Glycoaminooxazolines and N-Glycothiazolines from Glycals"
- Abstract: As part of our ongoing research program aimed at the generation of novel glycosidase inhibitors we became interested in the development of a convergent approach for the synthesis of a small library of carbohydrate fused substituted oxazolines based on the natural product Allosamidin (I) and Trahazolin (II). Thus a novel one-pot syntheses of N-glycooxazolines (IV) (N at C-1), N-glycothiazolines (V) and N-glycoaminooxazolines (VI) were synthesized by reacting tri-O-benzyl-D-glucal or tri-O-benzyl-D-galactal with aryl amides, heteroaryl amides, thioamides and substituted ureas in the presence of N-iodosuccinamide (NIS) in dry propionitrile at 45 degrees C. When tris-O-tert-butyldimethylsilyl-D-glucal was employed, the 2-deoxy-2-iodoglycosylamide was isolated instead. Treatment of this newly formed glycosylamide with an anhydrous base afforded the O-glycooxazoline (O at C-1) in high to moderate yields. Product outcomes and overall reaction stereoselectivity were found to be highly dependent on the nature of the sugar protecting group, the nature of the substituent on the amide, and the reaction temperature.
- Dr. Nathan Lents (John Jay College of Criminal Justice, CUNY)
- November 1, 2013
- Title: "Divalent Cations as Adulterants in Urine Drug Testing"
- Abstract: The seminar is on the effectiveness of zinc and other dietary supplements as adulterants or preventatives during routine urine drug testing via a series of in vitro and in vivo studies.
- Dr. Paul Sideris (QCC, CUNY)
- October 10, 2013
- Title: "Nuclear Magnetic Resonance Spectroscopic Studies of CFx-Ag2V4O11 Hybrid Cathodes"
- Abstract: The continued development and adoption of next-generation implantable medical devices and biotelemetry systems critically rely on advancements in primary battery technology. It was discovered by Medtronic Inc. that mixtures of two cathode materials, CFx and Ag2V4O11 (SVO), met the desired power requirements of these new implantable medical devices without compromise. The high power SVO provides the major share of current during rapid discharge and becomes partially recharged by the high-energy CFx phase via physical contact during the resting phase of the battery. Results from a preliminary solid state nuclear magnetic resonance (NMR) investigation of hybrid cathode materials harvested from partially discharged cells as a function resting time after initial discharge will be presented. The initial discharge was monitored by the 7Li NMR signal attributed to the Li intercalated in the SVO phase. Subsequent transfer of Li+ ions to the CFx phase of the hybrid cathode, following the prescribed storage interval, is inferred by observing the growth of the 19F signal characteristic of LiF, as well as changes of the 7Li signal compared to the initial discharge state.
- Dr. Markus Enders (Anorganisch-Chemisches Institut, Universität Heidelberg, Heidelberg, Germany)
- April 5, 2013
- Title: "Olefin Polymerisation with Organochromium Catalysts"
- Abstract: Polyolefins like polypropylene or polyethylene are the most important synthetic polymers. Polyethylene is produced by a radical process, leading to low density polyethylene (LDPE), or by transition metal catalyzed processes leading to high density polyethylene (HDPE). The chromium based, heterogeneous Phillips catalyst is used for the bigger part of HDPE. In the past twenty years molecular chromium based catalysts have been developed which are able to polymerize ethylene with high activity, and the properties of the resulting polymers can be adjusted to a large extent. The seminar will summarize the present knowledge about molecular organochromium polymerization catalysts and will then switch to the research conducted in Heidelberg in this area. The molecular catalysts developed by us show preferential features which make them interesting for industrial application. In addition to that the molecular nature of the catalysts allows experimental and theoretical investigations of reaction mechanisms and kinetics so that a deeper understanding helps to systematically improve these catalytic systems and hence the resulting polymeric materials.
- Dr. John A. Reffner (John Jay College of Criminal Justice, CUNY)
- March 13, 2013
- Title: "The Impact of Microspectroscopy on Forensic Investigations"
- Abstract: Applying the scientific method and advanced technologies to analyze evidence in legal matters is the foundation of forensic science. Because of advances in infrared, Raman, ultraviolet and visible light micro-spectroscopy, molecular spectroscopy now plays a major role in forensic investigations. When microscopes became available accessories to Fourier transform spectrometer benches, the forensic community quickly recognized their advantages for microanalysis of trace evidence. In 1986, California equipped each of their 12 regional state forensic laboratories with FT-IR microscopes. Today, every major crime lab around the world has infrared microspectroscopy instrumentation. When the internal reflection objective was introduced in 1989, it was quickly put to work analyzing evidence. An advantage internal reflection is its ability to produce ATR spectra from the surface of thick samples. Paint transferred onto paint in a hit-run case could be analyzed directly without removing the transferred paint. More recently, diamond ATR objectives became available for analyzing glass and minerals which would damage earlier internal reflection elements. Using diamond extended the range of samples the forensic scientist could analyze by ATR.
The acceptance of molecular spectroscopy by forensic scientists increased with the availability of spectral data bases. Spectra of unknowns can be compared with standard reference materials in spectral libraries. This is of special interest in the analysis of powders related to homeland security issues. Field portable infrared or Raman spectrometers are used by first responders to identify "white powders". These units contain spectral libraries of hazardous chemical agents and are used for on-site, real-time analysis. The library searching software quickly suggests leads to assist the analyst in the identification of an unknown and its potential hazard. The advances in spectrometer design, solid-state lasers, low noise /high sensitive detectors, and improved notch filters have led to the development of new Raman spectrometers and micro-probes. These systems are being used in numerous forensic laboratories and show much promise for forensic applications. The future for molecular spectroscopy in forensic investigations is very exciting. Molecular spectroscopy provides rapid, reliable and reviewable record to aid investigators and the courts.
- Dr. John Regan (QCC, CUNY)
- February 7, 2013 (The LI-ACS Seminar)
- Title: "Searching for Safer Anti-inflammatory Drugs"
- Abstract: During the past fifty years the successful treatment of inflammatory diseases has relied on the use of glucocorticoid (GC) agonists such as dexamethasone and prednisolone. While effective in controlling asthma, rheumatoid arthritis, and other disorders, GC therapy is fraught with a number of severe side effects that hampers high dose and chronic administration. The probability of identifying a GC agonist with a better safety profile compared to existing therapies has substantially increased with newer understandings of the molecular mechanism of action. After an agonist enters a target cell and binds to the glucocorticoid hormone receptor (GR), the ligand-activated complex (GRC) translocates into the nucleus where direct and indirect functional pathways can be accessed. Acting directly, the GRC serves as an endogenous transcription factor by binding to specific DNA sequences and coactivator proteins, thereby initiating transcription of metabolic and endocrine genes. GRC-mediated transactivation of these genes is believed to contribute to the side effect profile of GC therapy. Acting indirectly, the GRC adopts a conformation with an affinity for transcription factors (e.g., NF-kB and AP-1). Subsequent binding to these transcription factors results in the inhibition of expression of pro-inflammatory cytokines such as TNF-α and IL-6. This process, known as transrepression, is thought to contribute, in part, to the anti-inflammatory component of GCs. Therefore, the search for GC agonists with a dissociated profile (greater transrepression than transactivation activity) has accelerated in recent years with an appreciation of the complex molecular pathways and the anticipation of an improved safety margin. We report on structure-activity-relationships (SAR) of a hybrid class of non-steroidal glucocorticoid agonists which combine essential pharmacophores of steroid A- and D-rings. Their biological assessment for nuclear receptor binding affinity, cellular activity of transrepression and transactivation, and anti-inflammatory properties will be discussed. In addition, the importance of optimum physicochemical properties for drug development will be highlighted.