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Biomedical subjects

Cody Timmons

Publications and source records attributed to Cody Timmons.

10 recordsLinked to original sources
PubMed2006

Novel approach to multifunctionalized homoallylic alcohols via regioselective ring opening of aryl oxiranes with 3-iodo allenoates.

[reaction: see text] 3-Iodo allenoates were generated in situ and utilized, for the first time, in the ring opening of oxiranes in a regioselective fashion. This simple one-pot three-component reaction protocol provides easy access to highly functionalized homoallylic alcohols in good yields and moderate to very good (Z/E) selectivity. The two functional groups (ester and halogen) can be further subjected to many synthetic transformations.

Alcohols↗
PubMed2006

FeCl3-Catalyzed aminohalogenation of arylmethylenecyclopropanes and arylvinylidenecyclopropanes and corresponding mechanistic studies.

[reaction: see text] The aminochlorination of methylenecyclopropanes (MCPs) 1 and vinylidenecyclopropanes (VCPs) has been explored with use of FeCl(3) (20 mol %) as a Lewis acid catalyst in acetonitrile under convenient mild conditions. The stereochemistry has been unambiguously confirmed by X-ray structural analysis. The aziridinium-based mechanism, accounting for both regio- and stereoselectivity, has been carefully studied. A linear free-energy relationship study of this reaction confirms consistency with the Hammet equation.

Journal Article↗
PubMed2006

Vicinal diamino functionalities as privileged structural elements in biologically active compounds and exploitation of their synthetic chemistry.

The chemistry, synthetic routes and medicinal properties of vicinal diamines and imidazolines are discussed. Synthetic routes towards chemically and pharmaceutically important molecules containing vicinal diamine functionality are discussed in detail. This mini review article covers the new developments of diamine chemistry between 2000 and 2005.

Diamines↗
PubMed2005

Asymmetric halo-Mannich-type reaction provides access to pyrrolidines and beta-proline derivatives.

[reaction: see text] A new halo-Mannich-type reaction is reported using cyclopropyl carbonyl-derived enolates and sulfonyl-protected imines. Chiral oxazolidinones auxiliaries were found to be effective for completely controlling the stereochemistry of the products. Variations in the oxazolidinone, protecting group, and imine components show this to be a quite general reaction. The initial iodo-Mannich products were found to be readily cyclized in the presence of triethylamine to afford the resulting protected pyrrolidines, which could be readily deprotected under standard conditions.

Magnetic Resonance Spectroscopy↗
PubMed2004

Construction of a bacterial autoinducer detection system in mammalian cells.

Quorum sensing (QS) is a cell density-dependent signaling system used by bacteria to coordinate gene expression within a population. QS systems in Gram negative bacteria consist of transcription factors of the LuxR family and their acyl homoserine lactone (AHL) ligands. We describe here a method for examining QS signaling systems in mammalian cells that uses engineered LuxR-type proteins from the opportunistic pathogen, Pseudomonas aeruginosa, which can function as AHL-dependent transcription factors. The engineered proteins respond to their cognate ligands and display sequence specific DNA binding properties. This system has several potential biotechnological and biological applications. It may be used to characterize any LuxR-type protein, screen animal and plant cell extracts or exudates for compounds that mimic or interfere with AHL signaling or to screen different cell types for AHL inactivating activities.

Journal Article↗
PubMed2004

MgI2-catalyzed halo aldol reaction: a practical approach to (E)-beta-iodovinyl-beta'-hydroxyketones.

A novel generation of 1-iodo-3-siloxy-1,3-butadienes has been developed by reacting trimethylsilyl iodide (TMS-I) with alpha, beta-unsaturated ketones in dichloromethane at 0 degrees C without the use of any catalyst. The halo aldol reaction of these butadiene intermediates with aldehydes was efficiently carried out by using magnesium iodide as the catalyst. Twelve beta-iodo-alpha,beta-unsaturated-beta'-hydroxyketones (halo aldols) have been synthesized under the new condition with excellent geometric selectivity and good chemical yields (>80% chemical yields for 11 examples).

Catalysis↗
PubMed2004

New asymmetric halo aldol reaction provides a novel approach to biologically important chiral cyclothers and cycloamines.

[reaction: see text] A new asymmetric halo aldol reaction has been developed by reacting cyclopropyl carbonyl derived enolates with aldehydes. The absolute structure was unambiguously confirmed by X-ray structural analysis. Eight examples were reported with good yields and up to complete control of diastereomeric excesses. These halo aldol products have been readily cyclized in the presence of weak bases to produce chiral 2,3-disubstituted tetrahydrofuran derivatives in good yield without any observed epimerization.

Aldehydes↗
PubMed2003

Asymmetric halo aldol reaction (AHA).

[reaction: see text] The asymmetric halo aldol reaction (AHA) using Evans oxazolidinones as chiral auxiliaries has been established for tandem I-C/C-C bond formations. The new asymmetric reaction provides a practical approach to a variety of halo aldols of a non-Evans type that cannot be easily synthesized by other methods. Excellent diastereoselectivity (>95%) and yields (80-93%) have been obtained for eight examples.

Heterocyclic Compounds, 2-Ring↗