Laramie P. Jameson

Aza-BODIPY: improved synthesis and interaction with soluble Aβ1-42 oligomers.

Dye-binding assays that are used to evaluate anti-aggregation ability of small molecule inhibitors towards amyloids are known to be prone to false-positive effects due to spectral overlaps between the dye and the inhibitor. Aza-BODIPY dye, which has both excitation and emission maxima above 600nm, exhibits a significant increase in its fluorescence intensity in the presence of soluble oligomers of Aβ1-42. These results indicate that aza-BODIPY could serve as a near-IR probe for detecting conformational changes of Aβ1-42 soluble oligomers in vitro, and it should eliminate false-positive effects that are associated with currently utilized thioflavin T-based dyes. In addition, a facile synthesis of aza-BODIPY has been developed, which might further expand the applications of this dye.

Effect of ionic liquids on the conformation of a porphyrin -based viscometer

Structure of the cationic and anionic counterparts of ionic liquids has a significant impact on the conformational bias of the porphyrin rotor; an apparent correlation between the conformation and the viscosity of ionic liquids was noted, albeit it was found to be distinct and more complex from that found in molecular solvents.

Expeditious, mechanochemical synthesis of BODIPY dyes.

Summary BODIPY dyes have been synthesized under solvent-free or essentially solvent-free conditions, within about 5 minutes in an open-to-air setup by using a pestle and mortar, with yields that are comparable to those obtained via traditional routes that typically require reaction times of several hours to days.

Spectroscopic Studies on Tetracycline in Room-Temperature Ionic Liquids

Circular dichroism and steady-state fluorescence of tetracycline (1) were investigated in a series of 1-butyl-3-methylimidazolium room-temperature ionic liquids. The identity of the anion of the ionic liquids was found to modulate the conformation as well as the emission intensity of tetracycline over a wide range.

Conformational preference of a porphyrin rotor in confined environments

The amount of twisted conformation of a porphyrin rotor, when confined within ionic liquid reverse micelles, increased as compared to the neat solvents within a set of 1-alkyl-3-methylimidazolium ionic liquids. A similar trend was noted within DMSO-containing reverse micelles, indicating that the confinement might be a major contributor in the control of the rotors conformation.

Ionic liquid-controlled conformational bias of tetracycline

The conformational bias of tetracycline was investigated in a series of room-temperature 1-alkyl-3-methyl-imidazolium ionic liquids. Spectroscopic techniques such as circular dichroism, absorbance and fluorescence suggested that the switch between the extended and twisted conformation of tetracycline might be controlled by the aggregation state of the ionic liquids, which could be easily assessed by the resonance light scattering of homologous sets of ionic liquids with a common anion.

Spectroscopic differentiation between monomeric and aggregated forms of BODIPY dyes: effect of 1,1-dichloroethane

1,1-Dichloroethane induces a monomer–aggregate equilibrium of common BODIPY dyes in organic solvents at low μM dye concentrations, thus providing an opportunity to study monomeric, aggregate-free forms of BODIPY dyes.

Effect of imidazolium room-temperature ionic liquids on aggregation of amphotericin B: a circular dichroism study

The nature of the anion of imidazolium-based ionic liquids was found to control the aggregate–monomer equilibrium of amphotericin B. This is in contrast to aqueous solutions of inorganic salts and imidazolium-based ionic liquids, which were previously found to favor the disaggregation of amphotericin B. The results further establish the designer solvent ability of ionic liquids, specifically as it relates to their ability to influence intermolecular interactions.

Ginkgolides and Their Derivatives: Synthetic and Bioorganic Studies

The effect of the extract from Ginkgo biloba tree has been investigated in relation to an extended range of disorders and diseases. Commercial preparations of the extract, over-the-counter dietary supplements, or prescription products worldwide have long been advocated for their ability to improve various cognitive functions. Several extensive reviews on the chemistry, therapeutic effect, and the neuropsychological efficacy of the Ginkgo biloba extract have been published in recent years (Abad et al. 2010; Mahadevan and Park 2008; Crews et al. 2005) and they will not be discussed here. Although the exact molecular mechanisms of Ginkgo biloba extracts’ action remain unclear, the neuromodulatory activity has been attributed to the so-called terpene trilactone fractions. The synthetic and biological aspects of the compounds that comprise the terpene trilactone fraction will be presented here.