This tutorial review surveys the recent advances in electrochemical transformations as they pertain to the synthesis of complex organic molecules. Electrochemistry has emerged as a powerful tool to synthetic chemists, yet many have never considered electrochemical methodology as a means for synthesis. Here, an introduction to electrochemistry and voltammetry will be provided with descriptions of the four types of electrochemical cells. In addition, recent examples of both anodic oxidations and cathodic reductions will be discussed, along with the experimental setups for carrying out each reaction.
Amide
couplings are one of, if not the most common chemical reactions
performed in the pharmaceutical industry. Many amide bonds are generated
with the help of highly active peptide coupling reagents. These reagents
have garnered wide use in the pharmaceutical industry, but many contain
high-energy functional groups. As a result, significant time is spent
assessing the thermal stability of these reagents before scale-up
commences. This paper assesses the thermal stability of 45 common
peptide coupling reagents by differential scanning calorimetry and
accelerating rate calorimetry. Those compounds which flagged as potentially
impact-sensitive or potentially explosive were tested by drop hammer
and explosivity screening techniques. The data are presented in an
effort to drive the development of these reactions toward the use
of one of the more thermally stable reagents.
Tau is a microtubule‐associated protein that promotes microtubule assembly and stability. In Alzheimer’s disease and related tauopathies, tau fibrillizes and aggregates into neurofibrillary tangles. Recently, oleocanthal isolated from extra virgin olive oil was found to display non‐steroidal anti‐inflammatory activity similar to ibuprofen. As our unpublished data indicates an inhibitory effect of oleocanthal on amyloid β peptide fibrillization, we reasoned that it might inhibit tau fibrillization as well. Herein, we demonstrate that oleocanthal abrogates fibrillization of tau by locking tau into the naturally unfolded state. Using PHF6 consisting of the amino acid residues VQIVYK, a hexapeptide within the third repeat of tau that is essential for fibrillization, we show that oleocanthal forms an adduct with the lysine via initial Schiff base formation. Structure and function studies demonstrate that the two aldehyde groups of oleocanthal are required for the inhibitory activity. These two aldehyde groups show certain specificity when titrated with free lysine and oleocanthal does not significantly affect the normal function of tau. These findings provide a potential scheme for the development of novel therapies for neurodegenerative tauopathies.
Organic chemistry Z 0200 Furans, Thiophenes and Related Heterocycles in Drug Discovery -[35 refs.]. -(SPERRY, J. B.; WRIGHT, D. L.; Curr. Opin. Drug Discovery Dev. 8 (2005) 6, 723-740; Dep. Chem., Dartmouth Coll., Hanover, NH 03755, USA; Eng.) -Lindner 15-242
Oleocanthal, a major phenolic compound in extra-virgin olive oil with antiinflammatory properties, elicits an unusual oral pungency sensed almost exclusively in the throat. This contrasts with most other common oral irritants, such as cinnamaldehyde, capsaicin, and alcohol, which irritate mucus membranes throughout the oral cavity. Here, we show that this rare irritation pattern is a consequence of both the specificity of oleocanthal for a single sensory receptor and the anatomical restriction of this sensory receptor to the pharynx, within the oral cavity. We demonstrate, in vitro, that oleocanthal selectively activates the hTRPA1 channel in HEK 293 cells and that its ability to excite the trigeminal nervous system in rodents requires a functional TRPA1. Moreover, we similarly demonstrate that the over-the-counter analgesic, ibuprofen, which elicits the same restricted pharyngeal irritation as oleocanthal, also specifically excites rodent sensory neurons via TRPA1. Using human sensory psychophysical studies and immunohistochemical TRPA1 analyses of human oral and nasal tissues, we observe an overlap of the anatomical distribution of TRPA1 and the regions irritated by oleocanthal in humans. These results suggest that a TRPA1 (ANKTM1) gene product mediates the tissue sensitivity to oleocanthal within the oral cavity. Furthermore, we demonstrate that, despite the fact that oleocanthal possesses the classic electrophilic reactivity of many TRPA1 agonists, it does not use the previously identified activation mechanism via covalent cysteine modification. These findings provide an anatomical and molecular explanation for a distinct oral sensation that is elicited by oleocanthal and ibuprofen and that is commonly experienced around the world when consuming many extra-virgin olive oils.
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