The preparation of alkynes from carbonyl compounds via a one-carbon homologation has become a very useful pathway for the synthesis of acetylenic compounds, both internal and terminal. This tutorial review provides an overview of the different methods available for this transformation, including their scope and limitations, recent developments and applications in total syntheses.
The ability of nonsteroidal anti-inflammatory drugs (NSAIDs) to inhibit cyclooxygenase (Cox)-1 and Cox-2 underlies the therapeutic efficacy of these drugs, as well as their propensity to damage the gastrointestinal (GI) epithelium. This toxic action greatly limits the use of NSAIDs in inflammatory bowel disease (IBD) and other chronic pathologies. Fatty acid amide hydrolase (FAAH) degrades the endocannabinoid anandamide, which attenuates inflammation and promotes GI healing. Here, we describe the first class of systemically active agents that simultaneously inhibit FAAH, Cox-1, and Cox-2 with high potency and selectivity. The class prototype 4 (ARN2508) is potent at inhibiting FAAH, Cox-1, and Cox-2 (median inhibitory concentration: FAAH, 0.031 6 0.002 mM; Cox-1, 0.012 6 0.002 mM; and Cox-2, 0.43 6 0.025 mM) but does not significantly interact with a panel of >100 off targets. After oral administration in mice, ARN2508 engages its intended targets and exerts profound therapeutic effects in models of intestinal inflammation. Unlike NSAIDs, ARN2508 causes no gastric damage and indeed protects the GI from NSAID-induced damage through a mechanism that requires FAAH inhibition. Multitarget FAAH/Cox blockade may provide a transformative approach to IBD and other pathologies in which FAAH and Cox are overactive.-Sasso, O., Migliore,
Pain and inflammation are major therapeutic areas for drug discovery.
Current drugs for these pathologies have limited efficacy, however, and often
cause a number of unwanted side effects. In the present study, we identify the
non-steroid anti-inflammatory drug, carprofen, as a multi-target-directed ligand
that simultaneously inhibits cyclooxygenase-1 (COX-1), COX-2 and fatty acid
amide hydrolase (FAAH). Additionally, we synthesized and tested several racemic
derivatives of carprofen, sharing this multi-target activity. This may result in
improved analgesic efficacy and reduced side effects (Naidu, et al
(2009) J Pharmacol Exp Ther 329, 48-56;
Fowler, C.J. et al. (2012) J Enzym Inhib Med Chem
Jan 6; Sasso, et al (2012) Pharmacol Res 65, 553).
The new compounds are among the most potent multi-target FAAH/COXs inhibitors
reported so far in the literature, and thus may represent promising starting
points for the discovery of new analgesic and anti-inflammatory drugs.
The intracellular delivery of nucleic acid molecules is a complex process involving several distinct steps; among these the endosomal escape appeared to be of particular importance for an efficient protein production (or inhibition) into host cells. In the present study, a new series of ionizable vectors, derived from naturally occurring aminoglycoside tobramycin, was prepared using improved synthetic procedures that allow structural variations on the linker and hydrophobic domain levels. Complexes formed between the new ionizable lipids and mRNA, DNA, or siRNA were characterized by cryo-TEM experiments and their transfection potency was evaluated using different cell types. We demonstrated that lead molecule 30, bearing a biodegradable diester linker, formed small complexes with nucleic acids and provided very high transfection efficiency with all nucleic acids and cell types tested. The obtained results suggested that the improved and "universal" delivery properties of 30 resulted from an optimized endosomal escape, through the lipid-mixing mechanism.
Calyculins, highly cytotoxic polyketides, originally isolated from the marine sponge Discodermia calyx by Fusetani and co-workers, belong to the lithistid sponges group. These molecules have become interesting targets for cell biologists and synthetic organic chemists. The serine/threonine protein phosphatases play an essential role in the cellular signalling, metabolism, and cell cycle control. Calyculins express potent protein phosphatase 1 and 2A inhibitory activity, and have therefore become valuable tools for cellular biologists studying intracellular processes and their control by reversible phosphorylation. Calyculins might also play an important role in the development of several diseases such as cancer, neurodegenerative diseases, and type 2-diabetes mellitus. The fascinating structures of calyculins have inspired various groups of synthetic organic chemists to develop total syntheses of the most abundant calyculins A and C. However, with fifteen chiral centres, a cyano-capped tetraene unit, a phosphate-bearing spiroketal, an anti, anti, anti dipropionate segment, an α-chiral oxazole, and a trihydroxylated γ-amino acid, calyculins reach versatility that only few natural products can surpass, and truly challenge modern chemists’ asymmetric synthesis skills.
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