Stable and easily available sulfide surrogates allow a stereoselective activation of alcohols.

Isothiouronium salts are easily accessible and stable compounds. Herein, we report their use as versatile deoxasulfenylating agents enabling a stereoselective, thiol-free protocol for synthesis of thioethers from alcohols. The method is simple, scalable and tolerates a broad range of functional groups otherwise incompatible with other methods. Late-stage modification of several pharmaceuticals provides access to multiple analogues of biologically relevant molecules. Performed experiments give insight into the reaction mechanism.

Toward a Structural View of hERG Activation by the Small-Molecule Activator ICA-105574.

Outward current conducted by human ether-à-go-go-related gene type 1 (hERG1) K+ channels is important for action potential repolarization in the human ventricle. Rapid, voltage-dependent inactivation greatly reduces outward currents conducted by hERG1 channels and involves conformational changes in the ion selectivity filter (SF). Recently, compounds have been found that activate hERG1 channel function by modulating gating mechanisms such as reducing inactivation. Such activating compounds could represent a novel approach to prevent arrhythmias associated with prolonged ventricular repolarization associated with inherited or acquired long QT syndrome. ICA-105574 (ICA), a 3-nitro-n-(4-phenoxyphenyl) benzamide derivative activates hERG1 by strongly attenuating pore-type inactivation. We previously mapped the putative binding site for ICA to a hydrophobic pocket located between two adjacent subunits. Here, we used the recently reported cryoelectron microscopy structures of hERG1 to elucidate the structural mechanisms by which ICA influences the stability of the SF. By combining molecular dynamics simulations, voltage-clamp electrophysiology, and the synthesis of novel ICA derivatives, we provide atomistic insights into SF dynamics and propose a structural link between the SF and S6 segments. Further, our study highlights the importance of the nitro moiety, at the meta position of the benzamide ring, for the activity of ICA and reveals that the (bio)isosteric substitution of this side chain can switch the activity to weak inhibitors. Our findings indicate that ICA increases the stability of the SF to attenuate channel inactivation, and this action requires a fine-tuned compound geometry.

Unusual mechanisms in Claisen rearrangements: an ionic fragmentation leading to a meta-selective rearrangement.

A mechanistic investigation of the acid-catalysed redox-neutral oxoarylation reaction of ynamides using electrospray ionisation mass-spectrometry (ESI-MS) and quantum chemical calculations (DFT and MP2) is presented. This study reveals the diversity of pathways and products available from an otherwise deceptively simple-looking, classical transformation: fragmentation, an unusual meta-arylation and competing α-carbonyl cation pathways are some of the alternatives unveiled by ESI-MS and mechanistic experiments. Detailed calculations explain the observed trends and rationalise the results.

C2-Modified Sparteine Derivatives Are a New Class of Potentially Long-Acting Sodium Channel Blockers.

The lupin alkaloid sparteine is a well-known chiral diamine with a range of applications in asymmetric synthesis, as well as a blocker of voltage-gated sodium channels (VGSCs). However, there is only scarce information on the VGSC-blocking activity of sparteine derivatives where the structure of the parent alkaloid is retained. Building on the recent renewed availability of sparteine and derivatives we report herein how modification of sparteine at position 2 produces irreversible blockers of VGSCs. These compounds could be clinically envisaged as long-lasting local anesthetics.

Intramolecular hydrogen bonding in conformationally semi-rigid α-acylmethane derivatives: a theoretical NMR study.

Conformational mobility is a core property of organic compounds, and conformational analysis has become a pervasive tool for synthetic design. In this work, we present experimental and computational (employing Density Functional Theory) evidence for unusual intramolecular hydrogen bonding interactions in a series of α-acylmethane derivatives, as well as a discussion of the consequences thereof for their NMR spectroscopic properties.

A non-Diels-Alder approach to the cis-decalin core of branimycin.

The synthesis of the highly substituted cis-decalin core of branimycin has been accomplished. A catalytic copper mediated SN2' opening of oxabicycle 7 with Grignard reagent and ring-closing metathesis served as key transformations.

Global and local alignments in HIV/AIDS prevention trainings: a case study from Burkina Faso.

This article presents a linguistic analysis of data from an ongoing research project exploring HIV/AIDS education in West African Burkina Faso. I argue that we can identify different, sometimes even competing, discourses about the disease in prevention interactions. Thus, communication about HIV/AIDS in Burkina Faso--and probably in most of the Sub-Saharan countries--might be characterized by what I will call, with reference to Bakhtin, discursive heteroglossia. There is clear evidence of such discursive heteroglossia, that is, the participants' alignment to local and global HIV discourses, deployed in the communication of health workers. In my analysis of peer educators training sessions, I draw on theoretical and methodological principles from discourse analysis and interactional linguistics. I focus on the linguistic devices and conversational strategies the participants use to indicate the relevance of the local or the global discourses. Three particular devices--namely, metaphors, epistemic and evidential markers, and word explanations--will be examined in a more detailed way. I will also show how the local and the global interweave at different levels of prevention discourse.

Synthesis of the C1-C13 Fragment of Kendomycin: Atropisomerism around a C-Aryl Glycosidic Bond.

The left-hand fragment 2 of the novel antibiotic kendomycin (1) has been synthesized by an aldol addition and a Michael-type 1,4-addition of a C5 alcohol with a C9-C11 enone. Compound 2 shows an interesting atropisomerism around the C4a-C5-sp2 -sp3 bond. The atropisomers can be separated in pure forms by low-temperature high-pressure liquid chromatography.