Metabolomics with multi-block modelling of mass spectrometry and nuclear magnetic resonance in order to discriminate Haplosclerida marine sponges.

A comprehensive metabolomic strategy, integrating H NMR and MS-based multi-block modelling in conjunction with multi-informational molecular networking, has been developed to discriminate sponges of the order Haplosclerida, well known for being taxonomically contentious. An in-house collection of 33 marine sponge samples belonging to three families (Callyspongiidae, Chalinidae, Petrosiidae) and four different genera (Callyspongia, Haliclona, Petrosia, Xestospongia) was investigated using LC-MS/MS, molecular networking, and the annotations processes combined with NMR data and multivariate statistical modelling. The combination of MS and NMR data into supervised multivariate models led to the discrimination of, out of the four genera, three groups based on the presence of metabolites, not necessarily previously described in the Haplosclerida order.

GGGCTA repeats can fold into hairpins poorly unfolded by replication protein A: a possible origin of the length-dependent instability of GGGCTA variant repeats in human telomeres.

Human telomeres are composed of GGGTTA repeats and interspersed with variant repeats. The GGGCTA variant motif was identified in the proximal regions of human telomeres about 10 years ago and was shown to display a length-dependent instability. In parallel, a structural study showed that four GGGCTA repeats folded into a non-canonical G-quadruplex (G4) comprising a Watson-Crick GCGC tetrad.

Novel library synthesis of 3,4-disubstituted pyridin-2(1)-ones via cleavage of pyridine-2-oxy-7-azabenzotriazole ethers under ionic hydrogenation conditions at room temperature.

In our hands, efficient access to the 4-amino-3-carboxamide disubstituted pyridine-2(1)-one kinase hinge-binder motif proved to be more challenging than anticipated requiring a significant investment in route scouting and optimization. This full paper focuses on the synthesis issues that we encountered during our route exploration and the original solutions we found that helped us to identify two optimized library-style processes to prepare our large kinase inhibitor library.

Diastereoselective Ring Homologation of Bicyclic Hydrazines: Access to -1,3-Diaminocyclohexitols.

A sequence of oxidative cleavage/double nitroaldol condensation followed by a few simple synthetic transformations can lead to polyhydroxylated di- and triaminocyclohexanes from a readily available bicyclic hydrazine. This new synthetic route provides a simple and general access to densely substituted privileged scaffolds or fragments with a perfect control of their relative configuration.

Deracemizing α-Branched Carboxylic Acids by Catalytic Asymmetric Protonation of Bis-Silyl Ketene Acetals with Water or Methanol.

We report a highly enantioselective catalytic protonation of bis-silyl ketene acetals. Our method delivers α-branched carboxylic acids, including nonsteroidal anti-inflammatory arylpropionic acids such as Ibuprofen, in high enantiomeric purity and high yields. The process can be incorporated in an overall deracemization of α-branched carboxylic acids, involving a double deprotonation and silylation followed by the catalytic asymmetric protonation.