Rapid Assembly of Saturated Nitrogen Heterocycles in One-Pot: Diazo-Heterocycle “Stitching” by N-H Insertion and Cyclization

Magnetically Separable Chiral Poly(ionic liquid) Microcapsules Prepared Using Oil-in-Oil Emulsions

This article presents a method for producing chiral ionic liquid-based polyurea microcapsules that can be magnetically separated. The method involves entrapping hydrophilic magnetic nanoparticles within chiral polyurea microspheres. The synthetic process for creating these magnetic polyurea particles involves oil-in-oil (o/o) nano-emulsification of an ionic liquid-modified magnetite nanoparticle (MNPs-IL) and an ionic liquid-based diamine monomer, which comprises a chiral bis(mandelato)borate anion, in a nonpolar organic solvent, toluene, and contains a suitable surfactant. This is followed by an interfacial polycondensation reaction between the isocyanate monomer, polymethylenepolyphenyl isocyanate (PAPI 27), and the chiral diamine monomer, which generates chiral polyurea microcapsules containing magnetic nanoparticles within their cores. The microcapsules generated from the process are then utilized to selectively adsorb either the R or S enantiomer of tryptophan (Trp) from a racemic mixture that is dissolved in water, in order to evaluate their chiral recognition capabilities. During the experiments, the magnetically separable chiral poly(ionic liquid) microcapsules, which incorporated either the R or S isomer of chiral bis(mandelato)borate, exhibited exceptional enantioselective adsorption performance. Thus, the chiral polymeric microcapsules embedded with the R-isomer of the bis(mandelato)borate anion demonstrated significant selectivity for adsorbing L-Trp, yielding a mixture with 70% enantiomeric excess after 96 h. In contrast, microcapsules containing the S-isomer of the bis(mandelato)borate anion preferentially adsorbed D-Trp, achieving an enantiomeric excess of 73% after 48 h.

Construction of NH-Unprotected Spiropyrrolidines and Spiroisoindolines by [4+1] Cyclizations of γ-Azidoboronic Acids with Cyclic N-Sulfonylhydrazones

The reactions of N‐sulfonylhydrazones derived from cyclic ketones with γ‐azidopropylboronic acid and 2‐(azidomethyl)phenylboronic acid give rise to spirocyclic pyrrolidines and spiroisoindolines, respectively. The reactions proceed without the need of any transition‐metal catalyst through a domino process that comprises the formation of a Csp³‐C and a Csp³‐N bond of the former hydrazonic carbon. The scope of the reaction has been explored by the preparation of over 50 examples of NH‐unprotected spirocyclic derivatives. Importantly, this methodology could be applied for the preparation of alkaloid steroids from steroid N‐tosylhydrazones.

Design and Synthesis of 56 Shape-Diverse 3D Fragments

Fragment-based drug discovery is now widely adopted for lead generation in the pharmaceutical industry. However, fragment screening collections are often predominantly populated with flat, 2D molecules. Herein, we describe a workflow for the design and synthesis of 56 3D disubstituted pyrrolidine and piperidine fragments that occupy under-represented areas of fragment space (as demonstrated by a principal moments of inertia (PMI) analysis). A key, and unique, underpinning design feature of this fragment collection is that assessment of fragment shape and conformational diversity (by considering conformations up to 1.5 kcal mol-1 above the energy of the global minimum energy conformer) is carried out prior to synthesis and is also used to select targets for synthesis. The 3D fragments were designed to contain suitable synthetic handles for future fragment elaboration. Finally, by comparing our 3D fragments with six commercial libraries, it is clear that our collection has high three-dimensionality and shape diversity.