Physicochemical and Biological Evaluation of gem-Difluorinated Saturated Oxygen Heterocycles as Bioisosteres for Drug Discovery.

A comprehensive study on the physicochemical properties of gem-fluorinated O-heterocyclic substituents is reported. Systematic additive effects of introducing O- and gem-CF group introduction on acidic properties (pK) of the corresponding carboxylic acids/protonated primary amines were demonstrated. The impact of the O/CF moieties on lipophilicity (LogP) was found to be complex; significant mutual influence of the corresponding polar moieties governed the compound's overall properties in this case.

Parallel Minisci Reaction of -Difluorocycloalkyl Building Blocks.

Parallel Minisci reactions of nonfluorinated and -difluorinated C-C cycloalkyl building blocks (trifluoroborates and carboxylic acids) with a series of electron-deficient heterocycles were studied. A comparison of the reaction's outcome revealed better product yields in the case of carboxylic acids as the radical precursors in most cases, albeit these reagents were used with three-fold excess under optimized conditions. The nature of the heterocyclic core was found to be important for successful incorporation of the cycloalkyl fragment.

C-C Coupling through Nitrogen Deletion: Application to Library Synthesis.

Invited for the cover of this issue are Oleksandr Grygorenko and his Ukrainian colleagues at Enamine Ltd., Taras Shevchenko National University of Kyiv, National Academy of Sciences of Ukraine, and ChemSpace, as well as Mark Levin at the University of Chicago. The image depicts application of a nitrogen-deleting anomeric amide to parallel C(sp )-C(sp ) coupling.

C-C Coupling through Nitrogen Deletion: Application to Library Synthesis.

A protocol for parallel C(sp )-C(sp ) coupling of (hetero)aromatic aldehydes and (hetero)arylmethyl amines based on a reductive amination - "nitrogen deletion" reaction sequence has been developed. After preliminary validation experiments, an illustrative compound library of 25 members was prepared with 76 % synthetic efficiency. The estimated chemical space accessible by the proposed approach covers almost 600 000 representatives that are scarcely represented in current compound databases.

Fluorinated Cycloalkyl Building Blocks for Drug Discovery.

The review covers various aspects of fluorinated cycloalkyl (C -C ) building blocks for drug discovery, including their synthesis, key physicochemical properties, and biological and medicinal applications of their derivatives. The discussed synthetic methods include classical nucleophilic fluorinations of various substrates, the addition of fluorine and another heteroatom to double bonds, cycloadditions and other transformations of fluorine-containing substrates, as well as some newer reactions like fluorination of non-activated and remotely activated C-H bonds, decarboxylative and deborylative fluorinations, etc. The known data on the effect of introducing the fluorinated cycloalkyl groups on the compound's key in vitro parameters (such as acidity/basicity, lipophilicity, conformational behavior, and short contact capabilities) are surveyed.