Advances and Challenges in Development of Transition Metal Catalysts for Heterogeneous Hydrogenation of Organic Compounds.

Actual problems of development of catalysts for hydrogenation of heterocyclic compounds by hydrogen are summarized and discussed. The scope of review covers composites of nanoparticles of platinum group metals and 3d metals for heterogeneous catalytic processes. Such problems include increase of catalyst activity, which is important for reduction of precious metals content; development of new catalytic systems which do not contain metals of platinum group or contain cheaper analogues of Pd; control of factors which make influence on the selectivity of the catalysts; achievement of high reproducibility of the catalyst's performance and quality control of the catalysts.

Catalytic Oxidation of Benzoins by Hydrogen Peroxide on Nanosized HKUST-1: Influence of Substituents on the Reaction Rates and DFT Modeling of the Reaction Path.

In this research, the oxidation of a series of benzoins, R-C(=O)-CH(OH)-R, where R = phenyl, 4-methoxyphenyl, 4-bromophenyl, and 2-naphthyl, by hydrogen peroxide in the presence of nanostructured HKUST-1 (suspension in acetonitrile/water mixture) was studied. The respective benzoic acids were the only products of the reactions. The initial average reaction rates were experimentally determined at different concentrations of benzoin, HO and an effective concentration of HKUST-1.

A Close-up Look at the Chemical Space of Commercially Available Building Blocks for Medicinal Chemistry.

The ability to efficiently synthesize desired compounds can be a limiting factor for chemical space exploration in drug discovery. This ability is conditioned not only by the existence of well-studied synthetic protocols but also by the availability of corresponding reagents, so-called building blocks (BBs). In this work, we present a detailed analysis of the chemical space of 400 000 purchasable BBs.

Reductive Recyclization of sp-Enriched Functionalized Isoxazolines into α-Hydroxy Lactams.

An efficient synthesis (up to a 200 g scale) of 3-hydroxypyrrolidin-2-ones bearing alkyl substituents or functional groups at the C-5 position is described. The reaction sequence started from 1,3-dipolar cycloaddition of generated nitrile oxides with (meth-)acrylates into 3-substituted isoxazoline-5-carboxylates. The catalytic hydrogenolysis of the isoxazoline N-O bond was optimal upon using H (1 atm) at rt, with the following order of the catalyst activity: Pd-C > Pd(OH)-C > Pt-C.

Third Generation Buchwald Precatalysts with XPhos and RuPhos: Multigram Scale Synthesis, Solvent-Dependent Isomerization of XPhos Pd G3 and Quality Control by H- and P-NMR Spectroscopy.

The third generation Buchwald precatalysts Pd(ABP)(Phos)(OMs) (also known as Phos Pd G3)) with XPhos and RuPhos were prepared in multigram scale by a modified procedure (ABP = fragment of C-deprotonated 2-aminobiphenyl, XPhos = 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl, RuPhos = 2-dicyclohexylphosphino-2',6'-diisopropoxybiphenyl, OMs = CHSO). The H- and P-NMR spectra of the title complexes and some impurities, measured by various 1D and 2D techniques, were analyzed in detail. The solvent-dependent isomerization of Pd(ABP)(XPhos)(OMs) was studied by NMR, and the X-ray structures of two isomers were determined.