Ruthenium Complexes Can Accelerate the Development of New Medicines

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A group of scientists at INEOS RAS, HSE University, and MIPT have synthesised catalysts containing a ruthenium atom and an aromatic ring. The scientists have isolated the mirror forms of these catalysts and investigated their effectiveness in producing heterocycles, which are commonly found in the structures of drugs. The research findings have been published in Chemical Communications.

Isoquinoline derivatives exhibit high biological activity and are widely used as medicines such as diuretics, antibacterials, and antioxidants. One of the key stages in the synthesis of these substances is the activation of carbon-hydrogen bonds in the initial reagents. Typically, this stage must be conducted using catalysts that contain metal atoms.

Palladium compounds are most often used for such syntheses and can rightfully be considered leaders in the number of reactions they accelerate. However, they are not universally applicable. In 1993, a paper by Japanese scientists was published in Nature that described, for the first time, the carbon–hydrogen bond activation using a ruthenium catalyst. Over the last decade, the potential of these reactions has captivated scientists worldwide, with more than 300 papers published on this topic annually.

A group of Russian scientists at the A.N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences, HSE University, and MIPT has extensive experience working with ruthenium compounds. Thus, in 2022, they obtained a ruthenium complex with an aromatic derivative of natural camphor, but it proved to be ineffective in catalysis. This year, they modified the structure of the compound to make the metal atom more accessible to reagents. A derivative of tetralin, an oil refining product, was chosen as the aromatic ring for binding ruthenium.

The resulting catalyst was separated into two enantiomers. Enantiomers are substances with the same chemical composition but different structures, similar to an object and its mirror image. The scientists used chromatography to separate the enantiomers. This process can be compared to the absorption of liquid by a sponge, where a specially selected compound acts as the sponge, absorbing the enantiomers at different rates.

Dmitry Perekalin

'We aimed to make the synthesis as brief and straightforward as possible so that other scientists could easily use this method,' explains Dmitry Perekalin, Professor at the Joint Department of Organoelement Chemistry with the INEOS RAS, HSE Faculty of Chemistry, and Head of the Laboratory of Functional Organoelement Compounds at INEOS RAS.

The scientists used the obtained catalyst enantiomers to activate the bonds in benzamide and subsequently complete the cyclic structure of dihydroisoquinoline. The yield of the target substances was between 50% and 80%. According to the authors, the method they have developed can be used for the synthesis of other chiral catalysts, and research in this direction will continue.

The study was supported by the Russian Science Foundation, Grant 23-13-00345.