The secret weapon for high throughput screening photocatalyst loaded on glass microspheres

When it comes to fast and automated screening methods, people will inevitably think of high-throughput. High throughput screening technology has become a core tool for reaction condition screening and new drug synthesis research and development. At first, the lack of effective high-throughput screening techniques hindered the progress and application of high-throughput reaction screening. In the past few years, transformative progress has only begun to emerge in this field: Merck and Pfizer have pioneered the use of bioactivity assay devices and flow chemistry technology, making high-throughput nanomolar scale reaction screening possible. Automated machine injection for parallel reactions and efficient analytical methods are used to screen a large number of nanomolar experimental conditions, which not only greatly improves the efficiency of substrate screening but also reduces the amount of substrate used. However, an unresolved key challenge is how to accurately weigh compounds at the nanomolar level. The reduction of reaction scale requires higher accuracy of symmetry, and precise weighing is crucial, as even a tiny difference can lead to a thousand miles of error. Until 2019, researchers Ying Wang et al. from AbbVie Corporation first coated compounds onto glass microspheres to form ChemBeads, which can accurately transfer nanomolar amounts of compounds and successfully apply them to high-throughput screening of trace reactions.

Dry powder coating technology is widely used in the pharmaceutical industry to improve the physical properties of processed solids. Using this technology, glass microspheres and solid chemical reagents are adsorbed together by van der Waals forces to achieve accurate weighing of nanomolar compounds. Glass microspheres have high fluidity, inertness, and a smooth circular surface, making them an ideal dry powder coating material. When the compound (1-5% by mass) is mixed with glass microspheres using a mixer, the compound is uniformly coated on the surface of the glass microspheres. In addition to common catalysts, ligands, inorganic bases, and reactants, reagents sensitive to air and moisture can also be effectively coated onto glass microspheres.

In recent years, photocatalytic chemistry has received increasing attention from scientists. Photocatalytic synthesis is more environmentally friendly and in line with the concept of green chemistry than traditional synthesis methods, and has great development prospects. In 2019, Abbvie's researcher Y Wang et al. reported the screening of 55 substrate conditions using Chembeads as a template for Suzuki reaction, and obtained the optimal 2 reaction conditions. Adsorbing photocatalysts onto glass microspheres and applying them specifically to the distribution mechanism of automatic sampling machines provides a faster and more efficient way to achieve quantitative feeding on fully automated high-throughput chemical synthesis workstations. ChemScene has launched a series of photocatalysts loaded with glass microspheres, which have the characteristics of precise weighing, high dissolution rate, uniform loading, and good stability. In addition to photocatalysts, other solid reagents such as catalysts loaded with glass microspheres can also accept customized services. The example products of photocatalysts loaded with glass microspheres are as follows:

1. Triphenylpyridine iridium loaded on glass microspheres
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2. 2,4,5,6-tetra (9H-carbazol-9-yl) isophthalic acid loaded on glass microsphere
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3. Yvonne Y disodium salt loaded on glass microspheres
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4. 9-isopropylphenyl-2,7,10-trimethylacridine perchlorate loaded on glass microspheres
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