A team of scientists led by Professor Dr. Frank Glorius from the University of Münster has found a solution
Amino alcohols, especially ethanolamine, are widelyused in the production of detergents, emulsifiers, cosmetics and medicines, and also as absorbers of acid gases (for example, CO₂). The purpose of using amino alcohols in cosmetics is: replacing ammonia in ammonia-free formulations, neutralizing and buffering formulations, absorbing odor, stabilizing color, improving dispersion, stabilizing rheology. The best amino alcohol for these purposes is tromethamine (INCI). Amino alcohols include choline, which plays an important role in metabolism in humans and animals; Choline preparations are used to treat the liver. Some alkaloids, such as ephedrine, are amino alcohols, and the important hormone adrenaline also belongs to them.
Vicinal amino alcohols can exist in twovarious variants - regioisomers, in which the functional groups of the amine and alcohol change positions. Although they are very similar, their biochemical properties differ. Installing both amine and alcohol groups in one step is a major challenge. The discovery of an asymmetric amino hydroxylation reaction, by which one of the regioisomers can be obtained, even led to the award of the Nobel Prize to chemist Barry Sharpless in 2001. Another regioisomer could not be synthesized by a similar method and remained a long-standing problem. However, with the new chemical method of photoinitiated reaction, the synthesis of another regioisomer has now also become efficient.
Non-activated alkenes containing a double bondcarbon-carbon, often used in reaction processes because of their availability. As a rule, the introduction of both amine and alcohol groups in one step through the carbon-carbon double bond of an unactivated alkene is always initiated by the amino group followed by the addition of the alcohol group. As a result, a certain regioisomer of the vicinal amino alcohol is always formed.
Now scientists have identified a special classamine-like compounds that are reactive and yet stable enough to allow the addition of an alcohol group to the carbon-carbon double bond first and then the addition of an amino group.
“Just as plants use chlorophyllTo convert light into energy, we use a so-called photocatalyst,” explains Dr. Tuhin Patra, first author of this study. — These particles can absorb light from blue LEDs and transfer their energy to the molecule directly involved in the reaction. In this case, amine and alcohol groups are simultaneously released.” This process, in which molecules transfer electrons to each other, is called energy transfer, the scientist explains.
Interestingly, the new method generates the least accessible regioisomer from vicinal amino alcohols in such a way that both alcohol and amine groups are protected from further reactions.
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