Save your silver! It is used better for jewelry than as a catalyst for fabrics.
Rice University researchers have developed a very simplified method for the production of fluoroketones, precursors to drug design, and manufacturing that typically requires a silver catalyst.
Rice chemist Julian West and graduate students Yen-Chu Lu and Helen Jordan introduced a process for rapid and scalable synthesis of fluoroketones that has so far been challenging and expensive to manufacture.
Their open-access work adorns the front page of 21
The laboratory’s new process replaces silver with cerium-based cerium ammonium nitrate (CAN), which produces functional precursors under mild conditions of approximately 30 minutes.
“We could make batches of this in a bathtub,” West said.
Cerium has shown such potential in other laboratories, and the fact that it is 800 times more abundant in the earth’s crust than silver made it of great interest to the Rice team.
“Ketones are a gateway-functional group in molecules that you can use to make various things, like anti-cancer compounds,” said West, who came to Rice in 2019 with funding from the Cancer Prevention and Research Institute in Texas and was named Forbes. 30 Under 30 science “game changer” last year.
“They are a good foothold for becoming an alkene or an aromatic ring,” he said. “The important part of this paper is that we incorporate fluorine into these fragments. Fluorine is an interesting element and quite abundant, but it is hardly used in biology.
“Fluorine has some extreme properties: It’s incredibly electronegative, so it holds on to its electrons,” West said. “It makes it difficult for enzymes in biological processes to handle them in drugs like anticancer molecules.”
Hydrogen atoms in drug molecules are easy for the liver to process, but replacing them with fluoride “is like armor in that position,” he said. “It helps drugs last much longer in the body, so you don’t have to take that much. It’s desirable for chemotherapeutics.” He noted that atorvastatin (aka Lipitor), one of the most commonly prescribed drugs in the United States, incorporates fluoride for the same purpose.
“We want to place fluoride in specific places in the molecule where we know it will make a difference, and this ketone functional group allows us to do that,” West said. “People have used a silver catalyst, but the process requires a lot of silver, it takes a long time at high temperature, and it must be carried out under a carefully controlled nitrogen or argon atmosphere.
“Our process is cheap bucket chemistry and we think the reaction is carried out in about five minutes,” he said. “But we leave it at 30, just to be safe.”
The process is very scalable. “When Yen-Chu tripled the original recipe, he got exactly the same result,” West said. “It’s rare in this kind of reaction.”
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Yen-Chu Lu et al. Rapid and scalable synthesis of fluoroketones via cerium-mediated CC binding cleavage, Chemical communication (2021). DOI: 10.1039 / D0CC08183C
Provided by Rice University
Citation: Cerium sidelines silver for making drug precursor (2021, February 26) retrieved February 28, 2021 from https://phys.org/news/2021-02-cerium-sidelines-silver-drug-precursor.html
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