Now, after nearly 25 years of work by chemists at the University of California, Berkeley, those hydrocarbon bonds -- two-thirds of all the chemical bonds in petroleum and plastics -- have fully yielded, opening the door to the synthesis of a large range of novel organic molecules, including drugs based on natural compounds.
"Carbon-hydrogen bonds are usually part of the framework, the inert part of a molecule," said John Hartwig, the Henry Rapoport Chair in Organic Chemistry at UC Berkeley. "It has been a challenge and a holy grail of synthesis to be able to do reactions at these positions because, until now, there has been no reagent or catalyst that will allow you to add anything at the strongest of these bonds."
Hartwig and other researchers had previously shown how to add new chemical groups at C-H bonds that are easier to break, but they could only add them to the strongest positions of simple hydrocarbon chains.
In the May 15 issue of the journal Science, Hartwig and his UC Berkeley colleagues described how to use a newly designed catalyst to add functional chemical groups to the hardest of the carbon-hydrogen bonds to crack: the bonds, typically at the head or tail of a molecule, where a carbon has three attached hydrogen atoms, what's called a methyl group (CH3).
"The primary C-H bonds, the ones on a methyl group at the end of a chain, are the least electron-rich and the strongest," he said. "They tend to be the least reactive of the C-H bonds."
UC Berkeley postdoctoral fellow Raphael Oeschger discovered a new version of a catalyst based on the metal iridium that opens up one of the three C-H bonds at a terminal methyl group and inserts a boron compound, which can be easily replaced with more complex chemical groups. The new catalyst was more than 50 times more efficient than previous catalysts and just as easy to work with.
"We now have the ability to do these types of reactions, which should enable people to rapidly make molecules that they would not have made before," Hartwig said. "I wouldn't say these are molecules that could not have been made before, but people wouldn't make them because it would take too long, too much time and research effort, to make them."
The payoff could be huge. Each year, nearly a billion pounds of hydrocarbons are used by industry to make solvents, refrigerants, fire retardants and other chemicals and are the typical starting point for synthesizing drugs.
Journal Reference:
Raphael Oeschger, Bo Su, Isaac Yu, Christian Ehinger, Erik Romero, Sam He, John Hartwig. Diverse functionalization of strong alkyl C–H bonds by undirected borylation. Science, 2020; 368 (6492): 736 DOI: 10.1126/science.aba6146
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One Millionth Comment!
On 2020-05-28 the SoylentNews community attained an amazing milestone: the posting of its one millionth comment!
First off, please accept my sincere thanks and gratitude to the community for all your contributions to the site to get us to this point. Never did I imagine in those first few days when comment IDs were 3 or 4 digits long that such a milestone was even feasible! I mean the site was crashing several times a day. Not an auspicious start, that's for sure! But we all pulled together, weathered some challenges, and got things pulled together.. and we're still here!
So, who was the lucky poster of comment 1,000,000? And who was the runner-up at comment 999,999 (which has a nice palindromic ring to it, wouldn't you agree?
The honor of the very first 7-digit comment fittingly goes to story-submitter extraordinaire takyon. Yes, not content to post comment ID 1000000 because that could be just a one-shot lucky break. No, he has posted (as of this writing) 18,731 comments. Oh, and as for submitting stories, he is unfortunately omitted from the "Most Active Authors" list on the SoylentNews Hall of Fame because he is also an editor. So, please join me in thanking takyon for submitting 5,852 stories! Oh! And as an editor, he has also pushed out 1,350 stories! Whenever I see one of his subs in the queue, I know it only needs a quick review before pushing it out to the story queue. He makes my job as an editor much easier and makes SoylentNews look good! Thanks takyon!
So who was our runner-up with comment number 999,999? Well, he wasn't just spinning his tires when he posted this comment. None other than our also-prolific Runaway1956! He is no slouch when it comes to posting comments, either, as he has posted 18,483 of them so far. He has taken an active part in comment moderation, too with 2,968 moderations of which 78% were upmods. As if that were not enough, he is also an active contributor to our Folding@Home team, sitting currently at 3rd place and making a hard run for 2nd place! (F@H investigates — via computer modelling — how proteins fold.) The F@H group's efforts have almost exclusively been redirected to understanding the SARS-CoV-2 virus which causes COVID-19 disease.
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Speaking of volunteers, it brings me great pleasure to call out another major milestone, fnord666 has now edited over 5,000 stories on SoylentNews! (See Most Active Authors.) Thanks so very much, fnord666, for all your hard work and sacrifices to make that happen!
Thanks everybody! Here's to many more years!
(Score: 2) by takyon on Thursday May 28 2020, @12:56AM (2 children)
https://en.wikipedia.org/wiki/Designer_drug [wikipedia.org]
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 1, Informative) by Anonymous Coward on Thursday May 28 2020, @01:07AM (1 child)
That's a 1000000
dollarcomment question if ever there was one.(Score: 0) by Anonymous Coward on Thursday May 28 2020, @05:55AM
+1
Only 999999 to go