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Employing an Electrochemical Strategy for the Direct Carboxylation of Pyridines

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A chemistry partnership resulted in a novel approach to deploying carbon dioxide to good—and even healthy—use: by electrosynthesizing it into a series of organic molecules critical to pharmaceutical research.

Image Credit: Zita/Shutterstock.com

During the approach, the team made a novel finding. They could make two completely distinct products, both of which are valuable in medicinal chemistry, by altering the type of electrochemical reactor.

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The study was published in the journal Nature on January 5th, 2023. Postdoctoral researchers Peng Yu and Wen Zhang, as well as Guo-Quan Sun of Sichuan University in China, are the paper’s co-lead authors.

The Cornell group, headed by Song Lin, a Professor of chemistry and chemical biology in the College of Arts and Sciences, has earlier combined simple carbon molecules to create complex compounds using the electrochemical process, doing away with the need for precious metals or other catalysts to speed up the chemical reaction.

Researchers narrowed their focus for the new initiative to pyridine, the second-most common heterocycle among FDA-approved drugs. Heterocycles are organic compounds in which the atoms of the molecules are connected into ring structures, one of which is not carbon. These structural units are known as “pharmacophores” because they are frequently found in medicinally active substances. They are also widely found in agrochemicals.

The researchers wanted to create carboxylated pyridines, which are pyridines with carbon dioxide attached to them. The addition of carbon dioxide to a pyridine ring has the advantage of changing the functioning of the molecule and ultimately assisting it in binding to certain targets like proteins. The two molecules, however, are not natural companions. Pyridine is a reactive molecule, whereas carbon dioxide is an inert gas.

There are very few ways of directly introducing carbon dioxide to a pyridine. The current methods have very severe limitations,” added said Lin, the co-senior author of the paper, along with Da-Gang Yu of Sichuan University.

Lin’s laboratory successfully synthesized carboxylated pyridines by combining its electrochemistry skills with Yu’s group’s experience in using carbon dioxide in organic synthesis.

Electrochemistry gives you that leverage to dial in the potential that is sufficient to activate even some of the most inert molecules. That’s how we were able to achieve this reaction.

Song Lin, Professor, Chemistry and Chemical Biology, College of Arts and Sciences, Cornell University

While performing the electrosynthesis, the researchers made a coincidental finding. An electrochemical reaction is normally carried out in one of two ways by chemists: either in an undivided electrochemical cell (where the anode and cathode that supply the electric current are in the same solution) or in a divided electrochemical cell (where the cathode and anode are separated by a porous divider that blocks huge organic molecules but allows ions to pass through). Although one strategy is more efficient than the other, they both generate the same product.

Lin’s group discovered that transitioning from a divided to an undivided cell allowed them to selectively attach the carbon dioxide molecule to different places of the pyridine ring, resulting in two distinct products: C4-carboxylation in the undivided cell and C5-carboxylation in the divided cell.

This is the first time we discovered that by just simply changing the cell, what we call the electrochemical reactor, you completely change the product. I think that mechanistic understanding of why it happened will allow us to continue to apply the same strategy to other molecules, not just pyridines, and maybe make other molecules in this selective but controlled fashion. I think that’s a general principle that can be generalized to other systems.

Song Lin, Professor, Chemistry and Chemical Biology, College of Arts and Sciences, Cornell University

While the project’s method of utilizing carbon dioxide will not solve the world-wide problem of climate change, Lin stated, “it’s a small step towards using excessive carbon dioxide in a useful way.”

The study co-authors included postdoctoral researcher Yi Wang and doctoral student Zhipeng Lu; and researchers from Sichuan University.

National Institute of General Medical Sciences, Eli Lilly, Cornell, and the Sloan Foundation funded the research.

Journal Reference

Sun, G.-Q., et al. (2023) Electrochemical reactor dictates site selectivity in N-heteroarene carboxylations. Nature. doi.org/10.1038/s41586-022-05667-0.

Source: https://www.cornell.edu/

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Kemptville author’s book being sent to the moon

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One of Michael Blouin’s books is going to be launched into space on a microdisk and stay on the surface of the moon. (Submitted by Michael Blouin)

An author from North Grenville, Ont., is going to be part of a small club of authors whose works will be sent to the moon.

Michael Blouin of Kemptville says he’s been interested in space travel since the Apollo 11 mission that landed humans on the moon for the first time.

To be part of a group of hundreds of authors having their work immortalized within the vast expanse of space has him “gobsmacked.”

“I take comfort in the fact that no matter what happens, it looks like my books … will survive and be there,” he said.

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“I sometimes wake up at night and say ‘Oh yeah, I’m going to the moon. Wow.’ It’s kind of amazing.”

How it came to be

Blouin said he’s been a lifelong fan of NASA and space exploration, so when the opportunity to get his work in the Writers on the Moon project came up, he had to take it.

Then around the deadline to apply, his house burned down.

Amid the chaos of not having anywhere to live and then moving into his son’s house, he realized he’d missed his chance.

“I had missed the deadline to apply for this program for books to go to the moon by 12 hours and I was just kicking myself,” he said.

“I lost everything and now I’d missed out on my chance to do something I’d always dreamed about doing.”

Luckily a friend and author in Newfoundland, Carolyn R. Parsons, said she had managed to get some of her work included in the project and had enough space on her microdisk to include him as well.

A rocket sits upright.
This rocket will carry a lander and books from a couple hundred authors up to the moon. (United Launch Alliance)

When do the books go?

The NASA launch is scheduled for Feb. 25 at Cape Canaveral in Florida, which will see his book Skin House brought to the stars along with other works of independent fiction.

Blouin is getting the chance to see the launch.

“These launches sometimes get delayed due to technical reasons or due to weather,” he said.

“But I’m hoping to give myself a big enough window that I’ll actually be on site.”

Blouin had some advice for people who aspire to write or create.

“Any young person aspiring in the arts just shouldn’t give up. Keep trying,” he said. “It can be a tough go but it’s worth every moment.”

He’s getting another of his books — I am Billy the Kid — up to the moon in 2024.

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Green comet zooming our way, last visited 50,000 years ago – Cochrane Today

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CAPE CANAVERAL, Fla. (AP) — A comet is streaking back our way after 50,000 years.

The dirty snowball last visited during Neanderthal times, according to NASA. It will come within 26 million miles (42 million kilometers) of Earth Wednesday before speeding away again, unlikely to return for millions of years.

So do look up, contrary to the title of the killer-comet movie “Don’t Look Up.”

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Discovered less than a year ago, this harmless green comet already is visible in the northern night sky with binoculars and small telescopes, and possibly the naked eye in the darkest corners of the Northern Hemisphere. It’s expected to brighten as it draws closer and rises higher over the horizon through the end of January, best seen in the predawn hours. By Feb. 10, it will be near Mars, a good landmark.

Skygazers in the Southern Hemisphere will have to wait until next month for a glimpse.

While plenty of comets have graced the sky over the past year, “this one seems probably a little bit bigger and therefore a little bit brighter and it’s coming a little bit closer to the Earth’s orbit,” said NASA’s comet and asteroid-tracking guru, Paul Chodas.

Green from all the carbon in the gas cloud, or coma, surrounding the nucleus, this long-period comet was discovered last March by astronomers using the Zwicky Transient Facility, a wide field camera at Caltech’s Palomar Observatory. That explains its official, cumbersome name: comet C/2022 E3 (ZTF).

On Wednesday, it will hurtle between the orbits of Earth and Mars at a relative speed of 128,500 mph (207,000 kilometers). Its nucleus is thought to be about a mile (1.6 kilometers) across, with its tails extending millions of miles (kilometers).

The comet isn’t expected to be nearly as bright as Neowise in 2020, or Hale-Bopp and Hyakutake in the mid to late 1990s.

But “it will be bright by virtue of its close Earth passage … which allows scientists to do more experiments and the public to be able to see a beautiful comet,” University of Hawaii astronomer Karen Meech said in an email.

Scientists are confident in their orbital calculations putting the comet’s last swing through the solar system’s planetary neighborhood at 50,000 years ago. But they don’t know how close it came to Earth or whether it was even visible to the Neanderthals, said Chodas, director of the Center for Near Earth Object Studies at NASA’s Jet Propulsion Laboratory in California.

When it returns, though, is tougher to judge.

Every time the comet skirts the sun and planets, their gravitational tugs alter the iceball’s path ever so slightly, leading to major course changes over time. Another wild card: jets of dust and gas streaming off the comet as it heats up near the sun.

“We don’t really know exactly how much they are pushing this comet around,” Chodas said.

The comet — a time capsule from the emerging solar system 4.5 billion years ago — came from what’s known as the Oort Cloud well beyond Pluto. This deep-freeze haven for comets is believed to stretch more than one-quarter of the way to the next star.

While comet ZTF originated in our solar system, we can’t be sure it will stay there, Chodas said. If it gets booted out of the solar system, it will never return, he added.

Don’t fret if you miss it.

“In the comet business, you just wait for the next one because there are dozens of these,” Chodas said. “And the next one might be bigger, might be brighter, might be closer.”

___

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group. The AP is solely responsible for all content.

Marcia Dunn, The Associated Press

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How to spot the planets hiding in plain sight – CBC.ca

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This video was produced by Trevor Kjorlien as part of the CBC Creator Network. Learn more about the Creator Network here.

Most people are aware that if you live in the city, light pollution limits your view of the night sky. If you want to see lots of stars, comets and the Milky Way, you have to get out into the countryside, where the sky is dark.

However noble the cause, awareness campaigns to educate people about light pollution have had an unintended side effect: people think you can’t see anything in the urban night sky except a handful of bright stars and the moon.

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So if you are a city dweller and you don’t look up, what are you missing out on?

The planets.

Even in the most light-polluted skies, we can see five planets with the naked eye: Mercury, Venus, Mars, Jupiter and Saturn.

If you’d been walking through Montreal’s Jeanne-Mance Park in the early morning of June 26, 2022, you would have seen the planet Venus above the city skyline, next to the crescent moon. (Trevor Kjorlien/CBC Creator Network)

How to find the planets

It’s not unusual to be able to see the planets. Normally, some appear in the evening and some in the morning, depending on where they are in their orbit around the sun.

How do you know when and where to look?

In June 2022, we had a rare opportunity: all the naked-eye planets were visible in the early morning. At dawn, you could see all five of them lined up before the sun rose and washed their light away.

Why did they appear to line up, as they did then?

The sun rises in the east and sets in the west. In the northern hemisphere, the sun appears to move through the sky in the south.

Now imagine a line was drawn out behind the sun as it travels in the sky through the day. Astronomers call this “the path of the ecliptic.”

In a rare sight, the planets lined up in the southern sky above downtown Montréal on the early morning of June 26, 2022, roughly following the path of the ecliptic. (Trevor Kjorlien/CBC Creator Network)

At night, you can roughly follow this imaginary line, and that’s where the planets can be found. This is because the planets all orbit the Sun on the same plane, much like a frisbee or a vinyl record. Because all the planets travel more or less on the same plane, from our view on Earth, they appear to line up and are always visible in the southern sky from the northern hemisphere.

Embedded in our daily lives

We can see seven significant celestial objects with the naked eye: the sun, the moon and the five planets closest to the sun.

Test yourself: what day are you reading this article? Which celestial object does this day refer to? (Trevor Kjorlien/CBC Creator Network)

Where else do we see the number seven in our day-to-day lives?

In the calendar.

Through the magic of myth and etymology, each day of the week corresponds to these celestial objects.

  • Monday is moon day, named for the moon. (In French, la lune becomes lundi.)
  • Tuesday, named for Tiw, the Germanic god of war, corresponds to the Roman war god Mars (in French, mardi).
  • Wednesday is named for Woden, the Germanic god corresponding to the Roman god Mercury (in French, mercredi).
  • Thursday is named for Thor, the Norse god corresponding to the Roman god Jupiter. (In French, from the Latin Jovis, a name for Jupiter, we get jeudi.)
  • Friday is named for Frigga, the Germanic goddess corresponding to the Roman goddess of love, Venus (in French, vendredi).
  • Saturday is named for Saturn.
  • Sunday is named for the sun.

Think about which day you’re reading this. Which celestial object does it correspond to?

Not only are the planets hiding in plain sight in the urban night sky, they’re hiding in our calendars — embedded in our daily lives.


The Creator Network, which works with emerging visual storytellers to bring their stories to CBC platforms, produced the piece. If you have an idea for the Creator Network, you can send your pitch here.

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