Thursday, December 18, 2014

Greener Nylon Synth? Just Add UV and Ozone!

"Any sufficiently-developed technology is indistinguishable from magic" - Arthur C. Clarke

Looks like we'll soon have a more straightforward way to make stockings, zip-ties, and tire belts. 

Adipic acid, a six-carbon diacid representing one of the "sixes" in Nylon 6-6, apparently takes quite a bit of industrial "elbow grease" to make. The current process, starting from cyclohexane, requires cobalt, manganese, copper, and vanadate salts, high pressures of oxygen gas, and hot nitric acid. Out the other side, its responsible for 5-8% of the nitrous oxide we humans spew into the atmosphere each year.

From Science 2014, Hwang and Sagadevan

Now, researchers Hwang and Sagadevan (National Tsing Hua University, Taiwan) believe they have a better method. Reporting in this week's Science, the two disclose a method that sounds so much simpler: flush a sample of cyclohexane with ozone and UV light, and, presto! Solid adipic acid at the bottom of your reactor. No metal salts, no nitrous oxide, no high pressures or temperatures.

Wow, that looks a lot simpler.

The researchers note that zapping ozone produces both singlet oxygen, 1O2, and a single singlet oxygen atom O(1D). The highly reactive single singlet (say that three times fast!) can easily insert into C-H bonds, and, since it seems to prefer insertion next to an already-oxidized carbon, the diol, diketone, and finally diacid products are formed preferentially.

Applause, please: Look at this beautiful pictorial SI!
Twice, in two days.

Just for fun, Hwang and Sagadevan crack open some larger hydrocarbons, and check the selectivity of alkyl-functionalized rings and aromatics. There are tantalizing possibilities here that I'm sure, given the ease of this reaction setup, most organic chemists will already be trying: how do complex natural products* react under these conditions? If anyone tries it this weekend, please drop me a line.

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*For that matter, I wonder if this pathway is operative in human tissues under physiological conditions? Sunlight does have some 300 nm band, and we certainly come into contact with ozone out in the wide world. Hmm.

Wednesday, December 17, 2014

More Pictures in Supporting Information? Please!

Just stop what you're doing right now, and look at the gorgeous reaction setups in this Nature SI.

From SI page S16. Source: Nature / Baran lab

My kudos to Phil & co - they sure do capture a good visual chronology of their reactions!

Also prompted one of my more tongue-in-cheek Twitter exchanges in recent memory...


Do these pics remind you of anything? : )

...and now for Something Completely Different

I've been mulling over a version of this post for far too long, so here goes:

It's time to make some changes around here.

As I've quipped before, all careers in chemistry eventually leave the lab. Nearly gone are the days of the frizzy white-haired scientist holding aloft the shimmering vial and shouting "Eureka!"

Today, we often find ourselves in transition: Post-docs become professors, who write papers and manage a group. Bench chemists move into operations or regulatory roles. Technicians re-train and become patent clerks. Even med-chem project leaders eventually hire enough people that they think project strategy and logistics far more than they shake sep funnels or run TLCs.

Adapting to change can be ruff.

And so it is with me -- I find myself at a career inflection point. My Twitter handle reads: one foot in, one foot out. Ever wondered what I meant? It means I'm no longer your friendly "workaday synthetic chemist." I'm still in a role where I think about chemistry daily, and I apply my skills to solve problems. . . I just don't run reactions with my own two (gloved) hands.

At this juncture, one feels a complex mixture of emotions, to be sure:

Excitement, to learn new things and travel more frequently.
Embarrassment, that I've been blogging about chemistry and yet haven't touched a rinse bottle of acetone in months!
Fear, that I won't be as good at this new venture as (I thought) I was at synthesis.
Resolve, that I'm going to buck up and do my best, despite my nerves.

So, gentle readers, please bear with me. I'm going to probably shift away from lab stories and synthetic methods, and try to return to the theme of my very first post:
"This blog will reach out to the wider world about science, and especially chemistry."
I may write more stream-of-consciousness posts about navigating complex organizations, managing expectations and people, and thinking strategically. I may say "vision" or "collaborative."
[Oh great, thinks half my audience, he's really drinking the corporate Kool-Aid now!]

Fine - I'll also still write about chemistry. When something really awesome catches my eye : )

Thanks again, as always,
See Arr Oh

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I admire and applaud all who made it to the end of this short chautauqua. If you'd like to leave any kind advice on steering one's blog in a new direction, comments are open!

Tuesday, December 9, 2014

Fond Farewells

Today marked endings* (of sorts) for two prominent members of the chem-blogging community.

First up, Carmen Drahl - intrepid Chemical and Engineering News reporter - announced she was stepping down:


Just a few hours later, Paul Docherty of Totally Synthetic, arguably the blog that gave rise to post-peer-review in synthetic chemistry, called it quits to focus on a burgeoning informatics career.

I'd like to wish both Carmen and Paul a teary, heartfelt good-bye. After all, they both got me into blogging; see my Haystack and TotSyn guest posts. Moreover, they built the bridge from the Tenderbutton / In the Pipeline / The Chem Blog era into the rich and diverse bloggy landscape we enjoy today (see just a fraction of them, in my blogroll, at right).

Best wishes to both Carmen and Paul as they ride into the Internet sunset.

It's a road, off in the distance. Like a metaphor, or something.

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*But not for me. Sorry, chemblogosphere, you're stuck with the pup for yet another year.

Wednesday, December 3, 2014

Confusing 'Chemistry' Image of the Day

This image appeared in an NPR Shots blog post outlining the CDC's recent recommendations on male circumcision:

Source: NPR News / Corbis Images

Please help me understand - What on earth do the floating molecules have to do with this story? 

I grok that the image suggests two men deep in conversation. The article doesn't mention any drugs. Nor bodily substances. No pheremones, hormones, biomarkers, or viral particles enter the conversation. Just another case of stock images gone wrong?

Sunday, November 30, 2014

'Magic Berries' Pack Phorbol Punch

Could plant extracts still surprise us? "Magical rainforest berry kills tumors with single injection" read last month's FiercePharma headline. The Guardian reinforced the hype, narrowing down the berry's source (Queensland, Australia) and the compound: EBC-46*, promoted by local biotech QBiotics and tested by colleagues at the QIMR Berghofer Medical Research Institute.


Digging down to the PLoS One article behind the research, I uncovered the drug's structure and proposed mode of action. Now, where have I seen a compound like that before? Oh, right! Ingenol. Both compounds belong to the phorbol ester family, and both appear to activate protein kinase C, spurring tissue necrosis and tumor shrinkage when directly injected into mouse skin cancer lesions.

The authors indicate that they're preparing GMP product for Phase I human trials; whether that's derived from magical rainforest berries - or just plain process chemistry - hasn't been disclosed.
Stay tuned.

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*The published structure doesn't match the molecular weight (562.25 g/mol) the PLoS authors suggest, and no stereochemistry is specified. I'm guessing it's structurally similar to phorbol, and I've gently highlighted in red a hydrogen that's probably supposed to be a methyl group.

WWWTP? "Always Sunny" Edition

Charlie, Mac, Dee, and Dennis, the self-involved social group of FXX's It's Always Sunny in Philadelphia, would never advocate cautious, logical behavior as the best way to approach a situation. The dark humor that inevitably follows their ill-advised actions propels the show.

With nine seasons on the books, nothing's really changed. In the recent episode "Flowers for Charlie" - likely an homage to the late Daniel Keyes* - two scientists approach slightly-below-average Charlie with a pill ("a cerebral enhancement formula") to increase his IQ. Look at the chemical structures on those chalkboards!** Would you take medicine from these men?

Texas carbons, Wyoming nitrogens, and...a propeller?
Source: Fox Entertainment

Perhaps these "scientists" should win a Nobel for the first-ever aromatic spirocycle.
Source: Fox Entertainment

Spoiler Alert! After faking his way through French, philosophy, Beethoven, Tolstoy, chemistry, chess, Mandarin Chinese (not to mention a terribly put-on English accent), it turns out Charlie remains slightly-below-average, as reinforced by several chuckle-worthy graphs.

Colored fluids in condensers...sigh.
Source: Fox Entertainment
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*If you've never read "Flowers for Algernon," don't walk - RUN - to your local library and grab a copy.
**They're like prehistoric whiteboards.