Molecules: You'd better learn to live with them.
Hmmm, people don't like being told not to leave certain comments. Thanks for the snark and corrections of the chemical formula. I am off banned drug-related entries for a long while again, they're just not worth the hassle, and there's plenty of worthy molecules out there. Sorry to anyone who felt snubbed; let's talk about a giant ketone!
Civetone is a macrocyclic ketone expressed by an animal that looks photoshopped: the African Civet. It is used in perfumery.
"Macrocycles" are tricky to make - Nature loves five- and six-sided rings, but larger ones, such as civetone, are nearly as hard to make as the small three- and four-membered ones - like epoxides, cyclobutanes, and aziridines. They're not that uncommon, though - lots of plants hum away every day making big rings, and lots of graduate students in total synthesis curse away every day trying to duplicate them. Life manages to make all sorts of weird stuff - the ubiquitous erythromycin, for instance, is a macrocycle made by a bacterium (and even though it was synthesized successfully over 25 years ago, we still rely on bacteria to make it).
What's unique about these macrocyclic ketones is their austere lack of functionalization - usually you see the tell-tale signs of assembly from isoprene units or amino acids. If anyone knows much about the biosynthesis of civetone or related compounds (e.g., muscone), feel free to pass it along.
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Comments
The molecular drawing for Civetone in the Wikipedia entry looks like an animal!
Posted by: joeylawn | July 31, 2007 9:21 PM
a molecule like that will come together in ~4 steps these days, such is the beauty of RCM chemistry
Posted by: kiwi | August 1, 2007 5:51 AM
You missed all the fun (aside from symmetric civetone)! The cycloolefin is the pivot. Open chain ketone diolefin, ketalize, then extrude ethylene with a Grubbs olefin metathesis catalyst.
http://www.ias.ac.in/chemsci/Pdf-May2006/223.pdf
Ethylene extrusion a facile general synthesis of huge families of substituted cyclomusks and analogs... and cycloolefin antibiotics.
Google
musk grubbs 745 hits
musk metathesis 657 hits
erythromycin grubbs 735
erythromycin metathesis 573
Posted by: Uncle Al | August 1, 2007 1:00 PM
Civetone "nice smelling"? What concentration are you looking at here? Neat civetone is anything but nice smelling. In perfumery it's hugely diluted and does smell nice. Same contrast for things like ionone and even indole.
Posted by: Wavefunction | August 2, 2007 1:48 PM
WHOA. Is that, relatively speaking, a really big ring? While not a chemist, I've browsed around a few websites, and it looks like it to me. What's the biggest ring you find in a reasonable molecule?
The civet is also essential to the production of the famous Kopi Luwak.
Posted by: Adam | August 3, 2007 11:58 PM