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DBL%20Hendrix%20small.png College chemistry, 1983

Derek Lowe The 2002 Model

Dbl%20new%20portrait%20B%26W.png After 10 years of blogging. . .

Derek Lowe, an Arkansan by birth, got his BA from Hendrix College and his PhD in organic chemistry from Duke before spending time in Germany on a Humboldt Fellowship on his post-doc. He's worked for several major pharmaceutical companies since 1989 on drug discovery projects against schizophrenia, Alzheimer's, diabetes, osteoporosis and other diseases. To contact Derek email him directly: Twitter: Dereklowe

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« Chemists and Biologists, In Detail | Main | Resveratrol Explained. A Little Bit. »

May 1, 2012

Flip That Glucose, Please

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Posted by Derek

Just another nitpicking note: if you're going to publish a paper on glucose conjugates of drugs (aspirin, in this case), you might want to be sure to draw the glucose as the correct enantiomer. I had to do a little head-scratching with this one, since the sugar ring is drawn from a perspective that no carbohydrate chemist would ever use, but as far as I can tell, that's L-glucose instead of D. . .

This is not as big a deal in the grand scheme of things, but it particularly gets to me, as someone who worked with sugars as chiral starting materials for 4 1/2 years. And then, every chemical drawing program extant will draw you the correct stereochemistry. . .

Comments (20) + TrackBacks (0) | Category: The Scientific Literature


1. Curious Wavefunction on May 1, 2012 11:18 AM writes...

Reminds me of that giant ad I once saw in the Atlanta airport in which glucose was drawn with all hydroxyls axial.

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2. Sugar Heretic on May 1, 2012 11:22 AM writes...

Chemist Confession: I want to care about sugar stereochem but I find it so hard. My brain says "sugar" and then that's about it. Analyzing the structure any further is like doing my taxes.

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3. LittleGreenPills on May 1, 2012 12:06 PM writes...

I do not have access to the article, but did they really form the linkage through the 3 position and not the more common 1 (anomeric) position?

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4. PharmaJap on May 1, 2012 12:39 PM writes...

Unless I'm mistaken, that looks to be β-D-Mannose.

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5. PharmaJap on May 1, 2012 12:42 PM writes...

Sorry, meant to say β-L-Mannose. And now I remember why I hate carbohydrate chemistry.

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6. Mike on May 1, 2012 12:57 PM writes...

They should have just gone with depicting no stereochemistry, as they did with structures 2 and 3. No chance of error that way.

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7. petros on May 1, 2012 1:02 PM writes...

From this company

"Organomed Corporation was founded in 1991 and it specializes in custom synthesis of fine chemicals and intermediates and in research and development of new drugs. It was founded by scientists from the University of Rhode Island with over 30 years of research and development experience. We have a team of highly respected scientists backed by practical experience and knowledge of the latest development in organic and medicinal chemistry."

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8. Rick Wobbe on May 1, 2012 1:58 PM writes...

I feel the same way every time I see the DNA double helix drawn as left-handed in magazines and newspapers.

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9. Formerdrughunter on May 1, 2012 2:28 PM writes...

Love the comment from the company. Silly when they could just fix it. Sometimes chemists can draw structures and sometimes they can make compounds. It appears they make do a few reactions but underwater in the carbohydrate community.

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10. Anon on May 1, 2012 3:12 PM writes...

That's an L-sugar derivative. It's a known compound on planet Tharg, where highly advanced sauropods take this by the kilo for pain relief following battles with carnivorous foes.

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11. carbene acetal on May 1, 2012 3:19 PM writes...

No one is bothered by the acetyl phenol representation (OCOCH3 vs OOCMe)?

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12. RD on May 1, 2012 4:16 PM writes...

In the middle of a carbohydrate chemistry based Ph.D and still this looks like a very ugly structure.
Using models and tracing the fischer projection I can confirm that the sugar drawn fits perfectly as L-mannose.
It's drawn in a 1C4 conformation and then rotated to look down an unorthodox axis before attempting to move the bonds into a "more equitorial" position....
I take it a carbohydrate chemist did not review this!!!!

I take it a carbohydrate chemist did not review this!!!!

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13. dan on May 1, 2012 4:52 PM writes...

RD: let's get everything correct. equatorial, not equitorial!

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14. toocantsamsondelilah on May 1, 2012 5:08 PM writes...

How about the Resveratrol paper published today Derek et. al.?

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15. Steve on May 1, 2012 5:56 PM writes...

Isn't the diagram as drawn in the paper just amibiguous without any bold lines indicating which lines come out? In that case it could be the right enantiomer, although you would have to see it in a way counterintuitive to most organic chemists.

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16. Anne on May 1, 2012 7:05 PM writes...

Hey Derek, I'm not sure if you've mentioned this here but I couldn't find it in your archives. I think Vertex's cystic fibrosis drug Kalydeco deserves a mention:
I just saw a talk given by the VP of the program at Vertex, and the story is quite impressive. It's the first drug to treat the underlying cause of CF and has quite dramatic effects. Unfortunately it only works on a small subpopulation of CF patients, but from a molecular level I think it's interesting to this audience. It's also a funky little molecule, with two t-butyl groups poking off it like antlers.

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18. RD on May 2, 2012 6:16 AM writes...

@Dan : Apologies for the misspelling, thanks for the correction.

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19. processchemist on May 2, 2012 6:42 AM writes...


Yes, they start from diacetone glucose.

I've seen glycosidation used to modulate PK and to obtain lower cytotoxicity, but in my experience glucosides are too prone to fast enzymatic degradation (I suppose that position 4 is more stable than position 2).

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20. cowboychemist on May 17, 2012 2:04 PM writes...

No wonder I have problems getting my sophomores to recognize/draw correct carbohydrate structures. The -OH at C-2 in the graphical abstract is sort of hemi-equatorial, but clearly not axial. The structure of 4 in Scheme 1 is better, with all groups on the pyranose equatorial. But we have comments calling the carbohydrate, L-Mannose?? If all substituents on the tetrahydropyran ring are equatorial, it has to be glucose. The only way to foul it up is to draw the wrong chair conformation - the 'flipimer' with the oxygen on a 'down' vertex and you then have L-glucose.

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