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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: derekb.lowe@gmail.com Twitter: Dereklowe

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April 26, 2010

Maitotoxin Revisited

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Posted by Derek

Last year I wrote about the hideous structure of maitotoxin, with a note about how various groups were kicking around synthetic approaches to it. Now K. C. Nicolaou has a paper out in JACS on the synthesis of a portion of the molecule, which includes the line: ". . .as a prelude to a possible synthesis of large domains of this molecule for biological investigations. . .". Yeah, sure. Betting will now commence on whether or not he'll be able to resist going for the whole thing. As to whether or not that's a good idea, well. . .my views on the subject have already been aired pretty thoroughly.

Comments (56) + TrackBacks (0) | Category: Chemical News


COMMENTS

1. anchor on April 26, 2010 10:08 AM writes...

Pleasantly surprised to see that there are only 3 workers, who really accomplished a lot on target molecule that fills in a page.

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2. DC on April 26, 2010 10:17 AM writes...

Why KCN has to be first author on all his papers?

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3. Sili on April 26, 2010 10:23 AM writes...

And to think that three rings were usually enough to make us talk of chickenwire chemistry.

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4. Christian Hesketh on April 26, 2010 10:26 AM writes...

"If you're looking for 10mg of each isomer to add to your screening collection (no sense in going back and making them again), then you're looking at a good bit over half the mass of the entire Earth."

Wait a minute - ah OK, 98 chiral centres! Wow. 2^98 is a very large number :).

"an intraperitoneal injection of 0.13 µg/kg was lethal in mice" - at least it'll be selective!

To be fair though, 3422 g/mol is only about 5 times as heavy as the largest small molecules.

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5. chemist on April 26, 2010 10:27 AM writes...

I think people doing total synthesis just do it for the kick and thrill they get out of it. Taxpayers money gets wasted for someone's hobby.

Even if successful, synthesis of this kind of molecule is going to be a sheer waste of money, time and energy that could be used elsewhere.
It would be pity if US or any government funds this kind of project.

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6. You're Pfizered on April 26, 2010 10:29 AM writes...

#2

I had a similar thought. Clearly no-one else deserves it.

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7. Hap on April 26, 2010 10:50 AM writes...

I don't really have a problem with KCN being first author - if it's consistent, I can factor for it to see what others' contributions are, and I probably look for his name, anyway, when I read articles. In lots of cases, it is probably his ideas. The credit probably isn't entirely misplaced.

I don't really understand the point of synthesizing maitotoxin though. Structure determination methods would probably be generally useful, but unless the hands skills of dealing with small amounts of lagre fragments are generally useful, making maitotoxin seems like a whole lot of money for not much useful technology or knowledge. You never know what you'll get from research, but that doesn't mean that spending $100M on a guess is a good idea.

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8. Rhenium on April 26, 2010 10:51 AM writes...

What is it exactly with KCN?

I had heard legends of his presentations on this blog and so went to see his talk at the SF ACS meeting. Slides dense, speaking style dissociated, Greek motifs everywhere.

Is he one of the "had to be there to see it" kind of speakers?

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9. Hap on April 26, 2010 10:53 AM writes...

I don't really have a problem with KCN being first author - if it's consistent, I can factor for it to see what others' contributions are, and I probably look for his name, anyway, when I read articles. In lots of cases, it is probably his ideas. The credit probably isn't entirely misplaced.

I don't really understand the point of synthesizing maitotoxin though. Structure determination methods would probably be generally useful, but unless the hands skills of dealing with small amounts of lagre fragments are generally useful, making maitotoxin seems like a whole lot of money for not much useful technology or knowledge. You never know what you'll get from research, but that doesn't mean that spending $100M on a guess is a good idea.

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10. startup on April 26, 2010 11:13 AM writes...

We might as well bet on whether or not Lindsey Lohan will be mentioned in this week's issue of the National Enquirer.

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11. bbooooooya on April 26, 2010 11:24 AM writes...

"Is he one of the "had to be there to see it" kind of speakers?"

yes. it is a spectacle, comparing oneself to the gods on mt olympus....

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12. Yap on April 26, 2010 11:31 AM writes...


KCN........second coming of Aristotle. End of debate.

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13. Hap on April 26, 2010 11:32 AM writes...

Doesn't that usually get you a lightning bolt in the butt, though?

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14. Chemjobber on April 26, 2010 11:33 AM writes...

So who are the peers in the NIH study sections who are rating this stuff? And why are they doling out funds for it?

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15. anon the II on April 26, 2010 12:06 PM writes...

There are a number of reasons that one might want to make this molecule. Let's examine them.

1. Train new scientists in the art of making molecules. As we can tell from numerous posts on this blog, the last thing we need are more scientist competing for a vanishing job pool.

2. Prove the structure. Actually, no one really cares what the structure is. If one center is off, well, big deal.

3. Develop new methodology. KCN has been working in this class of molecules for 30 years as have a host of other people. Enough already.

4. It's bigger than palytoxin! Is it? Yes, it is.

5. Most of the pieces were lying around the lab already. Hmmm! Maybe!

6. If they make it, Derek will another column on "Stuff I won't work with" to write.

There you are, all the possible reasons to make maitotoxin. You decide.

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16. Hap on April 26, 2010 12:18 PM writes...

I think the NIH is still going to be funding more chemists than we may be able to employ - so I think the question is whether the NIH gets more from funding the synthesis of maitotoxin than it would funding many smaller total syntheses. What does working on maitotoxin give you that working on other natural products wouldn't?

1) I assume there are challenges in working with small amounts of complex fragments through lots of steps. I don't know where else this would be useful, though - pharma isn't likely to make drugs this complicated (though if they can't make them, they can't even think about them), and the chance of making analogs is probably nil.

2) Skills in handling highly biologically active substances. This is probably helpful, though there might be cheaper and easier ways to get people with this capability. Also hard to see as consistent with the lax safety in graduate schools and universities in general - you'd be asking for trouble.

I'm not really seeing why making maitotoxin would be better than funding lots of smaller total syntheses, let alone whether it's better than funding other chemistry projects. It just doesn't seem to make sense to me. The stories would be cool, but not $100M cool. (Sorry, I wouldn't want to pay more to hear about maito than I would to go to a Rush concert.) KCN's group has done lots of interesting molecules - this just doesn't seem interesting enough to merit the needed funding.

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17. Anonymous on April 26, 2010 1:51 PM writes...

@ #2 and #6: I've been told that he's the first author on the paper, a la Scott Denmark papers, because when people reference papers in some journals or presentations, they often just use "first author, et al.". This way the PI's name always appears. It also takes the competitiveness away from assigning first author - which could be good or bad.

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18. Aspirin on April 26, 2010 2:39 PM writes...

Sorry KCN, you are still not going to get the Nobel

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19. Jose on April 26, 2010 3:06 PM writes...

Stares in mirror- "I'm just as good as Kishi. And papa EJ, too! And, and, people like me!" (stomps his feet, starts to cry).

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20. Anonymous on April 26, 2010 3:12 PM writes...

"Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should."

- Dr. Ian Malcolm "Jurassic Park"


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21. retread on April 26, 2010 4:14 PM writes...

As an old Woodward grad student ('60 - '62) the comments above make me feel like Woody Allen in "Sleeper" when he wakes up in the future and is told that hamburgers and cigarettes are actually good for you.

If you want to see a huge investment in research dollars that has produced relatively little and has the prospect of producing even less in the future, have a look at the current post on Chemiotics II. It's called GWAS (Genome Wide Association Studies) and was reasonable to do when first started, but the prospect of finding very much useful by throwing more money at it is small (the Wellcome foundation coughed up 45 Million (pounds? dollars?) for it in 2007. That buys a lot of synthetic organic chemistry.

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22. Will on April 26, 2010 4:26 PM writes...

In defense of MTX of a target - because it is so large, problems that don't come up in traditional small molecule NP synthesis might arise - compound folding effects, solubility problems etc...solving them in the context of MTX might actually lead to generally useful knowledge

The alternative more NP synthesis groups is the alkaloid or macrolide du jour, to me that type of synthesis is less likely to produce anything of real "value" other than hand waving to tell the world how clever you are for synthesizing bigdealamine in 8 steps

Did I really just defend KCN? Excuse me while I light myself on fire

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23. small but perfectly formed on April 26, 2010 4:42 PM writes...


This thing contains 32 cyclic ethers, 28 of which are tetrahydropyrans, so why not just cut to the chase and spend $100M of research funding on soaking tetrahydropyran into the crystal structure of the target protein of this thing ? The ultimate in fragment-based drug discovery. Right, Derek ?

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24. Christian Hesketh on April 26, 2010 6:18 PM writes...

I am not a chemist, so can someone explain to me the great importance of total synthesis? Why is this such an important topic in chemistry? Wouldn't it be more impressive and less expensive to use some sort of biological reaction/fermentation process to produce these natural products. Is it mainly for the intellectual challenge to synthesis such large molecules? I'm genuinely interested.

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25. milkshake on April 26, 2010 6:45 PM writes...

#24: have you seen Shrek animated comedy? There is a scene where the two main characters are gasping in disbelief at the ginormous castle belonging to prince Farquaad. Then the Donkey observes "Maybe he is compensating for something..."

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26. Achilles last stand on April 26, 2010 8:51 PM writes...

Anyone notice that this paper reported the ABCDEFG rings of where the last one had GHIJKLMNO? Someone better warn KCN that he's got an extra G ring.

BTW - where did the $100M number come from? I would guess $100K/grad student year and I think that's pretty generous. If it really is 3 students then it shouldn't cost more than $3M more or less (3X10yrPhDX100K/yr). Who wouldn't want to pay that for a half a milligram of maitotoxin?

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27. milkshake on April 26, 2010 9:25 PM writes...

Since most PhD chemistry students do not pay for their grad school with their own money, and the university overhead + stipend + health coverage and other costs must be 40-50k/year per student, it is not that cheap to invest 20 man-years into developing a synthetic route to a molecule that is quite useless (apart from getting into the new edition of the "Classics"). I think it would be more satisfactory for the students to work on smaller molecules, and it would be probably a better chemistry training for too.

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28. AlchemX on April 26, 2010 10:29 PM writes...

Gotta agree with Milkshake. We really need a PhD shaped more like an MD. (I said shaped, not exactly like the MD) teach us as much manual skills, concepts and whatever else that would make us functional enough to start doing some research. Earning a PhD on a molecule that may/may not every get done is way too nerve racking and can make a person too narrowly trained to be attractive to future employers. Society would also benefit much more.

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29. fungus on April 26, 2010 10:33 PM writes...

Because someone had to post it:

http://despair.com/achievement.html

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30. Eraser on April 26, 2010 10:36 PM writes...

Usually when the PI is first author, the second spot is reserved for the person who did most of the work. Hence, this person still gets "first author credit" and the competitiveness is still there.

As far as I have heard from KCN people a lot of the ideas come from the group.

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31. sethcohen on April 26, 2010 10:50 PM writes...

i think KCN's going for the double-G-ring MTX analog. probably going to be twice as potent...

as for the Ph.D. being like an MD (#28) - that's just not what academics are about. The goal of a Ph.D. should be to add something to the field (not just an introverted focus on gaining personal skills).

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32. Jose on April 26, 2010 11:48 PM writes...

"In defense of MTX of a target - because it is so large, problems that don't come up in traditional small molecule NP synthesis might arise - compound folding effects, solubility problems etc...solving them in the context of MTX might actually lead to generally useful knowledge"

Sorry, but the palytoxin saga negates 100% of this argument.

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33. Anon on April 27, 2010 3:27 AM writes...

I am surprised no one has mentioned Eribulin yet.

http://www.fiercebiotech.com/press-releases/eisai-submits-simultaneous-regulatory-applications-approval-eribulin-mesylate-japan-u

Eisai are looking for FDA approval of this compound at the memonet. It is made entirely by total synthesis, with a longest linear sequence of >35 steps.
So total synthesis is not entirely useless - this one could save lives.

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34. processchemist on April 27, 2010 6:35 AM writes...

@35

The Merck bile acid cortisone process (commercial production) was in 26 synthetic steps. The synthesis of fondaparinux is about 30 steps. Total synthesis and glycochemistry are not useless at all.

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35. Anonymous on April 27, 2010 6:56 AM writes...

While maitotoxin or similar NPs might look impossible to synthesize on the face of it, they're not anything alien. Retrosynthetically, even the most scary-looking the cycles can be opened into chiral alcohol-ketones that self-condense conveniently. And these precursors are not arcane knowledge. As much as simple counting of stereocenters may impress people, that doesn't make the molecule inherently alien.

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36. 70s OS jockey on April 27, 2010 8:02 AM writes...

You all have it wrong. Maitotoxin is a terrific molecule to teach the art of organic synthesis. When KC's students finish their schooling, they will have all the skills necessary to be a depressed, unemployed starving artist. These skills may or may not important at graduation, but they certainly will be vital once they pass age 40.

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37. p on April 27, 2010 8:18 AM writes...

I think most of this debate is too black and white. You can poke holes in almost any research by pointing to some of the more (in retrospect) dumb ideas and looking at how much is spent to achieve little. But isn't this the idea that is killing industry? The idea that we'll sit down, think real hard about what we want to do and how and then we'll ONLY do that. Voila, profit! Only we don't know - can't know - until we do some research. In other words, you simply can't make innovation efficient. You have to play with an idea before it becomes practical. If industry doesn't wish to do this playing (and for sure there isn't much profit in it) then someone else will have to.

As to maitotoxin, yes, it is a ridiculous target if someone is going to simply brute force it. If KCN or anyone else want to approach it by using known reactions and lots of man-power then, yes, it's a waste of money. We won't learn anything except that synthetic chemists have perseverance in great amount.

BUT, it's a perfect target for innovation in synthetic chemistry. How would you make it in, say, 15 steps for less than $1million. Think of new reactions and techniques. Problem solve. If someone has a reasonable idea on how to do that, they should get (a reasonable amount of) funding and if they're successful, it would be a significant advance for science and knowledge. Synthesis of organic molecules doesn't only impact pharma. Knowing how to make and manipulate massive molecules may well end up being important in a number of materials sciences.

It's pretty easy to sit back and say everything in a given field is known and has been done and further work is useless and a waste of time, money and energy. But just about everyone who has ever said this about a field has been wrong.

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38. Hap on April 27, 2010 9:34 AM writes...

I WAGd the $100M figure. I don't think three students is going to cut it, though - brevetoxin (less than half the size, and with some of the same issues) took at least 12 person-years to make - if it ends up as only 30 person/years, then it might only be $3M. I'm still thinking that that's the low end - I could be off by an order of magnitude (aka wrong), but that would still be $10M.

The problem isn't whether synthesizing MTX is useless, but whther making it is less useful than the projects that would use the money instead. It's possible that something could come from this, but less likely than from a bunch of smaller synthesis projects, or methodologies. You can't make analogs easily, and you can't use 0.25 mg of MTX as a biotool, so you'd better be hoping for something synthetic to come out of this, and based on related large molecules (brevetoxin, palytoxin), that's pretty optimistic. (I don't think the methodogy from brevetoxin has been generally useful, while palytoxin contributed the always joyful thallium salts in Suzuki couplings.) This time could be different, but I say that with lottery tickets, too, and they don't cost $10M.

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39. BACE on April 27, 2010 9:34 AM writes...

Milkshake is right. I don't think MTX provides training that would not be acquired from the synthesis of other hard-to-make and more valuable smaller molecules. Plus, I am seriously interested in knowing whether there novel chemistry here, especially different from that employed in KC's own synthesis of brevetoxin. It's not like nobody has synthesized marine polyethers before.

And all this is quite separate from the question of which student the MTX fragments kill first.

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40. J-bone on April 27, 2010 10:43 AM writes...

And all this is quite separate from the question of which student the MTX fragments kill first.

On the other hand, it's the perfect way to find out which fragment is most critical to the bioactivity.

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41. milkshake on April 27, 2010 11:11 AM writes...

it may not be a clear-cut method. Given the potency of these things, there will be no-one left left behind to figure out which of the the two fragments was actually spilled there on that fateful day

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42. anon on April 27, 2010 11:12 AM writes...

#38 Your comments reminded me that about a year or two ago Crimmins published a total synthesis of brevetoxin in Org Lett that was far shorter than KCN's synthesis of brevetoxien. So I find it annoying that Crimmins ends up in Org Lett, and KCN's recycling of methodology for a part of a bigger molecule gets to