May 11, 2007
by Ryan Sasaki, NMR Product Manager, ACD/Labs
Of course they are. But I think it is a fair question to pose.
The reason I say this is because a while back I was having a conversation with a medicinal chemist in a major pharmaceutical company in the US, and they told me point blank:
"I bet that 75% of the chemists in my group aren’t even using NMR to confirm structures. In fact, I KNOW some aren’t. Many just look at the mass value from the LC-MS…and move on."
I’ve posed the question to several spectroscopists who support chemists, and some scream in horror when I mention this, while others say it’s possible.
Of course I am not implying that 75% of medicinal chemists in pharma don’t use NMR. I am sure these people are in the very, very low minority, they are trained in chemistry after all, and in several companies it’s a medicinal chemist who serves as the resident NMR spectroscopist. There are loads of medicinal chemists out there with outstanding proficiency in NMR.
Perhaps in some instances it’s OK for them to pass over the NMR…but my guess is that this is a slippery slope. I can’t imagine there is a chemist our there who has abandoned NMR completely.
NMR can be very difficult. Reading a mass is easy. There’s certainly a barrier to overcome when you consider how busy these folks are.
What role can software companies like mine play in this? I’d say making the tool as easy to work with as possible and providing applications that assist the chemist in making the decision of whether or not an NMR spectrum is consistent with the structure.
We’re working on it…more details to follow over the next several months on this blog.
Teaser: We announced the upcoming release of a new product at the ENC this year. ACD/1D NMR Assistant.
So I speak with quite a few spectroscopists and chemists in working in various industrial and pharmaceutical labs. Furthermore, in a previous life I supported the NMR and LC/MS intstruments for a group of about 100 working Medicinal Chemists. My take on the comment: while most chemists are indeed relying more heavily in MS (specifically LC/MS) to confirm completion of their reaction, they still need some sort of “proof” of the structure beyond MW (or really M+H, but that’s a whole other blog!). A 1H NMR and LC/MS (perhaps also elemental analysis or accurate mass) is the minimum most labs agree on as the proof of structure needed for entering the synthetic material into a corporate registration system.
I would assert that for sure LC/MS is supplanting TLC as a means of confirming reaction completion. Also, the Chromatogram also gives the chemist an idea of purity (let’s not talk about residual solvents, or salts present…). That said, 1H NMR is still considered the minimum for confirming structure.
Most chemistries employed in the med chem lab are fairly well controlled and predictable. However I don’t believe that a chemist can argue that a structure is correct because the correct M+H is observed in the LC/MS.
Anyhow, I see the need for chemists to work as fast as possible to accelerate the drug discovery process. Can they omit the assurance of quality that good analytical results provide them? I for one hope not!