Comments on: Vanillin (Wherein I venture into the dangerous world of describing smells again) http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/ Molecules: You'd Better Learn to Live With Them Sat, 22 Nov 2008 06:33:42 +0000 http://wordpress.org/?v=2.0.2 by: Propter Doc http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-324 Thu, 29 Jun 2006 18:36:29 +0000 http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-324 JCB - I tried demethylating safrole right before I gave up on this route. BBr3 1M in DCM, -78 warming to 0 over a couple of hours. I always felt this should go easier than the dimethoxy variant, once you get half the molecule off, it should be easy. It was always just the workup - got purple liquid when the product should (according to lit) be a white powder, crude NMR showed it worked perfectly, but the impurity always interfered with the next step. Motd - I believe gamma-butyrolactone is scheduled now, or at least very restricted. We have a bottle, and make lactone based polymers for bio apps. Always worry about what the breakdown projuct might be...;-) JCB - I tried demethylating safrole right before I gave up on this route. BBr3 1M in DCM, -78 warming to 0 over a couple of hours. I always felt this should go easier than the dimethoxy variant, once you get half the molecule off, it should be easy. It was always just the workup - got purple liquid when the product should (according to lit) be a white powder, crude NMR showed it worked perfectly, but the impurity always interfered with the next step.

Motd - I believe gamma-butyrolactone is scheduled now, or at least very restricted. We have a bottle, and make lactone based polymers for bio apps. Always worry about what the breakdown projuct might be…;-)

]]> by: motd http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-309 Thu, 29 Jun 2006 00:58:23 +0000 http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-309 <strong>Jean-Claude:</strong> I swear I've seen milder stuff used for methylenedioxy deprotection, which would stand to reason, since it really is just an acetal. Something like BCl3 in DCM at 0C for a few hours. This was from a reasonably close substrate to whatever you're using, too, the catechol nucleus having had a fair bit of attention. I can't seem to find the paper right now, but I remember marveling at how mild the conditions were. Take a look at some of the <a rel="nofollow" href="http://designer-drugs.com/pte/12.162.180.114/dcd/chemistry/methylenation.html">sketchier, drugs-of-abuse</a> type sites. I have come across procedures on these sites that actually worked really well (I forget what for, oddly, but it stands to reason that they work OK, since a lot of these are intended for only semi-trained hands). Someone in a synth lab I was working in needed gamma-butyrolactone a few years ago, right when the hysteria was going on. For some reason, we couldn't even get a hold of it (in a medchem lab at a big uni, maybe it's scheduled now, I've never had cause to get some). So he used some prep from the drug-chef literature. Worked OK, not much of a yield. I think it was the KMnO<sub>4</sub> oxidation of THF, or something along those lines. Ugly. Anyway, this probably won't be much of a help, but my sympathies go out to you, good luck! I like what you're doing with the blog, etc! <strong>Lauren:</strong> Vindicated again. My <a rel="nofollow" href="http://www.harvard-magazine.com/on-line/0103101.html">favorite food writer</a> has railed on vanillin on numerous occasions, but I never got it. I usually trust JS on these matters too. I took out my artificial and natural vanilla extracts (of course I keep both!) and smelled them after I wrote the entry. They are very much different, but I really don't notice it as much in the cooked dishes. I fear the only way for me to settle my preference once and for all is a side-by-side creme brulee standoff. Jean-Claude: I swear I’ve seen milder stuff used for methylenedioxy deprotection, which would stand to reason, since it really is just an acetal. Something like BCl3 in DCM at 0C for a few hours. This was from a reasonably close substrate to whatever you’re using, too, the catechol nucleus having had a fair bit of attention. I can’t seem to find the paper right now, but I remember marveling at how mild the conditions were. Take a look at some of the sketchier, drugs-of-abuse type sites.

I have come across procedures on these sites that actually worked really well (I forget what for, oddly, but it stands to reason that they work OK, since a lot of these are intended for only semi-trained hands). Someone in a synth lab I was working in needed gamma-butyrolactone a few years ago, right when the hysteria was going on. For some reason, we couldn’t even get a hold of it (in a medchem lab at a big uni, maybe it’s scheduled now, I’ve never had cause to get some). So he used some prep from the drug-chef literature. Worked OK, not much of a yield. I think it was the KMnO4 oxidation of THF, or something along those lines. Ugly. Anyway, this probably won’t be much of a help, but my sympathies go out to you, good luck! I like what you’re doing with the blog, etc!

Lauren: Vindicated again. My favorite food writer has railed on vanillin on numerous occasions, but I never got it. I usually trust JS on these matters too. I took out my artificial and natural vanilla extracts (of course I keep both!) and smelled them after I wrote the entry. They are very much different, but I really don’t notice it as much in the cooked dishes. I fear the only way for me to settle my preference once and for all is a side-by-side creme brulee standoff.

]]> by: Lauren http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-304 Wed, 28 Jun 2006 21:43:34 +0000 http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-304 Cook's Illustrated did a taste test and found that people liked synthetic vanillin better than real vanilla! Cook’s Illustrated did a taste test and found that people liked synthetic vanillin better than real vanilla!

]]> by: Jean-Claude Bradley http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-294 Wed, 28 Jun 2006 13:11:33 +0000 http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-294 Propter - do you know if methylenedioxy is harder to remove than the dimethyl ether catechol derivatives? Propter - do you know if methylenedioxy is harder to remove than the dimethyl ether catechol derivatives?

]]> by: Propter Doc http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-288 Wed, 28 Jun 2006 00:00:20 +0000 http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-288 Hmmm, and I just happened to burn all my vanillin tlc indicator today on plates....the lab smells strangely of burnt vanillin! I previously tried to demethylate similar compounds with boron tribromide...couldn't separate the product from the inorganic byeproducts, although proton NMR was clean for the product. Hmmm, and I just happened to burn all my vanillin tlc indicator today on plates….the lab smells strangely of burnt vanillin!

I previously tried to demethylate similar compounds with boron tribromide…couldn’t separate the product from the inorganic byeproducts, although proton NMR was clean for the product.

]]> by: motd http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-287 Tue, 27 Jun 2006 23:32:17 +0000 http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-287 I was actually trying to fold it into a ring system, I had a bunch of benzaldehydes and was trying to tune redox properties with substituents. Never bothered with -OH. I was actually trying to fold it into a ring system, I had a bunch of benzaldehydes and was trying to tune redox properties with substituents. Never bothered with -OH.

]]> by: Jean-Claude Bradley http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-283 Tue, 27 Jun 2006 12:22:48 +0000 http://www.moleculeoftheday.com/2006/06/26/vanillin-wherein-i-venture-into-the-dangerous-world-of-describing-smells-again/#comment-283 What a small chemical world! We just ordered veratraldehyde and related catechol derivatives as analogues of DOPAL in our synthesis of anti-malarial compounds. http://usefulchem.blogspot.com/2006/06/dopal-nmr-and-phosphoric-acid.html Nice to know it will smell like waffles in the lab :) In your prior research, do you have a recommendation for demethylation of catechol ethers? What a small chemical world! We just ordered veratraldehyde and related catechol derivatives as analogues of DOPAL in our synthesis of anti-malarial compounds.
http://usefulchem.blogspot.com/2006/06/dopal-nmr-and-phosphoric-acid.html

Nice to know it will smell like waffles in the lab :)

In your prior research, do you have a recommendation for demethylation of catechol ethers?

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