Richy - 16-2-2005 at 17:43
Does the decomposition of niacin produce pyridine? if so, at what temperature? of not, could anyone suggest any other synthesis routes to the latter?
runlabrun - 17-2-2005 at 04:24
back at the hive this was discussed to the nth degree....
i believe the endpoint of the discussion was that the common decarbox as used for benzoic acid to benzene by heating sodium benzoate and NaOH worked
for this proceedure but either the temps required were to high to be easily conducted or the heat required caused decomposition of the heterocycle...
Cant remember off the top of my head but those two possibilities ring a bell....
As for another synth method... maybe look at the Chichibabin Pyridine Synthesis. Merck has info.
May be one route to condense acetyldehyde with ammonia under pressure....
For me the whole issue about pyridines action on my family jewels keeps me away from it... What were you aiming at using it for? solvent or reactant?
-rlr
pyridine from niacin/CaO
prole - 4-8-2005 at 06:21
This is what I have from the Hive. Since they are offline, I will share what I have from there regarding this synthesis. I have not tried this.
"Re: niacin to pyridine---would this work?
Yes, it will work.
Mix 1 part of niacin w/1.2 parts CaO, place in a sand bath, heat to 320 C. After ~1.5 hrs decarboxylation's over (could bee longer, since in the
original source the rxn is performed on microscale and in a sealed ampoule - the latter requirement undoubtedly stems from the need to measure the
yield w/a great precision - figure how you measure the yield when woking w/12 mgs of niacin!). Distill the formed pyridine off.
The promised yield is 86-90%."
runlabrun - 4-8-2005 at 16:18
This thread was old and not valid anymore... people drag things up all the time...
Ok the method does work this we ALREADY KNOW...
The main problem with it was that pyridine is used as a solvent which is why we wanted to find a reliable synth for it... so therefore we needed a
synth to produce a fair volume with ease, this method produces small volumes but it takes alot of energy and alot of fiddling and fussing so for any
use of the pyridine u need to make alot and this would be so painfull via this method.
If you can find another way to make it in a large enough volume to be useful via a method that isnt as painful and time consuming as this it would be
fantasmigorical and i would personally thank you greatly... till then leave this topic alone, as i said originally it was discussed to the nth degree
already...
-rlr
praseodym - 4-8-2005 at 23:10
Formation of pyridine? I think the synthesis of acetaldehyde and ammonia may work.