jimwig
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pyridine by the light
(excuse this repetition but this has been posted a few minutes on the hive)
pyridine- over by the light Bookmark
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Here's some (i hope) good news about this hyterocyclic substance.....
US 1421743 Process for the manufacture of products from acetylene
US 3264307 Production of pyridines
US 3829429 Catalytic synthesis of substituted pyridines from acetylenes and nitriles
Cobalt-catalyzed pyridine synthese from alkynes and nitriles - Angew.Chem.Int.Engl. 17,505-515 (1978)
Cobalt-catalyzed synthesis of pyridiens from acetylenes and nitriles - Tetrahedron Letters No.36 p3383-3384 (1973)
First cobalt(I)- catalysed heterodyclotrimerization of theyne with nitriles to pyrides in water under mild conditions. - J.Chem.Soc. Chem. Comm. 1995
p179-180
Photo-assisted cocylization of acetylene and nitriles catalyzed by cobalt complexes at ambient temperature and normal pressure - Tetrahedorn letters
vol30,no.10,pp1229-1232, 1989
and the site that started this whole search
http://www.ifok.uni-rostock.de/e/Science/Projects/bhelle/ind...
and the site that lead me to that
http://www.sciencemadness.org/talk/index.php
I have been looking for this (potential) synth for a long time - just hope its realizable.
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Organikum
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eh, yes, overwhelming, hmn...
Glad for you that you found it!
You won´t mind I don´t look all this up and puzzle it together?
To be true I hope you will show us how these fragments belong together 
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Geomancer
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I was thinking today and came up with the following "synthesis":
1. React acetaldehyde with ammonia to get the imine.
2. Oxidize glycerol to 1,2 dihydroxypropanal. Easy to overdo it, but glycerol is cheap.
3. React products of 1 and 2. Result is a doubly unsaturated creature with a large swarm of tautomers.
4. Dehydrate the vulnerable secondary alcohol. The dienamine aldehyde tautomer will cyclize to an alcohol.
5. Dehydrate to form pyridine.
The whole thing is driven by the dehydration steps. I'm somewhat woried the stuff will condense to a pyran-like ring at the diol stage.
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guaguanco
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| Quote: | Originally posted by Geomancer
I was thinking today and came up with the following "synthesis":
1. React acetaldehyde with ammonia to get the imine.
2. Oxidize glycerol to 1,2 dihydroxypropanal. Easy to overdo it, but glycerol is cheap.
3. React products of 1 and 2. Result is a doubly unsaturated creature with a large swarm of tautomers.
4. Dehydrate the vulnerable secondary alcohol. The dienamine aldehyde tautomer will cyclize to an alcohol.
5. Dehydrate to form pyridine.
The whole thing is driven by the dehydration steps. I'm somewhat woried the stuff will condense to a pyran-like ring at the diol stage.
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This won't work. For instance, You will not get your desired product in 2), at least not in any pure or useable form. People have probably done
things like mix glycerol, ammonia, formaldehyde and sulfuric acid; might be worth a google search...
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Geomancer
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I, too, have my doubts, but obtaining glyceraldehyde isn't one of them. Trying to oxidize a whole pot of glycerol won't work, of course. You
have to accept a small conversion, and then find a way to do the separation, e. g. form the cellulose acetal (looks to be thermodynamicly favored) and
filter. Glyceraldehyde can also be obtained from an acrolein acetal with KMnO<sub>4</sub>. For a real pipe dream, try the EG acetal and
form yer acetaldehyde in situ from the cleaved EG.
The real problem involves the solvent and dehydrating reagent used. I can't think of an otc solvent that would work. Possibly ether. Sulfuric
acid can't be used to do the dehydration since it would protonate all the nitrogens.
Still, the idea is attractive. The industrial route is from coal tar. I like the above route because the precursors are simple, safe, and cheap.
Perhaps acetaldehyde+phosgene+ammonia?
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guaguanco
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| Quote: | Originally posted by Geomancer
I, too, have my doubts, but obtaining glyceraldehyde isn't one of them. Trying to oxidize a whole pot of glycerol won't work, of course. You
have to accept a small conversion, and then find a way to do the separation, e. g. form the cellulose acetal (looks to be thermodynamicly favored) and
filter. Glyceraldehyde can also be obtained from an acrolein acetal with KMnO<sub>4</sub>. For a real pipe dream, try the EG acetal and
form yer acetaldehyde in situ from the cleaved EG.
The real problem involves the solvent and dehydrating reagent used. I can't think of an otc solvent that would work. Possibly ether. Sulfuric
acid can't be used to do the dehydration since it would protonate all the nitrogens.
Still, the idea is attractive. The industrial route is from coal tar. I like the above route because the precursors are simple, safe, and cheap.
Perhaps acetaldehyde+phosgene+ammonia? |
I wish you luck. I think you'll need it...
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Geomancer
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Well, damn. The glyceraldehyde route seems to have many more problems than it's worth. The following should work, though.
1. addition of formyl chloride (I said phosgine by mistake) to acetaldehyde enolate (use hindered base, such as LDA)
2. quench with an ammonium salt
3. cook until it dehydrates.
Alas, LDA is not easily available, and formyl chloride is not exactly family friendly. There is a chance that simply putting together ammonium formate
and acetaldehyde under industrial conditions will yield the desired product. If so, that would be a useful method.
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CherrieBaby
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These are all taken from "Organic Chemistry", Bernthsen, Revised by Sudborough, 1941 edition, Blackie & Sons.
1. When pentamethylene-diamine hydrochloride is strongly heated it yields piperidine, and when this is oxidised with conc. H2SO4 at 300 degrees
pyridine is formed (Ladenburg):
NH2-CH2-CH2-CH2-CH2-CH2-NH2.HCl --> piperidine --> pyridine
2. A method very similar to this which may be employed at much lower temperatures is the elimination of HCl from 5-chloroamylamine,
(CH2Cl-(CH2)3-CH2-NH2. This elimination occurs when an aqueous solution of the base is heated on the water bath; ring formation takes place, and
piperidine HCl is formed. (which is then treated as above)
3. The conversion of Potassium-pyrrole into pyridine when heated with methylene chloride (or into pyridine chloride when heated with chloroform).
4. The conversion of quinoline into 2,3-pyridinedicarboxylic acid (or quinolinic acid) upon oxidation. Quinolinic acid is easily decarboxylated to
3-pyridine-carboxylic acid (Nicotinic Acid) upon heating. Nicotinic Acid will need to be strongly heated with a base (sodalime) to decarboxylate it to
pyridine.
Would anyone care to look up this ref. to discover how they go about decarboxylating nicotinic acid?
Journal of Radioanalytical and Nuclear Chemistry 230 (1-2): 71-74, 1998
Zielinski M; Zielinska A; Papiernik-Zielinska H; McKenzie JA; Bernasconi S; et al.
Carbon-13 and oxygen-18 isotope effects in the decarboxylation of nicotinic acid of natural isotopic composition.
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Phel
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Here's the requested journal CherrieBaby:
Attachment: journal.pdf (250kB)
This file has been downloaded 962 times
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wa gwan
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Heating glutaraldehyde (pentanedial) dioxime and strong mineral acid yields pyridine. I can't remember where that's from at the moment.
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CherrieBaby
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It says that in the Merck (12e), entry 4480 for glutaraldehyde. | Quote: | | Glutaraldehyde dioxime, C5H10N2O2, crystals from water or pyridine. mp 178, sublimes. Treatment with hot mineral acids gives pyridine.
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They didn't give a reference.
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