Templar - 17-8-2014 at 15:43
Hello everyone
I have stumbled across a synthesis for isatoic anhydride from phthalimide. It has been referenced in two pieces of seperate literature. But I am
unsure of the mechanism, it sounds a bit far fetched when you factor in the reported yields.
https://docs.google.com/viewer?url=patentimages.storage.goog...
http://www.tandfonline.com/doi/abs/10.1080/00304948209354906... (not to be prejudiced but theres a lot of shit papers that come out of india and
china imo...)
http://www.google.de/patents/US4419519
" Since the off-gas is advantageously trapped in aqueous alkali, eg. in sodium hydroxide or potassium hydroxide solution of from 5 to 20 percent
strength by weight, in which phthalimide dissolves, the resulting solutions can, for example, be employed directly as starting materials for the
synthesis of anthranilic acid and isatoic anhydride by reaction of an alkali metal phthalimidate with an alkali metal hypochlorite. On the other hand,
even a small proportion of phthalic anhydride present would also dissolve in alkali and would cause the subsequent synthesis to result in impure and
products, necessitating expensive and involved purification operations entailing losses of end products."
If you look on page 3/56 of the pdf attached, you will see reference to a similar hofmann type reaction but using bromine instead of chlorine.
I suppose the number of refs must mean there is a higher chance of this working, but I am still rather confused as to where the extra carbonyl group
appears from to make the larger molecule isatoic anhydride.
Which brings up the second question.
For the acetyl acetone synthesis,
Claisen Condensation of acetone with ethyl acetate in presence of NaOCH3 yields Acetylacetone.
http://bitnest.ca/Rhodium/pdf/acetylacetone.synthesis.pdf
http://www.orgsyn.org/demo.aspx?prep=cv3p0016
Potassium can be made by mixing KOH and Mg powder in refluxing mineral oil using a tert butanol catalyst. http://[youtube]JAo2F9ymKXA[/youtube]
The question is, could potassium methoxide replace sodium methoxide? I dont think there's any huge difference in reactivity?
If any alkali methoxide could be used for the claisen condensation, then it would actually be much easier to just use lithium from batteries which are
otc! I am unsure however how much of a spectator ion the alkali ion will be on an alkali methoxide.
https://the-collective.ws/forum/index.php?topic=23888.msg169...
Maybe more experienced members can have a quick look if they're interested
Attachment: 019.pdf (1.5MB)
This file has been downloaded 541 times
UnintentionalChaos - 17-8-2014 at 16:58
Why did you make a single thread for 2 completely different preps?
I don't see any reason that the isatoic anhydride preps wouldn't work. The reaction of phthalic acid monoamide (or phthalimide) with hypohalite is a
very classic hoffman rearrangement reaction. There are numerous preps of anthranilic acid from phthalimide. These all involve strong heating, which
presumably hydrolyzes the isatoic anhydride to give the desired product. The preps you give, at a glance, do not heat as strongly.
The intermediate in the Hoffman is an isocyanate. In the case of anthranilic acid, it is 2-isocyanatobenzoic acid. In the high pH environment, the
benzoic acid would be deprotonated. The carboxylate oxygen, acting as a nucleophile would readily do an intramolecular nucleophlilic attack on the
isocyanate's carbon to give isatoic anhydride.
EDIT: With regards to "Potassium can be made by mixing KOH and Mg powder in refluxing mineral oil using a tert butanol catalyst.
http://[youtube]JAo2F9ymKXA[/youtube]"
We did it first. And before we did it, Versuchschemie did it. Our thread is stickied at the top of chemistry in general.
[Edited on 8-18-14 by UnintentionalChaos]
Templar - 17-8-2014 at 17:34
I did not think this would be against the rules.
Very good explanation there, thank you.
Would the choice of alkali ion on the methoxide group make a difference? That condensation of ethyl acetate and acetone calls for it. Li methoxide
would be far more convenient, or even k methoxide.
Im not sure if anyone cracked that reaction for Na
Scr0t - 18-8-2014 at 13:32
You could try making the ethoxide since it can be made from NaOH and EtOH and the formed NaOEt can be precipitated by addition of acetone also mentioned here.
Or you can form the methoxide/ethoxide by dehydrating with 3A molecular sieves also mentioned in the above links.
Templar - 19-8-2014 at 05:16
Ah.. and doesnt require a lot of Na metal...
I thought this method was only viable for moderate concentrations of ethoxide, I stand corrected. Cheers
Templar - 8-9-2014 at 06:27
isatoic anhydride synthesis.
http://www.sciencemadness.org/talk/viewthread.php?tid=33344