nikotyna1939
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Mood: THINK 3R REDUCE REUSE RECYCLE
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carboxylation of skatole
can anyone show the ingredient to carboxylate skatole for making indole -3 carboxylic acid
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TheMasterOfTheInternet
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Potassium permanganate, sodium dichromate and several other oxidants will oxidise the -CH3 to -COOH with ease
Though indole is quite sensitive to oxidation too, so unless you invest a lot of experiments and optimisations, the yield would be rather low and the
workup might be hard too.
Only ref that someone did it with success I could find for this reaction is Chemische Berichte, vol. 21, page 1930 (German language) and Gazzetta
Chimica Italiana, vol. 18, page 387 (Italian)
I would search for the articles but Wiley Libary Server has problems at the moment
Better way would be Indole+CO2
[Edited on 14-3-2019 by TheMasterOfTheInternet]
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TheMasterOfTheInternet
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Here's the German original (directly from the stone-age  )
http://sci-hub.se/https://onlinelibrary.wiley.com/doi/10.100...
Rougly translated (if I did understand correctly, autotranslate has bigger problems than usual, as the old letters aren't recognized correctly), in a
silver bowl 5-10g skatol was fused/molten with 10times the amount of dried KOH while covered with a water-cooled glass to avoid evaporation of the
skatole. When a black oil is formed, the cover is removed and the oxidation is done by stirring it in the athomsphere (so oxidation itself is done by
air) until the color stays homogenous.
After cooling down, the whole mess is completly dissolved in water, filtered, acidified and the crude indole 3 carboxolic acid precipitates.
The acid is redissolved in hot water (maybe with another addition of lye?), filtered through active charcoal, precipitated (by acid?)/cristallised
again and lastly recristallised a last time from benzene to get a pure product
I guess the "silver bowl" can be subsituted with a good stainless steel bowl, as I don't think silver has catalytic influence. Stainless steel wasn't
inventend/readily available at that time if I remember correctly, so that's the reason they took a silver bow I guess (inert to KOH and strong heat)
[Edited on 14-3-2019 by TheMasterOfTheInternet]
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Texium
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Thread Moved
13-3-2024 at 05:26 |
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