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Topic: Help with Some Organic Reactions  (Read 6473 times)

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Offline vivekrai

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Help with Some Organic Reactions
« on: February 18, 2012, 01:27:23 AM »


What may be the problem with me : May not be able to guess the significance of the reagent , never came across such reaction ( or named reaction) , or the things are actually not so obvious.
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Offline vivekrai

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Re: Help with Some Organic Reactions
« Reply #1 on: February 20, 2012, 06:58:10 AM »
Please Help.
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Offline discodermolide

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Re: Help with Some Organic Reactions
« Reply #2 on: February 20, 2012, 08:54:57 AM »


What may be the problem with me : May not be able to guess the significance of the reagent , never came across such reaction ( or named reaction) , or the things are actually not so obvious.

As far as I can tell:
reaction 1 the V2O5 will epoxidise the central double bond of the aromatic system, the epoxide will then be opened by NH3 and Br-
Reaction 2, nothing will happen?
Reaction 3: you will displace 2 adjacent F atoms to form a 6 membered ring or even two 6 membered rings!.

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Offline vivekrai

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Re: Help with Some Organic Reactions
« Reply #3 on: February 20, 2012, 11:32:39 AM »


Answers are not matching sir (for 1 and 2) . I check for the third one. What do I do now?
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Offline sjb

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Re: Help with Some Organic Reactions
« Reply #4 on: February 20, 2012, 12:01:44 PM »


Answers are not matching sir (for 1 and 2) . I check for the third one. What do I do now?

Doesn't look like this is the product from attack on the internal double bond, where are the remains of the other ring? Not sure if you get a diketone out of this or something? Is there a reason the top carbon is clearly identified as such...?

2) deprotonation, followed by ether formation (seems a bit odd?)

3) Not sure there is a reaction though?

Offline discodermolide

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Re: Help with Some Organic Reactions
« Reply #5 on: February 20, 2012, 01:15:01 PM »


Answers are not matching sir (for 1 and 2) . I check for the third one. What do I do now?

So you know the answers then?
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Offline Arctic-Nation

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Re: Help with Some Organic Reactions
« Reply #6 on: February 20, 2012, 06:06:10 PM »
I think that napthalene is first oxidized to phthalic anhydride (even though the procedure omits the oxygen gas needed in that case...), which is followed by conversion into 2-carbamoylbenzoic acid (the structure shown above). This is then reacted with KOBr to give a Hofmann rearrangement, resulting in the formation of 2-aminobenzoic acid.

Why anyone would write down KOBr instead of the commonly cited Br2/NaOH procedure is beyond me, though, as it seems to be an unusual homebrew variation.

No idea about the resorcinol reaction. I've found references to the synthesis of 2,6-dihydroxybenzoic acid, but the procedure quoted here would be woefully inadequate for that.

Offline Honclbrif

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Re: Help with Some Organic Reactions
« Reply #7 on: February 20, 2012, 07:51:14 PM »
For 2, if you evolve CO2 by boiling the carbonate you're all set up to do a famous name reaction.
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Offline vivekrai

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Re: Help with Some Organic Reactions
« Reply #8 on: February 21, 2012, 01:33:14 AM »
For 2, if you evolve CO2 by boiling the carbonate you're all set up to do a famous name reaction.

Got it sir, Kolbe–Schmitt reaction looks quite reasonable to me. So I get the answer for that. Thanks!
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Offline orgopete

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Re: Help with Some Organic Reactions
« Reply #9 on: February 23, 2012, 10:15:51 AM »
In light of comments here (http://www.chemicalforums.com/index.php?topic=56348.0), let me correct 1.

I didn't know that V2O5 was a method to convert naphthalene to phthalic acid. It will not result in the anhydride. Treating an anhydride with ammonia would give an ammonium salt of an amido carboxylic acid. That isn't what is being done here. Heating the diammonium salt of phthalic acid will convert it to phthalimide. (Wikipedia says fusing phthalic acid with ammonium carbonate as a method, http://en.wikipedia.org/wiki/Phthalimide.) Treatment of phthalimide with Br2/NaOH will effect a Hoffmann rearrangement (http://en.wikipedia.org/wiki/Hofmann_rearrangement). The product will be anthranilic acid
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