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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Rutherford on March 04, 2013, 10:52:48 AM

Title: Chemistry of phenols
Post by: Rutherford on March 04, 2013, 10:52:48 AM
This is the 18th problem here: http://icho2013.chem.msu.ru/materials/Preparatory_problems_IChO_2013.pdf

I need to finish this scheme:
(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fimg19.imageshack.us%2Fimg19%2F7541%2F97580224.gif&hash=83c84d2fbff1459bbd267217160e639da75023aa)
knowing that A is benzene and B is propene. I got that C is isopropylbenzene, but I can't figure out what is D, if it produces bisphenol A with phenol. What is D and what is the reaction with phenol?
Title: Re: Chemistry of phenols
Post by: discodermolide on March 04, 2013, 11:24:46 AM
How about acetone for compound D?
http://en.wikipedia.org/wiki/Bisphenol_A (http://en.wikipedia.org/wiki/Bisphenol_A)
Title: Re: Chemistry of phenols
Post by: Rutherford on March 04, 2013, 12:10:05 PM
Then the process of oxidation is strange because the oxidizer could cleavage the C-C bond, but it couldn't oxidize phenol to the aldehyde or acid.
Title: Re: Chemistry of phenols
Post by: discodermolide on March 04, 2013, 12:21:42 PM
Look here
http://en.wikipedia.org/wiki/Acetone (http://en.wikipedia.org/wiki/Acetone)
see if you can find any other links for example http://en.wikipedia.org/wiki/Cumene_process (http://en.wikipedia.org/wiki/Cumene_process)
Title: Re: Chemistry of phenols
Post by: Rutherford on March 05, 2013, 09:43:01 AM
Thanks for the useful link. I went now down to G and H.

Phenol reacts with nitric acid.
The molecule of G has two planes of symmetry (that of the molecule and an orthogonal one), while the plane of the molecule is the only element of symmetry for H. Starting with G, one can obtain paracetamol J via a two-stage process.

G should be the ortho isomer, while H should be the para isomer. Paracetamol has para -substituted groups, but G has ortho ones. Is this a mistake? The paracetamol should be obtained from H instead?

By reduction an amine is produced. Why will the amine group react with the anhydride, but not the hydroxy group?


Title: Re: Chemistry of phenols
Post by: discodermolide on March 05, 2013, 10:03:50 AM
Paracetamol is
OC1=CC=C(NC(C)=O)C=C1

The amine is more nucleophillic that the OH therefore will react with the anhydride.

What exactly have you got for the structures of G & H?
Title: Re: Chemistry of phenols
Post by: DrCMS on March 05, 2013, 10:18:58 AM
Quote from: Raderford on March 05, 2013, 09:43:01 AM
The molecule of G has two planes of symmetry (that of the molecule and an orthogonal one), while the plane of the molecule is the only element of symmetry for H. Starting with G, one can obtain paracetamol J via a two-stage process.

G should be the ortho isomer, while H should be the para isomer. Paracetamol has para -substituted groups, but G has ortho ones. Is this a mistake? The paracetamol should be obtained from H instead?

Why do you think the otho isomer has 2 planes of symetry but the para only has one?  I think you'll find the exact opposite is true.
Title: Re: Chemistry of phenols
Post by: Rutherford on March 05, 2013, 10:34:05 AM
Yes I mixed those two  ::).  G is the paranitrophenol and H is orthonitrophenol.

Quote from: discodermolide on March 05, 2013, 10:03:50 AM
Paracetamol is
OC1=CC=C(NC(C)=O)C=C1

The amine is more nucleophillic that the OH therefore will react with the anhydride.

What exactly have you got for the structures of G & H?

Why? Why won't both react?
Title: Re: Chemistry of phenols
Post by: discodermolide on March 05, 2013, 10:46:47 AM
The phenol will react when the acetic anhydride is in excess, but as they don't specify reaction conditions I don't know how much they used and/or how they removed the O-acyl group.
Title: Re: Chemistry of phenols
Post by: Rutherford on March 05, 2013, 12:02:20 PM
Okay.

L is a precursor of a dye Aluminon used for quantitative determination of aluminum and some other metals. Reaction of two equivalents of L with formaldehyde under acidic conditions affords N. Addition of one more equivalent of L to N in the presence of NaNO2 and sulfuric acid yields O , which finally gives Aluminon upon treatment with ammonia.

What is N and the reaction producing it?
I got that L is salicylic acid.
Title: Re: Chemistry of phenols
Post by: discodermolide on March 05, 2013, 12:11:38 PM
What is your structure for K?
Title: Re: Chemistry of phenols
Post by: Rutherford on March 05, 2013, 01:03:54 PM
It's the salt of salicylic acid where the Na replaces both the hydrogen from the carboxylic and hydrogen from the hydroxylic group, as it is said:
Two equivalents of an acid are required for acidification of
K to form compound L.
Title: Re: Chemistry of phenols
Post by: discodermolide on March 05, 2013, 01:17:39 PM
Compound N could be
OC1=CC=C(C([H])=O)C=C1C(O)=O
Title: Re: Chemistry of phenols
Post by: Rutherford on March 05, 2013, 01:27:42 PM
Quote from: Raderford on March 05, 2013, 12:02:20 PM
Okay.

L is a precursor of a dye Aluminon used for quantitative determination of aluminum and some other metals. Reaction of two equivalents of L with formaldehyde under acidic conditions affords N. Addition of one more equivalent of L to N in the presence of NaNO2 and sulfuric acid yields O , which finally gives Aluminon upon treatment with ammonia.

What is N and the reaction producing it?
I got that L is salicylic acid.
Two equivalents of L reacted.
Title: Re: Chemistry of phenols
Post by: discodermolide on March 05, 2013, 01:33:57 PM
With 2 x L it may give
OC1=CC=C(C(C2=CC(C(O)=O)=C(O)C=C2)=O)C=C1C(O)=O

what is your suggestion for L?
Title: Re: Chemistry of phenols
Post by: Rutherford on March 05, 2013, 01:46:31 PM
How would that reaction happen?
I wrote that I got that L is salicylic acid.
Title: Re: Chemistry of phenols
Post by: discodermolide on March 05, 2013, 01:48:39 PM
Quote from: Raderford on March 05, 2013, 01:46:31 PM
How would that reaction happen?
I wrote that I got that L is salicylic acid.


Sorry I meant N
Title: Re: Chemistry of phenols
Post by: Rutherford on March 05, 2013, 01:52:40 PM
I don't understand the previous reaction and I don't have a clue about the following one, but when going backwards I could say that N is similar to Aluminon, only all NH4- groups are replaced with hydrogens.
Title: Re: Chemistry of phenols
Post by: discodermolide on March 05, 2013, 02:00:06 PM
All that replacement is is forming the ammonium salts.
Have a look here.
http://en.wikipedia.org/wiki/Aurintricarboxylic_acid (http://en.wikipedia.org/wiki/Aurintricarboxylic_acid)

The reaction of 2 x L with formaldehyde and sulphuric acid to give N is surely a Friedel-Crafts acylation?
Title: Re: Chemistry of phenols
Post by: Rutherford on March 05, 2013, 02:41:19 PM
What reaction produces the electrophile?