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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: msam1981 on May 23, 2013, 09:27:29 AM

Title: nitration of anthrone mechanism
Post by: msam1981 on May 23, 2013, 09:27:29 AM
In my project, Anthrone was nitrated to 2,7-nitro-9,10-anthraquinone. but I only figure out half of the mechanism.

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The procedure is

Anthrone (20 g, 104 mmol) was added slowly with stirring to fuming nitric acid
(160 mL) at 5 - 0 °C. Subsequently, 400 ml of acetic acid was added slowly to the
reaction mixture with cooling. The resulting solution was allowed to stand at room
temperature for 1 week. At the end of the period, the yellow precipitate was
collected by filtration, washed with acetic acid (100 ml) and hexane (100 ml), and
dried under vacuum. The crude product was recrystallized twice from acetic acid
then recrystalised from nitrobenzene/ acetic acid (1:1 v/v) to obtain the target
product as yellow crystals.


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But I do not know how the oxidation mechanism occur.

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I though It might be like this,


Many thanks in advance


Title: Re: nitration of anthrone mechanism
Post by: camptzak on May 23, 2013, 11:23:36 AM
was the reaction mixture exposed to O2?
Title: Re: nitration of anthrone mechanism
Post by: msam1981 on May 23, 2013, 12:53:36 PM

Yes, It was
Title: Re: nitration of anthrone mechanism
Post by: camptzak on May 23, 2013, 01:27:33 PM
so do you think that the one of the protons is donated to H2O and the resulting carbanion attacks molecular oxygen?
Title: Re: nitration of anthrone mechanism
Post by: orgopete on May 23, 2013, 02:47:59 PM
Although I cannot write THE mechanism by which nitric acid acts as an oxidant, but that is a reaction it can do. Some examples are benzoin to benzil and cyclohexanone to adipic acid. In this case, you could also write a mechanism through an acinitro form of anthrone followed by hydrolysis.
Title: Re: nitration of anthrone mechanism
Post by: msam1981 on May 23, 2013, 06:04:26 PM
I think we should have carbocation in the 9-position (I do not know how), then as shown below

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Title: Re: nitration of anthrone mechanism
Post by: camptzak on May 23, 2013, 10:36:00 PM
http://www.asso-etud.unige.ch/aecb/rapports/2eme/chiorg/p39oxbenzoine_pacho.pdf
Title: Re: nitration of anthrone mechanism
Post by: msam1981 on May 24, 2013, 05:29:45 AM


Thank you for your help,

How can we have -OH on the 9- position.