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Author Topic: Reaction Mechanism/Idealogy?  (Read 404 times)

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Messi

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Reaction Mechanism/Idealogy?
« on: December 04, 2012, 02:36:53 PM »

Hey guys, I have the reaction shown below.

For step d), I was wondering what type of reaction that was, so I can look up the reaction mechanism.

Also, for step e), the percent yield was only 10%. I was wondering why this was the case? Why only 10%? What happened? What are the competing reactions perhaps?

Thanks!

Edit: Also, what do the square brackets mean?
« Last Edit: December 04, 2012, 02:51:08 PM by Messi »
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Messi

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Re: Reaction Mechanism/Idealogy?
« Reply #1 on: December 04, 2012, 03:39:06 PM »

Step d) is a nucleophilic aromatic substitution. I don't know what I was thinking!

For step e), the percent yield was only 10%. I was wondering why this was the case? Why only 10%? What happened? What are the competing reactions perhaps?

Thanks!

Edit: Also, what do the square brackets mean?
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discodermolide

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Re: Reaction Mechanism/Idealogy?
« Reply #2 on: December 04, 2012, 06:34:39 PM »

Something went wrong in the hydrogenation step.
Are there any intermediates in the reduction of a nitro group by hydrogen which can react with amines?
A compound in square brackets usually means that it is not isolated but taken through to the next step.
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Dan

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Re: Reaction Mechanism/Idealogy?
« Reply #3 on: December 04, 2012, 08:54:47 PM »

I think the 10% refers to the Pd loading on the charcoal (i.e. the Pd/C is 1:9 Pd:C).

The square brackets are usually used to indicate the product was not isolated but reacted further without purification (hence no yield reported). I think the scheme originally had a step f) that is missing, and the yield obtained over the two (or more) steps before purification would have been reported. The reagents list also ends in a semicolon, which hints that this is not the full sequence and that the rest of it has been edited out.
« Last Edit: December 05, 2012, 12:28:12 AM by Dan »
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Messi

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Re: Reaction Mechanism/Idealogy?
« Reply #4 on: December 05, 2012, 04:35:52 PM »

Oops, just told my professor that a possibly intermediate of the above reaction was a nitrosbenzene-like group (N=O) and that reacted with the amine group adjacent to it.

I told her that was possibly the reason why the yield was only 10% :)
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