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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: quantumnumber on July 25, 2014, 11:15:27 AM

Title: Doubt about electrophilic aromatic substitution
Post by: quantumnumber on July 25, 2014, 11:15:27 AM

Hi guys,
I have a doubt about the synthesis of 2-bromo-4-methylphenol. In the 4º step showed in the image attached, I transform the phenol in an ether so that the aromatic ring is less reactive. I did this because I thought that otherwise bromine would be substituted in the two ortho positions in relation with the -OH.

Is this step correct? Is the synthesis allright?

Thanks a lot!

Title: Re: Doubt about electrophilic aromatic substitution
Post by: zsinger on July 25, 2014, 01:38:00 PM

Other than that Bromination step, I think everything looks kosher.  It may very well be correct….im just not sure.
             -Zack

Title: Re: Doubt about electrophilic aromatic substitution
Post by: quantumnumber on July 25, 2014, 02:18:12 PM

I checked it in a book and I saw a similar route, but they transform the amino group first into an amide (in order to make the ring less reactive too), then they do the bromination step, and finally they recover the amino group and make the phenol in the last step.

Title: Re: Doubt about electrophilic aromatic substitution
Post by: phth on July 25, 2014, 03:45:52 PM

What the other people said about the bromination, and with the right molar equivalents the desired result will be obtained.  If you are actually doing the synthesis, the acyl chloride in step 4 should be substituted with acetic anhydride because its easier to handle.

Title: Re: Doubt about electrophilic aromatic substitution
Post by: quantumnumber on July 25, 2014, 04:00:36 PM

Thanks a lot!