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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: plain on November 29, 2006, 06:24:03 AM

Title: how to synthesize 4-bromoresorcinol using resorcin?
Post by: plain on November 29, 2006, 06:24:03 AM

 I know how to make 4-bromoresorcinol using 2,4-dihydroxybenzoic acid, but now want to make it using resorcin, please help me.

Title: Re: how to synthesize 4-bromoresorcinol using resorcin?
Post by: Custos on November 29, 2006, 07:33:28 PM

The direct bromination of resorcinol can be carried out using bromine in methanol (for example) but you will end up with a mixture of monobromoresorcinol (both 2 and 4) and di-bromoresorcinols... all difficult to separate. The Organic Synthesis prep of 4-bromoresorcinol (http://www.orgsyn.org/orgsyn/prep.asp?prep=cv2p0100)  goes through the benzoic acid. Or of course you could just buy 4-bromoresourcinol from Aldrich.

Title: Re: how to synthesize 4-bromoresorcinol using resorcin?
Post by: tbuihuu on November 29, 2006, 07:56:46 PM

 resorcinol reacts with Br₂/Fe --->4-bromresorciol (major)

Title: Re: how to synthesize 4-bromoresorcinol using resorcin?
Post by: maurice on November 29, 2006, 09:21:44 PM

NBS or Br2/H2O2

Title: Re: how to synthesize 4-bromoresorcinol using resorcin?
Post by: plain on November 30, 2006, 03:12:12 AM

I want to synthesize 1 kg 4-bromoresorcinol and what mean is the best choise for me to do it. Of course, the cost is as lower as possible and the process is simple. Thanks.

Title: Re: how to synthesize 4-bromoresorcinol using resorcin?
Post by: Custos on November 30, 2006, 06:57:42 PM

For large scale work I would stick to the Organic Synthesis prep. They are usually very robust as they have been tested, usually at reasonable scale. Make the dihydroxybenzoic acid from resorcinol using this prep: http://www.orgsyn.org/orgsyn/prep.asp?prep=cv2p0557 then brominate and decarboxylate using this prep: http://www.orgsyn.org/orgsyn/prep.asp?prep=cv2p0100

I seriously think that if you try a direct bromination you will end up with a mess of positional isomers and overbrominated products that will be difficult to purify.