PolytheneSam (Master Searcher)
02-25-02 02:36
No 273091
      Electro hydroquinone method  Bookmark   

While at the chemistry library today I happened to look through a book on electrochemistry and noticed in the section on electro-oxidation that benzene can be oxidized to hydroquinone or benzoquinone electrochemically.  An idea popped into my mind.  What if someone had some phenylacetic acid sitting around?  Could it be oxidized to 2,5-dihydroxyphenylacetic acid without oxidizing the side chain? This could then be converted into 2,5-dimethoxyphenylacetic acid by various means, ie. make the trisodium salt of 2,5-dihydroxyphenylacetic, add CH3MSO4 and steam distill (the methyl ester would probably distill over).  Someone experienced in the use of PAA might be interested in this idea.  As usual the USPTO was a good place to look for insight into this.  I found these two patents.

Patent US4046652 p-benzoquinone diketals, note examples 1 and 2 where they oxidize benzene to benzoquinone and then reduce it to hydroquinone with HI.  In examples 6 and 16 the methyl group on the benzene ring isn't oxidized.  It seems that methylhydroquinone could be made from toluene by this method.  What could you make with eugenol?  The allyl side chain might be converted to the diol form in the process.  After a couple steps you could make  2,4,5-trimethoxyP2P.....

Patent US5098531 2-arylhydroquinones, note in column 2 where they reduce the benzoquinone intermediate at the cathode.

(Master Searcher)
03-09-02 21:15
No 279659
      Re: Electro hydroquinone method  Bookmark   

I had this patent number in my notes, but forgot about it.  There's some more like it in class 205 subclass 447.

Patent US1322580