Dear bees, especially Antoncho:
I did not want to further stray from the topic of your post by changing the topic there to this question, so I have made a seperate thread to keep it intact.
The news of methylation of hydroquinone with benzoquinone, methanol, and sulfuric acid, to produce para-methoxyphenol, is wonderful indeed. I can see why it is so important to optimize the yield of the monomethyl ether, for the Reimer-Tiemann reaction. But I wonder about a seperate possibility: Is it known to be possible to dimethylate hydroquinone with the same procedure, with different conditions? Perhaps a higher benzoquinone/H2SO4/MeOH to hydroquinone ratio, by using less hydro per reaction, would result in higher yield of 2,5-dimethyoxybenzene?
Antoncho, I see in the posted reference that one of the reactions produced a 3% yield of the dimethylated product. It is possible I see, to produce dimethylated product afterall, but hopefully there are ways to drastically increase the yield of this product.
Is there more in the reference, anything related to this? Perhaps any references to negatives for the monomethylation reaction, such as, "Over addition of......results in the majority of yield being dimethylated product." or something similar?
The reaction mechanism stated does not seem to be so picky as to limit methylation to only one hydroxy. I do sincerely wonder about utilizing half the hydroquinone used in this reaction, with twice the reaction time, hopefully producing a majority of 2,5-dimethoxybenzene.
When you look at the dimethylated product as a benzene, it is not interesing, but when viewed as a phenyl hydride, you start thinking of alternative possibilities. Replace that hydrogen with a methyl group: toluhydroquinone --> 2,5-DiMeO-Toluene. Very cool.
Antoncho and others, what do you think?
PrimoPyro
The Water Will Be Your Only Mirror