jon - 24-1-2009 at 21:38
someone on this board at one time was complaining about the difficulty in obtaining p-cumene despite it's widespread indurtial use.
it's apparently not avail in small quantities.
what about electroaromatic substitution with isopropanol catalyzed by sufuric acid?
genreating the sec carbocation which further reacts with the aromatic pi system undergoing substution and releasing water?
it's textbook chemistry.
my intended use for it was to monohalogenate it and e1 eliminate hx with a strong base to give alpha-methylstyrene
since this even though widely produced is'nt really available in small quantities.
any input?
chemrox maybe?
[Edited on 25-1-2009 by jon]
UnintentionalChaos - 24-1-2009 at 23:03
p-cumene? There's only one substitution on cumene and that's an isopropyl group. There is nothing to be para to it.
Textbook chemistry is rarely pretty and tends to be messy or poor yielding in reality. You'll get polyalkylation even if it does work, and I suspect
that the water will be quite a problem, as might sulfonation of your product and of benzene. Escape of propene from the reaction would be another
concern.
There's a nice thread on making iPrBr from iPrOH, a bromide, and conc. H2SO4. Some of that in a large excess of benzene with anhydrous AlCl3 should do
the trick. Or you could always use a wittig reaction on benzophenone and go straight to your product without any halogenating involved.
Of course, if this is for drugs, you'll notice that you are a carbon short for amphetamine. so sorry. not.
[Edited on 1-25-09 by UnintentionalChaos]
panziandi - 27-1-2009 at 04:31
Benzophenone? wouldn't you have an amazing 2nd benzene ring stuck on the side of your cumene? :p
Perhaps a wittig on acetophenone could be more yielding towards cumene?
sparkgap - 27-1-2009 at 06:12
Maybe he confused cumene with cymene (isopropylmethylbenzene, which does have three isomers)...
But frankly a Wittig+hydrogenation is much ado about nothing for a relatively cheap petrochemical.
sparky (~_~)