This post is more a reaction/addition to
Post 405635
(demorol: "Cheap aromatic iodination & bromination", Novel Discourse) In that thread, I mentioned I read something about the formation of quinones when e.g. benzene-1,3-dioxole would be reacted with LTA (lead tetraacetate). I found some of my old notes on the subject, since I had a dream once reacting LTA with benzene-1,3-dioxole to obtain new precursors. Allow me...
Taken from:
Comprehensive Heterocyclic Chemistry, Vol 6: Five membered rings with two or more O, S or N atoms Chapter: Dioxoles and oxathioles
p 766: fused benzene rings
In electrophilic substitution reactions of benzo-1,3-dioxoles, only para-derivatives with respect to the oxygen atoms are formed. This differs from benzo-1,4-benzodioxanes where some ortho-isomer is obtained as well, and probably reflects the coplanarity of the rings in benzodioxoles resulting in an increased mesomeric effect <81H(15)1395>. Benzo-1,3-oxathiole derivatives undergo electrophilic substitution at the 5-position, i.e. para to the oxygen atom <53JCS1514>, although attack at the sulfer atom may be a complicating factor. 2,2-disubstituted benzo-1,3-dioxoles are oxidized by lead tetraacetate (LTA) to 5-acetoxy and 5,6-dione derivatives, as shown in equation (11) <80AJC527>. If the 2-position is not blocked, oxidation occurs there preferentially. The quinones are probably formed via a tetraacetoxy intermediate in a manner analogous to the oxidation of naphtyl ethers <79AJC1749>. As expected, metallation with n-BuLi takes place ortho to the oxygen atom in both systems provided that the 2-position is blocked.
Equation 11:
C C C
/ \ / \ / \
C C---O LTA AcO---C C---O O==C C---O
| | \ ------> | | \ + | | \
| | / | | / | | /
C C---O C C---O O==C C---O
\ / \ / \ /
C C C
80AJC527: ER Cole, G Crank, HTH Minh. Aust J Chem 33 (1980) 527-
My idea was to exploit the reaction to obtain as much as possible of one of the two compounds presented. The 5-acetoxybenzodioxole could be used for 3,4-methylenedioxy-5-alkoxyamphetamines, while the 5,6-dione might be useful for 2,3-methylenedioxy-5,6-dialkoxyamphetamines or 2,3,5,6-dimethylenedioxyamphetamines:
C
/ \
O---C C---O
/ | | \
\ | | /
O---C C---O
\ /
C
|
CH2---CH---CH3
|
NH2
If there are any bees out there interested in this, and they'd happen to have access to the mentioned Aust J Chem article, it would be most kind of them to post the details in this thread. Any remarks welcome, off course.
EDIT: Post 185131 (missing)
(hest: "New Amph. more potent than LSD", Serious Chemistry) is an example why latter compound might be interesting...
