mfilip62
pierced by a crossbow under a bridge while eating Billy goats
Posts: 140
Registered: 25-8-2006
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Mood: I like turtles!
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Foundamental reactions of Organic Chemistry applien on poliols and Phenylallys?
I was supprised to have such a hard time finding ANY usable infor or scientific papers/publications
on most basic reactions like Halogenation and Hydrohalogenation of alcohols and
Alkenes applied practically on poliols like ethandiol and ethylene glycol and (poly)PhenylAllyls!
For example,if one has allylbenzen,diphenylmethylallyl or safrole or something like that,is there some PUBLISHED
or widely known method how to make the proper isomeres of Halosafrole or it's Phenyl analog following Markonikovs rule applied everyday on things like
Propen!?
(Those are just most known example,but I really need it for something much more exotic than phenylethylamine/phenylpropylamine precursors.)
In short,is there some more easy and home frindly method with acceptable yields that
DOES NOT include incredibly hard to find/make dry HBr/HI in GAA or AA!?
I mean,on the first class of organic chemistry you are being thold that such reaction
(Halogenation and Hydrohalogenation of Propene) can be easily achieved trough the Markonikov rule and halogention of prim./sec./tert. Alcohols by
simply using varios simple techniques and catalysts,like bubbling HX or in situ production of same from KBr/H2SO4 or Lucas reagent.
(most common example being HBr) and keep it away from radical promoters (such as light,radiation,heat or peroxides,maybe even by adding some readily
available antioxidants)
But I can't find ANY publication of someone actually doing it without use of allreadymentioned and highly regulated chemicals like CONCETRATED DRY HI
or HBr in GAA or some other fringe method that results in incredibly lame/low yields and side reaction like Aromatic halogenation.
(Example being AlI3)
Speaking of polyols,specialy 1,2-ethylene glycol and 1,2-propylene glycol
logic suggest that once could use something as simple as Lucas reagent (ZnCl2+HCl)
to selectively halogenate secondary -OH firts or some other method to halogenate primary -OH first if one is about to make for example
1-dimethylamino-2-chloropropane or 1-chloro-2-dimethylamino-propane which are notoriously hard to obtain today.
Yes,one could make some by using Halogenated acetone or Hydroxyacetone.
But both of those chemicals are tricky to say at least (lachrymatory or too unstable) for hobby chemistry,not to mention the requirement of even
harder to get things/processes like PX3/PX5/SOCl2/RP+I and ketone protection/deprotection or metal promoted reductions.
Same goes for synthesis of 2-Halo-N,N-dimethylethylamine and
2-Halo-N,N-diethylethylamine hydrochloride and similar substances!
I was thinking about more available chemicals and friendlier processes
to make these substances by using things like
1,2-ethandiol Halogenation,ethanol,Bromethane,dimethylamine,Lucas reagent(ZnX2,HX(aq)),in situ
HBr formation for halogenation,etc...
Will it work or is it applicable only on the symple alcohols and not polyols?!
So,does anyone has any scientific publications,papers or work-ups regarding the more
OTC friendly chemistry of above mentioned (class of) chemicals!?
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JJay
International Hazard
Posts: 3440
Registered: 15-10-2015
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I remember discussing hydrohalogenation of alkenes in organic 1 but don't remember doing any actual labs on it. A lot of the classic examples of
hydrohalogenation involve sealed tubes and high pressure, but I think that's mainly because the reactants are volatile.
This is not exactly a phenylallyl, but it's close: http://www.orgsyn.org/demo.aspx?prep=cv2p0336 I would think it would be even easier to hydrohalogenate with hydrobromic or hydriotic acid.
I've seen lots of examples of halogenation of alcohols... there was a recent discussion of Lucas reagent... concentrated hydrobromic acid or hydriotic
acid will halogenate most alcohols in a reasonable amount of time, with primary alcohols being halogenated slowest and tertiary alcohols being
halogenated fastest. I'm not sure how diols halogenate offhand but I am guessing that diols halogenate more slowly than similar molecular weight
primary alcohols by a factor exceeding sqrt(2) even with a large excess of hydrohalic acid.
[Edited on 14-12-2017 by JJay]
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mfilip62
pierced by a crossbow under a bridge while eating Billy goats
Posts: 140
Registered: 25-8-2006
Member Is Offline
Mood: I like turtles!
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Thanks,this is actually very interesting link but still not what I asked.
I know that diols react differently than would primary or secondary -OH group on alcohol alone.
I am just curious is there any real research data on that!?
And as far as phenylallyls go,one of my friends apparently had much faster reaction
and yields using GAA/H2SO4/KBr+PhenylAllyl but I never confirmed how succeseful this
reaction was but it show exact same color change as anhydrous DMSO/NaBr/H2SO4+Phenylallyl
reaction reported by the Rhodium and some (meth)amphetamine cooks,which are not
most reliable persons. What I know for sure is that Sulphate or Hydrosulphate ion from H2SO4
forms bond with phenylallyls same way as HX,following ONLY Markonikov addition.
Good thing that this is exscelent leaving group that can be replaced even with pseudohalogens
so I imagine that this actually might be a great way of doing this reaction.
It's pitty I don't a have the way to test this properly.
Anyone willing and being able to do the mentioned reaction is welcom to PM me or send me the e-mail.
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