snickers572us - 18-2-2004 at 07:13
DOES ANYONE HAVE A VIABLE SYNTHETIC ROUTE FOR THE FOLLOWING
BENZENE--------------->CH3(CH2)6--BENZENE RING---CO2H
PLZZ EMAIL ME AT javon_e@hotmail.com
AngelEyes - 18-2-2004 at 08:36
Might it be possible to have a section of blurb sent to new members outlining proper procedure?
Like...
1. Always search before posting.
2. Don't type all in Capitals as it makes it look like you just don't care
3. Make every effort to spell and use grammar correctly. Not everyone's first language is English, granted, but using 'plzz' instead of
please (and such like) makes you come across as 'kewl'...and we don't like that
4. Get some chemical knowledge before you start. Don't expect us to spoonfeed you.
5. If you're going to write an equation please try to write it so we can see what you're on about. Unbalanced and without state symbols we
can live with, but what does the equation you typed out mean? CO<sub>2</sub>H - what the hell is that?
What are you trying to make from benzene? Or are you trying to synthesise something from CH<sub>3</sub>(CH<sub>2</sub>
<sub>6</sub> - what compound is that, exactly?
guaguanco - 18-2-2004 at 09:03
It looks like a typical O-Chem homework problem.
thunderfvck - 18-2-2004 at 09:04
Is that carbonyl group para to the heptyl group?
If it is I'm not sure how you would do this. The carbonyl group is a meta director. And if you start with adding the heptyl group (via friedel
crafts acylation), then direct a methyl group (friedel again, maybe alkylation this time, who knows) and THEN oxidize with KMnO4, you'll oxidize
both portions and end up with two carbonyl groups para to each other. And if you started with benzoic acid (as you specifically stated against),
we've got another meta director. Assuming it's supposed to be para anyway. Anyways, I'm sure there's other people who can answer
this better than I can. I'm just an organic II student, dammit!
Synthesis = Infinite possibilities.
Turel - 18-2-2004 at 10:54
AngelEyes: 1-4 are completely valid, 100%. But in my opinion, your fifth and final point is invalid and unjust. CO2H is a valid scripture for the
carboxyl group, often found in chemistry books and patents.
CH3(CH2)6- is a heptyl function. As for the stereoisomer, I also wish he would have specified, but it is not crucial. Just supply routes for all three
possibilities.
The three possible configurations for this compound are ortho, meta,and para, resulting in 2- or 3- or 4-heptylbenzoic acid.
The ortho and para can be achieved together, by simple FC alkylation with bromoheptane and benzene, to yield phenylheptane. Phenylheptane is
brominated with either a potassium or sodium salt, depending on the desired para or ortho stereoisomer excess. The intermediate ortho/para
bromophenylheptane is purified and used in a Grignard reaction with CO2 to produce the product acid after hydrolysis.
For the meta stereoisomer, FC acylate benzene with heptanoic chloride, or heptanoic acid and polyphosphoric acid, to produce heptiophenone, a meta
directing group. Brominate this compound to achieve heptiophen(3-bromo)one and then reduce the carbonyl function to a heptyl group. Then Grignard to
the acid.
Alternatively, one could try to acylate bromobenzene with heptanoic FC compound to achieve the same intermediate, followed by reducing the carbonyl,
and Grignard to the acid.
If these routes don't work for you, say so and we can cover others as well.
-T
[Edited on 18-2-2004 by Turel]
Actually
Turel - 18-2-2004 at 11:10
A little hasty, and I missed some things.
1.If acylating, it should be done to halobenzene, as halogenating a phenone could halogenate the alpha carbon on the chain.
2.If going by the method of #1, why bother acylating? FC alkylate bromobenzene instead of acylate for the same effect to save a step. Stupid things
happen when one is too presumptuous...
THANKS TUREL
snickers572us - 18-2-2004 at 11:18
thanks so much for setting mr angel (i know it all) eyes.......
actually i'm tryin gto make 3-heptyl benzoic acid from benzene.
I think i get the Friedel Crafts Acylation but i'm still kinda sketchy on the mechanism to producing the actual acid.
is it possible to use let's say chloroheptane or even iodoheptane instead of bromoheptane....
Yes
Turel - 18-2-2004 at 11:29
Angel Eyes was not being a knowitall, he had some valid points. Remember that dumb questions recieve dumb answers. Provide as much pertinent
information as you can, and people will gladly do the same for you in return. But expect the world on a silver platter when you ask for a shitclod,
and you will be repeatedly disappointed.
That said and behind us,
Acylation is not needed, and actually is undesirable, it creates an extra step. Brominate benzene to bromobenzene, and then FC alkylate bromobenzene
with heptyl halide. Yes it can be heptyl chloride or iodide. If you are unfamiliar with FC reactions, Google for them as "Friedel Crafts
Alkylation Mechanism"
http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8...
And for the mechanism for bromination:
http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8...
The last step, the conversion from 3-bromophenylheptane to the carboxylic acid, is done with what is called a Grignard Reaction. There is ample
information online to describe the mechanics of this reaction. There are tons of Grignard reactions, the only one of interest here is the reaction
with carbon dioxide to produce an acid.
http://www.google.com/search?hl=en&lr=&ie=UTF-8&...
and also
http://www.google.com/search?hl=en&lr=&ie=UTF-8&...
-T
AngelEyes - 19-2-2004 at 04:04
Know it all? No, hardly.
I have just not seen the carboxyl group written as CO<sub>2</sub>H before...COOH is how I know it. I was thinking to myself
CO<sub>2</sub>H - what the hell is that?
I thought Mr Snickers could have been another Navarone-type chump...I am happy to say that does not appear to be the case.
snickers572us - 19-2-2004 at 07:55
thank you very much
next time i'll provide better information....lol
Marvin - 20-2-2004 at 05:47
Depending on what level of answer is required, some other points might be helpful.
If you use alkylation the carbocation can equilibriate to a lower energy form. eg, 2-phenyl propane is much easier to produce than 1-phenyl propane.
Conditions can be used to minimise this but frequently we are taught to avoid this problem. Acylation avoids this nicely.
If you brominate the ring, I dont think this should intefere directly, but you are introducing an electron withdrawing group onto the ring, and this
generally causes freidel crafts to fail.
Aside from these Turels method looks fine.
I am a fish - 20-2-2004 at 12:20
Is it just me, or does "snickers572us" seem awfully like Navarone?
Navarone's key features are:
Asking very specific questions and expecting to be spoonfed answers.
Gollum-like flattery of people who help him, combined with insults against those who don't.
Semi-literacy.
An inability to use the shift key.
"Snickers572us" seems to match this profile.
Polverone - 20-2-2004 at 16:31
Yes, I thought there were some similarities too, but snickers signed up from an .ac.uk IP address, and I'm pretty sure navarone was an American
bozo. In any case, whether snickers is navarone or not, he'll not be banned or restricted unless he does something stupid (like navarone did).
snickers572us - 23-2-2004 at 03:23
ummm...who is navarone and what did he do? don't compare to no one please.
"shift" happy
thunderfvck - 23-2-2004 at 08:52
He did something terrible. Words cannot describe the horrendousness of his crime. But he is far away now, he can no longer trouble this board with his
plans of world corruption.
It has been weeks since we've last heard from him. Many of us still are deeply traumatised by his presence. The wounds will take long to heal but
the emotional damage is far worse. I will never forget him, and you should be cautious of using his name so openly, or you will live to regret the
terror that is navarone.
GeneralChemTutor - 24-2-2004 at 09:34
One way is to attach a meta directing reagent onto the benzene ring (e.g. use sulfuric acid). Alkylate the ring using the alkyl halide of CH3(CH2)6
(and a catalyst). Acylate the compound. Remove the sulfonate. Oxidize the carbonyl compound.
[Edited on 24-2-2004 by GeneralChemTutor]
axehandle - 24-2-2004 at 09:48
thunderfvck: That was the most hilarious thing I've read in a long time. Thank you! I'm happy again.