September 20, 2021, 07:43:47 AM
Forum Rules: Read This Before Posting


Topic: Synthesis~~  (Read 7460 times)

0 Members and 1 Guest are viewing this topic.

Offline nj_bartel

  • Sr. Member
  • *****
  • Posts: 1487
  • Mole Snacks: +76/-42
Synthesis~~
« on: March 05, 2009, 04:55:08 PM »
I'm trying to sythesize this

http://img15.imageshack.us/my.php?image=randomp.png

using anisole as my only organic carbon source.

So far, I cleaved anisole to give phenol, nitrated that to give para-nitrophenol, then reduced to give para-aminophenol.  I then set this product aside for later.

Then, I cleaved another anisole to give phenol, treated with PBr3 to give bromobenzene, treated with Mg to form a grignard, reacted with CO2 followed by acid to give benzoic acid, then treated with SOCl2 to give the acyl chloride of benzoic acid.  I then reacted this with the product I had set aside.

Unfortunately, that gives the product pictured, except without the methoxy substituent in the bottom left-hand corner, and I'm drawing blanks on where I can work it in.

Thanks for any help.

Offline frenchy

  • Regular Member
  • ***
  • Posts: 24
  • Mole Snacks: +1/-1
  • Gender: Male
Re: Synthesis~~
« Reply #1 on: March 05, 2009, 05:24:06 PM »
I'm not sure where this would react on your molecule but could you try trichloroacetyl chloride in a first reaction then in a second time react what you have with sodium methoxide.
PhD student in synthetic Inorganic and Supramolecular chemistry.

Offline nj_bartel

  • Sr. Member
  • *****
  • Posts: 1487
  • Mole Snacks: +76/-42
Re: Synthesis~~
« Reply #2 on: March 05, 2009, 05:29:27 PM »
Unless you have a way of synthesizing the trichloroacetyl chloride, I wouldn't be allowed to use that due to it being an organic molecule that's adding carbons.  Thanks though.

Offline nj_bartel

  • Sr. Member
  • *****
  • Posts: 1487
  • Mole Snacks: +76/-42
Re: Synthesis~~
« Reply #3 on: March 05, 2009, 06:21:17 PM »
Got it, nvm  :)

Offline macman104

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 1645
  • Mole Snacks: +168/-26
  • Gender: Male
Re: Synthesis~~
« Reply #4 on: March 05, 2009, 07:31:05 PM »
Share share! :D

Offline nj_bartel

  • Sr. Member
  • *****
  • Posts: 1487
  • Mole Snacks: +76/-42
Re: Synthesis~~
« Reply #5 on: March 05, 2009, 07:35:29 PM »
Went about the second part in the wrong way.

It's still anisole -> p-aminophenol as stated above

Then anisole is brominated, and the para product is isolated to give p-bromoanisole, which is used to form a grignard, which reacts with CO2 followed by acid to give p-methoxybenzoic acid, which is treated with thionyl chloride to give the acyl chloride, followed by p-aminophenol to product

Offline aldoxime_amine

  • Full Member
  • ****
  • Posts: 191
  • Mole Snacks: +7/-4
Re: Synthesis~~
« Reply #6 on: March 06, 2009, 10:38:29 AM »
Can we use protecting groups? Even then I think the last step is doubtful, giving us a mixture of amides...

Offline sjb

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 3579
  • Mole Snacks: +218/-42
  • Gender: Male
Re: Synthesis~~
« Reply #7 on: March 06, 2009, 11:11:47 AM »
What do you mean by a mixture, I think the Beckmann is fairly stereospecific (I think that's the right word) -  what I mean is that if you follow the mechanism as at



if R = Et, and R' = Me (i.e. the oxime from butanone), then you get the major product as N-ethylacetamide, rather than N-methylpropionamide. Forming the required oxime isomer selectively may be a different problem, though ;)

S

Offline aldoxime_amine

  • Full Member
  • ****
  • Posts: 191
  • Mole Snacks: +7/-4
Re: Synthesis~~
« Reply #8 on: March 06, 2009, 12:50:55 PM »
Forming the required oxime isomer selectively may be a different problem, though ;)


That was exactly my concern...the second to last step will give us a pair of diastereomers (in my scheme..) and hence we will get a mixture in the final step.

Offline sjb

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 3579
  • Mole Snacks: +218/-42
  • Gender: Male
Re: Synthesis~~
« Reply #9 on: March 07, 2009, 06:03:27 AM »
That was exactly my concern...the second to last step will give us a pair of diastereomers (in my scheme..) and hence we will get a mixture in the final step.

OK just checking, I read your initial post as suggesting that you get the (E)-oxime exclusively, then the scrambling occurs with the Beckmann. I suppose that if you're allowing separation of protected 4-hydroxy-4'-methoxybenzophenone and protected 4-hydroxy-2'-methoxybenzophenone then this may be OK.

Presumably we have a workable route from anisole to benzenesulfonyl chloride?

Offline aldoxime_amine

  • Full Member
  • ****
  • Posts: 191
  • Mole Snacks: +7/-4
Re: Synthesis~~
« Reply #10 on: March 07, 2009, 08:19:15 AM »

then this may be OK.


But won't we have to separate the 2 amides after the last step? I used PhSO2Cl as it did not add carbons, as it is only performing the work of an assistant.

Sponsored Links