April 25, 2024, 09:59:54 AM
Forum Rules: Read This Before Posting


Topic: Organic synthesis reaction with PCl5  (Read 14950 times)

0 Members and 1 Guest are viewing this topic.

Offline rapilch

  • Very New Member
  • *
  • Posts: 1
  • Mole Snacks: +0/-0
Organic synthesis reaction with PCl5
« on: May 08, 2011, 09:23:39 AM »
Does anyone what is occurring here? Im not sure how to show arrow pushing/intermediates.

Offline orgopete

  • Chemist
  • Sr. Member
  • *
  • Posts: 2636
  • Mole Snacks: +213/-71
    • Curved Arrow Press
Re: Organic synthesis reaction with PCl5
« Reply #1 on: May 11, 2011, 12:13:05 PM »
Given the starting materials and the products, I am doubtful of the first step, except for the acid. Then it looks like formation of a bromoimidate, cyclization, and tautomerization.
Author of a multi-tiered example based workbook for learning organic chemistry mechanisms.

Offline democanarchis

  • Regular Member
  • ***
  • Posts: 72
  • Mole Snacks: +9/-0
Re: Organic synthesis reaction with PCl5
« Reply #2 on: May 11, 2011, 04:25:30 PM »
My attempt:


Offline orgopete

  • Chemist
  • Sr. Member
  • *
  • Posts: 2636
  • Mole Snacks: +213/-71
    • Curved Arrow Press
Re: Organic synthesis reaction with PCl5
« Reply #3 on: May 11, 2011, 05:43:43 PM »
What you have drawn is somewhat reasonable. I doubt a chloride would add to a carboxylic acid, but I understand you are trying to make an acid chloride. Since the starting material is also listed as the ester, I didn't know formation of the acid chloride was necessary and I did not expect that PCl5 would convert that ester to its acid chloride. I am not saying it couldn't, but it isn't high on my list of probable reactions. If one heated the heck out of it, then okay.

I am skeptical of the cyclization of the nitrile with the acid chloride. I prefer to simply proton the nitrile and add bromide to it to form a bromo imidate. Now the nitrogen is sp2 and I think better aligned to add to a C=O group, either an ester or an acid chloride (if I understand the question correctly).
Author of a multi-tiered example based workbook for learning organic chemistry mechanisms.

Offline bessieboy521

  • Regular Member
  • ***
  • Posts: 24
  • Mole Snacks: +2/-0
Re: Organic synthesis reaction with PCl5
« Reply #4 on: May 13, 2011, 05:21:33 PM »
Ok so I am presuming the the methyl groups off the carbonyl in the middle of the reaction are chlorine atoms?
Also I do not see and Ester anywhere? Am I ignorant? I do see two carboxylic groups, which surely can be converted to acyl chlorides with PCl5...?

Offline orgopete

  • Chemist
  • Sr. Member
  • *
  • Posts: 2636
  • Mole Snacks: +213/-71
    • Curved Arrow Press
Re: Organic synthesis reaction with PCl5
« Reply #5 on: May 14, 2011, 12:19:13 PM »
Structure 8, E = COOMe
Author of a multi-tiered example based workbook for learning organic chemistry mechanisms.

Offline bessieboy521

  • Regular Member
  • ***
  • Posts: 24
  • Mole Snacks: +2/-0
Re: Organic synthesis reaction with PCl5
« Reply #6 on: May 14, 2011, 10:34:24 PM »
. ahh the read the original post shutdown procedure... sorry about that.

Sponsored Links