October 24, 2021, 03:13:58 AM
Forum Rules: Read This Before Posting


Topic: Role of DMF  (Read 24399 times)

0 Members and 1 Guest are viewing this topic.

Offline GSR

  • Regular Member
  • ***
  • Posts: 48
  • Mole Snacks: +9/-1
  • Gender: Male
  • Have Courage and Follow Your Own Path!
Role of DMF
« on: November 20, 2005, 03:45:06 AM »
Dear all,

I am doing a chlorination reaction with SOCl2/DMF. can anybody explain the role of DMF?. is it working as a catalyst or supressing the reaction.


regards

GSR

Offline movies

  • Organic Minion
  • Retired Staff
  • Sr. Member
  • *
  • Posts: 1973
  • Mole Snacks: +222/-20
  • Gender: Male
  • Better living through chemistry!
Re:Role of DMF
« Reply #1 on: November 20, 2005, 11:31:21 AM »
I don't know, it might actually react with the SOCl2 as it does with POCl3 in the Vilsmeier-Haack reaction.

laotree

  • Guest
Re:Role of DMF
« Reply #2 on: November 21, 2005, 08:06:23 PM »
This kind of small tricks used in organic synthesis is very common. DMF  is used as catalyst. SOCl2 or C2O2Cl2 reacts with DMF first to form very active species then reacts with acid. You could find mechanism from ecompound.com, reaction reference, reaction mechanism, S to Z, reactions without name. This mechanism is similar to Vilsmeier (A. Vilsmeier) -Haack (A. Haack) reagent mechanism.
 Another trick is using organic base to catalyze POCl3 chlorination of heterocycle ring.

Good luck!

Offline Jiro

  • Chemist
  • Regular Member
  • *
  • Posts: 60
  • Mole Snacks: +7/-5
  • Gender: Male
  • Faith.
Re:Role of DMF
« Reply #3 on: November 21, 2005, 10:23:32 PM »
It's role is to be a aprotic solvent. opposite of protic solvents such as water that undergo solvation. Example, here are 2 senerios F- verse I- in water solvent And F- verse I- in DMF or DMSO solvent. In water(protic) the F- is more strongly "solvated"(surrounded by H20 than I-) so therefore I- is the better nucleophile in water(or other protic solutions) than F-. In DMF the F- will behave as you might predict from comparing the acidities of the conjugate acid.

Offline movies

  • Organic Minion
  • Retired Staff
  • Sr. Member
  • *
  • Posts: 1973
  • Mole Snacks: +222/-20
  • Gender: Male
  • Better living through chemistry!
Re:Role of DMF
« Reply #4 on: November 22, 2005, 11:26:14 AM »
When you use DMF in an oxalyl chloride reaction you use a catalytic amount.  Is that what they use in this case, or do they use it as the solvent?

laotree

  • Guest
Re:Role of DMF
« Reply #5 on: November 22, 2005, 08:19:07 PM »
Always several drops. With several drops of DMF, the reaction becomes so fast that you can see bubbles from solution when you use oxalyl chloride.

Sponsored Links