[GSR]

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

[movies]

I don't know, it might actually react with the SOCl₂ as it does with POCl₃ in the Vilsmeier-Haack reaction.

[laotree]

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!

[Jiro]

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.

[movies]

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]

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.