Vilsmeier reagent

The Vilsmeier reagent is an organic compound with the formula [(CH3)2NCHCl]Cl. It is a salt consisting of the N,N-dimethyliminium cation ([(CH3)2N=CHCl]+) and chloride anion. Depending on the particular reaction, the anion can vary. In typical POCl3-based reactions, the anion is PO2Cl2−. The iminium cation [(CH3)2NC=HCl]+ is the reactive component of interest. This iminium species is a derivative of the imidoyl chloride CH3N=CHCl. Analogues of this particular reagent are generated when tertiary amides other than DMF are treated with POCl3.

Vilsmeier reagent
Names
Other names
(chloromethylene)dimethyliminium chloride
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.102.443
EC Number
  • 425-970-6
UNII
Properties
C3H7Cl2N
Molar mass 128.00 g·mol−1
Appearance white solid
Melting point 132 °C (270 °F; 405 K)
Hazards
GHS pictograms
GHS Signal word Danger
H290, H302, H314, H318, H360
P201, P202, P234, P260, P264, P270, P280, P281, P301+312, P301+330+331, P303+361+353, P304+340, P305+351+338, P308+313, P310, P321, P330, P363, P390, P404, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

The salt is a white solid that is soluble in polar organic solvents. Vilsmeier reagent is the active intermediate in the formylation reactions, the Vilsmeier reaction or Vilsmeier-Haack reaction that use mixtures of dimethylformamide and phosphorus oxychloride to generate the Vilsmeier reagent, which in turn attacks a nucleophilic substrate and eventually hydrolyzes to give formyl. It is a source of "O=CH+".[1]

Pathway for formation of Vilsmeier reagent and its mode of action.[2]

See also

References
  1. Paul R. Giles, Charles M. Marson. "Dimethylchloromethyleneammonium Chloride". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rd319m.CS1 maint: uses authors parameter (link)
  2. Jones, G.; Stanforth, S. P. (2000). "The Vilsmeier Reaction of Non-Aromatic Compounds". Org. React. 56 (2): 355–686. doi:10.1002/0471264180.or056.02.
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