Vilsmeier reagent

{{Chembox

| ImageFile = VilsReagent.png

| ImageSize = 134

| ImageAlt =

| PIN = 1-Chloro-N,N-dimethyl­methan­iminium chloride

| OtherNames = (chloromethylene)dimethyl­iminium chloride

|Section1={{Chembox Identifiers

| CASNo = 3724-43-4

| CASNo_Comment = hydrate

| PubChem = 77311

| EC_number = 425-970-6

| ChEMBL = 3183181

| UNII = Q39V7G8776

| ChemSpiderID = 69730

| StdInChI=1S/C3H7ClN.ClH/c1-5(2)3-4;/h3H,1-2H3;1H/q+1;/p-1

| StdInChIKey = QQVDYSUDFZZPSU-UHFFFAOYSA-M

| SMILES = C[N+](=CCl)C.[Cl-]

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|Section2={{Chembox Properties

| C=3|H=7|N=1|Cl=2

| MolarMass =

| Appearance = white solid

| Density =

| MeltingPtC = 132

| MeltingPt_notes =

| BoilingPt =

| Solubility = }}

|Section3={{Chembox Hazards

| GHSPictograms = {{GHS05}}{{GHS07}}{{GHS08}}

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|290|302|314|360}}

| PPhrases = {{P-phrases|201|202|234|260|264|270|280|281|301+312|301+330+331|303+361+353|304+340|305+351+338|308+313|310|321|330|363|390|404|405|501}}

| MainHazards =

| FlashPt =

| AutoignitionPt = }}

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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)₂N=CHCl]⁺ 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.

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⁺".{{cite journal|title=Dimethylchloromethyleneammonium Chloride|author=Paul R. Giles |author2=Charles M. Marson |journal=Encyclopedia of Reagents for Organic Synthesis|year=2001 |doi=10.1002/047084289X.rd319m|isbn=0-471-93623-5 }}

File:Vilsmeier.png|year = 2000|volume = 56|issue = 2|pages = 355–686|doi = 10.1002/0471264180.or056.02}}]]

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