Eschenmoser's salt

Eschenmoser's salt, dimethyl(methylidene)ammonium iodide, is a strong dimethylaminomethylating agent, used to prepare derivatives of the type RCH₂N(CH₃)₂.[1][2] Enolates, enolsilylethers, and even more acidic ketones undergo efficient dimethylaminomethylation. Once prepared, such tertiary amines can be further methylated and then subjected to base-induced elimination to afford methylidenated ketones. The salt was first prepared by the group of Albert Eschenmoser[3] after whom the reagent is named.

Eschenmoser's salt

Names
IUPAC name Dimethyl(methylidene)ammonium iodide
Identifiers
CAS Number	33797-51-2 (Iodide)^Y 30354-18-8 (Chloride)^N
3D model (JSmol)	Interactive image Interactive image
ChemSpider	2006292^Y
ECHA InfoCard	100.046.968
PubChem CID	2724133
UNII	5C42I004S1^Y
CompTox Dashboard (EPA)	DTXSID10369115
InChI InChI=1S/C3H8N.HI/c1-4(2)3;/h1H2,2-3H3;1H/q+1;/p-1^Y Key: VVDUZZGYBOWDSQ-UHFFFAOYSA-M^Y InChI=1/C3H8N.HI/c1-4(2)3;/h1H2,2-3H3;1H/q+1;/p-1 Key: VVDUZZGYBOWDSQ-REWHXWOFAW
SMILES C[N+](C)=C.[I-] [I-].[N+](=C)(C)C
Properties
Chemical formula	C3H8NI
Molar mass	185.01 g/mol
Appearance	colorless hygroscopic crystals
Melting point	116 °C (241 °F; 389 K)
Solubility in water	decomposes
Hazards
R-phrases (outdated)	R36/37/38
S-phrases (outdated)	S26 S36
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is ^YN ?)
Infobox references

Analogous salts, dimethyl(methylidene)ammonium chloride (Böhme's salt[1], after Horst Böhme) and trifluoroacetate, have similar properities and applications.[1]

See also

• Vilsmeier reagent, [(CH₃)₂NCHCl]Cl

References

1. E. F. Kleinman in "Dimethylmethyleneammonium Iodide and Chloride" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. doi:10.1002/047084289X.rd346
2. Horst Böhme; Eberhard Mundlos; Otto-Erich Herboth (1957). "Über Darstellung und Eigenschaften α-Halogenierter Amine". Chemische Berichte. 90 (9): 2003–2008. doi:10.1002/cber.19570900942.
3. Jakob Schreiber; Hans Maag; Naoto Hashimoto; Albert Eschenmoser (1971). "Dimethyl(methylene)ammonium Iodide". Angewandte Chemie International Edition in English. 10 (5): 330–331. doi:10.1002/anie.197103301.