Eschenmoser's salt

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Eschenmoser's salt
Eschenmoser's salt
IUPAC name
Dimethylmethylideneammonium iodide
3D model (JSmol)
ECHA InfoCard 100.046.968
Molar mass 185.01 g/mol
Appearance colorless hygroscopic crystals
Melting point 116 °C (241 °F; 389 K)
R-phrases (outdated) R36/37/38
S-phrases (outdated) S26 S36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).
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Infobox references

Eschenmoser's salt, dimethylmethylideneammonium 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 methylenated ketones. The salt was first prepared by the group of Albert Eschenmoser[3] after whom the reagent is named.

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


  1. ^ a b c 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.