Eschenmoser's salt
Appearance
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Names | |
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Preferred IUPAC name
N,N-Dimethylmethaniminium iodide | |
Identifiers | |
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3D model (
JSmol ) |
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ChemSpider | |
ECHA InfoCard
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100.046.968 |
PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
C3H8NI | |
Molar mass | 185.01 g/mol |
Appearance | colorless hygroscopic crystals |
Melting point | 116 °C (241 °F; 389 K) |
decomposes | |
Hazards | |
GHS labelling: | |
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Warning | |
H315, H319, H335 | |
P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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In
cation
[(CH3)2NCH2]+.
The dimethylaminomethylene cation is a strong dimethylaminomethylating agent, used to prepare
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.
Structure and bonding
Dimethylaminomethylene cation is described as a
resonance hybrid of the carbocation and an iminium
cation:
The C3N atoms are coplanar. The cation is isoelectronic with
isobutene
.
Preparation
Pyrolysis of iodomethyltrimethylammonium iodide affords the desired salt:[3]
An alternative route starts with bis(dimethylamino)methane:
Related salts
Other salts of the dimethylaminomethylene cation:
- Dimethyl(methylidene)ammonium trifluoroacetate.[4][1]
- Dimethyl(methylidene)ammonium chloride (Böhme's salt[1], after Horst Böhme)
See also
- Vilsmeier reagent, [(CH3)2NCHCl]Cl.
References
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