1,1,3,3-Tetramethylguanidine

1,1,3,3-Tetramethylguanidine
Names
	IUPAC name 1,1,3,3-Tetramethylguanidine
Identifiers
CAS Number	80-70-6 ;
3D model (JSmol)	Interactive image;
Beilstein Reference	969608
ChemSpider	59832 ;
ECHA InfoCard	100.001.185
EC Number	201-302-7;
MeSH	1,1,3,3-tetramethylguanidine
PubChem CID	66460;
UNII	VEZ101E7ZU ;
UN number	2920
CompTox Dashboard (EPA)	DTXSID2058835 ;
	InChI InChI=1S/C5H13N3/c1-7(2)5(6)8(3)4/h6H,1-4H3 Key: KYVBNYUBXIEUFW-UHFFFAOYSA-N ;
	SMILES CN(C)C(=N)N(C)C;
Properties
Chemical formula	C5H13N3
Molar mass	115.180 g·mol−1
Appearance	Colourless liquid
Density	918 mg mL−1
Melting point	−30 °C (−22 °F; 243 K)
Boiling point	160 to 162 °C (320 to 324 °F; 433 to 435 K)
Solubility in water	Miscible
Vapor pressure	30 Pa (at 20 °C)
Acidity (pKa)	13.0±1.0[1] (pKa of conjugate acid in water)
Refractive index (nD)	1.469
Hazards
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H226, H302, H314
GHS precautionary statements	P280, P305+351+338, P310
Flash point	60 °C (140 °F; 333 K)
Explosive limits	1–7.5%
Related compounds
Related compounds	Dimethylurea; Noxytiolin; Metformin; Buformin; Allantoic acid; Carmustine;
	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

Tetramethylguanidine is an organic compound with the formula HNC(N(CH₃)₂)₂. This colourless liquid is a strong base, as judged by the high pK_a of it conjugate acid.[2]

It was originally prepared from tetramethylthiourea via S-methylation and amination, but alternative methods start from cyanogen iodide.[3]

Uses

TMG is mainly used as a strong, non-nucleophilic base for alkylations, often as a substitute for the more expensive DBU and DBN.[3] Since it is highly water-soluble, it is easily removed from mixtures in organic solvents. It is also used as a base-catalyst in the production of polyurethane.[4]

References

Kaupmees, K.; Trummal, A.; Leito, I. (2014). "Basicities of Strong Bases in Water: A Computational Study". Croat. Chem. Acta. 87 (4): 385–395. doi:10.5562/cca2472.
Rodima, Toomas; Leito, I. (2002). "Acid-Base Equilibria in Nonpolar Media. 2. Self-Consistent Basicity Scale in THF Solution Ranging from 2-Methoxypyridine to EtP₁(pyrr) Phosphazene". J. Org. Chem. 67 (6): 1873–1881. doi:10.1021/jo016185p.
Ishikawa, T.; Kumamoto, T. (2006). "Guanidines in Organic Synthesis". Synthesis. 2006 (5): 737–752. doi:10.1055/s-2006-926325.
Geoghegan, J. T.; Roth, R. W. (2003). "Catalytic Effects of 1,1,3,3-Tetramethylguanidine for Isocyanate Reactions". J. Appl. Polym. Sci. 9 (3): 1089–1093. doi:10.1002/app.1965.070090325.

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[Kaupmees_CCA-1] Kaupmees, K.; Trummal, A.; Leito, I. (2014). "Basicities of Strong Bases in Water: A Computational Study". Croat. Chem. Acta. 87 (4): 385–395. doi:10.5562/cca2472.

[2] Rodima, Toomas; Leito, I. (2002). "Acid-Base Equilibria in Nonpolar Media. 2. Self-Consistent Basicity Scale in THF Solution Ranging from 2-Methoxypyridine to EtP₁(pyrr) Phosphazene". J. Org. Chem. 67 (6): 1873–1881. doi:10.1021/jo016185p.

[Ishik-3] Ishikawa, T.; Kumamoto, T. (2006). "Guanidines in Organic Synthesis". Synthesis. 2006 (5): 737–752. doi:10.1055/s-2006-926325.

[4] Geoghegan, J. T.; Roth, R. W. (2003). "Catalytic Effects of 1,1,3,3-Tetramethylguanidine for Isocyanate Reactions". J. Appl. Polym. Sci. 9 (3): 1089–1093. doi:10.1002/app.1965.070090325.