N,N-Diisopropylethylamine

N,N-Diisopropylethylamine

Names
IUPAC name Ethyldiisopropylamine
Other names Diisopropylethylamine Hunig's base
Identifiers
CAS Number	7087-68-5
ChemSpider	73565
EC Number	230-392-0
Jmol interactive 3D	Image
MeSH	N,N-diisopropylethylamine
PubChem	81531
UN number	2733
InChI InChI=1S/C8H19N/c1-6-9(7(2)3)8(4)5/h7-8H,6H2,1-5H3 Key: JGFZNNIVVJXRND-UHFFFAOYSA-N
SMILES CCN(C(C)C)C(C)C
Properties
Chemical formula	C8H19N
Molar mass	129.25 g·mol^−1
Appearance	Colorless liquid
Odor	Fishy, ammoniacal
Density	0.742 g mL^−1
Melting point	−50 to −46 °C (−58 to −51 °F; 223 to 227 K)
Boiling point	126.6 °C; 259.8 °F; 399.7 K
Vapor pressure	4.1 kPa (at 37.70 °C)
Refractive index (nD)	1.414
Hazards
GHS pictograms
GHS signal word	DANGER
GHS hazard statements	H225, H301, H314, H412
GHS precautionary statements	P210, P273, P280, P301+310, P305+351+338, P310
EU classification (DSD)	F C
R-phrases	R11, R22, R34, R52/53
S-phrases	S16, S26, S36/37/39
Flash point	10 °C (50 °F; 283 K)
Explosive limits	0.7–6.3%
Lethal dose or concentration (LD, LC):
LD50 (Median dose)	200–500 mg kg^−1 (oral, rat)
Related compounds
Related amines	Triethylamine 2,6-Di-tert-butylpyridine 1,5-Diazabicyclo(4.3.0)non-5-ene 1,8-Diazabicycloundec-7-ene
Related compounds	Triisopropylamine
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

N,N-Diisopropylethylamine, or Hünig's base, DIPEA or DIEA, is an organic compound and an amine. It is used in organic chemistry as a base. Because the nitrogen atom is shielded by the two isopropyl groups and an ethyl group only a proton is small enough to easily fit. Like 2,2,6,6-tetramethylpiperidine, this compound is a good base but a poor nucleophile, which makes it a useful organic reagent.^[1] Hünig's base is named after the German chemist Siegfried Hünig. The compound is a colourless liquid.

Hünig's base is commercially available. It is traditionally prepared by the alkylation of diisopropylamine with diethyl sulfate.^[2] If necessary, the compound can be purified by distillation from potassium hydroxide.

Reactions

Non-nucleophilic base

Hünig's base was investigated for its use as a selective reagent in the alkylation of secondary amines to tertiary amines by alkyl halides. This organic reaction is often hampered by a quaternization reaction to the quaternary ammonium salt but this side-reaction is absent when Hünig's base is present.^[3]

Synthesis of scorpionine

Hünig's base forms a complex heterocyclic compound called scorpionine by a reaction with disulfur dichloride catalyzed by DABCO in a one-pot synthesis.^[4]

References

1. Sorgi, K. L. (2001). "Diisopropylethylamine". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rd254.
2. Hünig, S.; Kiessel, M. (1958). "Spezifische Protonenacceptoren als Hilfsbasen bei Alkylierungs- und Dehydrohalogenierungsreaktionen". Chemische Berichte 91 (2): 380–392. doi:10.1002/cber.19580910223.
3. Moore, J. L.; Taylor, S. M.; Soloshonok, V. A. (2005). "An efficient and operationally convenient general synthesis of tertiary amines by direct alkylation of secondary amines with alkyl halides in the presence of Huenig’s base". Arkivoc 2005 (part vi): 287–292. EJ-1549C.
4. Rees, W.; Marcos, C. F.; Polo, C.; Torroba, T.; Rakitin O. A. (1997). "From Hünig's Base to Bis([1,2]dithiolo)-[1,4]thiazines in One Pot: The Fast Route to Highly Sulfurated Heterocycles". Angewandte Chemie International Edition 36 (3): 281–283. doi:10.1002/anie.199702811.