N,N-Diisopropylethylamine

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N,N-Diisopropylethylamine
Skeletal formula of N,N-diisopropylethylamine
Identifiers
CAS number 7087-68-5 YesY
PubChem 81531
ChemSpider 73565 YesY
EC number 230-392-0
UN number 2733
MeSH N,N-diisopropylethylamine
Jmol-3D images Image 1
Properties
Molecular formula C8H19N
Molar mass 129.24 g mol−1
Appearance Colorless liquid
Odor Fishy, ammoniacal
Density 0.742 g mL−1
Melting point −273.15 to −50 °C (−459.67 to −58.00 °F; 0.00 to 223.15 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 The flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The skull-and-crossbones pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
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 Flammable F Corrosive 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%
LD50 200–500 mg kg−1 (oral, rat)
Related compounds
Related amines
Related compounds
Except where noted otherwise, 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[edit]

Non-nucleophilic base[edit]

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]

The use of Hünig's base for alkylating secondary amines

Synthesis of scorpionine[edit]

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]

Hünig's  base in the synthesis of sscorpionine

References[edit]

  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.