1,8-Diazabicycloundec-7-ene

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The correct title of this article is 1,8-Diazabicyclo[5.4.0]undec-7-ene. The substitution or omission of any brackets is because of technical restrictions.
1,8-Diazabicyclo[5.4.0]undec-7-ene
DBU.svg
DBU molecule
Names
IUPAC name
2,3,4,6,7,8,9,10-octahydropyrimido[1,2-a]azepine
Other names
DBU,Diazabicycloundecene
Identifiers
6674-22-2 YesY
ChemSpider 73246 YesY
Jmol 3D model Interactive image
Properties
C9H16N2
Molar mass 152.24 g/mol
Appearance Colorless liquid
Density 1.018 g/mL liquid
Melting point −70 °C (−94 °F; 203 K)
Boiling point 80 to 83 °C (176 to 181 °F; 353 to 356 K) (0.6 mmHg); 261 °C (1 atm)
Acidity (pKa) 13.5±1.5[1] (pKa of conjugate acid in water); 24.34[2] (pKa of conjugate acid in acetonitrile)
Hazards
R-phrases R22 R34
S-phrases S24 S25
Flash point 119.9 °C (247.8 °F; 393.0 K)
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

1,8-Diazabicyclo[5.4.0]undec-7-ene, or more commonly DBU, is a chemical compound and belongs to the class of amidine compounds. It is used in organic synthesis as a catalyst, a complexing ligand, and a non-nucleophilic base.

Occurrence[edit]

Although DBU is typically produced synthetically, it is also an alkaloid isolated from the sponge Niphates digitalis.[3] The biosynthesis of DBU has been proposed to begin with suberic aldehyde and diaminopropane.[3]

Hypothetical biosynthesis of DBU

Uses[edit]

As a reagent in organic chemistry, DBU is used as a catalyst, a complexing ligand, and a non-nucleophilic base. It is also used as a curing agent for epoxy. It is used in fullerene purification with trimethylbenzene (it reacts with C70 and higher fullerenes, but not to C60 fullerenes); and it is also used as a catalyst in polyurethane production. It has a strong catalyst effect for the reactions of alicyclic and aliphatic isocyanates. It also exhibited its dual character (base and nucleophile) in the synthesis of aryl- & styryl- terminal acetylenes.

See also[edit]

References[edit]

  1. ^ Kaupmees, K.; Trummal, A.; Leito, I. (2014). "Basicities of Strong Bases in Water: A Computational Study". Croat. Chem. Acta 87: 385–395. doi:10.5562/cca2472. 
  2. ^ Kaljurand, I.; Kütt, A.; Sooväli, L.; Rodima, T.; Mäemets, V.; Leito, I.; Koppel, I. A. (2005). "Extension of the Self-Consistent Spectrophotometric Basicity Scale in Acetonitrile to a Full Span of 28 pKa Units:  Unification of Different Basicity Scales". J. Org. Chem. 70: 1019–1028. doi:10.1021/jo048252w. PMID 15675863. 
  3. ^ a b Regalado, E.L. et al., Nat. Prod. Commun., 2010, 5, 1187- 1190