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Names | |
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Preferred IUPAC name 2,3,4,6,7,8,9,10-Octahydropyrimido[1,2-a]azepine | |
Other names DBU, Diazabicycloundecene | |
Identifiers | |
3D model (JSmol) | |
ChemSpider | |
ECHA InfoCard | 100.027.013 |
EC Number |
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PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C9H16N2 | |
Molar mass | 152.241 g·mol−1 |
Appearance | Colorless liquid |
Density | 1.018 g/mL liquid[ citation needed ] |
Melting point | −70 °C (−94 °F; 203 K) |
Boiling point | 261 °C (502 °F; 534 K) (1 atm), 80 to 83 °C (0.6 mmHg) |
ethers, alcohols | |
Acidity (pKa) | 13.5±1.5 [1] (pKa of conjugate acid in water); 24.34 [2] (pKa of conjugate acid in acetonitrile) |
Hazards | |
GHS labelling: | |
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Danger | |
H301, H302, H312, H314, H412 | |
P260, P264, P270, P273, P280, P301+P310, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P322, P330, P363, P405, P501 | |
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). |
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. [3]
DBU can be synthesised in three steps from caprolactam and acrylonitrile. First, the nitrile undergoes an addition reaction at the caprolactam nitrogen, producing N-(2-cyanoethyl)-caprolactam. This is then hydrogenated to N-aminopropyl-caprolactam, followed by an intramolecular carbonyl condensation to form the imine. Water is removed by fractional distillation. [4]
Although all commercially available DBU is produced synthetically, it may also be isolated from the sea sponge Niphates digitalis . [5] The biosynthesis of DBU has been proposed to begin with adipaldehyde and 1,3-diaminopropane.
DBU is used: