1,5-Diazabicyclo [4.3.0]non-5-ene is a amidine base used in organic synthesis. It is employed for dehydrohalogenation reactions as well as base-catalyzed rearrangements. It can also be used as the nucleophilic catalyst for the Friedel-Crafts acylation of pyrroles and indoles2. Further, it is used as a resin curing agent and polyurethane catalyst.
Taylor, James E., et al. "Friedel−Crafts Acylation of Pyrroles and Indoles using 1,5-Diazabicyclo[4.3.0]non-5-ene (DBN) as a Nucleophilic Catalyst." Cheminform 42.13(2015):5740.
Distil DBN from BaO. It forms a hydroiodide on addition of 47% HI; dry it and dissolve it in MeCN, evaporate and repeat; recrystallise from EtOH, dry at 25o/1mm for 5hours, then at 80o/0.03mm for 12hours and store and dispense it in a dry box, m 154-156o [Jaeger et al. J Am Chem Soc 101 717 1979]. The methiodide is recrystallised from CHCl3/Et2O, m 248-250o, and hydrogen fumarate has m 159-160o and is crystallised from iso-PrOH [Rokach et al. J Med Chem 22 237 1979, Oediger et al. Chem Ber 99 2012 1966, Reppe et al. Justus Liebigs Ann Chem 596 210 1955]. [Beilstein 23/5 V 239.]
clear colorless to yellowish liquid