1,5-Diazabicyclo[4.3.0]non-5-ene (DBN) is a chemical compound with the formula CHN.Savoca, Ann. C. "1,5-Diazabicyclo[4.3.0]non-5-ene" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. It is an amidine base used in organic synthesis. A related compound with related functions is 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The relatively complex nature of the formal names for DBU and DBN (hence the common use of acronyms) reflects the fact that these compounds are bicyclic and contain several functional groups.
Synthesis DBN could be synthesized in the following manner, similarly to DBU:Möller, F.; Oediger, H. "1,5-Diazabicyclo[5.4.0]undec-5-ene, a New Hydrogen Halide Acceptor" Angew. Chem. Int. Ed. Engl. , 1967, 5, 76.
The synthetic procedure starts with a Michael addition of 2-pyrrolidone to acrylonitrile, followed by hydrogenation, and finally dehydration.
Uses As a base in organic synthesis Similar to many other organic bases, DBN could be employed for dehydrohalogenation reactions, base-catalyzed rearrangement reactions, as well as Aldol condensation.Oediger, H., Möller, F., & Eiter, K. "Bicyclic Amidines as Reagents in Organic Syntheses" Synthesis, 1972, 11, 591–598. Several examples are shown below: Elimination:
Epimerization of penicillin derivatives, catalyzed by DBN:Jackson, J.R. and Stoodley, R.J. "Equilibration of penicillanic acid derivatives" J. Chem. Soc. D, 1971, 647-648
Aldol condensation:Corey, E.J., Andersen, N.H., Carlson, R.M. "Total synthesis of prostaglandins. Synthesis of the pure dl-E1, -F1α, -F1β, -A1, and -B1 hormones" J. Am. Chem. Soc., 1968, 90, 12, 3245–3247
DBN salt as an ionic liquid The acetate salt of DBN is a room-temperature ionic liquid used for processing cellulose fibers by acting as a replacement for the unstable N-Methylmorpholine N-oxide used for making lyocell. Zhang, Jinming; Wu, Jin; Yu, Jian; Zhang, Xiaoyu; He, Jiasong; Zhang, Jun. "Application of ionic liquids for dissolving cellulose and fabricating cellulose-based materials: state of the art and future trends." Mat. Chem. Front. 2017, 1 (7), 1273-90. Ioncell - Enter the new era of textile production!
References