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.
Synthesis
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.2
Occurrence
Although all commercially available DBU is produced synthetically, it may also be isolated from the sea sponge Niphates digitalis.3 The biosynthesis of DBU has been proposed to begin with adipaldehyde and 1,3-diaminopropane.
Applications
DBU is used:
- As a reagent in organic chemistry, where DBU is used as a ligand and base. As a base, protonation occurs at the imine nitrogen.4 Lewis acids also attach to the same nitrogen.5
- As a catalyst, for example as a curing agent for epoxy resins and polyurethane.
- In the separation of fullerenes in conjunction with trimethylbenzene. It reacts with C70 and higher fullerenes, but not with C60.
- As a dehydrohalogenation agent.6
- In surface activation products (primers) for low-surface energy plastics and elastomers (such as PTFE, HDPE, PP, and silicone rubber), where DBU raises the surface energy enough for adhesives (such as cyanoacrylate and contact cement) to bond to these otherwise inert, non-stick materials.7
See also
References
Ghosh, Nandita (2004). "DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) - A Nucleophillic Base". Synlett (3): 574–575. doi:10.1055/s-2004-815436. https://doi.org/10.1055%2Fs-2004-815436 ↩
CN patent 101279973, Bi Zuowen, Gao Hongbin, Cao Hongbo, Wang Xiaomei, Liu Change, Xu Qin, Zhang Zonghua, "Preparation of 1,8-diazabicyclo[5.4.0]undec-7-ene", issued 2010-06-02, assigned to Shandong Xinhua Wanbo Chemical https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=CN101279973 ↩
E. L. Regalado; Judith Mendiola; Abilio Laguna; Clara Nogueiras; Olivier P Thomas (2010). "Polar alkaloids from the Caribbean marine sponge Niphates digitalis". Nat. Prod. Commun. 5 (8): 1187–1190. PMID 20839615. /wiki/PMID_(identifier) ↩
Parviainen, Arno; King, Alistair W. T.; Mutikainen, Ilpo; Hummel, Michael; Selg, Christoph; Hauru, Lauri K. J.; Sixta, Herbert; Kilpeläinen, Ilkka (2013). "Predicting Cellulose Solvating Capabilities of Acid–Base Conjugate Ionic Liquids". ChemSusChem. 6 (11): 2161–2169. Bibcode:2013ChSCh...6.2161P. doi:10.1002/cssc.201300143. ISSN 1864-5631. PMID 24106149. /wiki/Bibcode_(identifier) ↩
Romero, Erik A.; Zhao, Tianxiang; Nakano, Ryo; Hu, Xingbang; Wu, Youting; Jazzar, Rodolphe; Bertrand, Guy (2018-10-01). "Tandem copper hydride–Lewis pair catalysed reduction of carbon dioxide into formate with dihydrogen". Nature Catalysis. 1 (10): 743–747. doi:10.1038/s41929-018-0140-3. ISSN 2520-1158. /wiki/Doi_(identifier) ↩
Savoca, Ann C.; Urgaonkar, Sameer (2006). "1,8-Diazabicyclo[5.4.0]undec-7-ene". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rd011.pub2. ISBN 0-471-93623-5. 0-471-93623-5 ↩
"Novatio Silfix Primer SDS" (PDF). novatio.com. 2022. Archived from the original (PDF) on 2025-05-16. Retrieved 2025-05-16. https://web.archive.org/web/20250516111927/https://novatio.com/storage/files/87eab6b0-ac1a-4e81-87d8-af8743c9fd11/silfix-primer-sds-en-220714.pdf ↩