Deprotonation of hydrogen bonded Schiff bases by three strong nitrogen bases

作者：Schilf Wojciech^*; Cmoch Piotr; Szady Chelmieniecka Anna; Grech Eugeniusz

来源：Journal of Molecular Structure, 2009, 921(1-3): 34-37.

DOI：10.1016/j.molstruc.2008.12.013

• Schiff bases
• Intramolecular hydrogen bond
• Deprotonation
• Proton sponges
• (1)H
• (15)N NMR

Three Schiff bases obtained from Substituted salicylaldehydes and 2-hydroxy-1-naphthaldehyde and aliphatic amines were investigated in terms of possible withdrawal of tautomeric proton from intramolecular hydrogen bridge. Three strong nitrogen bases: 1,8-bis(dimethylamino)naphtalene (DMAN), 1,1,3,3-tetramethylguanidine (TMG) and 1.8-bis(tetramethylguanidino)naphthalene (TMGN) were used as deprotonating agents in acetonitrile solution at room temperature. In the specified conditions it was found that only in the case of 5-nitrosalicylaldehyde and isopropyl amine derivative this process could be performed using TMG and TMGN as a base. The other derivatives, where bridged proton is shifted to oxygen or nitrogen atom, do not undergo such reaction. The deprotonation process was monitored by nitrogen and proton NMR measurements.

• 出版日期2009-3-17