Description
1,4,7-Triazacyclononane, known as "TACN" which is pronounced "tack-en," is a cyclic organic compound with the formula C6H12(NH)3. TACN is derived, formally speaking, from cyclononane by replacing three equidistant CH2 groups with NH groups. TACN is one of the oligomers derived from aziridine, C2H4NH. Other members of the series include diazacyclohexane, C4H8(NH)2, and the cyclic tetramer 1,4,7,10-tetraazacyclododecane.
Chemical Properties
White - light yellow solid
Uses
Starting material for the synthesis of 1,4,7-trifunctionalized derivatives which have applications in metal complexation.
Uses
1,4,7-Triazacyclononane (TACN) is a versatile platform from which various ligands can be derived to form effective chelators for (radio)copper(II) complexation. The ability of TACN-derivatives to form highly stable complexes with copper(II) is greatly influenced by the number and type of substituents on the macrocyclic ring. The formed copper(II) complexes show a broad variability in their thermodynamic stability and kinetic inertness, varying in structure from square-pyramidal to distorted octahedral. TACN-based BFCAs have also been used for indirect radiolabelling of biomolecules, rendering them suitable for imaging and therapy.
Definition
ChEBI: 1,4,7-triazonane is a saturated organic heteromonocyclic parent, a crown amine and an azacycloalkane.
Preparation
The ligand is prepared from diethylene triamine as follows by macrocyclization using ethyleneglycol ditosylate.
H2NCH2CH2NHCH2CH2NH2 + 3 TsCl → Ts(H)NCH2CH2N(Ts)CH2CHH2N(H)Ts + 3 HCl Ts(H)NCH2CH2N(Ts)CH2CH2N(H)Ts + 2 NaOEt → Ts(Na)NCH2CH2N(Ts)CH2CH2N(Na)Ts Ts(Na)NCHH2CH2N(Ts)CH2CH2N(Na)Ts + TsOCH2CH2OTs + → [(CH2CH2N(Ts)]3 + 2 NaOTs [(CH2CH2N(Ts)]3 + 3 H2O → [CH2CH2NH]3 + 3 HOTs
Application
Starting material for the synthesis of 1,4,7-trifunctionalized derivatives which have applications in metal complexation.
Possible reagent for compleximetric titrations with high cation-binding selectivity.
Synthesis
General procedure for the synthesis of 1,4,7-tribenzyl-1,4,7-triazacyclononane from 1,4,7-tribenzyl-1,4,7-triazacyclononane: 1,4,7-tribenzyl-1,4,7-triazacyclononane (100 mg, 0.25 mmol) was dissolved in 15 mL of methanol. 10% Pd/C catalyst (100 mg) was added and the reaction mixture was stirred at 50 °C for 3 hours. Upon completion of the reaction, the Pd/C catalyst was removed by filtration. Subsequently, the solvent was evaporated under reduced pressure to afford 32 mg of 1,4,7-triazacyclononane in 100% yield.
References
[1] European Journal of Organic Chemistry, 2018, vol. 2018, # 13, p. 1546 - 1551
[2] Patent: CN108276353, 2018, A. Location in patent: Paragraph 0052; 0056; 0063; 0064; 0065
[3] Patent: US2014/142298, 2014, A1. Location in patent: Paragraph 0275; 0276
[4] European Journal of Organic Chemistry, 2014, vol. 2014, # 35, p. 7831 - 7838
