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Methylation of tris-(2-aminoethyl)amine (TREN); N,N,N’,N’,N’’,N’’-hexamethyl-[tris(aminoethyl)amine] (Me6TREN)

SyntheticPage 694
DOI: 10.1039/SP694
Submitted Sep 06, 2013, published Sep 06, 2013
Christopher Waldron (, Alexandre Simula (
A contribution from Dave Haddleton Group, Warwick University

			Reaction Scheme: <img src="/images/empty.gif" alt="" />Methylation of <span id="csm1378472728901" class="csm-chemical-name" title="tris-(2-aminoethyl)amine">tris-(2-aminoethyl)amine</span> (TREN)<img src="/images/empty.gif" alt="" />

Chemicals Used

Tris-(2-aminoethyl)amine (TREN)


Formic Acid

Sodium hydroxide (saturated solution in water)



To a 1 L RB flask formaldehyde 37% v/v (270.9 mL, 3.64 mol) and Formic acid (320 mL, 8.15 mol) was added. The reaction mixture was placed in an ice bath and Tris(2-Aminoethyl)amine (50 mL, 0.33 mol) was added dropwise over the course of at least 1h, with vigorous stirring. The reaction mixture was then refluxed at 120°C for 12 h (until the evolution of carbon dioxide had stopped).  After leaving to cool, the volatiles were removed by rotary evaporation to give an orange-yellow solution. The reaction mixture was placed in an ice bath and the pH was adjusted to pH 10 with a saturated NaOH solution. The resulting oil was then extracted using 3x 150 mL of Chloroform. The combined organic layers were dried over MgSO4 and the volatiles were removed by rotary evaporation to yield an orange-yellow oil. The oil was then distilled under reduced pressure (75-79°C, 10-3 mbar) to yield a colourless oil (48.01 g, 62 % yield).

Author's Comments

  • Upon adjustment to pH 10, the product precipitates out of the solution to form an oily layer. This may require a large amount of saturated NaOH
  • During the distillation, the first fraction (waste) was removed using a cryo-distillation technique. Then, the second fraction (which is the product) was extracted under reduced pressure (75-79°C, 10-3 mbar)


1H NMR (CDCl3, 400 MHz), δ (ppm): 2.55 and 2.32 (t, 12 H, (CH3)2-N-CH2-CH2-N-R), 2.17 (s, 18 H, (CH3)2-N-R)

13C NMR (CDCl3, 400 MHz), δ (ppm): 57.5, 53.1, 45.9

IR: 1035, 1124 (νC-N)

ESI-MS (m/z): [M+] 231.25 (230.25 Theo.)

Lead Reference

Ciampolini, M.; Nardi, N., Inorg. Chem. 1966, 5 (1), 41-44. DOI: 10.1021/ic50035a010

Supplementary Information

Interactive HNMR spectrum
Interactive CNMR spectrum
1H NMR Spectrum (1H Me6TREN.jcamp)
13C NMR Spectrum (13C-Me6TREN.jcamp)
FT-IR (Graph1.gif)

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Get structure file (.cdx, .sk2, .mol)

Keywords: amines, Eschweiler–Clarke, reduction, reductive amination

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