Beilstein J. Org. Chem. 2017, 13, 372–383.
0
.3 wt % camphorquinone, 0.4 wt % ethyl 4-dimethylamino- stirred for 2.5 h at rt. Then, the THF was evaporated, ethyl
benzoate and irradiated twice. After the first run a second run acetate was added and the resulting mixture was washed 3 times
was made that was subtracted from the first one. The subtrac- with 2 N HCl and once with water. The organic layer was dried
tion of these runs from one another removed the effect of sam- (Na2SO4), the solvent was evaporated and the residue was puri-
ple heating by illumination. The DSC experiments were carried fied by flash chromatography.
N,N'-Diacryloyl-N,N'-diallyl-1,4-but-2-enediamine (1):
Yield: 45%; purity (1H NMR) >98%; η23°C = 338 mPa·s;
nD20 = 1.529; 1H NMR (CDCl3) δ 6.50–6.43 (m, 2H,
H2CCHC(O)), 6.37–6.33 (m, 2H, H2CCHC(O)), 5.81–5.72 (m,
(1)
With Q/s being the heat flow per second at the global minimum 2H, H2CCHCH2), 5.69–5.66 (m, 2H, H2CCHC(O)), 5.59–5.56
of the first deviation of the respective measurement (maximum (m, 2H, H2CHCCHCH2), 5.22–5.11 (m, 4H, H2CCHCH2), 4.02
Q/s), M the molar mass of the monomer, n the number of (m, 4H, H2CHCCHCH2), 3.92 (m, H2CCHCH2); 13C NMR
double bonds per monomer molecule, ∆Hp the heat released per (CDCl3) δ 166.3, 166.1 (C(O)CHCH2), 132.9, 132.8
mole of double bonds reacted, and m the mass of the monomer (H2CCHCH2), 128.5–127.3 (H2CCHC(O), H2CHCCHCH2),
in the sample. Mechanical data was measured in the 3-point 117.5-116.7 (H2CCHCH2), 49.3–48.1 (H2CCHCH2), 47.1
bending mode according to ISO 4049:2009 using a Zwick (H2CHCCHCH2); FTIR max [cm−1]: 3517, 3080, 3018, 2986,
instrument. Sample activation was done by adding 0.3 wt % 2917, 1645, 1611, 1463, 1416, 1363, 1276, 1213, 1129, 1059,
camphorquinone and 0.4 wt % ethyl 4-dimethylaminobenzoate. 975, 919, 794.
FTIR spectra were measured using an iS10 FTIR spectrometer
(
Thermo Scientific). Viscosity was measured on an Anton Paar N,N'-Diacetyl-N,N'-diallyl-1,4-but-2-enediamine (2): Yield:
Physica MCR 300 equipped with CP 50-1 plate–plate geometry 24%; purity (1H NMR) >97%; Tm = 32 °C; nD20 = 1.505;
at a shear stress τ of 5 Pa and 25 data points from 0.72 to 1H NMR (CDCl3) δ 5.69–5.61 (m, 2H, H2CCHCH2), 5.43 (m,
1
450 rad were taken and averaged. Refractive indices (RI) were 2H, H2CHCCHCH2), 5.12–4.98 (m, 4H, H2CCHCH2)
measured using an Anton Paar Abbemat 200 refractometer at 3.88–3.74 (m, 8H, H2CHCCHCH2, H2CCHCH2), 2.00 (s, 6H,
0 °C. C(O)CH3); 13C NMR (CDCl3) δ 170.3–169.4 (C(O)CH3),
2
1
1
32.9–132.3 (H2CCHCH2), 127.9–127.0 (H2CHCCHCH2),
16.7–116.2 (H2CCHCH2), 49.9–46.2 (H2CCHCH2,
General procedure for the synthesis of
N,N’-diacyl-N,N’-dialkyl-1,4-diamines 1–6
H2CHCCHCH2) 21.1–21.0 (C(O)CH3); FTIR max [cm−1]:
Amination
3074, 3012, 2986, 2916, 1633, 1468, 1411, 1360, 1242, 1187,
a) Synthesis of 1,4-but-2-enediamine: Potassium carbonate 1035, 978, 919.
2.5 equiv) was added to the alkylamine (15 equiv) and cooled
(
to 0–5 °C. The corresponding dibromide (1 equiv) was added in N,N'-Diacryloyl-N,N'-diallyl-1,4-butanediamine (3): Yield:
portions and the resulting mixture was stirred for 3–5 h at rt. 35%; purity (1H NMR) >94%; η23°C = 382 mPa·s;
Then the remaining amine was removed by distillation and the nD20 = 1.515; 1H NMR (CDCl3) δ 6.58–6.28 (m, 4H,
resulting residue was suspended in acetone. After removing the H2CCHC(O)), 5.80–5.71 (m, 2H, H2CCHCH2), 5.68–5.60 (m,
salts by filtration the acetone was evaporated.
2H, H2CCHC(O)), 5.21–5.10 (m, 4H, H2CCHCH2), 4.02–3.93
m, 4H, H2CCHCH2), 3.41–3.40 (m, 4H, H2CH2CCH2CH2),
(
b) Synthesis of the 1,4-butanediamine: The corresponding alkyl 1.55 (m, 4H, H2CH2CCH2CH2); 13C NMR (CDCl3) δ 166.6,
chloride (2.1 equiv) was added drop wise to a solution of 1,4- 166.0 (C(O)CHCH2), 133.3, 133.0 (H2CCHCH2), 128.2–127.5
diaminobutane (1 equiv) in methanol at 50 °C. The resulting (H2CCHC(O)), 117.1–116.7 (H2CCHCH2), 50.1–48.6
mixture was stirred at 60 °C for 24 h. Then methanol was re- (H2CCHCH2), 46.9–45.9 (H2CH2CCH2CH2), 26.5–25.0
moved by distillation and the residue was diluted with 2 M (H2CH2CCH2CH2); FTIR max [cm−1]: 3472, 3082, 2924,
NaOH and extracted with DCM. The organic layer containing 1646, 1609, 1428, 1374, 1217, 1163, 1133, 1059, 978, 957, 918,
the crude product was dried (Na2SO4) and the solvent evaporat- 794.
ed.
N,N'-Diacryloyl-N,N'-diallyl-2,4-pent-2-enediamine (4):
Acrylation
Yield: 14%; purity (1H NMR) >98%; η23°C = 409 mPa·s;
The resulting diamines were dissolved in THF and triethyl- nD20 = 1.526; 1H NMR (CDCl3) δ 6.50–6.26 (m, 5H, 2x
amine (3.5 equiv) was added. Acryloyl chloride (2.2 equiv) was H2CCHC(O)), 5.84–5.70 (m, 2H, H2CCHCH2), 5.68–5.60 (m,
addeddrop wise at 0–5 °C after which the resulting mixture was 2H, H2CCHC(O)), 5.61–5.51 (m, 2H, H2CHCCHCH2), 5.31
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