Supporting Information
Stable Heterocumulene Monomer in Water; Synthesis and Polymerization of (Meth)Acrylates
Having an Isothiocyanate Structure
Ryota Seto,1 Kozo Matsumono,1,2 Takeshi Endo*1
1
Molecular Engineering Institute, Kinki University, 11-6 Kayanomori, Iizuka, Fukuoka Prefecture 820-
8555, Japan
2
Department of Biological & Environmental Chemistry, Kinki University, 11-6 Kayanomori, Iizuka,
Fukuoka Prefecture 820-8555, Japan
*Correspondence to: T. Endo (E-mail: tendo@moleng.fuk.kindai.ac.jp)
Contents
I. Experimental Section
II. Reactivity of Isothiocyanate with Water
III. Original Spectra (1H NMR, 13C NMR, and IR spectra) of all new monomers and polymers
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I. Experimental Section
1. Materials
Methacryloyl chloride (1), acryloyl chloride (2), 2-aminoethanol, hydrochloric acid, triphenylphosphine,
NaN3, CS2, N,N-dimethylformamide (DMF), CaCl2, NaSCN, CuCl2, and p-methoxyphenol were
purchased from Wako Pure Chemical Industries (Osaka, Japan) and used as received. Diethyl ether,
triethylamine, dichloromethane, methanol, acetone, and MgSO4 were purchased from Kanto Chemical
Co., Inc. (Tokyo, Japan) and used as received. Tetrabutylammonium bromide, and 2-bromoehtanol were
purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan) and used as received.
2. Characterization
1
H and 13C NMR spectra were recorded on a JEOL JNM-ECS 400 spectrometer at a resonance frequency
of 400 and 100 MHz for 1H and 13C, and JEOL JNM-AL 300 spectrometer at a resonance frequency of
300 and 75 MHz for 1H and
13
C with tetramethylsilane (TMS) as an internal standard. NMR chemical
shifts were reported in delta unit (δ). Infrared (IR) spectra were recorded on a Thermo Scientific Nicolet
iS10 spectrometer equipped with a Smart iTR Sampling Accessory. Melting points (mp) were measured
with a Stuart Scientific SMP3.
3. Experimental Procedure
3.1. Synthesis of 2-aminoethyl (meth)acrylate
2-Aminoethanol hydrochloride
To hydrochloric acid 40.6 mL (491 mmol), 2-aminoethanol 29.4 mL (30.0 g, 491 mmol) was added at
0 °C and stirred for 5 min. After 5 min, the mixture was concentrated in vacuo at 60 °C. Water was
separated as the methanol azeotrope and the mixture was lyophilized to afford 46.6 g (478 mmol) of 2aminoethanol hydrochloride as pale brown solid in 97% yield.
2-Aminoethanol hydrochloride: pale brown solid. {46.6 g (478 mmol, 97%)}: mp 82.0–83.8 °C (ref.1
82–86 °C). IR (ATR) νmax: 3333 (br, O–H, NH2), 2936 (br, C–H) cm–1.
1
H NMR (300 MHz, 293 K,
CD3OD, δ): 3.75 (t, J = 5.3 Hz, 2 H, HO–CH2), 3.04 (t, J = 5.3 Hz, 2 H, H2N–CH2) ppm.
13
C NMR (75
MHz, 293 K, CD3OD, δ): 58.89 (HO–CH2), 42.85 (H2N–CH2) ppm.
2-Aminoethyl methacrylate hydrochloride (3)2
A mixture of 2-aminoethanol hydrochloride 40.0 g (410 mmol), p-methoxyphenol (as polymerization
inhibitor, 509 mg, 4.1 mmol, 1 mol%), methacryloyl chloride 43.7 mL (47.1 g, 451 mmol, 1.1 eq.) was
heated to 80 °C and stirred for 2 h. After the reaction, the mixture was washed with diethyl ether and the
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white solid product was separated from the organic solvent by filtration, and dried under vacuum.
3: white solid. {67.8 g (409 mmol, 99%)}: mp 113.6–115.2 °C. IR (ATR) νmax: 2890 (br, C–H, NH2),
1714 (s, C=O), 1638 (w, C=C), 1154 (s, C–O) cm–1. 1H NMR (300 MHz, 293 K, CD3OD, δ): 6.22 (dq, J
= 1.6, 1.6 Hz, 1 H, C=CH2), 5.70 (dq, J = 1.6, 1.6 Hz, 1 H, C=CH2), 4.41 (t, J = 5.2 Hz, 2 H, –OCH2CH2–
), 3.31 (t, J = 5.2 Hz, 2 H, –CH2CH2NH2), 1.97 (dd, J = 1.6, 1.6 Hz, 3 H, C=C–CH3) ppm.
MHz, 293 K, CD3OD, δ
13
C NMR (75
C=O), 136.9 (CH2=C<), 127.3 (CH2=C<), 62.1 (–O–CH2–), 40.0 (–
CH2–NH2), 18.4 (–CH3) ppm.
2-Aminoethyl acrylate hydrochloride (4)
A mixture of 2-aminoethanol hydrochloride 40 g (410 mmol), p-methoxyphenol (as polymerization
inhibitor, 509 mg, 4.1 mmol, 1 mol%), acryloyl chloride 36.4 mL (40.8 g, 451 mmol, 1.1 eq.) was heated
to 80 °C and stirred for 20 min. After the reaction, the mitxture was washed with diethyl ether and the
white solid product was separated from the organic solvent by filtration, and dried under vacuum.
4: white solid. {52.8 g (348 mmol, 85%)}: mp 61.8–63.2 °C. IR (ATR) νmax: 2893 (br, C–H, NH2), 1722
(s, C=O), 1599 (w, C=C), 1201 (s, C–O) cm–1.
1
H NMR (300 MHz, 293 K, CD3OD, δ): 6.48 (dd, J =
17.3, 1.5 Hz, 1 H, C=CH2), 6.24 (dd, J = 17.3, 10.4 Hz, 1 H, CH2=CH–), 5.96 (dd, J = 10.4, 1.5 Hz, 1 H,
C=CH2), 4.40 (t, J = 5.1 Hz, 2 H, –OCH2CH2–), 3.29 (t, J = 5.1 Hz, 2 H, –OCH2CH2NH2) ppm.
13
C
NMR (75 MHz, 293 K, CD3OD, δ): 167.1 (C=O), 132.6 (CH2=C<), 128.8 (CH2=C<), 62.0 (–OCH2CH2–
), 39.9 (–OCH2CH2NH2) ppm.
3.2. Synthesis of 2-thiocyanatoethyl (meth)acrylate
R
O
Cl
R
Br
HO
R
O
Et3N
CH2Cl2, r.t. 12 h.
O
acetone, reflux, 12 h.
neat, 150 °C, 12 h.
S C N
R=CH3: 5
R=H: 6
O
TBAB, CuCl2
O
Br
R=CH3: 1
R=H: 2
O
NaSCN
O
R
R=CH3: TEMA
R=H: TEA
N C S
R=CH3: ITEMA
R=H: ITEA
Scheme S1. Synthesis of 2-thiocyanatoethyl (meth)acrylate.
2-Bromoehyl methacrylate (5)3
A mixture of 33.1 mL (58.0 g, 464 mmol) of 2-bromoethanol, 500 mL of dichloromethane and 64.4 mL
(46.9 g, 463 mmol) of triethylamine to a four-neck 1 L flask in an ice bath. Under nitrogen, followed by a
slow addition of a mixture of 48.4 g (463 mmol) of methacryloyl chloride (1) and 33 mL of
dichloromethane using an addition funnel for 30 min.
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The reaction mixture was stirred at room
temperature for 11 h and then poured into 300 mL of water. The organic layer was extracted with
dichloromethane for 3 times and washed with brine using a separation funnel. The residual water in the
organic layer was further removed with anhydrous magnesium sulfate. The organic solvent was then
removed by vacuum. The crude product was purified by distillation under reduced pressure (1.5 mmHg,
63 °C). 5 was yielded as a clear liquid in 75% yield.
5: clear and colorless oil. {67.2 g (348 mmol), 75%}: bp 63–65 °C (1.5 mmHg). Rf value 0.7 (eluent:
CH2Cl2). 1H NMR (300 MHz, 293 K, CDCl3, δ): 6.17 (dq, J = 1.6, 1.0 Hz, 1 H, C=CH2), 5.62 (dq, J =
1.6, 1.5 Hz, 1 H, C=CH2), 4.46 (t, J = 6.1 Hz, 2 H, –OCH2CH2–), 3.56 (t, J = 6.1 Hz, 2 H, –CH2CH2Br),
1.97 (dd, J = 1.5, 1.0 Hz, 3 H, C=C–CH3) ppm.
13
C NMR (75 MHz, 293 K, CDCl3, δ): 166.9, 135.8,
126.4, 64.0, 28.9, 18.3 ppm. IR (ATR) νmax: 2959 (w, C–H), 1716 (s, C=O), 1636 (m, C=C), 1296 (m, C–
O), 1148 (s, C–O), 924 (m, C–O) cm–1.
2-Bromoethyl acrylate (6)
A mixture of 38.8 mL (67.9 g, 543 mmol) of 2-bromoethanol, 300 mL of dichloromethane and 75.7 mL
(55.0 g, 544 mmol) of triethylamine to a four-neck 1 L flask in an ice bath. Under nitrogen, followed by a
slow addition of a mixture of 49.2 g (544 mmol) of acryloyl chloride (2) and 33 mL of dichloromethane
using an addition funnel for 40 min. The reaction mixture was stirred at room temperature for 12 h and
then poured into 300 mL of water. The organic layer was extracted with dichloromethane for 3 times and
washed with brine using a separation funnel. The residual water in the organic layer was further removed
with anhydrous magnesium sulfate. The organic solvent was then removed by vacuum. The crude
product was purified by distillation under reduced pressure (0.68 mmHg, 41 °C). 6 was yielded as a clear
colorless liquid in 80% yield.
6: clear and colorless oil. {78.1 g (436 mmol), 80%}: bp 41–43 °C (0.68 mmHg). Rf value 0.7 (eluent:
hexane / ethyl acetate: 2 / 1). 1H NMR (300 MHz, 293 K, CDCl3, δ): 6.47 (dd, J = 17.3, 1.4 Hz, 1 H,
C=CH2), 5.62 (dd, J = 17.3, 10.4 Hz, 1 H, CH2=CH–), 5.89 (dd, J = 10.4, 1.4 Hz, 1 H, C=CH2), 4.48 (t, J
= 6.2 Hz, 2 H, –OCH2CH2–), 3.56 (t, J = 6.2 Hz, 2 H, –CH2CH2Br) ppm.
13
C NMR (75 MHz, 293 K,
CDCl3, δ): 165.6, 131.7, 127.8, 63.9, 28.6 ppm. IR (ATR) νmax: 2965 (w, C–H), 1722 (s, C=O), 1635 (m,
C=C), 1406 (m, C=C), 1170 (s, C–O), 981 (m, C–O) cm–1.
2-Thiocyanatoethyl methacrylate (TEMA)
A mixture of 25.2 g (311 mmol, 1.1 eq.) of NaSCN, 54.6 g (283 mmol) of 5 and 142 mL of acetone (2.0
mol/L) to a 500 mL round flask. Under nitrogen, the reaction mixture was refluxed for 18 h and then
poured into 300 mL of water. The organic layer was extracted with dichloromethane for 3 times and
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washed with brine using a separation funnel. The residual water in the organic layer was further removed
with anhydrous magnesium sulfate. The organic solvent was then removed by vacuum. The crude
product was purified by distillation under reduced pressure (0.75 mmHg, 53 °C). TEMA was yielded as
a clear liquid in 81% yield.
TEMA: clear and colorless oil. {46.4 g (271 mmol) 81%}: bp 53–55 °C (0.75 mmHg). Rf value 0.4
(eluent: hexane / ethyl acetate: 2 / 1). aD26 1.4909. 1H NMR (300 MHz, 293 K, CDCl3, δ): 6.21 (dq, J =
1.2, 1.0 Hz, 1 H, C=CH2), 5.67 (dq, J = 1.6, 1.2 Hz, 1 H, C=CH2), 4.49 (t, J = 5.9 Hz, 2 H, –OCH2CH2–),
3.27 (t, J = 5.9 Hz, 2 H, –CH2CH2SCN), 1.98 (dd, J = 1.6, 1.0 Hz, 3 H, C=C–CH3) ppm. 13C NMR (75
MHz, 293 K, CDCl3, δ): 166.6, 135.3, 126.8, 111.5, 62.3, 32.6, 18.1 ppm. IR (ATR) νmax: 2957 (w, C–H),
2156 (m, C≡N), 1715 (s, C=O), 1636 (m, C=C), 1292 (m, C–O), 1148 (s, C–O), 944 (m, C–O) cm–1.
2-Thiocyanatoethyl acrylate (TEA)
A mixture of 37.0 g (456 mmol, 1.1 eq.) of NaSCN, 74.2 g (415 mmol) of 6 and 208 mL of acetone (2.0
mol/L) to a 500 mL round flask. Under nitrogen, the reaction mixture was refluxed for 20 h and then
poured into 300 mL of water. The organic layer was extracted with dichloromethane for 3 times and
washed with brine using a separation funnel. The residual water in the organic layer was further removed
with anhydrous magnesium sulfate. The organic solvent was then removed by vacuum. The crude
product was purified by distillation under reduced pressure (0.11 mmHg, 67 °C). TEA was yielded as a
clear liquid in 65% yield.
TEA: clear and colorless oil. {42.4 g (270 mmol) 65%}: bp 67–70 °C (0.11 mmHg). Rf value 0.4 (eluent:
hexane / ethyl acetate: 2 / 1). nD26 1.4938. 1H NMR (300 MHz, 293 K, CDCl3, δ): 6.50 (dd, J = 17.3, 1.4
Hz, 1 H, C=CH2), 6.16 (dd, J = 17.3, 10.4 Hz, 1 H, CH2=CH–), 5.93 (dd, J = 10.4, 1.4 Hz, 1 H, C=CH2),
4.51 (t, J = 5.9 Hz, 2 H, –OCH2CH2–), 3.26 (t, J = 5.9 Hz, 2 H, –CH2CH2SCN) ppm. 13C NMR (75 MHz,
293 K, CDCl3, δ): 165.4, 132.2, 127.3, 111.5, 62.1, 32.5 ppm. IR (ATR) νmax: 2953 (w, C–H), 2156 (m,
C≡N), 1720 (s, C=O), 1635 (m, C=C), 1406 (m, C=C), 1172 (m, C–O), 981 (m, C–O) cm–1.
Thermal rearrange of TEMA to synthesize ITEMA
A mixture of TEMA 500 mg (2.92 mmol), tetrabutylammonium bromide 94.1 mg (0.292 mmol, 10
mol%), and CuCl2 (as polymerization inhibitor, 19.6 mg, 0.146 mmol, 5 mol%) was heated to 150 °C and
stirred for 12 h. The thermal rearrange rate of TEMA was calculated from integral of 1H NMR spectra
(Figure S1). After 12 h, a conversion of the rearrangement was very low, and almost all thiocyanate
remained unchanged.
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Figure S1. 1H NMR spectra of TEMA during thermal rearrange examination.
3.3. Synthesis of ITEMA and ITEA via Staudinger reaction and aza-Wittig reaction
R
R
O
O
NaN3
DMF, 60 °C, 1 h.
Br
R=CH3: 5
R=H: 6
R
O
O
PPh3
ether, r.t. 8 h.
N3
R
O
CS2
O
O
O
ether, r.t. 10 h.
N PPh3
N C S
R=CH3: ITEMA
R=H: ITEA
Scheme S2. Synthesis of ITEMA and ITEA via Staudinger reaction and aza-Wittig reaction.
ITEMA
A mixture of 5 10.0 g (51.8 mmol), p-methoxyphenol (as polymerization inhibiter, 320 mg, 2.58 mmol, 5
mol%), NaN3 3.70 g (57.0 mmol, 1.1 eq.), and 100 mL of DMF (0.5 mol/L) to a 500 mL round flask. The
reaction mixture was heated to 60 °C and stirred for 1 h and then poured into 500 mL of water. The
organic layer was extracted with diethyl ether for 5 times and washed with brine using a separation
funnel. The residual water in the organic layer was further removed with anhydrous CaCl 2. The organic
solvent was then removed by vacuum to 100 mL of solvent. To the mixture, triphenylphosphine 13.6 g
(51.8 mmol, 1.0 eq.) was added and stirred for 10 h at room temperature. After the reaction, CS 2 15 mL
was added to the mixture and stirred for 5 h at room temperature. The mixture was filtered to remove a
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white solid of triphenylphosphine sulfide. The organic solvent was then removed by vacuum. The crude
product was purified by distillation under reduced pressure (0.0375 mmHg, 56 °C). ITEMA was yielded
as a clear liquid in 45% yield (4.02 g, 23.5 mmol).
ITEA
A mixture of 6 10.0 g (55.9 mmol), p-methoxyphenol (as polymerization inhibiter, 347 mg, 2.80 mmol, 5
mol%), NaN3 4.00 g (61.5 mmol, 1.1 eq.), and 100 mL of DMF (0.5 mol/L) to a 500 mL round flask. The
reaction mixture was heated to 60 °C and stirred for 1 h and then poured into 500 mL of water. The
organic layer was extracted with diethyl ether for 5 times and washed with brine using a separation
funnel. The residual water in the organic layer was further removed with anhydrous CaCl 2. The organic
solvent was then removed by vacuum to 100 mL of solvent. To the mixture, triphenylphosphine 14.7 g
(55.9 mmol, 1.0 eq.) was added and stirred for 8 h at room temperature. After the reaction, CS 2 15 mL
was added to the mixture and stirred for 10 h at room temperature. The mixture was filtered to remove a
white solid of triphenylphosphine sulfide. The organic solvent was then removed by vacuum. The crude
product was purified by distillation under reduced pressure (0.15 mmHg, 58 °C). ITEA was yielded as a
clear liquid in 18% yield (1.60 g, 10.2 mmol).
4. References
1. V. P. Wystrach, D. W. Kaiser, F. C. Schaefer, J. Am. Chem. Soc. 1955, 77, 5915–5918.
2. K. Deng, H. Tian, P. Zhang, X. Ren, H. Wang, J. Appl. Polym. Sci. 2009, 114, 176–184.
3. Y. Ye, Y. A. Elabd, Polymer, 2011, 52 1309–1317.
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II. Reactivity of Isothiocyanate with Water
To a NMR tube, ITEMA 10.3 mg (0.06 mmol), water 60 μL (3.3 mmol, 55 eq. 10 wt%), and acetone-d6
540 μL (0.1 mol/L) were added and heated to 60 °C. Figure S2 showed time course of 1H NMR spectra
of the mixture.
Figure S2. 1H NMR spectra of ITEMA with water.
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III. Original Spectra (1H NMR, 13C NMR, and IR spectra) of all monomers and polymers
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Figure S3. (a) 1H NMR, (b) 13C NMR, and (c) IR spectra of 2-aminoethanol hydrochloride.
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Figure S4. (a) 1H NMR, (b) 13C NMR, and (c) IR spectra of 3.
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Figure S5. (a) 1H NMR, (b) 13C NMR, and (c) IR spectra of 4.
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Figure S6. (a) 1H NMR, (b) 13C NMR, and (c) IR spectra of 5.
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Figure S7. (a) 1H NMR, (b) 13C NMR, and (c) IR spectra of 6.
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Figure S8. (a) 1H NMR, (b) 13C NMR, and (c) IR spectra of ITEMA.
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Figure S9. (a) 1H NMR, (b) 13C NMR, and (c) IR spectra of ITEA.
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Figure S10. (a) 1H NMR, (b) 13C NMR, and (c) IR spectra of TEMA.
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Figure S11. (a) 1H NMR, (b) 13C NMR, and (c) IR spectra of TEA.
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Figure S12. (a) 1H NMR, (b) 13C NMR, and (c) IR spectra of poly-ITEMA.
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Figure S13. (a) 1H NMR, (b) 13C NMR, and (c) IR spectra of poly-ITEA.
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