34
G. Y. N. Chan et al.
(0ꢀ94 g, 48%) (Found: C, 60ꢀ9; H, 7ꢀ6; N, 6ꢀ9. C10H15NO3
requires C, 60ꢀ9; H, 7ꢀ7; N, 7ꢀ1%). ꢀmax (NaCl)/cmꢁ1 3338,
2958, 1720, 1661, 1623, 1533. 1H n.m.r. ꢁ (CDCl3) 6ꢀ29,
br s, NH; 6ꢀ11, br m, RO2C(H3C)C=CHaHb; 5ꢀ68, br m,
RHNCO(H3C)C=CHcHd; 5ꢀ58, br m, RO2C(H3C)C=CHaHb;
5ꢀ33, br m, RHNCO(H3C)C=CHcH ; 4ꢀ28, t, J 5ꢀ4 Hz, OCH2;
3ꢀ63, dt, J 5ꢀ5, 5ꢀ3 Hz, NHCH2; 1ꢀd94, br m, CH3; 1ꢀ92, br m,
CH3. 13C n.m.r. ꢁ (CDCl3) 168ꢀ4, HNC=O; 167ꢀ4, OC=O;
139ꢀ6, RHNCO(H3C)C=CH2; 135ꢀ7, RO2C(H3C)C=CH2;
126ꢀ0, RO2C(H3C)C=CH2; 119ꢀ6, RHNCO(H3C)C=CH2;
63ꢀ1, OCH2; 36ꢀ9, NHCH2; 18ꢀ4, RHNCO(H3C)C=CH2;
18ꢀ1, ROOC(H3C)C=CH2. m/z (c.i., NH4) 198 ((MH)+, 74%),
128 (22), 112 (100), 111 (27) (Found: (MH)+ꢂ, 198ꢀ11318.
ꢀltration. The ꢀltrate was then cooled to 0ꢀC, and to this
stirred solution was added triethylamine (38 mmol, 5ꢀ3 ml)
under an atmosphere of nitrogen. A solution of methacryloyl
chloride (34 mmol, 3ꢀ3 ml) in chloroform (65 ml) was then
introduced dropwise. The workup as described for (3) and
puriꢀcation by chromatography aꢂorded (5) as a colourless oil
(2ꢀ32 g, 33%). Spectroscopic evidence for this compound was
consistent with (5) prepared by the two-step method.
Similarly, this methodology was used to aꢂord the crosslink-
ing monomers (3), (4) and (6) in yields of 15, 23 and 26%
respectively.
2-Bromoethyl Methacrylate (9)
C
10H16NO3 requires (MH)+ꢂ, 198ꢀ11300).
2-Bromoethanol (3ꢀ5 ml, 50 mmol) was heated with meth-
acrylicacid(5ꢀ1 ml, 60 mmol)inthepresenceof p-toluenesulfonic
acid (0ꢀ2 g, 1ꢀ1 mmol) and benzene (13 ml). The water pro-
duced during the reaction was removed azeotropically by using
a Dean–Stark trap. After completion of the reaction, the reac-
tion mixture was washed with water (15 ml), saturated sodium
carbonate (2ꢁ15 ml) and water (15 ml). The organic layer was
collected, dried and evaporated under reduced pressure to yield
2-bromoethyl methacrylate (9) as a clear, pale yellow liquid
(5ꢀ3 g, 55%) (Found: C, 37ꢀ0; H, 4ꢀ9. C6H9BrO2 requires
C, 37ꢀ3; H, 4ꢀ7). ꢀmax (NaCl)/cmꢁ1 3104, 1724, 1637. 1H
n.m.r. ꢁ (CDCl3, 300 MHz) 6ꢀ16, br m, (H3C)C=CHaHb;
5ꢀ60, br m, (H3C)C=CHaHb; 4ꢀ44, t, J 6ꢀ1 Hz, CH2O;
3ꢀ54, t, J 6ꢀ1 Hz, CH2Br; 1ꢀ95, br m, CH3. 13C n.m.r. ꢁ
(CDCl3, 75ꢀ4 MHz) 166ꢀ8, C=O; 135ꢀ8, (H3C)C=CH2; 126ꢀ2,
(H3C)C=CH2; 63ꢀ9, CH2O; 28ꢀ7, CH2Br; 18ꢀ2, CH3. m/z
(e.i., 70 eV) 193 (M+, 19%), 113 (39), 109 (81), 107 (84), 69
(100).
2-Acrylamidoethyl Methacrylate (5)
To a stirred solution of (7) (7ꢀ0 mmol, 0ꢀ8 g) and tri-
ethylamine (7ꢀ7 mmol, 1ꢀ1 ml) in chloroform (30 ml) at room
temperature, was added dropwise a solution of methacryloyl
chloride (7ꢀ7 mmol, 0ꢀ8 ml) in chloroform (15 ml) under an
atmosphere of nitrogen. The workup and chromatography as
described for (3) then aꢂorded (5) as a clear colourless oil
(0ꢀ78 g, 61%) (Found: C, 59ꢀ0; H, 7ꢀ2; N, 7ꢀ6. C9H13NO3
requires C, 59ꢀ0; H, 7ꢀ2; N, 7ꢀ6%). ꢀmax (NaCl)/cmꢁ1
3287, 3076, 2959, 1720, 1662, 1630, 1548. 1H n.m.r. ꢁ
(CDCl3) 6ꢀ29, dd, J 17ꢀ0, 1ꢀ4 Hz, RHNCOCH=CHaHb;
6ꢀ11, dd, J 17ꢀ2, 10ꢀ2 Hz, RHNCOCH=CHaHb; 6ꢀ10, br
m, RO2C(H3C)C=CHcHd; 6ꢀ09, br s, NH; 5ꢀ66, dd, J 10ꢀ3,
1ꢀ3 Hz, RHNCOCH=CHaHb; 5ꢀ60, m, RO2C(H3C)C=CHcHd;
4ꢀ28, t, J 5ꢀ3 Hz, OCH2; 3ꢀ63, q, J 5ꢀ5 Hz, NHCH2; 1ꢀ94,
br m, CH3. 13C n.m.r. ꢁ (CDCl3) 167ꢀ3, C=O; 165ꢀ8, C=O;
135ꢀ7, RO2C(H3C)C=CH2; 130ꢀ6, RHNCOCH=CH2; 126ꢀ3,
RHNCOCH=CH2; 126ꢀ0, RO2C(H3C)C=CH2; 63ꢀ1, OCH2;
38ꢀ6, NHCH2; 18ꢀ1, CH3. m/z (c.i., NH4) 184 ((MH)+,
100%), 116 (20), 98 (61), 72 (22) (Found: (MH)+ꢂ, 184ꢀ09661.
C9H14NO3 requires (MH)+ꢂ, 184ꢀ09735).
Attempted Syntheses of 2-Acrylamidoethyl Methacrylate (5)
from (9)
(A) To
a
suspension of potassium hydroxide (1ꢀ4 g,
25 mmol) in N,N -dimethylformamide (15 ml) maintained at
40ꢀC, were added acrylamide (1ꢀ4 g, 19ꢀ7 mmol), 2-bromoethyl
methacrylate (9) (3ꢀ8 g, 19ꢀ7 mmol) and phenothiazine (0ꢀ05 g,
0ꢀ3 mmol). The reaction mixture was then stirred for 4 h. The
solution was ꢀltered and the solvent removed under reduced
pressure (freeze dryer). To the resulting residue were added
benzene (10 ml) and water (5 ml). The mixture was then stirred
thoroughly at room temperature and the resulting phases were
separated. The aqueous layer was then extracted with benzene
(2ꢁ5 ml). The organic fractions were combined, dried and
evaporated under reduced pressure to aꢂord only ethylene
glycol dimethacrylate (2) as a clear liquid (0ꢀ6 g, 32%). 1H
n.m.r. ꢁ (CDCl3, 300 MHz) 6ꢀ03, br m, (H3C)C=CHaHb;
5ꢀ50, br m, (H3C)C=CHaHb; 4ꢀ31, s, CH2O; 1ꢀ85, br m,
CH3. 13C n.m.r. ꢁ (CDCl3, 75ꢀ4 MHz) 166ꢀ89, C=O; 135ꢀ8,
(H3C)C=CH2; 125ꢀ8, (H3C)C=CH2; 62ꢀ2, CH2; 18ꢀ1, CH3.
(B) A mixture of potassium hydroxide (0ꢀ3 g, 4ꢀ8 mmol),
2-bromoethyl methacrylate (9) (1ꢀ0 g, 5ꢀ0 mmol) and pheno-
thiazine (0ꢀ05 g, 0ꢀ3 mmol) in N,N -dimethylformamide (10 ml)
was maintained at 40ꢀC for 4 h. The solution was then ꢀltered
and the solvent removed under reduced pressure (freeze dryer).
The same workup as in (A) then aꢂorded only ethylene glycol
dimethacrylate (2) as a clear liquid (0ꢀ4 g, 86%). The 1H and
13C n.m.r. spectra obtained for the product were identical with
those obtained in (A).
2-Methacrylamidoethyl Acrylate (6)
To a stirred solution of (8) (10 mmol, 1ꢀ3 g) and triethyl-
amine (11 mmol, 1ꢀ5 ml) in chloroform (40 ml), was added
dropwise a solution of acryloyl chloride (11 mmol, 0ꢀ9 ml)
in chloroform (20 ml) at room temperature under a nitrogen
atmosphere. After the addition was complete, the reaction
mixture was stirred for a further 30 h. The workup as
for (3) followed by chromatography then gave the hybrid
crosslinking agent (6) as a clear colourless oil (0ꢀ57 g, 31%)
(Found: C, 59ꢀ0; H, 7ꢀ2; N, 7ꢀ5. C9H13NO3 requires C,
59ꢀ0; H, 7ꢀ2; N, 7ꢀ6%). ꢀmax (NaCl)/cmꢁ1 3337, 2958,
1725, 1662, 1622, 1533. 1H n.m.r. ꢁ (CDCl3) 6ꢀ42, br s,
NH; 6ꢀ38, dd, J 17ꢀ4, 1ꢀ2 Hz, RO2CCH=CHaHb; 6ꢀ08, dd,
J 17ꢀ4, 10ꢀ5 Hz, RO2CCH=CHaHb; 5ꢀ82, dd, J 10ꢀ4, 1ꢀ1
Hz, RO2CCH=CHaHb; 5ꢀ66, br m, RHNCO(H3C)C=CHcHd;
5ꢀ29, br m, RHNCO(H3C)C=CHcHd; 4ꢀ25, t, J 5ꢀ5 Hz,
OCH2; 3ꢀ58, dt,
J
5ꢀ5, 5ꢀ5 Hz, NHCH2; 1ꢀ91, br m,
CH3. 13C n.m.r. ꢁ (CDCl3) 168ꢀ5, HNC=O; 166ꢀ1, OC=O;
139ꢀ5, RHNCO(H3C)C=CH2; 131ꢀ2, RO2CCH=CH2; 127ꢀ7,
RO2CCH=CH2; 119ꢀ5, RHNCO(H3C)C=CH2; 62ꢀ9, OCH2;
38ꢀ7, NHCH2; 18ꢀ4, CH3. m/z (c.i., NH4) 184 ((MH)+,
100%), 112 (83), 111 (34), 98 (32), 97 (33), 96 (27), 95 (22)
(Found: (MH)+ꢂ, 184ꢀ09677. C9H14NO3 requires (MH)+ꢂ
,
(C) To
a
suspension of potassium hydroxide (0ꢀ8 g,
184ꢀ09735).
14ꢀ5 mmol) in N,N -dimethylformamide (10 ml) maintained
at 40ꢀC, were added methacrylic acid (0ꢀ9 ml, 10ꢀ0 mmol),
2-bromoethyl methacrylate (9) (1ꢀ9 g, 10ꢀ0 mmol) and phe-
nothiazine (0ꢀ05 g, 0ꢀ3 mmol). The reaction mixture was then
stirred for 4 h. By following the workup as described in (A), the
only product obtained was ethylene glycol dimethacrylate (2)
as a clear liquid (1ꢀ7 g, 83%). The 1H and 13C n.m.r. spectra
obtained for the product were identical with those obtained in
(A).
One-Pot Synthesis of (5)
Acryloyl chloride (38 mmol, 3ꢀ1 ml) in chloroform (38 ml)
was added dropwise to a stirred solution of ethanolamine
(75 mmol, 4ꢀ5 ml) in chloroform (75 ml) at 0ꢀC and under a
nitrogen atmosphere. After the addition was complete, the
reaction mixture was stirred at 0ꢀC for a further 2 h. The
ethanolamine monohydrochloride precipitate was removed by