(film) 3366, 3036, 2908, 1773, 1698 cm−1; dH 2.88 (1H, dd, J =
16.4, 2.8); 3.40 (1H, dd, J = 16.4, 5.6); 4.47 (1H, dd, J = 15.0,
6.0); 4.54 (1H, dd, J = 15.0, 6.0); 5.29 (1H, dd, J = 5.6, 2.8),
6.81 (1H, brs); 7.30–7.39 (9H, m); 7.55 (1H, dd, J = 8.4, 1.6); dC
43.68, 43.99; 56.69; 127.69, 127.72, 128.77, 129.29, 129.31, 129.36,
135.25, 137.83, 149.63, 165.43; ESI-MS m/z 334.84 (MNa+); Anal.
calcd. for C17H16N2O2S: C, 65.36; H, 5.16; N, 8.97; found C 65.12;
H 5.11; N 8.98.
with dichloromethane–ethyl acetate 9.5 : 0.5); 63%; m.p. 142–
144 ◦C; mmax (film) 3366, 3060, 3041, 2971, 1778, 1711, 1312,
1151 cm−1; dH 1.01 (3H, t, J = 7.2 Hz); 1.06 (3H, t, J = 7.2);
1.68 (1 H, dq, J = 14.4, 7.2); 1.95 (1 H, dq, J = 14.4, 7.2); 2.20
(1 H, dq, J = 14.4, 7.2); 2.47 (1 H, dq, J = 14.4, 7.2); 4.21 (1H,
dd, J = 14.8, 6.0); 4.33 (1H, dd, J = 14.8, 6.0); 4.75 (1H, s); 6.66
(1H, brs); 7.14 (2H, d, J = 7.6); 7.19–7.28 (3H, m); 7.47 (2H, t,
J = 7.6); 7.61 (1H, t, J = 7.6); 7.85 (2H, t, J = 7.6); dC 8.56, 8.90,
20.86, 25.12, 43.85, 67.05, 74.72, 127.43, 127.69, 128.74, 128.88,
129.18, 134.39, 137.36, 139.84, 148.99, 171.49; EI-MS m/z 400.05
(M+); Anal. calcd. for C21H24N2O4S: C, 62.98, H, 6.04, N, 6.99;
found, C, 63.11, H, 6.25, N, 7.12.
N-Benzylcarbamoyl-4-phenylsulfonylazetidin-2-one, 5d. Puri-
fied by column chromatography on silica gel (elution with
◦
dichloromethane–ethyl acetate 9.5 : 0.5); 81%; m.p. 159–161 C,
mmax (film) 3374, 3064, 3031, 2978, 1789, 1711, 1316, 1150 cm−1;
dH 3.48 (1H, dd, J = 16.8, 6.0); 3.67 (1H, dd, J = 16.8, 2.8); 4.33
(1H, dd, J = 14.8, 6.0); 4.39 (1H, dd, J = 14.8, 6.0); 5.20 (1H,
dd, J = 6.0, 2.8), 6.65 (1H, brs); 7.23 (2H, dd, J = 8.0, 1.2); 7.31–
7.38 (3H, m); 7.58 (2H, t, J = 8.0); 7.74 (1H, dt, J = 8.0, 1.2);
7.96 (2H, dd, J = 8.0, 0.8); dC 39.43, 43.86, 65.84, 127.58, 127.79,
128.77, 129.28, 129.39, 134.88, 136.75, 137.28, 148.39, 164.27; EI-
MS m/z: 344.00 (M+); Anal. calcd. for C17H16N2O4S: C, 59.29; H,
4.68; N, 8.13; found C, 59.41; H, 4.55; N, 8.01.
N-Benzylcarbamoyl-3,3-diethyl-4-benzylthioazetidin-2-one, 5i.
Purified by column chromatography on silica gel (elution with
dichloromethane–ethyl acetate 9.5 : 0.5); 53% as a yellow oil, mmax
(film) 3365, 1759, 1701 cm−1; dH 0.56 (3H, t, J = 7.4); 0.85 (3H, t,
J = 7.4); 1.44–1.69 (4H, m); 3.99 (1H, d, J = 12.8); 4.06 (1H, d,
J = 12.8); 4.31 (1H, dd, J = 15.3, 6.1); 4.36 (1H, dd, J = 15.3, 6.3);
4.70 (1H, s); 6.91 (1H, s); 7.10–7.27 (10H, m); dC 7.67; 8.90; 22.41;
24.44; 37.37; 43.61; 62.99; 65.84; 127.63; 127.72; 127.81; 129.01;
129.07; 129.80; 138.79; 139.62;150.96; 172.35; HPLC-ESIMS m/z
(MH+) 383.52; Anal. calcd. for C22H26N2O2S; C, 69.08; H, 6.85;
N, 7.32; found C, 69.10, H, 6.90; N, 7.30.
N-Benzylcarbamoyl-3,3-diethylazetidin-2-one,
5e. Purified
by column chromatography on silica gel (elution with
dichloromethane–ethyl acetate 9.5 : 0.5); 83% as a colourless oil,
mmax (film) 3364, 3071, 3031, 2969, 2924, 2875, 1757, 1702 cm−1;
dH 1.00 (6H, t, J = 7.6); (4H, q, J = 7.6); 3.42 (2H, s); 4.50 (2H,
d, J = 6.0); 6.93 (1H, brs); 7.28–7.38 (5H, m); dC 8.70, 25.71,
43.75, 47.04, 59.31, 127.44, 127.54, 127.65, 128.65,128.71, 137.98,
150.95, 172.83; ESI-MS m/z 261.10 (MH+); Anal. calcd. for
C15H20N2O2: C, 69.20, H, 7.74, N, 10.76; found C, 68.95; H, 7.80;
N, 10.59.
N-Benzylcarbamoyl-3,3-diethyl-4-benzylsulfonylazetidin-2-one,
5j. Purified by column chromatography on silica gel (elution
with diethyl ether–light petroleum 1 : 1; 52%; m.p. 93–94 ◦C; mmax
(film) 3365, 1778, 1313, 1165 cm−1; dH 0.79 (3H, t, J = 7.4); 1.01
(3H, t, J = 7.5); 1.62 (1 H, dq, J = 14.5, 7.3); 1.84 (1H, dd, J =
14.5, 7.3); 2.08 (1H, dq, J = 14.5, 7.4); 2.52 (1H, dq, J = 14.6,
7.4); 4.48 (1H, d, J = 13.9); 4.53 (2H, d, J = 5.9); 4.62 (1H, s);
5.01 (1H, d, J = 13.9); 6.95 (1H, t, J = 5.9); 7.19–7.59 (10H,
m); dC 8.27, 8.87, 20.90, 24.48, 44.12, 62.27, 66.46, 69.06, 127.59,
127.89, 128.91, 129.07, 131.37, 137.08, 150.20, 171.22; EI-MS
m/z 413.8 (MH+); Anal. calcd. for C22H26N2O4S; C, 63.75; H,
6.32; N, 6.76; found C, 63.70, H, 6.40; N, 6.60.
N-Benzylcarbamoyl-3,3-diethyl-4-phenoxyazetidin-2-one, 5f25.
Purified by column chromatography on silica gel (elution with
dichloromethane–ethyl acetate 9.5 : 0.5); 81%; m.p. 58–59 ◦C; mmax
(film) 3366, 3064, 3031, 2970, 2939, 2880, 1770, 1710 cm−1; dH
1.00 (3H, t, J = 7.6 Hz); 1.06 (3H, t, J = 7.6); 1.77–1.84 (3H,
m); 1.99 (1 H, dq, J = 14.4, 7.2); 4.47 (1H, dd, J = 15.6, 6.0);
4.51 (1H, dd, J = 15.6, 6.0); 5.68 (1H, s); 6.93 (1H, brs); 7.07
(1H, t, J = 7.2); 7.22–7.35 (9H, m); dC 8.58, 8.84, 21.23, 23.86,
43.75, 64.35, 86.76, 117.76, 123.17, 127.63, 127.67, 128.76, 129.67,
137.66, 150.14, 157.47, 172.23; ESI-MS m/z 353.29 (MH+); Anal.
calcd. for C21H24N2O3: C, 71.57, H, 6.86, N, 7.95; found 71.84,
6.78, 8.18.
Large scale reaction of N-benzylcarbamoyl-4-
phenylsulfonylazetidin-2-one with excess sodium methoxide
N-Benzylcarbamoyl-4-phenylsulfonylazetidin-2-one (0.29 mmol),
5d, was added to a solution of sodium methoxide (1.5 mmol)
in methanol (15 mL). The reaction mixture was stirred at room
temperature and monitored by TLC. The solvent was removed
under reduced pressure and the residue was taken up in water
(20 mL), acidified with 10% HCl until pH 2 and extracted with
ethyl acetate (3 × 30 mL). After drying and evaporating off the
solvent, the residue was purified by column chromatography on
silica gel (elution with dichloromethane–ethyl acetate 8 : 2), to
yield the product, 3-benzylpyrimidine-2,4(1H,3H)-◦dione, 11, as a
white solid (79%); m.p. 177–179 ◦C (lit.,47 181–182 C); mmax (film)
3084, 2965, 1625, 1601 cm−1; dH 5.12 (2H, s); 5.81 (1H, dd, J =
7.2, 1.2); 7.14 (1H, dd, J = 7.2, 6.0); 7.26–7.34 (3H, m); 7.46 (2H,
d, J = 7.2); 9.35 (1H, brs); dC 43.71, 102.26, 127.70, 128.46,128.80,
136.49, 138.17, 163.12; EI-MS m/z 202.05 (M+); Anal. calcd. for
C11H10N2O2, C, 65.34; H, 4.98; N, 13.85; found, C, 65.55, H, 5.25,
N, 13.81.
N-Benzylcarbamoyl-3,3-diethyl-4-phenylthioazetidin-2-one, 5g.
Purified by column chromatography on silica gel (elution with
dichloromethane–ethyl acetate 9.5 : 0.5); 70%; m.p. 80–81 ◦C; mmax
(film) 3361, 3061, 2968, 1758, 1701 cm−1; dH 0.94 (3H, t, J =
8.0 Hz); 1.06 (3H, t, J = 8.0); 1.75–1.98 (3H, m); 1.99 (1 H, dq,
J = 14.4, 7.2); 4.51 (1H, dd, J = 15.6, 6.0); 4.55 (1H, dd, J = 15.6,
6.0); 5.06 (1H, s); 6.95 (1H, brs); 7.28–7.39 (8H, m); 7.77 (2H, d,
J = 8.0); dC 8.43, 9.01, 23.11, 24.74, 43.74, 63.95, 71.42, 127.60,
127.65, 128.17, 128.74, 129.19, 133.24, 137.71, 150.13, 172.04; EI-
MS m/z 368.15 (M+); Anal. calcd. for C21H24N2O2S: C, 68.45, H,
6.56, N, 7.60; found, C, 68.22, H, 6.65, N, 7.88.
N-Benzylcarbamoyl-3,3-diethyl-4-phenylsulfonylazetidin-2-one,
5h. Purified by column chromatography on silica gel (elution
This journal is
The Royal Society of Chemistry 2007
Org. Biomol. Chem., 2007, 5, 2617–2626 | 2623
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