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(s, 3H), 4.50 (d, J ¼ 5.6 Hz, 2H), 4.89 (s, br, 1H), 7.26 (dt, J ¼ 1.2, 8.4 Hz,
1H), 7.34 (dt, J ¼ 1.2, 7.6 Hz, 1H), 7.53 (s, 1H), 7.58 (d, J ¼ 7.6 Hz, 1H),
8.13 (d, br, J ¼ 7.2 Hz, 1H); 13C NMR (400 MHz, CDCl3) d 28.1, 36.3,
52.2, 83.8, 115.3, 117.7, 119.1, 122.7, 123.9, 124.7, 129.1, 135.7, 149.6,
156.9; ESI-MS: m/z (%) 327 (100, M þ Naþ): HRMS calcd. for
C16H20N2NaO4. 327.1317; found 327.1320.
3d. Purification by chromatography on silica gel (ethyl acetate/petroleum
ether 1:5) afforded a white solid. Mp: 1288C. IR: 965, 1174, 1271, 1365, 1448,
1
1529, 1701, 3337 cm21; H NMR (400 MHz, CDCl3) d 2.34 (s, 3H), 3.70
(s, 3H), 4.87 (d, J ¼ 8.0 Hz, 2H), 4.89 (s, br, 1H), 7.23 (d, J ¼ 8.4 Hz, 3H),
7.27 (t, J ¼ 7.6 Hz, 1H), 7.50 (s, 1H), 7.55 (d, J ¼ 8.0 Hz, 1H), 7.77
(d, J ¼ 8.4 Hz, 2H), 8.00 (d, J ¼ 8.4 Hz, 1H); 13C NMR (400 MHz, CDCl3)
d 21.5, 36.3, 52.3, 113.7, 119.6, 119.8, 123.3, 124.0, 125.0, 126.8, 127.2,
129.4, 129.9, 135.1, 135.3, 145.0, 156.9; ESI-MS: m/z (%) 381 (100,
M þ Kþ); HRMS calcd. for C18H18N2NKO4S: 381.0879; found 381.0868.
3e. Purification by chromatography on silica gel (ethyl acetate/petroleum
ether 1:6) afforded a white solid. Mp: 748C. IR: 974, 1020, 1119, 1250, 1368,
1
1448, 1522, 1700 cm21; H NMR (400 MHz, CDCl3) d 1.27 (t, J ¼ 7.6 Hz,
3H), 2.34 (s, 3H), 4.15 (q, J ¼ 2.0 Hz, 2H), 4.48 (d, J ¼ 5.6 Hz, 2H), 4.85
(s, br, 1H), 7.22 (d, J ¼ 4.8 Hz, 2H), 7.26 (d, J ¼ 8.0 Hz, 1H), 7.34
(t, J ¼ 4.8 Hz, 1H), 7.49 (s, 1H), 7.55 (d, J ¼ 8.0 Hz, 1H), 7.76
(d, J ¼ 8.4 Hz, 2H), 7.97 (d, J ¼ 8.4 Hz, 1H); 13C NMR (400 MHz, CDCl3)
d 14.5, 21.4, 36.0, 61.0, 113.6, 119.7, 119.7, 123.2, 123.9, 124.9,
126.7, 129.4, 129.8, 135.0, 135.2, 144.9, 156.2; EI-MS: m/z (%) 372
(14, Mþ), 343 (2), 217 (19), 189 (7), 145 (10), 118 (16); ESI-MS: m/z (%)
395 (5, M þ Naþ); HRMS calcd. for C19H20N2NaO4S: 395.1036; found
395.1048.
3f. Purification by chromatography on silica gel (ethyl acetate/petroleum
ether 1:5) afforded a white solid. Mp: 1358C. IR: 970, 1119, 1175, 1253, 1364,
1532, 1681, 1703, 3303 cm21
;
1H NMR (400 MHz, CDCl3) d 1.23
(d, J ¼ 6.3 Hz, 6H), 2.33 (s, 3H), 4.46 (d, J ¼ 5.6 Hz, 2H), 4.87 (s, br, 1H),
4.94 (m, J ¼ 6.4 Hz, 1H), 7.21 (d, J ¼ 8.4 Hz, 2H), 7.25 (t, J ¼ 8.0 Hz, 1H),
7.32 (t, J ¼ 8.0 Hz, 1H), 7.48 (s, 1H), 7.55 (d, J ¼ 7.6 Hz, 1H), 7.75
(d, J ¼ 8.4 Hz, 2H), 7.97 (d, J ¼ 8.4 Hz, 1H); 13C NMR (400 MHz, CDCl3)
d 21.52, 22.13, 29.68, 36.14, 68.47, 113.72, 119.68, 120.00, 121.85, 123.30,
123.97, 125.01, 126.82, 129.47, 129.90, 135.39, 144.98, 156.13; ESI-MS:
m/z (%) 409 (7, M þ Naþ); HRMS calcd. for C20H22N2NaO4S: 409.1192;
found 409.1203.
3g. Purification by chromatography on silica gel (ethyl acetate/petroleum
ether 1:7) afforded a white solid. Mp: 868C. IR: 937, 967, 1092, 1172, 1293,
1366, 1448, 1526, 1683, 2978, 3334 cm21; 1H NMR (400 MHz, CDCl3) d 1.46
(s, 9H), 2.34 (s, 3H), 4.42 (d, J ¼ 5.6 Hz, 2H), 4.72 (s, br, 1H), 7.23
(d, J ¼ 5.6 Hz, 2H), 7.24 (d, J ¼ 1.2 Hz, 1H), 7.33 (t, J ¼ 8.0 Hz, 1H), 7.48
(s, 1H), 7.55 (d, J ¼ 8.0 Hz, 1H), 7.76 (d, J ¼ 8.4 Hz, 2H), 7.97
(d, J ¼ 8.4 Hz, 1H); 13C NMR (400 MHz, CDCl3) d 21.4, 28.3, 35.7, 79.5,