Med Chem Res
5-(1-Acetyl-5-(4-methoxyphenyl)-4,5-dihydro-3-pyrazolyl)-2-
mercapto-7-methoxybenzoxazole (6g) Yield: 75.9 %; MP:
150–154 °C; 1H NMR (400 MHz, DMSO-d6): d 13.803 (s,
1H), 7.249 (s, 1H), 7.134–7.114 (d, 3H, J = 8.12 Hz),
6.847–6.826 (d, 2H, J = 8.60 Hz), 5.547–5.507 (dd, 1H,
5-(1-Acetyl-5-(2,5-Dimethoxyphenyl)-4,5-dihydro-3-pyraz-
olyl)-2-mercapto-7-methoxybenzoxazole (6k) Yield: 62.0 %;
MP: 156–160 °C; 1H NMR (400 MHz, DMSO-d6): d
13.812 (s, 1H), 7.206–7.204 (d, 1H, J = 1.0 Hz), 7.103
–7.100 (d, 1H, J = 1.12 Hz), 6.894–6.872 (d, 1H,
J = 8.88 Hz), 6.764–6.734 (dd, 1H, J = 3.0 Hz, J =
8.84 Hz), 6.472–6.464 (d, 1H, J = 2.96 Hz), 5.718–5.676
00
JHH = 4.44 Hz, JHH = 11.8 Hz), 4.030 (s, 3H), 3.849–
0
0
3.775 (quartet, 1H, JH H = 17.92 Hz, JHH = 11.88 Hz),
00
0
0
00
00 0
(dd, 1H, JHH = 4.56 Hz, JHH = 11.76 Hz), 4.008 (s, 3H),
3.754 (s, 3H), 3.184–3.123 (dd, 1H, JH H = 17.88 Hz,
JHH = 4.56 Hz), 2.356 (s, 3H); 13C NMR (400 MHz,
00
0
3.807 (s, 3H), 3.807–3.743 (quartet, 1H, JH H = 17.76 Hz,
00
0
DMSO-d6): d 23.16, 43.91, 59.74, 61.17, 78.39, 106.31,
115.48, 116.26, 129.83, 133.06, 134.48, 141.04, 143.00,
143.36, 156.67, 167.43, 180.77; ESI–MS: 398.4 (M ? 1).
JHH = 11.84 Hz), 3.676 (s, 3H), 3.050–2.994 (dd, 1H,
JH H = 18.0 Hz, JHH = 4.8 Hz), 2.391 (s, 3H); 13C NMR
(400 MHz, DMSO-d6): d 23.26, 43.33, 59.38, 60.66, 60.90,
78.34, 106.52, 115.08, 117.62, 129.47, 133.38, 142.63,
144.60, 145.32, 145.53, 149.37, 156.70, 168.57, 180.61;
ESI–MS: 428.1 (M ? 1).
0
00
00
5-(1-Acetyl-5-(2-chlorophenyl)-4,5-dihydro-3-pyrazolyl)-
2-mercapto-7-methoxybenzoxazole (6h) Yield: 70.5 %;
MP: 126–129 °C; 1H NMR (400 MHz, DMSO-d6): d
13.795 (s, 1H), 7.447–7.405 (m, 1H), 7.274–7.224 (m, 3H),
7.117–7.115 (d, 1H, J = 0.92 Hz), 7.071–7.048 (m, 1H),
5-(1-Acetyl-5-(3-bromophenyl)-4,5-dihydro-3-pyrazolyl)-
2-mercapto-7-methoxybenzoxazole (6l) Yield: 78.3 %;
MP: 110–112 °C; 1H NMR (400 MHz, DMSO-d6): d
13.774 (s, 1H), 7.398–7.375 (d, 1H, J = 8.84 Hz), 7.353
(s, 1H), 7.263–7.224 (t, 2H), 7.183–7.164 (d, 1H,
J = 7.8 Hz), 7.115–7.112 (d, 1H, J = 1.24 Hz), 5.579–
00
5.863–5.821 (dd, 1H, JHH = 4.96 Hz, JHH = 11.96 Hz),
0
0
4.019 (s, 3H), 3.964–3.889 (quartet, 1H, JH H = 17.88 Hz,
00
0
0
00
JHH = 12.0 Hz), 3.120–3.063 (dd, 1H, JH H = 17.88 Hz,
JHH = 5.0 Hz), 2.423 (s, 3H); 13C NMR (400 MHz,
00
00 0
5.537 (dd, 1H, JHH = 4.8 Hz, JHH = 11.92 Hz), 4.033 (s,
DMSO-d6): d 23.16, 44.74, 59.17, 77.39, 106.31, 115.48,
127.26, 129.73, 129.86, 131.48, 133.06, 136.33, 137.67,
137.82, 143.78, 145.35, 149.93, 156.49, 167.51, 180.65;
ESI–MS: 402.3 (M ? 1, 100 %), 404.1(35 %).
0
3H), 3.888–3.813 (quartet, 1H, JH H = 17.92 Hz,
00
0
0
00
JHH = 12.0 Hz), 3.218–3.161 (dd, 1H, JH H = 17.92 Hz,
JHH = 4.88 Hz), 2.394 (s, 3H); 13C NMR (400 MHz,
00
DMSO-d6): d 23.14, 44.63, 59.41, 79.54, 106.09, 115.83,
124.78, 126.66, 126.30, 131.10, 133.99, 134.17, 137.81,
142.12, 143.49, 149.76, 156.62, 168.43, 180.79; ESI–MS:
446.1 (M ? 1, 100 %), 448.0 (90 %).
5-(1-Acetyl-5-(3-chlorophenyl)-4,5-dihydro-3-pyrazolyl)-
2-mercapto-7-methoxybenzoxazole (6i) Yield: 83.9 %;
MP: 123–125 °C; 1H NMR (400 MHz, DMSO-d6): d
13.785 (s, 1H), 7.325–7.289 (m, 1H), 7.244–7.196 (m, 3H),
00
7.143–7.120 (m, 2H), 5.589–5.548 (dd, 1H, JHH = 4.6 Hz,
5-(1-Acetyl-5-(4-bromophenyl)-4,5-dihydro-3-pyrazolyl)-
2-mercapto-7-methoxybenzoxazole (6m) Yield: 76.7 %;
MP: 122–125 °C; 1H NMR (400 MHz, DMSO-d6): d
13.768(s, 1H), 7.461–7.440 (d, 2H, J = 8.4 Hz), 7.232–
7.229 (d, 1H, J = 1.2 Hz), 7.146–7.125 (d, 2H, J =
8.44 Hz), 7.102–7.099 (d, 1H, J = 1.16 Hz), 5.573–5.531
0
JHH = 11.88 Hz), 4.032 (s, 3H), 3.893–3.819 (quartet, 1H,
0
00
0
JH H = 17.96 Hz, JHH = 12.0 Hz), 3.222–3.165 (dd, 1H,
JH H = 17.92 Hz, JHH = 4.7 Hz), 2.392 (s, 3H); 13C
NMR (400 MHz, DMSO-d6): d 23.14, 44.85, 59.91, 78.66,
106.38, 115.71, 126.17, 126.24, 128.89, 128.20, 133.09,
134.84, 142.13, 144.93, 149.60, 156.47, 167.75, 180.73;
ESI–MS: 402.1 (M ? 1, 100 %), 404.1 (20 %).
0
00
00
00
(dd, 1H, JHH = 4.72 Hz, JHH = 11.88 Hz), 4.031 (s, 3H),
0
0
00
3.881–3.806 (quartet, 1H, JH H = 17.88 Hz, JHH
0
=
0
00
00
12.0 Hz), 3.188–3.132(dd, 1H, JH H = 17.88 Hz, JHH
=
5-(1-Acetyl-5-(4-chlorophenyl)-4,5-dihydro-3-pyrazolyl)-2-mer-
capto-7-methoxybenzoxazole (6j) Yield: 78.1 %; MP: 136–
138 °C; 1H NMR (400 MHz, DMSO-d6): d 13.840 (s, 1H),
7.323–7.301 (d, 2H, J = 8.44 Hz), 7.238–7.236 (d, 1H,
J = 0.96 Hz), 7.210–7.189 (d, 2H, J = 8.44 Hz), 7.121–
00
4.84 Hz), 2.377 (s, 3H); 13C NMR (400 MHz, DMSO-d6):
d 23.21, 45.76, 60.68, 78.95, 106.16, 115.37, 124.79, 133.16,
134.58, 137.95, 141.65, 141.77, 149.72, 156.41, 167.55,
180.77; ESI–MS: 446.0 (M ? 1, 100 %), 447.9 (100 %).
7.119 (d, 1H, J = 0.88 Hz), 5.587–5.545 (dd, 1H, JHH
=
General procedure for the synthesis of 5-(1-acetyl-5-aryl-
4,5-dihydro-3-pyrazolyl)-2-mercaptobenzoxazole (7a–7e)/
5-(1-acetyl-5-aryl-4,5-dihydro-3-pyrazolyl)-2-mercapto-7-
methoxybenzoxazole (7f–7g)
0
4.76 Hz, JHH = 11.88 Hz), 4.022 (s, 3H), 3.895–3.819
0
(quartet, 1H, JH H = 17.92 Hz, JHH = 11.96 Hz), 3.206–
00
0
0
00
00
3.149 (dd, 1H, JH H = 17.92 Hz, JHH = 4.84 Hz), 2.363
(s, 3H); 13C NMR (400 MHz, DMSO-d6): d 23.21, 45.55,
60.90, 78.63, 106.41, 115.66, 131.37, 133.15, 136.99,
138.36, 138.87, 141.27, 144.05, 149.67, 156.51, 167.43,
180.72; ESI–MS: 402.2 (M ? 1, 100 %), 404.1 (35 %).
4-(1-Acetyl-5-aryl-4,5-dihydro-3-pyrazolyl)-2-aminophe-
nol derivatives (5a–5e)/4-(1-acetyl-5-aryl-4,5-dihydro-3-
pyrazolyl)-2-amino-5-methoxyphenol derivatives (5f–5m)
123