Med Chem Res
(2-phenyl-5-benzoxazolyl)phenyl methanone (4a) (So and
Decaire 1998)
H-4). 13C NMR (100 MHz, CDCl3) δ: 195.9 (C, C-8), 163.7
(C, C-2), 153.5 (C, C-7a), 142.0 (C, C-3a), 138.5 (C, C-5′),
137.8 (C, C-5), 134.8 (C, C-12), 132.6 (CH, C-7a′), 130.2
(CH, C-4′ and CH, C-6′), 129.6 (CH, C-11 and CH, C-13),
129.2 (CH, C-10 and CH, C-14), 128.5 (C, C-9), 127.9
(CH, C-3a′ and CH, C-7′), 125.0 (CH, C-6), 122.9 (CH, C-
4), 110.8 (CH, C-7). pKa = 14.7. HRMS-ESI: m/z calcd. for
C20H12ClNO2 (M+Na)+: 356.0449; found: 356.0440;
calcd. for (M+H)+: 334.0634; found: 334.0619; calcd. for
(M + 2 + H)+: 336.0605; found: 336.0597.
71% yield, white solid after column chromatography
(hexane/ethyl acetate, 95:05v/v); M.p. 182–193 °C; clogP
= 4.84; IR (νmax cm–1): 3052, 1643, 1603, 1596, 1278,
1048. 1H NMR (400 MHz, CDCl3) δ: 7.50 (2H, t, H-3a′ and
3
H-7′, J = 8.0 Hz), 7.53–7.58 (3H, m, H-11, H-12 and H-
13), 7.61 (1H, tt, H-7a′, 3J = 7.6 Hz, 4J = 1.2 Hz), 7.69 (1H,
3
3
d, H-7, J = 8.4 Hz), 7.69 (1H, d, H-7, J = 8.4 Hz), 7.84
(2H, dd, H-4′ and H-6′, 3J = 8.2 Hz, 4J = 1.2 Hz), 7.94 (1H,
dd, H-6, 3J = 8.4 Hz, 4J = 1.6 Hz), 8.21 (1H, d, H4, 4J = 1.6
Hz), 8.28 (2H, dd, H-10 and H-14, 3J = 7.8 Hz, 4J = 1.2 Hz).
13C NMR (100 MHz, CDCl3) δ: 196.1 (C, C-8), 164.7 (C,
C-2), 153.5 (C, C-7a), 142.1 (C, C-3a), 137.9 (C, C-5′),
134.7 (C, C-5), 132.6 (CH, C-7a′), 132.2 (C, C-9), 130.2
(CH, C-4′ and CH, C-6′), 129.2 (CH, C-11 and CH, C-13),
128.5 (CH, C-12), 127.9 (CH, C-3a′ and CH, C-7′), 127.8
(CH, C-10 and CH, C-14), 126.8 (CH, C-6), 122.9 (CH, C-
4), 110.8 (CH, C-7). pKa = 14.7. HRMS-ESI: m/z calcd. for
[2-(4-methoxyphenyl)-5-benzoxazolyl]phenyl methanone
(4d)
33% yield, white solid after column chromatography
(hexane/ethyl acetate, 95:05v/v); M.p. 170–175 °C; clogP
= 4.86; IR (νmax cm–1): 3067, 2922, 1645, 1608, 1498,
1292, 1030. 1H NMR (400 MHz, CDCl3) δ: 3.90 (3H, s, H-
3
15), 7.04 (2H, d, H-11 and H-13, J = 9.2 Hz), 7.50 (2H, t,
C20H14NO2 (M+H)+: 300.1019; found: 300.1020.
H-3a′ and H-7′, 3J = 7.6 Hz), 7.59–7.62 (1H, m, H-7a′), 7.64
+
3
3
(1H, d, H-7, J = 8.4 Hz), 7.83 (2H, d, H-4′ and H-6′, J =
3
4
[2-(4-nitrophenyl)-5-benzoxazolyl]phenyl methanone (4b)
7,2 Hz), 7.90 (1H, dd, H-6, J = 8.4 Hz, J = 1.6 Hz), 8.16
(1H, d, H-4, 4J = 1.2 Hz), 8.21 (2H, d, H-10 and H-14, 3J =
8.8 Hz). 13C NMR (100 MHz, CDCl3) δ: 196.1 (C, C-8),
164. 8 (C, C-2), 162.9 (C, C-12), 153.5 (C, C-7a), 142.2 (C,
C-3a), 137.9 (C, C-5′), 134.5 (C, C-5), 132.5 (C, C-7a′),
130.2 (CH, C-4′ and CH, C-6′), 129.8 (CH, C-3a′ and CH,
C-7′), 128.5 (CH, C-6), 127.4 (C, C-9), 122.4 (CH, C-4),
119.2 (CH, C-10 and CH, C-14), 114.6 (CH, C-11 and CH,
C-13), 110.5 (CH, C-7), 55.7 (CH3, C-15). pKa = 14.7.
HRMS-ESI: m/z calcd. for C21H15NO3(M+Na)+:
352.0944; found: 352.0944.
40% yield, yellow solid after column chromatography
(hexane/ethyl acetate, 95:05v/v); M.p. 221–225 °C, with
decomposition; clogP = 4.60; IR (νmax cm–1): 3108, 1654,
1
1596, 1554, 1512, 1340, 1281, 1049. H NMR (300 MHz,
3
CDCl3) δ: 7.51 (2H, t, H-3a′ and H-7′, J = 7.2 Hz), 7.62
3
4
(1H, tt, H-7a′, J = 7.2 Hz, J = 1.5 Hz), 7.73 (1H, d, H-7,
3J = 8.4 Hz), 7.83 (2H, dd, H-4′ and H-6, 3J = 7.2 Hz, 4J =
1.5 Hz), 7.99 (1H, dd, H-6, J = 8.7 Hz, J = 1.5 Hz), 8.24
3
4
4
3
(1H, d, H-4, J = 1.2 Hz), 8.39 (2H, d, H-10 and H-14, J
= 9.0 Hz), 8.44 (2H, d, H-11 and H-13, J = 9.0 Hz). 13C
3
NMR (75 MHz, CDCl3) δ: 195.7 (C, C-8), 162.2 (C, C-2),
153.6 (C, C-7a), 149.8 (C, C-12), 141.8 (C, C-3a), 137.6 (C,
C-5′), 135.3 (C, C-9), 132.8 (C, C-5), 132.3 (CH, C-7a′),
130.2 (CH, C-10 and CH, C-14), 128.7 (CH, C4′, CH, C-6′,
CH, C-11, and CH, C-13), 128.5 (CH, C-3a′ and CH, C-6′),
124.4 (CH, C-6), 123.4 (CH, C-4), 111.1 (CH, C-7). pKa =
1-(2-phenyl-5-benzoxazolyl)ethanone (4e) (Ge et al. 2012)
21% yield, white solid after column chromatography
(hexane/ethyl acetate, 95:05v/v); M.p. 160–165 °C; clogP
= 3.24; IR (νmax cm–1): 3066, 2920, 1672, 1610, 1554,
1267, 1059. 1H NMR (400 MHz, CDCl3) δ: 2.69 (3H, s, H-
15), 7.52–7.58 (3H, m, H-11, H-12 and H-13), 7.63 (1H, d,
+
14.9. HRMS-ESI: m/z calcd. for C20H13N2O3 (M+H)+:
345.0870; found: 345.0870.
3
3
4
H-7, J = 8.4 Hz), 8.05 (1H, dd, H-6, J = 8.4 Hz, J = 1.6
3
4
[2-(4-chlorophenyl)-5-benzoxazolyl]phenyl methanone (4c)
Hz), 8.26 (2H, dd, H-10 and H-14, J = 8.0 Hz, J = 1.,2
Hz), 8.37 (1H, d, H-4, J = 1.6 Hz). 13C NMR (100 MHz,
4
60% yield, white solid after column chromatography
(hexane/ethyl acetate, 95:05v/v); M.p. 195–198 °C; clogP
= 5.56; IR (νmax cm–1): 3067, 1657, 1617, 1596, 1293,
1048, 1016. 1H NMR (400 MHz, CDCl3) δ: 7.48–7.54 (4H,
CDCl3) δ: 197.3 (C, C-8), 164.6 (C, C-2), 153.6 (C, C-7a),
142.2 (C, C-3a), 134.6 (C, C-5), 132.3 (C, C-9), 129.2 (CH,
C-11 and CH, C-13), 127.9 (C, C-12), 126.7 (CH, C-10 and
CH, C-14), 125.9 (CH, C-6), 121.1 (CH, C-4), 110.8 (CH,
C-7), 26.9 (CH3, C-15). pKa = 14.7. HRMS-ESI: m/z calcd.
3
m, H-11, H-13, H-3a′, H-7′), 7.61 (1H, tt, H-7a′, J = 7.2
4
3
5
+
Hz, J = 1.2 Hz), 7.66 (1H, dd, H-7, J = 8.4 Hz, J = 0.4
Hz), 7.82–7.84 (2H, m, H-4′ and H-6′), 7.94 (1H, dd, H-6,
for C15H12NO2 (M+H)+: 238.0863; found: 238.0870.
3J = 8.4 Hz, J = 1.6 Hz), 8.18–8.22 (3H, m, H-10, H-14,
4