B. Long, B. Tian, Q. Tang et al.
Tetrahedron 96 (2021) 132382
J ¼ 7.7 Hz, 2H), 7.47e7.40 (m, 2H), 7.40e7.33 (m, 2H), 7.02 (t,
5-phenyl-N-(o-tolyl)-1,3,4-oxadiazol-2-amine (4a) [23] ob-
tained as green solid in 78 % yield; M.p. 150e153 ꢀC; 1H NMR
J ¼ 7.3 Hz, 1H); 13C NMR (150 MHz, DMSO‑d6)
d 164.78, 163.13,
160.41, 157.51, 139.08, 129.59, 128.62, 128.56, 122.40, 121.06, 117.55,
117.14, 116.99. HRMS (ESI): m/z [MþH]þ Calcd for C14H11N3OF:
256.0886; Found: 256.0885.
(600 MHz, DMSO‑d6)
(m, 1H), 7.57e7.55 (m, 3H), 7.26e7.22 (m, 2H), 7.05 (t, J ¼ 7.3 Hz,
1H), 2.32 (s, 3H); 13C NMR (150 MHz, DMSO‑d6)
161.58, 158.47,
d 9.66 (s, 1H), 7.90e7.80 (m, 2H), 7.78e7.75
d
5-(2-bromophenyl)-N-phenyl-1,3,4-oxadiazol-2-amine (3l) [24]
137.14, 131.33, 131.12, 129.80, 129.50, 127.01, 125.91, 124.46, 124.33,
121.49, 18.39. HRMS (ESI): m/z [MþH]þ Calcd for C15H14N3O:
252.1137; Found: 252.1142.
obtained as white solid in 74 % yield; M.p. 186e189 ꢀC; 1H NMR
(600 MHz, DMSO‑d6)
d 10.73 (s, 1H), 8.05e7.95 (m, 1H), 7.89 (d,
J ¼ 7.8 Hz, 1H), 7.79-7.77 (m, 1H), 7.62 (d, J ¼ 7.8 Hz, 2H), 7.55 (t,
5-phenyl-N-(m-tolyl)-1,3,4-oxadiazol-2-amine (4b) [13] ob-
J ¼ 7.9 Hz, 1H), 7.38 (t, J ¼ 7.9 Hz, 2H), 7.03 (t, J ¼ 7.3 Hz, 1H); 13C
tained as yellow solid in 71 % yield; M.p. 138e140 ꢀC; 1H NMR
NMR (150 MHz, DMSO‑d6)
d
160.60, 156.95, 138.94, 134.09, 132.11,
(600 MHz, DMSO‑d6)
(m, 3H), 7.47e7.40 (m, 2H), 7.25 (t, J ¼ 7.8 Hz, 1H), 6.84 (d, J ¼ 7.6 Hz,
1H), 2.32 (s, 3H); 13C NMR (150 MHz, DMSO‑d6)
160.40, 158.17,
d 10.60 (s, 1H), 7.93e7.87 (m, 2H), 7.62e7.56
129.61,128.35,126.46,124.99,122.77,122.52,117.62. HRMS (ESI): m/
z [MþH]þ Calcd for C14H11N3OBr: 316.0085; Found: 316.0087.
d
5-(3-chlorophenyl)-N-phenyl-1,3,4-oxadiazol-2-amine
(3m)
139.05, 138.83, 131.43, 129.82, 129.42, 126.00, 124.35, 123.14, 118.02,
[13] obtained as pale-yellow solid in 68 % yield; M.p. 179e181 ꢀC;
114.78, 21.77. HRMS (ESI): m/z [MþH]þ Calcd for
1H NMR (600 MHz, DMSO‑d6)
d
10.73 (s, 1H), 7.98e7.77 (m, 2H),
C
15H14N3O:252.1137; Found: 252.1143.
7.72e7.52 (m, 4H), 7.39-7.35 (m, 2H), 7.03 (t, J ¼ 7.4 Hz, 1H); 13C
5-phenyl-N-(p-tolyl)-1,3,4-oxadiazol-2-amine (4c) [13] ob-
NMR (150 MHz, DMSO‑d6)
d
160.61, 157.08, 138.95, 134.41, 131.90,
tained as white solid in 73 % yield; M.p. 212e214 ꢀC; 1H NMR
131.20, 129.60, 126.26, 125.49, 124.64, 122.52, 117.63. HRMS (ESI):
m/z [MþH]þ Calcd for C14H11N3OCl: 272.0591; Found: 272.0594.
5-propyl-N-phenyl-1,3,4-oxadiazol-2-amine (3n) obtained as
white solid in 61 % yield; M.p. 109e111 ꢀC; 1H NMR (600 MHz,
(600 MHz, DMSO‑d6)
(m, 3H), 7.51 (d, J ¼ 8.4 Hz, 2H), 7.18 (d, J ¼ 8.3 Hz, 2H), 2.27 (s, 3H);
13C NMR (150 MHz, DMSO‑d6)
160.49, 158.09, 136.63, 131.38,
d 10.55 (s, 1H), 7.94e7.84 (m, 2H), 7.64e7.54
d
131.24,129.96,129.82,125.97,124.39, 117.59, 20.80. HRMS (ESI): m/z
DMSO‑d6)
d
10.33 (s, 1H), 7.54 (d, J ¼ 7.7 Hz, 2H), 7.30e7.34 (m, 2H),
[MþH]þ Calcd for C15H14N3O: 252.1137; Found: 252.1143.
6.97 (t, J ¼ 7.4 Hz,1H), 2.73 (t, J ¼ 7.3 Hz, 2H),1.74e1.66 (m, 2H), 0.96
N-(4-(tert-butyl)
phenyl)-5-phenyl-1,3,4-oxadiazol-2-amine
(t, J ¼ 7.4 Hz, 3H); 13C NMR (150 MHz, DMSO‑d6)
d
160.25, 160.12,
(4d) obtained as white solid in 84 % yield; M.p. 233e235 ꢀC; 1H
NMR (600 MHz, DMSO‑d6) 10.56 (s, 1H), 7.94e7.85 (m, 2H),
7.61e7.55 (m, 3H), 7.53 (d, J ¼ 8.7 Hz, 2H), 7.39 (d, J ¼ 8.7 Hz, 2H),
1.28 (s, 9H); 13C NMR (150 MHz, DMSO‑d6)
160.54, 158.11, 144.75,
139.39, 129.48, 121.98, 117.24, 26.73, 19.88, 13.82. HRMS (ESI): m/z
d
[MþH]þ Calcd for C11H14N3O: 204.1137; Found: 204.1140.
5-isopropyl-N-phenyl-1,3,4-oxadiazol-2-amine (3o) obtained as
white solid in 57 % yield; M.p. 127e129 ꢀC; 1H NMR (600 MHz,
d
136.56, 131.39, 129.83, 126.22, 125.97, 124.39, 117.36, 34.42, 31.73.
HRMS (ESI): m/z [MþH]þ Calcd for C18H20N3O: 294.1606; Found:
294.1609.
DMSO‑d6) d 10.35 (s, 1H), 7.60-7.50 (m, 2H), 7.40e7.25 (m, 2H), 6.97
(t, J ¼ 7.4 Hz, 1H), 3.15e3.06 (m, 1H), 1.29 (d, J ¼ 7.0 Hz, 6H); 13C
NMR (150 MHz, DMSO‑d6)
d
164.22, 160.09, 139.40, 129.48, 121.97,
N-(4-methoxyphenyl)-5-phenyl-1,3,4-oxadiazol-2-amine (4e)
117.23, 25.88, 20.19. HRMS (ESI): m/z [MþH]þ Calcd for C11H14N3O:
[18] obtained as white solid in 80 % yield; M.p. 207e210 ꢀC; 1H NMR
204.1137; Found: 204.1139.
(600 MHz, DMSO‑d6)
(m, 2H), 7.52 (d, J ¼ 8.4 Hz, 2H), 6.96 (d, J ¼ 8.4 Hz, 2H), 3.74 (s, 3H);
13C NMR (150 MHz, DMSO‑d6)
160.65, 157.99, 154.95, 132.37,
d 10.45 (s, 1H), 8.00e7.79 (m, 2H), 7.68e7.63
5-cyclopropyl-N-phenyl-1,3,4-oxadiazol-2-amine (3p) obtained
as red solid in 54 % yield; M.p. 125e127 ꢀC; 1H NMR (600 MHz,
d
DMSO‑d6)
d
10.29 (s, 1H), 7.52 (d, J ¼ 8.0 Hz, 2H), 7.32 (t, J ¼ 7.8 Hz,
131.32, 129.80, 125.92, 124.43, 119.08, 114.83, 55.72. HRMS (ESI): m/
z [MþH]þ Calcd for C15H14N3O2: 268.1086; Found: 268.1091.
N-(4-fluorophenyl)-5-phenyl-1,3,4-oxadiazol-2-amine (4f) [18]
obtained as white solid in 74 % yield; M.p. 237e240 ꢀC; 1H NMR
2H), 6.96 (t, J ¼ 7.3 Hz, 1H), 2.19e2.04 (m, 1H), 1.10e1.02 (m, 2H),
0.97e0.89 (m, 2H); 13C NMR (150 MHz, DMSO‑d6)
d 161.53, 159.53,
139.33, 129.46, 121.96, 117.19, 7.35, 6.11. HRMS (ESI): m/z [MþH]þ
Calcd for C11H12N3O: 202.0980; Found: 202.0980.
(600 MHz, DMSO‑d6)
d 10.72 (s, 1H), 7.92 - 7.86 (m, 2H), 7.70 - 7.62
2-benzyl-5-(pyridin-2-yl)-1,3,4-oxadiazole (3q) [25] obtained
as white solid in % yield; M.p. 227e229 ꢀC; 1H NMR (600 MHz,
DMSO‑d6)
(m, 5H), 7.22 (t, J ¼ 8.2 Hz, 2H); 13C NMR (150 MHz, DMSO‑d6)
d
160.39, 158.59, 158.23, 157.01, 135.58, 131.47, 129.83, 126.02,
d
10.84 (s, 1H), 8.75e8.72 (m, 1H), 8.14e8.07 (m, 1H),
124.31, 119.17, 119.12, 116.26, 116.11. HRMS (ESI): m/z [MþH]þ Calcd
8.04e7.98 (m, 1H), 7.62 (m, 2H), 7.58e7.55 (m, 1H), 7.43e7.33 (m,
for C14H11N3OF: 256.0886; Found: 256.0891.
2H), 7.04 (t, J ¼ 7.4 Hz, 1H); 13C NMR (150 MHz, DMSO‑d6)
d
161.00,
N-(4-chlorophenyl)-5-phenyl-1,3,4-oxadiazol-2-amine (4g) [13]
obtained as pale-yellow solid in 73 % yield; M.p. 265e266 ꢀC; 1H
158.05, 150.53, 143.65, 138.96, 138.14, 129.61, 125.95, 122.54, 122.23,
117.61. HRMS (ESI): m/z [MþH]þ Calcd for C13H11N4O: 239.0933;
Found: 239.0931.
NMR (600 MHz, DMSO‑d6)
d 10.87 (s, 1H), 7.88e7.92 (m, 2H), 7.64
(d, J ¼ 8.2 Hz, 2H), 7.43e7.53 (m, 3H), 7.43 (d, J ¼ 8.2 Hz, 2H); 13C
2-benzyl-5-(thiophen-2-yl)-1,3,4-oxadiazole (3r) [13] obtained
NMR (150 MHz, DMSO‑d6) d 160.15, 158.38, 138.10, 131.54, 129.84,
as white solid in 65 % yield; M.p. 212e214 ꢀC; 1H NMR (600 MHz,
129.46, 126.07, 125.98, 124.24, 119.12. HRMS (ESI): m/z [MþH]þ
DMSO‑d6)
d
10.70 (s, 1H), 7.84e7.80 (m, 1H), 7.71e7.50 (m, 3H),
Calcd for C14H11N3OCl: 272.0591; Found: 272.0594.
7.37e7.26 (m, 3H), 7.02 (t, J ¼ 7.0 Hz, 1H); 13C NMR (150 MHz,
N-(2-chlorophenyl)-5-phenyl-1,3,4-oxadiazol-2-amine
obtained as yellow solid in 60 % yield; M.p. 136e139 ꢀC; 1H NMR
(600 MHz, DMSO‑d6)
10.04 (s, 1H), 8.06 (d, J ¼ 8.1 Hz, 1H),
7.96e7.84 (m, 2H), 7.61e7.56 (m, 3H), 7.50e7.54 (m, 1H), 7.44e7.37
(m, 1H), 7.20e7.11 (m, 1H); 13C NMR (150 MHz, DMSO‑d6)
160.97,
(4h)
DMSO‑d6)
d 159.81, 154.63, 138.99, 130.38, 129.58, 129.01, 128.79,
125.42, 122.42, 117.54. HRMS (ESI): m/z [MþH]þ Calcd for
d
C
12H10N3OS: 244.0545; Found: 244.0549.
2-benzyl-5-(furan-2-yl)-1,3,4-oxadiazole (3s) [21] obtained as
d
white solid in 62 % yield; M.p. 184e186 ꢀC; 1H NMR (600 MHz,
158.96, 135.73, 131.56, 130.31, 129.84, 128.45, 126.06, 125.34, 124.41,
124.26, 122.65. HRMS (ESI): m/z [MþH]þ Calcd for C14H11N3OCl:
272.0591; Found: 272.0596.
DMSO‑d6)
d
10.72 (s, 1H), 7.99 (d, J ¼ 1.6 Hz, 1H), 7.60 (d, J ¼ 7.8 Hz,
2H), 7.37 (t, J ¼ 7.9 Hz, 2H), 7.14 (d, J ¼ 3.5 Hz, 1H), 7.02 (t, J ¼ 7.3 Hz,
1H), 6.77 (dd, J ¼ 3.5, 1.7 Hz, 1H); 13C NMR (150 MHz, DMSO‑d6)
N-ethyl-5-phenyl-1,3,4-oxadiazol-2-amine (4i) [26] obtained as
d
159.74, 151.44, 146.45, 139.40, 138.94, 129.59, 122.48, 117.55,
white solid in 72 % yield; M.p. 109e111 ꢀC; 1H NMR (600 MHz,
112.84, 40.54. HRMS (ESI): m/z [MþH]þ Calcd for C12H10N3O2:
DMSO‑d6) d 7.84e7.80 (m, 2H), 7.78e7.70 (m, 1H), 7.56e7.49 (m,
228.0773; Found: 228.0775.
3H), 3.30 - 3.26 (m, 2H), 1.19 (t, J ¼ 7.2 Hz, 3H); 13C NMR (150 MHz,
7