The Journal of Organic Chemistry
Note
NMR (400 MHz, CDCl3) δ 9.50 (d, J = 6.9 Hz, 1H), 7.82 (d, J = 8.9
Hz, 1H), 7.57 (dd, J = 8.0 Hz, 7.8 Hz, 1H), 7.46 (d, J = 8.3 Hz, 2H),
7.30 (d, J = 8.3 Hz, 2H), 7.21 (d, J = 8.3 Hz, 2H), 7.15−7.12 (m, 3H)
ppm; 13C{1H} NMR (100 MHz, CDCl3) δ 185.6, 153.6, 147.5, 138.5,
136.9, 132.8, 131.6, 131.1, 130.9, 129.6, 128.2, 123.2, 119.8, 117.6,
114.9 ppm; HRMS (ESI-TOF) m/z [M + H]+ calcd for
C20H13BrClN2O 410.9900, found 410.9901.
TOF) m/z [M + H]+ calcd for C20H14ClN2O2 349.0744, found
349.0737.
3-(4-Chlorobenzoyl)-2-(4-hydroxy-3,5-dimethoxyphenyl)-
imidazo[1,2-a]pyridine (X): yellow solid; 194 mg, 48% yield, mp >
200 °C; 1H NMR (400 MHz, CDCl3) δ 9.50 (d, J = 5.0 Hz, 1H), 7.82
(d, J = 7.2 Hz, 1H), 7.56 (d, J = 7.8 Hz, 3H), 7.17 (d, J = 8.1 Hz, 2H),
7.11 (dd, J = 6.7 Hz, 6.6 Hz, 1H), 6.65 (s, 2H), 3.73 (s, 6H) ppm;
13C{1H} NMR (100 MHz, CDCl3) δ 185.6, 154.6, 147.4, 146.7,
138.4, 137.3, 135.7, 130.9, 129.5, 128.2, 124.7, 119.4, 117.3, 114.7,
107.6, 97.9, 56.2 ppm; HRMS (ESI-TOF) m/z [M + H]+ calcd for
C22H18ClN2O4 409.0955, found 409.0956.
3-(4-Chlorobenzoyl)-2-(4-fluorophenyl)imidazo[1,2-a]pyridine
1
(III): brown solid; 210 mg, 66% yield, mp = 162−165 °C; H NMR
(500 MHz, CDCl3) δ 9.50 (d, J = 6.8 Hz, 1H), 7.79 (d, J = 8.8 Hz,
1H), 7.55 (dd, J = 7.5 Hz, 7.9 Hz, 1H), 7.43 (d, J = 8.4 Hz, 2H),
7.30−7.27 (m, 2H), 7.12−7.08 (m, 3H), 6.84 (t, J = 8.4 Hz, 2H)
ppm; 13C{1H} NMR (100 MHz, CDCl3) δ 185.7, 162.9 (C−F, 1JC−F
= 246 Hz), 153.9, 147.5, 138.3, 136.9, 132.0, 131.9, 130.9, 130.0,
3-(4-Chlorobenzoyl)-2-(quinolin-3-yl)imidazo[1,2-a]pyridine (XI):
1
light yellow solid; 268 mg, 70% yield, mp = 186−189 °C; H NMR
(400 MHz, CDCl3) δ 9.60 (d, J = 6.8 Hz, 1H), 8.80 (s, 1H), 8.24 (s,
1H), 8.04 (d, J = 8.4 Hz, 1H), 7.90 (d, J = 8.9 Hz, 1H), 7.76−7.69
(m, 2H), 7.64 (dd, J = 8 Hz, 7.8 Hz, 1H), 7.56 (dd, J = 7.5 Hz, 7.4
Hz, 1H), 7.50 (d, J = 8.3 Hz, 2H), 7.20 (dd, J = 6.8 Hz, 6.9 Hz, 1H),
7.01 (d, J = 8.3 Hz, 2H) ppm; 13C{1H} NMR (100 MHz, CDCl3) δ
185.6, 150.8, 147.9, 147.2, 138.5, 137.0, 136.7, 130.8, 130.3, 129.9,
129.1, 128.4, 128.4, 127.9, 127.1, 127.0, 120.5, 117.6, 115.2 ppm;
HRMS (ESI-TOF) m/z [M + H]+ calcd for C23H15ClN3O 384.0904,
found 384.0901.
2
130.0, 129.6, 128.2, 128.2, 119.8, 117.5, 115.0 (C−F, JC−F = 21.7
Hz), 114.9 ppm; 19F NMR (470 MHz, CDCl3) δ −112.05 ppm;
HRMS (ESI-TOF) m/z [M + H]+ calcd for C20H13ClFN2O
351.0700, found 351.0698.
3-(4-Chlorobenzoyl)-2-(4-cyanophenyl)imidazo[1,2-a]pyridine
1
(IV): light yellow solid; 256 mg, 72% yield, mp = 185−187 °C; H
NMR (400 MHz, CDCl3) δ 9.49 (d, J = 6.9 Hz, 1H), 7.84 (d, J = 8.9
Hz, 1H), 7.60 (dd, J = 8.2 Hz, 7.5 Hz, 1H), 7.46 (m, 6H), 7.16 (m,
3H) ppm; 13C{1H} NMR (100 MHz, CDCl3) δ 185.4, 152.3, 147.6,
138.9, 138.5, 136.7, 131.6, 130.9, 130.7, 129.9, 128.4, 128.2, 120.1,
118.4, 117.8, 115.4, 112.1 ppm. HRMS (ESI-TOF) m/z [M + H]+
calcd for C21H13ClN3O 358.0747, found 358.0739.
3-(4-Chlorobenzoyl)-2-(quinolin-4-yl)imidazo[1,2-a]pyridine
1
(XII): faint white solid; 153 mg, 40% yield, mp = 178−179 °C; H
NMR (400 MHz, DMSO-d6) δ 9.33 (d, J = 6.8 Hz, 1H), 8.41 (d, J =
4.3 Hz, 1H), 7.76 (d, J = 8.9 Hz, 1H), 7.72 (d, J = 8.4 Hz, 1H), 7.67
(d, J = 8.3 Hz, 1H), 7.57 (dd, J = 7.9, 7.5 Hz 1H), 7.51 (dd, J = 7.4,
7.3 Hz, 1H), 7.32 (dd, J = 8.3, 7.4 Hz, 1H), 7.20 (dd, J = 6.8, 6.7 Hz,
1H), 7.08 (d, J = 4.3 Hz, 1H), 6.99 (d, J = 8.2 Hz, 2H), 6.55 (d, J =
8.2 Hz, 2H) ppm; 13C{1H} NMR (100 MHz, DMSO-d6) δ 190.1,
155.6, 154.2, 152.5, 152.3, 145.2, 142.6, 141.1, 135.7, 135.0, 134.6,
134.1, 133.5, 132.2, 132.1, 131.3, 130.9, 128.7, 126.9, 122.6, 121.0
ppm; HRMS (ESI-TOF) m/z [M + H]+ calcd for C23H15ClN3O
384.0904, found 384.0910.
3-(4-Chlorobenzoyl)-2-(4-nitrophenyl)imidazo[1,2-a]pyridine
1
(V): light yellow solid; 236 mg, 63% yield, mp = 230−233 °C; H
NMR (400 MHz, CDCl3) δ 9.49 (d, J = 6.8 Hz, 1H), 8.04 (d, J = 8.4
Hz, 2H), 7.86 (d, J = 8.9 Hz, 1H), 7.62 (dd, J = 8 Hz, 7.8 Hz, 1H),
7.54 (d, J = 8.4 Hz, 2H), 7.49 (d, J = 8.2 Hz, 2H) 7.20−7.14 (m, 3H)
ppm; 13C{1H} NMR (100 MHz, CDCl3) δ 185.3, 151.7, 147.6, 147.4,
140.4, 139.0, 136.8, 131.0, 130.9, 129.9, 128.4, 128.2, 123.0, 120.3,
117.8, 115.4 ppm; HRMS (ESI-TOF) m/z [M + H]+ calcd for
C20H13ClN3O3 378.0645, found 378.0642.
8-(Benzyloxy)-3-(4-chlorobenzoyl)-2-(4-cyanophenyl)imidazo-
[1,2-a]pyridine (XIII): brown solid; 253 mg, 56% yield, mp = 206−208
3-(4-Chlorobenzoyl)-2-(p-tolyl)imidazo[1,2-a]pyridine (VI): light
1
1
°C; H NMR (400 MHz, CDCl3) δ 9.04 (d, J = 6.8 Hz, 1H), 7.53−
yellow solid; 190 mg, 55% yield, mp = 167−169 °C; H NMR (400
7.50 (m, 4H), 7.47−7.34 (m, 7H), 7.14 (d, J = 8.4 Hz, 2H), 6.97 (dd,
J = 7.6, 7.0 Hz, 1H), 6.86 (d, J = 7.6 Hz, 1H), 5.46 (s, 2H) ppm;
13C{1H} NMR (100 MHz, CDCl3) δ 185.5, 151.2, 147.8, 141.9,
MHz, CDCl3) δ 9.53 (d, J = 6.9 Hz, 1H), 7.81 (d, J = 8.9 Hz, 1H),
7.54 (dd, J = 7.9 Hz, 7.8 Hz, 1H), 7.45 (d, J = 8.4 Hz, 2H), 7.21 (d, J
= 7.9 Hz, 2H), 7.12−7.07 (m, 3H), 6.95 (d, J = 7.8 Hz, 2H), 2.30 (s,
3H) ppm; 13C{1H} NMR (100 MHz, CDCl3) δ 185.9, 155.3, 147.5,
138.7, 137.9, 137.1, 130.9, 130.8, 130.1, 129.4, 128.6, 128.2, 128.0,
119.7, 117.4, 114.6, 21.2 ppm; HRMS (ESI-TOF) m/z [M + H]+
calcd for C21H16ClN2O 347.0951, found 347.0956.
138.9, 138.4, 136.6, 135.6, 131.4, 130.9, 128.8, 128.3, 127.2, 121.0,
120.7, 118.4, 115.1, 111.9, 108.3, 71.1 ppm; HRMS (ESI-TOF) m/z
[M + H]+ calcd for C28H19ClN3O2 464.1166, found 464.1161.
3-(4-Methoxybenzoyl)-2-(4-methoxyphenyl)imidazo[1,2-a]-
pyridine (XIV): brown solid; 161 mg, 45% yield, mp = 198−200 °C;
1H NMR (400 MHz, CDCl3) δ 9.37 (d, J = 6.8 Hz, 1H), 7.76 (d, J =
8.0 Hz, 1H), 7.56 (d, J = 7.4 Hz, 2H), 7.47 (dd, J = 7.8, 7.8, 1H), 7.33
(d, J = 7.8 Hz, 2H), 7.03 (dd, J = 6.8, 6.8 Hz, 1H), 6.67 (d, J = 7.9 Hz,
2H), 6.64 (d, J = 7.5 Hz, 2H), 3.75 (s, 3H), 3.74 (s, 3H) ppm;
13C{1H} NMR (100 MHz, CDCl3) δ 186.2, 162.5, 159 6, 153.4,
3-(4-Chlorobenzoyl)-2-(4-methoxyphenyl)imidazo[1,2-a]-
pyridine (VII): light yellow solid; 256 mg, 71% yield, mp = 101−103
°C; 1H NMR (400 MHz, CDCl3) δ 9.55 (d, J = 6.9 Hz, 1H), 7.81 (d,
J = 8.9 Hz, 1H), 7.55 (dd, J = 7.4 Hz, 7.8 Hz 1H), 7.47 (d, J = 8.4 Hz,
2H), 7.26 (d, J = 8.7 Hz, 3H), 7.12−7.09 (m, 2H), 6.68 (d, J = 8.7
Hz, 2H), 3.56 (s, 3H) ppm; 13C{1H} NMR (100 MHz, CDCl3) δ
185.9, 160.1, 137.8, 137.1, 131.6, 130.9, 129.4, 128.3, 128.0, 126.1,
117.3, 114.6, 113.5, 55.4 ppm; HRMS (ESI-TOF) m/z [M + H]+
calcd for C21H16ClN2O2 363.0900, found 363.0908.
147.1, 131.9, 131.5, 131.1, 128.6, 127.9, 126.4, 119.6, 117.1, 114.0,
113.4, 113. 2, 55.3, 55.2 ppm; HRMS (ESI-TOF) m/z [M + H]+
calcd for C22H19N2O3 359.1396, found 359.1384.
3-(4-Chlorobenzoyl)-2-(3,4,5-trimethoxyphenyl)imidazo[1,2-a]-
pyridine (VIII): white solid; 350 mg, 83% yield, mp = 128−130 °C; 1H
NMR (400 MHz, CDCl3) δ 9.57 (d, J = 7.0 Hz, 1H), 7.84 (d, J = 8.9
Hz, 1H), 7.59 (ddd, J = 1.2 Hz, 8.3 Hz, 8.8 Hz, 1H), 7.51 (d, J = 8.5
Hz, 2H), 7.22−7.07 (m, 3H), 6.59 (s, 2H), 3.81 (s, 3H), 3.72 (s, 6H)
ppm; 13C{1H} NMR (100 MHz, CDCl3) δ 185.6, 154.9, 152.8, 147.4,
138.9, 138.2, 137.4, 130.7, 129.6, 129.2, 128.3, 128.0, 119.7, 117.4,
114.9, 107.8, 61.1, 56.0 ppm; HRMS (ESI-TOF) m/z [M + H]+ calcd
for C23H20ClN2O4 423.1112, found 423.1115.
3-(4-Methoxybenzoyl)-2-(3,4,5-trimethoxyphenyl)imidazo[1,2-
a]pyridine (XV): off-white solid; 221 mg, 53% yield, mp = 125−127
°C; 1H NMR (400 MHz, CDCl3) δ 9.41 (d, J = 6.9 Hz, 1H), 7.80 (d,
J = 8.9 Hz, 1H), 7.61 (d, J = 8.8 Hz, 2H), 7.51 (ddd, J = 6.9, 6.8, 1.1,
1H), 7.08 (ddd, J = 6.9, 6.9, 1.0 Hz, 1H), 6.69−6.67 (m, 4H), 3.79 (s,
3H), 3.77 (s, 3H), 3.70 (s, 6H) ppm; 13C{1H} NMR (100 MHz,
CDCl3) δ 185.9, 162.9, 153.4, 152.7, 147.0, 138.3, 131.8, 131.3, 129.3,
128.8, 128.0, 119.8, 117.2, 114.3, 113.2, 107.6, 60.8, 55.9, 55.4 ppm;
HRMS (ESI-TOF) m/z [M + H]+ calcd for C24H23N2O5 419.1607,
found 419.1604.
6-Chloro-3-(4-methoxybenzoyl)-2-(4-cyanophenyl)imidazo[1,2-
a]pyridine (XVI): light yellow solid; 238 mg, 62% yield, mp = 198−
200 °C; 1H NMR (400 MHz, CDCl3) δ 9.40 (s, 1H), 7.74 (d, J = 9.4
Hz, 1H), 7.54−7.44 (m, 7H), 6.65 (d, J = 8.56, 2H), 3.79 (s, 3H)
ppm; 13C{1H} NMR (100 MHz, CDCl3) δ 185.4, 163.5, 151.0, 145.5,
138.3, 132.0, 131.6, 130.6, 130.4, 130.2, 125.9, 123.2, 120.6, 118.5,
3-(4-Chlorobenzoyl)-2-(4-hydroxyphenyl)imidazo[1,2-a]pyridine
1
(IX): light yellow solid; 140 mg, 40% yield, mp = 191−192 °C; H
NMR (400 MHz, CDCl3) δ 9.53 (d, J = 5.9 Hz, 1H), 7.80 (d, J = 8.6
Hz, 1H), 7.58 (dd, 7.6 Hz, 7.6 Hz, 1H), 7.47 (d, J = 7.6 Hz, 2H), 7.13
(s, 5H), 6.55 (d, J = 7.0 Hz, 2H) ppm; 13C{1H} NMR (100 MHz,
CDCl3) δ 186.0, 157.6, 154.6, 147.2, 138.0, 136.9, 131.7, 131.0, 129.9,
128.3, 128.1, 124.5, 119.4, 116.8, 115.3, 114.9 ppm; HRMS (ESI-
5384
J. Org. Chem. 2021, 86, 5380−5387