Synthesis of Coumarin-benzotriazole Hybrids and Evaluation of their Anti-tubercular Activity
Letters in Organic Chemistry, 2018, Vol. 15, No. 1 25
2.1.3.2. 4-((5-((1H-benzo[d][1,2,3]triazol-1-yl)methyl)-
1,3,4-oxadiazol-2-ylthio)methyl)-7,8-dimethyl-2H-
chromen-2-one (5b)
CDCl3, δ ppm): 32.19, 42.54, 116.13, 117.31, 119.53, 119.92,
120.36, 124.25, 130.09, 132.31, 133.05, 134.21, 144.37,
150.04, 152.64, 154.99, 160.51, 161.12, 162.14 ESI-MS: 409
[M+1]: Anal. calcd for C19H13N5O4S- C, 56.01; H, 3.`22; N,
17.19%. Found: C, 56.11; H, 3.14; N, 17.27%.
Off-white solid; Mp 141-142 °C; IR (KBr) (vmax/cm-1):
1704 (C=O of coumarin), 1611 (C=N of triazole) cm-1, 971
1
(C-S),; H NMR (400 MHz, CDCl3, δ ppm): 2.31 (s, 3H,
2.1.3.6. 4-((5-((1H-benzo[d][1,2,3]triazol-1-yl)methyl)-
1,3,4-oxadiazol-2-ylthio)methyl)-6- methoxy-2H-chromen-
2-one (5f)
CH3), 2.66 (s, 3H, CH3), 4.83 (s, 2H, CH2,), 6.40 (s, 2H,
CH2), 6.50 (s, 1H, Ar-H), 7.07 (d, 1H, Ar-H), 7.43-7.49 (m,
1H, Ar- H), 7.60-7.61 (m, 1H, Ar-H), 7.88 (d, 1H, J = 10.8
Hz, Ar-H), 8.09 (d, 1H, J = 5.6 Hz, Ar-H),13C NMR (300
MHz, CDCl3, δ ppm): ): 20.56, 23.27, 36.13, 41.98, 110.44,
114.61, 115.71, 117.94, 119.31, 124.37, 127.12, 127.94,
129.89, 132.88, 135.84, 142.21, 150.72, 154.81, 159.00,
163.05; ESI-MS: 421.12[M+2]+: Anal calcd for C21H17N5O3S:
C, 60.13; H, 4.09; N, 16.70%. Found: C, 60.19; H, 4.16; N,
16.56%.
Off white solid: Mp 152-153 °C; IR (KBr) (vmax/cm-1):
1706 (C=O of coumarin), 1617 (C=N of triazole) cm-1, 947
1
(C-S); H NMR (300 MHz, CDCl3, δ ppm): 3.82 (s, 3H, -
OCH3), 4.73 (s, 2H, -CH2), 6.39 (s, 2H, -CH2), 6.54 (s, 1H),
7.23-7.27 (m, 1H), 7.37-7.48 (m, 3H), 7.49-7.56 (m, 1H), 7.86
(d, 1H, J = 8.4 Hz), 8.10 (d, 1H, J = 11.4 Hz, H), 13C NMR
(300 MHz, CDCl3, δ ppm): 32.33. 41.99, 55.65, 108.20,
110.40, 110.51, 116.06, 117.89, 119.32, 119.49, 125.08,
128.077, 132.67, 144.81, 147.52, 149.71, 155.85, 159.62,
163.75; ESI-MS: 422.2 [M+2]+: Anal calcd for C20H15N5O4S:
C, 57.00; H, 3.59; N, 16.62%, Found: C, 56.90; H, 3.64; N,
16.70%.
2.1.3.3. Ethyl 4-((5-((1H-benzo[d][1,2,3]triazol-1-
yl)methyl)-1,3,4-oxadiazol-2-ylthio)methyl)-2-oxo-2H-
chromen-7-ylcarbamate (5c)
Off-white colour powder; Mp 129-130°C; IR (KBr)
(vmax/cm-1): 3284 (NH), 1703 (C=O of coumarin), 1686
(NHC=O); 1615 (C=N of triazole) cm-1, 946 (C-S),; 1H NMR
(300 MHz, CDCl3, δ ppm): 1.28 (t, 3H, J = 6.9 Hz, CH3),
4.18 (q, 2H, J = 7.2 Hz, CH2), 4.65 (s, 2H, CH2, C4), 6.38 (s,
2H, CH2), 6.40 (s, 2H, CH2), 7.39-7.47 (m, 2H, H), 7.57-7.59
(m, 2H, H), 7.83-7.84 (m, 2H, H), 8.10 (d, 1H, J = 8.2 Hz,
H), 10.19 (s, 1H, N-H); 13C NMR (300 MHz, CDCl3, δ ppm):
14.35, 31.92, 41.97, 60.73, 104.67, 110.44, 112.03, 112.94,
114.26, 119.32, 124.37, 125.79, 127.95, 132.87, 143.13,
145.11, 149.80, 153.28, 154.28,159.58, 162.93, 163.61. ESI-
MS: 477.08 [M-1]+: Anal. calcd for C22H18N6O5S: C, 55.22;
H, 3.79; N, 17.56 %. Found: C, 55.13; H, 3.86; N, 17.51%.
2.1.3.7. 4-((5-((1H-benzo[d][1,2,3]triazol-1-yl)methyl)-
1,3,4-oxadiazol-2-ylthio)methyl)-5,7-dimethyl-2H-
chromen-2-one (5g)
Pale yellow powder: Mp 129-130 °C; IR (KBr) (vmax/cm-1):
1702 (C=O of coumarin), 1623 (C=N of triazole) cm-1, 963
1
(C-S),; H NMR (400 MHz, CDCl3, δ ppm): : 2.35 (s, 3H,
CH3), 2.68 (s, 3H, CH3), 4.82 (s, 2H, CH2), 6.39 (s, 2H,
CH2), 6.49 (s, 1H, Ar-H), 7.05-7.12 (d, 2H, Ar-H), 7.42-7.49
(m, 1H, Ar-H), 7.56-7.60 (m, 1H, Ar-H), 7.86 (d, 1H, J = 8.4
Hz, Ar-H), 8.08 (d, 1H, J = 8.0 Hz, Ar-H), 13C NMR (300
MHz, CDCl3, δ ppm): 20.56, 23.27, 36.13, 41.98, 110.44,
114.61, 115.71, 117.94, 119.31, 124.37, 127.12, 127.94,
129.89, 132.89, 135.84, 142.21, 145.11, 150.72, 154.82,
159.00, 163.05; ESI-MS: 418.27 [M+2]-: Anal calcd for
C21H17N5O3S: C, 60.13; H, 4.09; N, 16.70%. Found: C,
60.23; H, 4.13; N, 16.61%.
2.1.3.4. Methyl 4-((5-((1H-benzo[d][1,2,3]triazol-1-
yl)methyl)-1,3,4-oxadiazol-2-ylthio)methyl)-2-oxo-2H-
chromen-7-ylcarbamate (5d)
Off-white solid; Mp 136-137°C; IR (KBr) (vmax/cm-1):
3281 (NH), 1707 (C=O of coumarin carbonyl), 1691
(NHC=O); 1619 (C=N of triazole) cm-1, 941 (C-S),; 1H NMR
(300 MHz, CDCl3, δ ppm): 10.23 (s, 1H, N-H), 8.09 (d, 1H,
J = 7.6 Hz, Ar-H), 7.76 (d, 1H, J = 8.8 Hz, Ar-H), 7.63-7.57
(m, 2H, H), 7.40 (d, 2H, J = 8.8 Hz, Ar-H), 6.55 (s, 1H, H),
6.42 (s, 2H, CH2), 5.36 (s, 2H, CH2, C4), 3.73 (s, 3H, CH3),
13C NMR (300 MHz, CDCl3, δ ppm) : 29.29, 35.51, 45.13,
105.17, 110.22, 112.63, 113.02, 114.13, 115.03, 116.49,
119.42, 124.23, 127.11, 128.34, 131.12, 132.18, 133.52,
143.12, 145.10, 153.03, 154.49, 159.76, 162.04, 162.70; ESI-
MS: 465.39 [M]+: Anal. calcd for C21H16N6O5S-C, 54.31; H,
3.47; N, 18.09 %. Found: C, 54.22; H, 3.53; N, 18.15%.
2.1.3.8. 4-((5-((1H-benzo[d][1,2,3]triazol-1-yl)methyl)-
1,3,4-oxadiazol-2-ylthio)methyl)-6-chloro-2H-chromen-2-
one (5h)
Pale yellow powder: Mp 146-147°C; IR (KBr) (vmax/cm-1):
1721 (C=O of coumarin), 1609 (C=N of triazole) cm-1, 976
1
(C-S),; H NMR (400 MHz, CDCl3, δ ppm): 4.42 (s, 2H,
CH2), 6.38 (s, 2H, CH3), 6.58 (s, 1H), 7.26 (d, 1H, J = 3.2
Hz), 7.38-7.48 (m, 2H), 7.64 (s, 1H, Ar-H), 7.78 (d, 1H, J =
7.2 Hz), 8.06 (d, 1H, J = 12.6 Hz), 13C NMR (400 MHz, CD-
Cl3, δ ppm): 32.12, 43.14, 116.82, 117.54, 118.51, 119.02,
120.26, 124.35, 130.29, 132.41, 133.85, 144.27, 150.35,
154.01, 160.51, 162.24. 163.01; ESI-MS: 425.4 [M]+, 426.4
[M+1]+: Anal calcd for C19H12ClN5O3S: C, 53.59; H, 2.84;
N, 16.45% . Found: C, 53.68; H, 2.76; N, 16.38%.
2.1.3.5. 4-((5-((1H-benzo[d][1,2,3]triazol-1-yl)methyl)-1,3,
4-oxadiazol-2-ylthio)methyl)-7-hydroxy-2H-chromen-2-one
(5e)
2.1.3.9. 4-((5-((1H-benzo[d][1,2,3]triazol-1-yl)methyl)-
1,3,4-oxadiazol-2-ylthio)methyl)-7-chloro-2H-chromen-2-
one (5i)
Light brown colour: Mp 146-147°C; IR (KBr) (vmax/cm-1):
1719 (C=O of coumarin), 1611 (C=N of triazole) cm-1, 971
1
(C-S),; H NMR (300 MHz, CDCl3, δ ppm): 4.52 (s, 2H,
CH2), 6.30 (s, 2H, CH2), 6.62 (s, 1H, H), 7.27-7.35 (m, 1H,
H), 7.41-7.46 (m, 3H, H), 7.57 (d, 1H, H), 7.63 (d, 1H, J =
5.4 Hz, H), 8.02 (d, 1H, J = 6.6 Hz, H), 13C NMR (300 MHz,
Off-white powder: Mp 116-117°C; IR (KBr) (vmax/cm-1):
1718 (C=O of coumarin), 1606 (C=N of triazole) cm-1, 969
1
(C-S),; H NMR (400 MHz, CDCl3, δ ppm): 4.52 (s, 2H,