Molecules 2019, 24, 174
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6-Chloro-2-methylbenzo[d]thiazole (4b) [43]: The product was obtained as yellow solid in 85% yield. m.p.:
◦
79–82 C 1H-NMR
δ
7.80 (d, J = 8.6 Hz, 1H), 7.74 (s, 1H), 7.35 (d, J = 8.6 Hz, 1H), 2.78 (s, 3H). 13C-NMR
δ 167.78, 151.49, 136.64, 130.79, 126.85, 123.05, 121.08, 20.13. (See Supplementary Materials).
5-Chlo◦ro-2-methylbenzo[d]thiazole (4c) [43]: The product was obtained as white solid in 80% yield. m.p.:
60–62 C. 1H-NMR
δ 7.93 (d, J = 2.0 Hz, 1H), 7.73 (d, J = 8.5 Hz, 1H), 7.33 (d, J = 6.5 Hz, 1H), 2.84 (s, 3H).
13C-NMR
δ 169.04, 154.13, 133.85, 132.00, 125.24, 122.29, 122.09, 20.23. (See Supplementary Materials).
2-Methyl-6-nitrobenzo[d]thiazole (4d) [44]: The product was obtained as yellow solid in 75% yield. m.p.:
◦
1
161–162 C. H-NMR
δ 8.78 (s, 1H), 8.34 (d, J = 6.7 Hz, 1H), 8.04 (d, J = 8.9 Hz,1H), 2.93 (s, 3H).
13C-NMR
δ
173.30, 157.09, 144.81, 136.02, 122.65, 121.59, 118.01, 20.71. (See Supplementary Materials).
2-(4-Methoxyp◦henyl)benzo[d]thiazole (4e) [21]: The product was obtained as white solid in 87% yield.
m.p.: 119–120 C. 1H-NMR
δ 8.04 (d, J = 8.6 Hz, 3H), 7.87 (d, J = 7.6 Hz, 1H), 7.47 (t, J = 7.4 Hz, 1H), 7.35
(t, J = 7.6 Hz, 1H), 7.00 (d, J = 8.8 Hz, 2H), 3.87 (s, 3H).13C-NMR
δ 167.91, 161.96, 154.11, 134.80, 129.15,
126.36, 126.25, 124.83, 122.80, 121.53, 114.57, 114.39, 77.26, 77.13, 55.49. (See Supplementary Materials).
2-Phenylbenzo[d]thiazole (4f) [21]: The product was obtained as white solid in 79% yield. m.p.:
◦
1
111–113 C. H-NMR
δ
8.12–8.08 (m, 3H), 7.91 (d, J = 8.0 Hz, 1H), 7.50 (p, J = 4.1 Hz, 4H), 7.39
168.15, 153.99, 135.00, 133.52, 131.06, 129.07, 127.62, 126.39, 125.26, 123.23,
(t, J = 7.6 Hz, 1H). 13C-NMR
δ
121.66. (See Supplementary Materials).
2-(4-Nitrophenyl)benzo[d]thiazole (4g) [45]: The product was obtained as yellow solid in 60% yield. m.p.:
224–226 ◦C. 1H-NMR
δ
8.29 (d, J = 8.9 Hz, 2H), 8.21 (d, J = 8.8 Hz, 2H), 8.07 (d, J = 8.2 Hz, 1H), 7.89 (d,
J = 7.8 Hz, 1H), 7.51–7.48 (m, 1H), 7.42–7.39 (m,1H). 13C-NMR
δ
163.82, 153.08, 148.02, 138.16, 134.46,
127.23, 125.90, 125.21, 123.30, 122.92, 120.82. (See Supplementary Materials).
2-(4-Chlorophenyl)benzo[d]thiazole (4h) [46]: The product was obtained as white solid in 82% yield. m.p.:
114–115 ◦C. 1H-NMR)
δ
8.07 (d, J = 8.2 Hz, 1H), 8.04–8.01 (m, 2H), 7.90 (dd, J = 8.0, 1.1 Hz, 1H), 7.50
(ddd, J = 8.2, 7.1, 1.2 Hz, 1H), 7.47–7.45 (m, 2H), 7.41–7.38 (m, 1H). 13C-NMR
δ
166.65, 154.02, 137.06,
135.04, 132.08, 129.29, 128.73, 126.52, 125.45, 123.30, 121.67. (See Supplementary Materials).
2-(2-Chlorophenyl)benzo[d]thiazole (4i) [46]: The product was obtained as white solid in 79% yield. m.p.:
81–83 ◦C. 1H-NMR
δ
8.24–8.19 (m, 1H), 8.16–8.12 (m, 1H), 7.95 (dd, J = 8.1, 1.1 Hz, 1H), 7.57–7.51 (m,
2H), 7.47–7.39 (m, 3H). 13C-NMR
δ
164.20, 152.38, 136.05, 132.71, 132.19, 131.76, 131.17, 130.81, 127.12,
126.32, 125.47, 123.43, 121.40. (See Supplementary Materials).
2-(Pyridin-2-yl)benzo[d]thiazole (4j) [47]: The product was obtained as white solid in 75% yield. m.p.:
◦
1
133–135 C. H-NMR)
7.97 (d, J = 7.6 Hz, 1H), 7.86 (t, J = 7.7 Hz, 1H), 7.51 (t, J = 7.0 Hz, 1H), 7.44–7.38 (m, 2H). 13C-NMR
169.35, 154.22, 151.37, 149.65, 137.05, 136.11, 126.30, 125.67, 125.29, 123.57, 122.02, 120.81. (See
δ 8.70 (d, J = 4.0 Hz, 1H), 8.39 (d, J = 8.0 Hz, 1H), 8.10 (d, J = 8.2 Hz, 1H),
δ
Supplementary Materials).
3-Benzothiazol-2-yl-1-phenyl-propan-1-one (4k) [48]: The product was obtained as white solid in 82%
yield. m.p.: 93–95 ◦C. 1H-NMR
δ 8.02 (d, J = 7.8 Hz, 2H), 7.95 (d, J = 8.1 Hz, 1H), 7.83 (d, J = 8.0 Hz,
1H), 7.57 (t, J = 7.4 Hz, 1H), 7.50–7.40 (m, 3H), 7.34 (t, J = 7.6 Hz, 1H), 3.66 (t, J = 7.1 Hz, 2H), 3.57 (t,
J = 7.1 Hz, 2H). 13C-NMR δ 197.87, 170.59, 153.09, 136.50, 135.24, 133.36, 128.69, 128.14, 125.97, 124.85,
122.52, 121.54, 37.64, 28.29. (See Supplementary Materials).
Supplementary Materials: The following are available online, general procedure for 2-substituted benzoxazoles
and 2-substituted benzothiazoles of cyclization reaction and 1H-NMR and 13C-NMR spectra of all products.
Author Contributions: Q.T. and J.Y. conceived and designed the experiments; Q.T. and W.L. performed the
experiments; Z.G. data curation; D.L. and X.W. analyzed the data; H.W., Z.D. and D.L. contributed reagents/
materials/analysis tools; Q.T. wrote the paper.
Funding: This study was financially supported by the Chongqing science and Technology Commission
(cstc2018jscx-msybx0294).