PAPER
Synthesis of Benzothiazoles from 1-Iodo-2-nitrobenzenes
949
1H NMR (400 MHz, CDCl3): δ = 8.10–8.11 (m, 1 H), 8.07 (d, J =
8.0 Hz, 1 H), 7.93 (d, J = 8.8 Hz, 1 H), 7.90 (d, J = 8.4 Hz, 1 H),
7.50 (t, J = 8.2 Hz, 1 H), 7.38–7.46 (m, 3 H).
13C NMR (100 MHz, CDCl3): δ = 166.23, 153.89, 135.17, 135.08,
135.01, 130.81, 130.21, 127.32, 126.49, 125.63, 125.51, 123.38,
121.65.
7.22–7.30 (m, 5 H), 3.42 (t, J = 8.0 Hz, 2 H), 3.21 (t, J = 8.0 Hz, 2
H).
13C NMR (100 MHz, CDCl3): δ = 170.89, 153.14, 140.14, 135.07,
128.54, 128.39, 126.39, 125.90, 124.72, 122.53, 121.48, 35.96,
35.49.
2-Methyl-1,3-benzothiazole (3ar)11a
Yellow oil; yield: 48 mg (0.32 mmol, 32%).
1H NMR (400 MHz, CDCl3): δ = 7.95 (d, J = 8.4 Hz, 1 H), 7.82 (d,
J = 8.0 Hz, 1 H), 7.45 (t, J = 7.2 Hz, 1 H), 7.34 (t, J = 8.0 Hz, 1 H),
2.84 (s, 3 H).
13C NMR (100 MHz, CDCl3): δ = 166.92, 153.34, 135.61, 125.88,
124.66, 122.35, 121.36, 20.10.
2-(2-Chlorophenyl)-1,3-benzothiazole (3ak)11a
Colorless solid; yield: 178.9 mg (0.73 mmol, 73%); mp 80–82 °C.
1H NMR (400 MHz, CDCl3): δ = 8.18–8.21 (m, 1 H), 8.12 (d, J =
8.0 Hz, 1 H), 7.91 (d, J = 8.0 Hz, 1 H), 7.48–7.52 (m, 2 H), 7.36–
7.42 (m, 3 H).
13C NMR (100 MHz, CDCl3): δ = 164.05, 152.39, 136.00, 132.59,
132.15, 131.65, 131.04, 130.71, 127.02, 126.20, 125.35, 123.36,
121.30.
1,3-Benzothiazole (3as)10a
Colorless oil; yield: 32 mg (0.24 mmol, 24%).
1H NMR (400 MHz, CDCl3): δ = 8.98 (s, 1 H), 8.14 (d, J = 8.4 Hz,
1 H), 7.95 (d, J = 8.0 Hz, 1 H), 7.51 (t, J = 8.4 Hz, 1 H), 7.43 (t, J =
8.0 Hz, 1 H).
13C NMR (100 MHz, CDCl3): δ = 153.82, 153.14, 133.60, 126.07,
125.45, 123.54, 121.79.
2-(1-Naphthyl)-1,3-benzothiazole (3al)11a
White solid; yield: 211 mg (0.81 mmol, 81%); mp 78–80 °C.
1H NMR (400 MHz, CDCl3): δ = 8.93 (d, J = 8.4 Hz, 1 H), 8.19 (d,
J = 8.0 Hz, 1 H), 7.90–7.97 (m, 4 H), 7.61 (dt, J = 7.6, 1.4 Hz, 1 H),
7.51–7.57 (m, 3 H), 7.43 (t, J = 8.0 Hz, 1 H).
13C NMR (100 MHz, CDCl3): δ = 167.56, 154.06, 135.36, 133.91,
131.02, 130.73, 130.54, 129.35, 128.35, 127.60, 126.46, 126.22,
125.79, 125.24, 124.94, 123.48, 121.35.
5-Methoxy-2-phenyl-1,3-benzothiazole (3ba)24
White solid; yield: 202 mg (0.84 mmol, 84%); mp 75–77 °C.
1H NMR (400 MHz, CDCl3): δ = 8.04–8.06 (m, 2 H), 7.71 (d, J =
8.8 Hz, 1 H), 7.57 (d, J = 2.4 Hz, 1 H), 7.46–7.47 (m, 3 H), 7.01 (dd,
J = 8.8, 2.4 Hz, 1 H), 3.88 (s, 3 H).
13C NMR (100 MHz, CDCl3): δ = 169.21, 159.04, 155.30, 133.62,
130.81, 128.93, 127.29, 126.81, 121.76, 115.42, 105.37, 55.51.
2-(2-Naphthyl)-1,3-benzothiazole (3am)20
White solid; yield: 214 mg (0.82 mmol, 82%); mp 127–129 °C.
1H NMR (400 MHz, CDCl3): δ = 8.55 (s, 1 H), 8.19 (d, J = 8.8 Hz,
1 H), 8.11 (d, J = 8.0 Hz, 1 H), 7.85–7.96 (m, 4 H), 7.48–7.56 (m, 3
H), 7.39 (t, J = 7.6 Hz, 1 H).
13C NMR (100 MHz, CDCl3): δ = 167.06, 153.13, 134.03, 133.51,
132.08, 129.86, 127.76, 126.81, 126.50, 126.46, 126.41, 125.83,
125.34, 124.19, 123.35, 122.15, 120.60.
5-Methoxy-2-(4-methoxyphenyl)-1,3-benzothiazole (3bb)25
White solid; yield: 222 mg (0.82 mmol, 82%); mp 120–122 °C.
1H NMR (400 MHz, CDCl3): δ = 7.99 (d, J = 8.8 Hz, 2 H), 7.69 (d,
J = 8.8 Hz, 1 H), 7.52 (d, J = 2.4 Hz, 1 H), 6.96–7.00 (m, 3 H), 3.88
(s, 3 H), 3.85 (s, 3 H).
13C NMR (100 MHz, CDCl3): δ = 169.05, 161.77, 158.97, 155.37,
128.84, 126.56, 126.45, 121.65, 114.84, 114.26, 105.18, 55.51,
55.38.
2-(2-Pyridyl)-1,3-benzothiazole (3an)21
Yellow solid; yield: 161 mg (0.76 mmol, 76%); mp 136–138 °C.
1H NMR (400 MHz, CDCl3): δ = 8.68 (d, J = 4.4 Hz, 1 H), 8.36 (d,
J = 8.0 Hz, 1 H), 8.09 (d, J = 8.0 Hz, 1 H), 7.95 (d, J = 8.4 Hz, 1 H),
7.83 (t, J = 8.0 Hz, 1 H), 7.50 (t, J = 7.6 Hz, 1 H), 7.41 (t, J = 7.6
Hz, 1 H), 7.36 (d, J = 6.0 Hz, 1 H).
5-Methoxy-2-(4-tolyl)-1,3-benzothiazole (3bc)26
White solid; yield: 207 mg (0.81 mmol, 81%); mp 98–100 °C.
13C NMR (100 MHz, CDCl3): δ = 169.34, 154.22, 151.32, 149.63,
137.02, 136.06, 126.27, 125.64, 125.28, 123.54, 122.01, 120.70.
1H NMR (400 MHz, CDCl3): δ = 7.95 (d, J = 8.0 Hz, 2 H), 7.71 (d,
J = 8.8 Hz, 1 H), 7.54 (d, J = 2.4 Hz, 1 H), 7.27 (d, J = 8.0 Hz, 2 H),
7.00 (dd, J = 6.4, 2.4 Hz, 1 H), 3.89 (s, 3 H), 2.41 (s, 3 H).
13C NMR (100 MHz, CDCl3): δ = 169.43, 159.01, 155.33, 141.28,
130.98, 129.65, 127.23, 126.69, 121.72, 115.19, 105.29, 55.56,
21.47.
2-(2-Furyl)-1,3-benzothiazole (3ao)11a
White solid; yield: 141 mg (0.70 mmol, 70%); mp 106–108 °C.
1H NMR (400 MHz, CDCl3): δ = 8.04 (d, J = 8.0 Hz, 1 H), 7.87 (d,
J = 7.6 Hz, 1 H), 7.59 (s, 1 H), 7.48 (t, J = 8.0 Hz, 1 H), 7.36 (t, J =
7.6 Hz, 1 H), 7.18 (d, J = 3.6 Hz, 1 H), 6.58 (dd, J = 2.4, 2.0 Hz, 1
H).
5-Fluoro-2-phenyl-1,3-benzothiazole (3ca)27
White solid; yield: 183 mg (0.80 mmol, 80%); mp 116–118 °C.
13C NMR (100 MHz, CDCl3): δ = 157.48, 153.66, 148.65, 144.63,
134.18, 126.41, 125.12, 123.04, 121.49, 112.47, 111.36.
1H NMR (400 MHz, CDCl3): δ = 8.05–8.07 (m, 2 H), 7.78–7.82 (m,
1 H), 7.74 (dd, J = 7.2, 2.4 Hz, 1 H), 7.47–7.50 (m, 3 H), 7.15 (dt,
J = 8.8, 2.4 Hz, 1 H).
13C NMR (100 MHz, CDCl3): δ = 170.51, 161.89 (d, J = 241.9 Hz),
154.92 (d, J = 12.2 Hz), 133.30, 131.24, 130.38, 129.05, 127.49,
122.22 (d, J = 9.9 Hz), 113.83 (d, J = 24.4 Hz), 109.30 (d, J = 23.7
Hz).
2-Hexyl-1,3-benzothiazole (3ap)22
Yellow oil; yield: 118 mg (0.54 mmol, 54%).
1H NMR (400 MHz, CDCl3): δ = 7.97 (d, J = 8.0 Hz, 1 H), 7.84 (d,
J = 8.0 Hz, 1 H), 7.45 (t, J = 7.6 Hz, 1 H), 7.35 (t, J = 8.4 Hz, 1 H),
3.11 (t, J = 8.0 Hz, 2 H), 1.85–1.87 (m, 2 H), 1.34–1.35 (m, 3 H),
1.31–1.33 (m, 3 H), 0.89 (t, J = 8.0 Hz, 3 H).
5-Fluoro-2-(4-methoxyphenyl)-1,3-benzothiazole (3cb)1a
White solid; yield: 202 mg (0.78 mmol, 78%); mp 123–124 °C.
1H NMR (400 MHz, CDCl3): δ = 8.01 (d, J = 9.2 Hz, 2 H), 7.78 (dd,
J = 5.2, 3.6 Hz, 1 H), 7.70 (dd, J = 10.4, 2.4 Hz, 1 H), 7.12 (dt, J =
8.8, 2.4 Hz, 1 H), 7.00 (d, J = 8.8 Hz, 2 H), 3.88 (s, 3 H).
13C NMR (100 MHz, CDCl3): δ = 172.48, 153.12, 135.04, 125.80,
124.55, 122.40, 121.44, 34.31, 31.44, 29.67, 28.80, 22.46, 14.03.
2-(2-Phenylethyl)-1,3-benzothiazole (3aq)23
White solid; yield: 124 mg (0.52 mmol, 52%); mp 58–60 °C.
1H NMR (400 MHz, CDCl3): δ = 7.98 (d, J = 8.0 Hz, 1 H), 7.82 (d,
J = 8.0 Hz, 1 H), 7.45 (t, J = 7.2 Hz, 1 H), 7.34 (t, J = 8.4 Hz, 1 H),
© Georg Thieme Verlag Stuttgart · New York
Synthesis 2013, 45, 943–951