1930
X. Tu et al.
128.23, 127.64, 120.85, 119.69, 116.11, 115.63,
38.07 ppm; MS (ESI): m/z = 307 ([M ? H]?).
9- and 10-Ethoxy-3-(trifluoromethyl)-5H-benzimidazo-
[1,2-a][3, 1]benzothiazine, mixture of isomers
(3k, C17H13F3N2OS)
9- and 10-Nitro-5H-benzimidazo[1,2-a][3, 1]-
Yield: 91 %; white solid; m.p.: 165–168 °C; 1H NMR
(300 MHz, CDCl3): d = 7.92 (m, 1H), 7.67 (m, 3H), 7.23
(d, J = 2.3 Hz, 1H), 6.96 (m, 1H), 4.12 (m, 4H), 1.47 (td,
J = 7.0, 2.3 Hz, 3H) ppm; 13C NMR (75 MHz, CDCl3):
d = 156.37, 150.50, 148.66, 145.12, 138.30, 128.88,
127.78, 127.34, 126.74, 126.09, 125.19, 121.78, 119.99,
117.85, 113.02, 112.20, 111.66, 103.33, 97.42, 64.42,
64.04, 29.63, 14.79 ppm; MS (ESI): m/z = 351
([M ? H]?).
benzothiazine, mixture of isomers (3g, C14H9N3O2S)
Yield: 61 %; light yellow solid; m.p.: 214-216 °C; 1H
NMR (300 MHz, CDCl3) d = 8.74 (d, J = 2.0 Hz, 1H),
8.59 (d, J = 2.0 Hz, 1H), 8.25 (ddd, J = 8.9, 5.2, 2.2 Hz,
2H), 7.88 (d, J = 9.0 Hz, 1H), 7.80 (dd, J = 17.0, 8.5 Hz,
3H), 7.57 (m, 2H), 7.48 (d, J = 6.8 Hz, 2H), 7.38 (td,
J = 7.5, 1.7 Hz, 2H), 4.11 (d, J = 4.9 Hz, 4H) ppm; 13C
NMR (101 MHz, CDCl3): d = 152.27, 151.57, 144.82,
142.53, 135.10, 133.08, 131.25, 129.03, 128.27, 126.26,
125.71, 124.01, 123.25, 120.15, 119.60, 118.14, 111.70,
30.37 ppm; MS (ESI): m/z = 284 ([M ? H]?).
9- and 10-Methyl-5H-benzimidazo[1,2-a]-1,3-dioxolo-
[4,5-g][3, 1]benzothiazine, mixture of isomers
(3l, C16H12N2O2S)
Yield: 74 %; white solid; m.p.: 166–169 °C; 1H NMR
(300 MHz, CDCl3): d = 7.61 (d, J = 8.3 Hz, 1H), 7.51 (s,
1H), 7.36 (d, J = 9.2 Hz, 1H), 7.13 (dd, J = 8.3, 4.0 Hz,
1H), 6.86 (s, 1H), 6.03 (d, J = 4.0 Hz, 2H), 3.92 (d,
J = 2.0 Hz, 2H), 2.51 (d, J = 9.9 Hz, 3H) ppm; 13C NMR
(75 MHz, CDCl3): d = 147.84, 144.93, 143.90, 141.65,
132.95, 130.51, 129.81, 124.58, 124.11, 119.32, 118.93,
118.61, 110.94, 110.39, 107.92, 101.83, 100.23, 29.59,
21.82, 21.34 ppm; MS (ESI): m/z = 297 ([M ? H]?).
3-(Trifluoromethyl)-5H-benzimidazo[1,2-a][3, 1]-
benzothiazine (3h, C15H9F3N2S)
Yield: 87 %; white solid; m.p.: 134–136 °C; 1H NMR
(300 MHz, CDCl3): d = 7.98 (d, J = 8.4 Hz, 1H), 7.80
(m, 1H), 7.77 (d, J = 1.6 Hz, 1H), 7.75 (m, 1H), 7.71 (s,
1H), 7.37 (m, 2H), 4.11 (s, 2H) ppm; 13C NMR (101 MHz,
CDCl3): d = 172.23, 154.63, 135.14, 133.83, 130.23,
129.36, 128.51, 126.38, 120.52, 117.17, 114.31, 77.36,
77.04, 76.72, 30.94 ppm; MS (ESI): m/z = 307
([M ? H]?).
9- and 10-Chloro-5H-benzimidazo[1,2-a]-1,3-dioxolo-
[4,5-g][3, 1]benzothiazine, mixture of isomers
(3m, C15H9ClN2O2S)
9- and 10-Methyl-3-(trifluoromethyl)-5H-benzimidazo-
[1,2-a][3, 1]benzothiazine, mixture of isomers
(3i, C16H11F3N2S)
Yield: 75 %; white solid; m.p.: 196–198 °C; 1H NMR
(300 MHz, CDCl3): d = 7.71 (dd, J = 8.4, 1.9 Hz, 1H),
7.63 (dd, J = 8.6, 3.0 Hz, 1H), 7.29 (dd, J = 5.0, 2.5 Hz,
1H), 7.25 (d, J = 2.1 Hz, 1H), 6.87 (s, 1H), 6.07 (d,
J = 3.4 Hz, 2H), 3.95 (d, J = 1.0 Hz, 2H) ppm; 13C NMR
(75 MHz, DMSO-d6): d = 152.15, 151.45, 147.56, 145.07,
144.01, 141.80, 132.69, 130.96, 128.56, 127.48, 123.30,
122.70, 119.66, 119.35, 118.04, 112.95, 111.57, 108.22,
102.02, 100.60, 100.29, 29.28 ppm; MS (ESI): m/z = 317
([M ? H]?).
Yield: 92 %; light yellow solid; m.p.: 174–176 °C; 1H
NMR (300 MHz, CDCl3): d = 7.95 (m, 1H), 7.74 (t,
J = 7.2 Hz, 1H), 7.68 (d, J = 6.2 Hz, 1H), 7.63 (d,
J = 7.4 Hz, 1H), 7.56 (d, J = 14.0 Hz, 1H), 7.17 (dd,
J = 7.3, 5.1 Hz, 1H), 4.08 (s, 2H), 2.51 (d, J = 11.1 Hz,
3H) ppm; 13C NMR (75 MHz, CDCl3): d = 150.18,
149.52, 144.34, 142.09, 138.14, 133.89, 133.60, 132.61,
130.44, 126.13, 125.09, 124.58, 119.70, 119.17, 118.09,
111.41, 110.82, 29.64 ppm; MS (ESI): m/z = 321
([M ? H]?).
9- and 10-Ethoxy-5H-benzimidazo[1,2-a]-1,3-dioxolo-
[4,5-g][3, 1]benzothiazine, mixture of isomers
9- and 10-Chloro-3-(trifluoromethyl)-5H-benzimidazo-
[1,2-a][3, 1]benzothiazine, mixture of isomers
(3n, C17H14N2O3S)
Yield: 75 %; white solid; m.p.: 217–220 °C; 1H NMR
(300 MHz, CDCl3) d = 7.60 (dd, J = 8.8, 1.5 Hz, 1H),
7.25 (m, 2H), 6.93 (m, 1H), 6.86 (d, J = 2.2 Hz, 1H), 6.05
(d, J = 2.4 Hz, 2H), 4.11 (m, 2H), 3.93 (d, J = 1.7 Hz,
2H), 1.46 (td, J = 7.0, 2.2 Hz, 3H) ppm; 13C NMR
(75 MHz, DMSO-d6): d = 155.93, 147.95, 145.03, 144.61,
138.08, 133.07, 129.79, 119.71, 112.59, 111.48, 108.01,
103.01, 101.90, 100.10, 96.86, 64.21, 29.27, 14.86 ppm;
MS (ESI): m/z = 327 ([M ? H]?).
(3j, C15H8ClF3N2S)
Yield: 90 %; white solid; m.p.: 184–186 °C; 1H NMR
(300 MHz, CDCl3): d = 7.89 (q, 1H), 7.78 (d, J = 2.0 Hz,
1H), 7.72 (t, J = 5.1 Hz, 2H), 7.66 (m, 1H), 7.32 (m, 1H),
4.11 (s, 2H) ppm; 13C NMR (75 MHz, CDCl3):
d = 151.61, 144.91, 142.59, 137.64, 132.85, 131.00,
129.50, 126.23, 125.37, 124.55, 123.67, 120.40, 119.60,
118.13, 111.90, 111.51, 77.41, 76.98, 76.56, 29.64 ppm;
MS (ESI): m/z = 341 ([M ? H]?).
123