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rafluorobenzoyl chloride in 3 mL of anhydrous aceto-
nitrile. The mixture was heated for 5 min at 40°C, the
precipitate of ammonium chloride was filtered off, and
a solution of 6 mmol of 1-methyl-1H-pyrrole or
1-methyl-1H-indole in 5 mL of acetonitrile was added
to the filtrate containing isothiocyanate 1a or 1b. The
mixture was stirred for 3 h at room temperature, and
the precipitate (mixture 2/4 or 3/5) was filtered off and
washed with hexane. The product was dissolved in
10 mL of anhydrous toluene (2a/4a, 2b/4b, 3a/5a,
3b/5b) or 3 mL of anhydrous DMF (2a/4a, 3a/5a),
0.18 mL (1.2 mmol) of triethylamine was added, and
the mixture was refluxed for 3 h. After cooling, the
precipitate was filtered off, washed with water, and
recrystallized from DMSO.
5-Fluoro-2-(1-methyl-1H-indol-3-yl)-1,3-benzo-
thiazin-4-one (5a). Yield 81% (in DMF), 69% (in
toluene), mp 190–192°C. H NMR spectrum, δ, ppm:
1
3.92 s (3H, CH3), 7.33–7.37 m (3H, 5′-H, 6-H, 6′-H),
7.50 m (1H, 8-H), 7.58 m (1H, 7′-H), 7.70 m (1H,
7-H), 8.44 m (1H, 4′-H), 8.53 s (1H, 2′-H). 13C NMR
spectrum, δC, ppm: 33.5 (CH3), 99.5 (C3′), 111.2 (C7′),
112.3, 112.6 (C4a, J = 11 Hz), 116.4 (C6, J = 22 Hz),
121.8 (C4′), 122.1 (C8, J = 5 Hz), 122.8, 123.6, 124.7,
134.0 (C7, J = 10 Hz), 136.8 (C2′), 137.9 (C7′a), 161.7
(C5, J = 267 Hz), 164.2 (C2), 166.0 (C=O, J = 4 Hz).
19F–{1H} NMR spectrum: δF –109.02 ppm. Mass spec-
trum, m/z (Irel, %): 310 (15) [M]+, 157 (11), 156 (100),
155 (24), 154 (15), 126 (12). Found, %: C 65.87;
H 3.66; N 9.21. C17H11FN2OS. Calculated, %: C 65.79;
H 3.57; N 9.03. M 310.35.
5-Fluoro-2-(1-methyl-1H-pyrrol-2-yl)-1,3-benzo-
thiazin-4-one (4a). Yield 86% (in DMF), 82% (in
6,7,8-Trifluoro-2-(1-methyl-1H-indol-3-yl)-1,3-
benzothiazin-4-one (5b). Yield 64%, mp 307–309°C.
1H NMR spectrum, δ, ppm: 3.98 s (3H, CH3), 7.34 m
(2H, 5′-H, 6′-H), 7.57 m (1H, 7′-H), 8.08 d.d.d (1H,
5-H, J = 9.6, 8.0, 1.7), 8.50 m (1H, 4′-H), 8.70 s (1H,
2′-H). 13C NMR spectrum, δC, ppm: 34.6 (CH3), 110.9,
113.5, 118.6 (C5, J = 18, 5 Hz), 120.2, 121.4, 121.9,
122.3, 122.8, 136.9, 137.1, 137.9 (C8a, J = 11 Hz),
145.4 (C8, J = 259, 18, 5 Hz), 152.2 (C7, J = 258, 17,
12 Hz), 157.9 (C6, J = 254, 17, 6 Hz), 162.8 (C2),
164.8 (C=O). 19F–{1H} NMR spectrum, δF, ppm:
–134.01 d.d (1F, 6-F, J = 21.4, 5.0 Hz), –135.42 d.d
(1F, 8-F, J = 20.6, 5.0 Hz), –152.90 d.d (1F, 7-F, J =
20.8, 21.4 Hz). Mass spectrum, m/z (Irel, %): 346 (12)
[M]+, 190 (3.6), 157 (12), 156 (100), 155 (23). Found,
%: C 59.05; H 2.70; N 8.03. C17H9F3N2OS. Calculated,
%: C 58.96; H 2.62; N 8.09. M 346.33.
1
toluene), mp 148–150°C. H NMR spectrum, δ, ppm:
4.10 s (3H, CH3), 6.26 d.d (1H, 4′-H, J = 4.1, 2.5 Hz),
7.17 d.d (1H, 3′-H, J = 4.1, 1.6 Hz), 7.28 m (1H, 5′-H),
7.31 d.d (1H, 6-H, J = 10.1, 8.4Hz), 7.44 d (1H, 8-H,
J = 8.0 Hz), 7.69 t.d (1H, 7-H, J = 8.1, 5.0 Hz).
13C NMR spectrum, δC, ppm: 37.7 (CH3), 99.5 (C4′),
110.0 (C3′), 112.2 (C4a, J = 10 Hz), 116.5 (C6, J =
22 Hz), 119.6 (C5′), 122.2 (C8, J = 4 Hz), 126.6 (C2′),
134.2 (C7, J = 8 Hz), 137.0 (C8a, J = 1 Hz), 160.3 (C2),
161.8 (C5, J = 260 Hz), 165.7 (C=O, J = 4 Hz).
19F–{1H} NMR spectrum: δF –109.50 ppm. Mass spec-
trum, m/z (Irel, %): 260 (30) [M]+, 154 (100), 126 (29),
110 (21), 106 (26), 105 (13), 69 (11). Found, %:
C 60.07; H 3.56; N 10.11. C13H9FN2OS. Calculated,
%: C 59.99; H 3.49; N 10.77. M 260.29.
6,7,8-Trifluoro-2-(1-methyl-1H-pyrrol-2-yl)-1,3-
benzothiazin-4-one (4b). Yield 71% mp 199–201°C.
1H NMR spectrum, δ, ppm: 4.06 s (3H, CH3), 6.32 d.d
(1H, 4′-H, J = 4.2, 2.5 Hz), 7.31 d.d (1H, 3′-H, J = 4.2,
1.6 Hz), 7.40 m (1H, 5′-H), 7.96 d.d.d (1H, 5-H, J =
10.5, 7.5, 2.2 Hz). 13C NMR spectrum, δC, ppm: 37.7
(CH3), 110.1 (C4′), 112.2 (C3′), 115.1 (C2′), 118.4 (C5,
J = 18, 4 Hz), 120.8 (C5′), 124.4 (C4a), 137.0 (C8a, J =
11 Hz), 145.3 (C8, J = 258, 17, 4 Hz), 151.6 (C7, J =
263, 16, 13 Hz), 158.3 (C6, J = 252, 18, 5 Hz), 161.9
2,6-Difluoro-N-(1-methyl-1H-pyrrole-2-carbo-
thioyl)benzamide (2a) was isolated by recrystalliza-
tion of mixture 2a/4a from ethanol, mp 117–119°C.
1H NMR spectrum, δ, ppm: 3.94 s (3H, CH3), 6.11 m
(1H, 4′-H), 6.88 m (1H, 3′-H), 7.05 m (2H, 3-H, 5-H),
7.19 m (1H, 5′-H), 7.49 m (1H, 4-H), 11.9 br.s (1H,
NH). 19F–{1H} NMR spectrum: δF –112.78 ppm. Mass
spectrum, m/z (Irel, %): 280 (43) [M]+, 141 (100)
[C6H3F2C(O)]+, 123 (29), 113 (39), 112 (11), 107
(69), 106 (23), 105 (13), 80 (19), 63 (20), 39 (11).
Found, %: C 55.77; H 3.65; N 9.92. C13H10F2N2OS.
Calculated, %: C 55.71; H 3.60; N 9.99. M 280.30.
19
(C2), 164.5 (C=O). F–{1H} NMR spectrum, δF, ppm:
–136.87 d.d (1F, 6-F, J = 21.1, 5.9 Hz), –139.38 d.d
(1F, 8-F, J = 20.7, 4.5 Hz), –155.25 d.d (1F, 7-F, J =
20.7, 21.1 Hz). Mass spectrum, m/z (Irel, %): 296 (25)
[M]+, 194 (35), 190 (34), 177 (47), 162 (27), 149 (37),
106 (100), 105 (26), 99 (39), 93 (12), 85 (75), 80 (13),
69 (10), 57 (11), 45 (12), 44 (39), 43 (18), 41 (11).
Found, %: C 52.67; H 2.26; N 9.51. C13H7F3N2OS.
Calculated, %: C 52.70; H 2.38; N 9.46. M 296.27.
1
The H, 13C, and 19F NMR spectra were recorded
from solutions in DMSO-d6 on a Bruker Avance-400
spectrometer; the chemical shifts were measured
relative to tetramethylsilane (1H, 13C) or CFCl3 (19F) as
internal standard. The mass spectra (electron impact)
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 3 2019