Molecules 2020, 25, 138
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N-(6-chloropyrazin-2-yl)-3,5-dimethylbenzenesulfonamide (8b). Dark yellow-brownish solid. Yield
25%; M.p. 148.1–150.1 ◦C; IR (ATR-Ge, cm−1): 2930 (NH stretch), 1573, 1525, 1494 (arom. stretch),
1394 (S=O unsymmetrical stretch), 1159 (S=O symmetrical stretch); 1H-NMR (500 MHz, DMSO-d6)
δ
11.82 (bs, 1H, sulfonamide), 8.35 (s, 2H, pyrazine), 7.58 (s, 2H, arom.), 7.35 (s, 1H, arom.), 2.38 (s,
6H, –CH3).13C-NMR (125 MHz, DMSO-d6)
δ147.5, 145.6, 139.2, 138.9, 137.2, 135.1, 132.8, 125.2, 20.9.
Elemental analysis found: C, 48.35%; H, 4.49%; N, 14.15%; S, 10.05%. Calculated for C12H12ClN3O2S
(MW 297.03): C, 48.41%; H, 4.06%; N, 14.11%; S, 10.77%.
2,4,6-trimethyl-N-(pyrazin-2-yl)benzenesulfonamide (9a). White solid. Yield 67%; M.p. 200–201.9 ◦C;
IR (ATR-Ge, cm−1): 2949 (NH stretch), 1601, 1586, 1530 (arom. stretch), 1337 (S=O unsymmetrical
stretch), 1154 (S=O symmetrical stretch); 1H-NMR (500 MHz, DMSO-d6)
δ
11.52 (bs, 1H, sulfonamide),
8.22 (s, 1H, pyrazine), 8.08 (d, J = 2.5 Hz, 2H, pyrazine), 7.01 (s, 2H, arom.), 2.64 (s, 6H, -CH3), 2.22 (s,
3H, -CH3).13C-NMR (125 MHz, DMSO-d6)
148.9, 142.5, 142.0, 139.4, 138.1, 134.2, 134.1, 131.8, 22.4,
δ
20.6. Elemental analysis found: C, 56.22%; H, 5.42%; N, 14.88%; S, 11.92%. Calculated for C13H15N3O2S
(MW 277.34): C, 56.30%; H, 5.45%; N, 15.15%; S, 11.56%.
N-(6-chloropyrazin-2-yl)-2,4,6-trimethylbenzenesulfonamide (9b). Beige solid. Yield 45%; M.p.
179.7–180.2 ◦C; IR (ATR-Ge, cm−1): 2925 (NH stretch), 1566, 1525, 1498 (arom. stretch), 1331 (S=O
unsymmetrical stretch), 1186 (S=O symmetrical stretch); 1H-NMR (500 MHz, DMSO-d6)
δ
11.95 (bs,
1H, sulfonamide), 8.24 (s, 1H, pyrazine), 8.15 (s, 1H, pyrazine), 7.04 (s, 2H, arom.), 2.66 (s, 6H, –CH3),
2.24 (s, 3H, –CH3).13C-NMR (125 MHz, DMSO-d6)
156.8, 145.1, 144.9, 141.1, 137.2, 135.1, 134.9,
δ
130.4, 22.6, 21.9. Elemental analysis found: C, 49.87%; H, 4.51%; N, 13.11%; S, 9.99%. Calculated for
C13H14ClN3O2S (MW 311.78): C, 50.08%; H, 4.53%; N, 13.48%; S, 10.28%.
2,3,5,6-tetramethyl-N-(pyrazin-2-yl)benzenesulfonamide (10a). White solid. Yield 49%; M.p. 221–223.7
◦C; IR (ATR-Ge, cm−1): 2955 (NH stretch), 1585, 1526, 1500 (arom. stretch), 1362 (S=O unsymmetrical
stretch), 1174 (S=O symmetrical stretch); 1H-NMR (500 MHz, DMSO-d6)
δ
11.55 (bs, 1H, sulfonamide),
8.18 (s, 1H, pyrazine), 8.09 (d, J = 2.5 Hz, 2H, pyrazine), 7.23 (s, 1H, arom.), 2.55 (s, 6H, –CH3), 2.21 (s,
6H, –CH3). 13C-NMR (125 MHz, DMSO-d6)
148.9, 142.1, 138.1, 135.9, 135.7, 135.3, 134.6, 134.0, 20.7,
δ
17.5. Elemental analysis found: C, 57.45%; H, 5.79%; N, 14.08%; S, 10.72%. Calculated for C14H17N3O2S
(MW 291.37): C, 57.71%; H, 5.88%; N, 14.42%; S, 11.00%.
N-(pyrazin-2-yl)-2,3-dihydrobenzo[b][1,4]dioxine-6-sulfonamide (11a). Light yellow solid. Yield 17%;
M.p. 264–267.1 ◦C; IR (ATR-Ge, cm−1): 2930 (NH stretch), 1591, 1569, 1540 (arom. stretch), 1350 (S=O
unsymmetrical stretch), 1161 (S=O symmetrical stretch); 1H-NMR (500 MHz, DMSO-d6)
δ
11.41 (bs,
1H, sulfonamide), 8.35 (s, 1H, pyrazine), 8.21 (d, J = 2.4 Hz, 2H, pyrazine), 7.44 (s, 1H, arom.), 6.98
(d, J = 8.4 Hz, 2H, arom.), 4.33–4.25 (m, 4H, –CH2–). 13C-NMR (125 MHz, DMSO-d6)
156.2, 153.9,
δ
147.0, 144.5, 137.4, 136.1, 131.9, 117.3, 115.3, 111.9, 64.2. Elemental analysis found: C, 49.47%; H, 3.97%;
N, 14.55%; S, 10.87%. Calculated for C12H10N3O4S (MW 293.30): C, 49.14%; H, 3.78%; N, 14.33%; S,
10.93%.
N-(6-chloropyrazin-2-yl)-2,3-dihydrobenzo[b][1,4]dioxine-6-sulfonamide (11b). White solid. Yield 8%;
M.p. 244.6–247◦C; IR (ATR-Ge, cm−1): 2896 (NH stretch), 1580, 1529, 1498 (arom. stretch), 1323 (S=O
unsymmetrical stretch), 1162 (S=O symmetrical stretch); 1H-NMR (500 MHz, DMSO-d6)
δ 11.81 (bs,
1H, sulfonamide), 8.34 (s, 2H, pyrazine), 8.28 (s, 1H, arom.), 7.41 (d, J = 9 Hz, 2H, arom.), 4.42–4.26
(m, 4H, –CH2–). 13C-NMR (125 MHz, DMSO-d6) 156.8, 153.9, 147.0, 144.9, 135.1, 134.9, 131.9, 117.3,
115.3, 111.9, 64.2. Elemental analysis found: C, 43.74%; H, 3.01%; N, 12.54%; S, 9.54%. Calculated for
C12H10ClN3O4S (MW 327.74): C, 43.98%; H, 3.08%; N, 12.82%; S, 9.78%.
N-(pyrazin-2-yl)-[1,10-biphenyl]-4-sulfonamide (12a). Light yellow solid. Yield 79%; M.p. 242.2–244.3
◦C; IR (ATR-Ge, cm−1): 3070 (NH stretch), 1594, 1566, 1531 (arom. stretch), 1345 (S=O unsymmetrical
stretch), 1172 (S=O symmetrical stretch); 1H-NMR (500 MHz, DMSO-d6)
δ
11.62 (bs, 1H, sulfonamide),
8.40 (s, 1H, pyrazine), 8.24 (d, J = 2.5 Hz, 2H, pyrazine), 7.79 (d, J = 9.2 Hz, 4H, arom.), 7.65 (d, J = 9 Hz,
2H, arom.), 7.39 (t, J = 9 Hz, 3H, arom.). 13C-NMR (125 MHz, DMSO-d6)
148.3, 144.9, 142.4, 139.1,
δ