HETEROCYCLES, Vol. 83, No. 4, 2011
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to cool down. The pH is made slightly basic (pH 7–8) by addition of 5% aqueous potassium bicarbonate
before being extracted with EtOAc. The organic phase is washed with brine and dried over magnesium
sulfate. The solvent was removed to afford the amine, which was immediately dissolved in pyridine (5
mL) and then reacted with 4-methylbenzenesulfonyl chloride (0.26 g, 1.25 mmol) at room temperature for
24 h. After the reaction mixture was concentrated in vacuo, the resulting residue was purified by flash
chromatography (eluted with EtOAc/hexane 1/9).
N-(2-Allyl-7-ethoxy-2H-indazol-4-yl)-4-methylbenzenesulfonamide (4a). Yield: 53%, colorless solid,
1
mp 143-145 °C. H NMR (DMSO-d6): δ 1.33 (t, 3H, CH3, J = 7.0 Hz), 2.28 (s, 3H, CH3), 4.05 (q, 2H,
CH2O, J = 7.0 Hz), 4.95-4.98 (m, 2H, NCH2), 5.08-5.24 (m, 2H, =CH2), 5.95-6.05 (m, 1H, =CH), 6.40 (d,
1H, H-6, J = 8.1 Hz), 6.55 (d, 1H, H-5, J = 8.1 Hz), 7.24 (d, 2H, ArH, J = 7.8 Hz), 7.53 (d, 2H, ArH, J =
13
7.8 Hz), 8.08 (s, 1H, H-3), 9.86 (s, 1H, NH). C NMR (DMSO-d6): δ 15.1 (CH3), 21.4 (CH3), 55.6
(NCH2), 63.7 (CH2O), 103.8 (CH), 115.5 (CH), 118.9 (=CH2), 120.3 (C), 122.0 (C), 123.4 (CH-3), 127.2
(2CH), 129.8 (2CH), 133.8 ( =CH), 137.4 (C), 142.0 (C), 143.3 (C), 147.3 (C). MS: m/z 372 (M + 1)+.
Anal. Calcd for C19H21N3O3S: C, 61.44; H, 5.70; N, 11.31. Found: C, 61.70; H, 5.54; N, 11.51.
N-(2-Allyl-2H-indazol-4-yl)-4-methylbenzenesulfonamide (5a). Yield: 44% , colorless solid, mp
1
150-152 °C. H NMR (DMSO-d6): δ 2.25 (s, 3H, CH3), 4.96-5.01 (m, 2H, NCH2), 5.13-5.23 (m, 2H,
=CH2), 5.96-6.06 (m, 1H, =CH), 6.77 (d, 1H, J = 7.2 Hz), 7.04 (t, 1H, J = 7.3 Hz), 7.23 (d, 1H, J = 7.2
Hz), 7.55 (d, 2H, ArH, J = 7.4 Hz), 7.65 (d, 2H, ArH, J = 7.4 Hz), 8.37 (s, 1H, H-3), 10.34 (s, 1H, NH).
13C NMR (DMSO-d6): δ 21.3 (CH3), 55.7 (NCH2), 111.0 (CH) 113.6 (CH), 119.1 (=CH2), 120.3 (C),
122.0 (C), 123.2 (CH-3), 126.1 (CH), 127.2 (2CH), 129.8 (2CH), 133.8 (=CH), 137.3 (C), 142.0 (C),
149.4 (C). MS: m/z 328 (M + 1)+. Anal. Calcd. for C17H17N3O2S: C, 62.37; H, 5.23; N, 12.83. Found: C,
62.52; H, 5.08; N, 12.95.
N-(2-Benzyl-7-ethoxy-2H-indazol-4-yl)-4-methylbenzenesulfonamide (4b). Yield: 45%, colorless
solid, mp 156-158 °C. 1H NMR (CDCl3): δ 1.47 (t, 3H, CH3, J = 7.1 Hz), 2.32 (s, 3H, CH3), 4.15 (q, 2H,
CH2O, J = 7.1 Hz), 5.54 (s, 2H, NCH2), 6.33 (d, 1H, H-6, J = 7.9 Hz), 6.56 (d, 1H, H-5, J = 7.9 Hz), 7.10
(d, 2H, ArH, J = 7.7 Hz), 7.23-7.35 (m, 5H, ArH), 7.53 (d, 2H, ArH, J = 7.7 Hz), 7.82 (s, 1H, H-3), 8.96
(s, 1H, NH). 13C NMR (CDCl3): δ 14.6 (CH3), 21.5 (CH3), 57.5 (NCH2), 64.0 (CH2O), 103.3 (CH), 118.4
(CH), 120.3 (C), 121.2 (C), 122.9 (CH-3), 127.4 (2CH), 128.2 (2CH), 128.5 (CH), 128.9 (2CH), 129.4
(2CH), 135.2 (C), 136.0 (C), 142.0 (C), 143.6 (C), 148.2 (C). MS: m/z 422 (M + 1)+. Anal. Calcd for
C23H23N3O3S: C, 65.54; H, 5.50; N, 9.97. Found: C, 65.68; H, 5.42; N, 10.11.
N-(2-Benzyl-2H-indazol-4-yl)-4-methylbenzenesulfonamide (5b). Yield: 38%, colorless solid, mp
180-182 °C, 1H NMR (CDCl3): δ 2.31 (s, 3H, CH3), 5.60 (s, 2H, NCH2), 6.84 (d, 1H, J = 7.8 Hz), 7.13 (d,
2H, ArH, J = 7.8 Hz), 7.28-7.41 (m, 7H, ArH), 7.66 (d, 2H, ArH, J = 7.8 Hz), 7.82 (s, 1H, H-3), 8.85 (s,
13
1H, NH). C NMR (CDCl3): δ 21.5 (CH3), 57.3 (NCH2), 113.0 (CH), 114.1 (CH), 117.3 (C), 124.7