The general procedure for the synthesis of (5-chloro-1H-indol-2-yl)(4-methylpiperazin-1-yl)methanone from N-methylpiperazine and 5-chloroindole-2-carboxylic acid was as follows: 5-chloroindole-2-carboxylic acid (0.234 g), HATU (0.569 g), HOAT (0.203 g), and N,N-diisopropylethylamine (0.191 mL) were dissolved in DMF (0.6 mL), N-methylpiperazine (0.1 mL) was added, and the reaction was stirred at room temperature for 48 hours. After the reaction was completed, the solvent was removed by concentration under reduced pressure. The residue was dissolved in ethyl acetate and washed sequentially with 1 M hydrochloric acid, saturated sodium bicarbonate solution and brine, the organic phase was dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: 3-10% 2M ammonia in methanol solution/dichloromethane) to afford the target product (5-chloro-1H-indol-2-yl)(4-methylpiperazin-1-yl)methanone (0.18 g). The product was characterized by 1H NMR (400 MHz, CDCl3): δ 9.60 (br s, 1H), 7.65 (d, J = 1.5 Hz, 1H), 7.40 (d, J = 8.6 Hz, 1H), 7.29 (d, J = 2.0 Hz, 1H), 7.26 (d, J = 1.8 Hz, 1H), 6.76 (d, J = 1.5 Hz, 1H), 4.0 (d, J = 1.5 Hz, 1H), 6.76 (d, J = 1.5 Hz, 1H), 6.76 (d, J = 1.5 Hz, 1H), 6.76 (d, J = 1.5 Hz, 1.0) 1H), 4.0 (br m, 4H), 2.56 (t, J = 5.1 Hz, 4H), 2.41 (s, 3H). Elemental analysis results (C14H16ClN3O): calculated values C, 60.54; H, 5.81; N, 15.13; measured values C, 59.99; H, 5.94; N, 18.87.
