1-ethyl-1H-indazol-5-ylboronic acid

Step 2. l-Ethyl-iH-indazol-5-ylboronic acidA solution of 5-bromo-l -ethyl-iH-indazole (598 mg, 2.67 mmol) in dry tetrahydrofuran (30 mL) was cooled below -60°C. Then a solution of butyllithium in hexane (2.5 ml, 2.5M) was added dropwise. It was warmed to -10°C during 45 min and stirred at this temperature for another 30 min. The mixture was cooled again below -60°C followed by dropwise addition of triisopropyl borate (1.5 g, 7.98 mmol). After warming to room temperature the mixture was quenched with hydrochloric acid (3N) and stirred for 1 h. The alkaline aqueous layer was brought to pH 5 and extracted with ethyl acetate (3 x 80 ml). All organic layers were combined, dried over sodium sulfate, and concentrated in vacuum to give 1-ethyl-iH- indazol-5-ylboronic acid (450 mg, 89percent) which was used for the next step without further purification.*H-NMR (300 MHz, DMSO) δ 8.29(d, / = 1.5 Hz, 1H), 8.24 (s, 1H), 8.07 (d, / = 0.6 Hz, 1H), 7.77 - 7.80 (m, 1H), 7.59 (d, / = 8.4 Hz, 1H), 4.39 - 4.46 (m, 2H), 1.29 -1.41 (m, 3H)Step 2. l-Ethyl-iH-indazol-5-ylboronic acidA solution of 5-bromo-l -ethyl-iH-indazole (598 mg, 2.67 mmol) in dry tetrahydrofuran (30 mL) was cooled below -60°C. Then a solution of butyllithium in hexane (2.5 ml, 2.5M) was added dropwise. It was warmed to -10°C during 45 min and stirred at this temperature for another 30 min. The mixture was cooled again below -60°C followed by dropwise addition of triisopropyl borate (1.5 g, 7.98 mmol). After warming to room temperature the mixture was quenched with hydrochloric acid (3N) and stirred for 1 h. The alkaline aqueous layer was brought to pH 5 and extracted with ethyl acetate (3 x 80 ml). All organic layers were combined, dried over sodium sulfate, and concentrated in vacuum to give 1-ethyl-iH- indazol-5-ylboronic acid (450 mg, 89percent) which was used for the next step without further purification.*H-NMR (300 MHz, DMSO) delta 8.29(d, / = 1.5 Hz, 1H), 8.24 (s, 1H), 8.07 (d, / = 0.6 Hz, 1H), 7.77 - 7.80 (m, 1H), 7.59 (d, / = 8.4 Hz, 1H), 4.39 - 4.46 (m, 2H), 1.29 -1.41 (m, 3H)Step 3. Methyl 2-(l-ethyl-7H-indazol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6- carboxylateTo a solution of l-ethyl-iH-indazol-5-ylboronic acid (196 mg, 1.03 mmol) in dioxane (6 mL) was added methyl 2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (Scheme I, 120 mg, 0.41 mmol), K3P04 (259 mg, 1.23 mmol), Pd(PPh3)4 (20 mg, 0.02 mmol) and water (5drops) with stirring for 4 h at 90°C in an oil bath under an inert atmosphere of nitrogen. The reaction mixture was concentrated under vacuum and then purified by a silica gel column with 1 percent to 5percent ethyl acetate in petroleum ether to afford methyl 2-(l-ethyl-7H- indazol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate as a light yellow solid (80 mg, 49percent).LC/MS (ES, m/z): [M+H]+ 404.0'H-NMR (300 MHz, CDC13) delta 8.80 (s, 1H), 8.34 (s, 1H), 8.10 - 8.13 (m, 3H), 7.93 - 7.97 (m, 1H), 7.58 (d, / = 8.7 Hz, 1H), 4.42 - 4.55 (m, 3H), 4.01 (s, 3H), 2.87 (s, 3H), 1.55 - 1.61 (t, J = 7.2 Hz, 3H), 1.13 (d, 7 = 6.6 Hz, 6H)

Molecular Weight:190.01
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:2
Exact Mass:190.0913578
Monoisotopic Mass:190.0913578
Topological Polar Surface Area:58.3
Heavy Atom Count:14
Complexity:203
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes