Potassium Carbonate → 6-Chloro-5-(4-(1-hydroxycyclobutyl)phenyl)-1H-indazole-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of 5,5,5′,5′-tetramethyl-2,2′-bi-1,3,2-dioxaborinane (800 mg, 2.34 mmol), 1-(4-bromophenyl)cyclobutanol (500 mg, 2.20 mmol), potassium acetate (1.0 g, 10 mmol) and [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane adduct (136 mg, 0.17 mmol) in 1,4-dioxane (12 mL) was degassed with N2 for 5 minutes, and subjected to microwave irradiation at 115° C. for 1 hour. The cooled reaction mixture was filtered through a cotton plug and concentrated in vacuo. The resulting dark solid was dissolved in 1:1 toluene/EtOH (10 mL) and to this solution was added 5-bromo-6-chloro-1H-indazole-3-carboxylic acid (551 mg, 2.00 mmol) followed by 2 N aqueous potassium carbonate solution (4.0 mL, 8.0 mmol). The reaction mixture was degassed with N2, treated with [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane adduct (98.0 mg, 0.12 mmol) under N2, and heated in a sealed pressure tube to 110° C. for 3 hours. The cooled reaction mixture was concentrated in vacuo and the residue was partitioned between EtOAc (20 mL) and 2 N citric acid solution (20 mL). The layers were separated and the aqueous layer was extracted with EtOAc. The combined organic layers were dried over Na2SO4 and concentrated in vacuo. The crude material was purified by reverse phase chromatography (Biotage C18 column, 20-60% MeCN/water) to give the title compound (78 mg, 10% yield) as a solid. MS (ES−) 341.5 (M−H)+. 1H NMR (500 MHz, DMSO-d6) δ 8.01 (s, 1H), 7.88 (s, 1H), 7.59 (d, J=8.05 Hz, 2H), 7.42 (d, J=8.05 Hz, 2H), 5.55 (br. s, 1H), 2.39-2.46 (m, 2H), 2.23-2.35 (m, 2H), 1.89-2.01 (m, 1H), 1.64-1.76 (m, 1H).

Provenance & Evidence