Reaction Steps
To a solution of 5-Bromo-3-(3-chlorobenzofuran-2-yl)-pyridin-2-ylamine (57.9 mg, 0.179 mmol) and 4-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-pyrazol-1-yl]-piperidine-1-carboxylic acid tert-butyl ester (69.5 mg, 0.184 mmol) in 1,4-dioxane (2.5 mL, 32 mmol) in a microwave reactor tube were added PS-PPh3-Pd (0.10 mmol/g loading; 100 mg, 0.0100 mmol; Argonaut) and a solution of Cs2CO3 (117 mg, 0.358 mmol) in H2O (0.75 mL, 42 mmol). The tube was sealed, evacuated and refilled with nitrogen (3×), and heated in the microwave reactor to 105° C. for 30 min. More 4-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-pyrazol-1-yl]-piperidine-1-carboxylic acid tert-butyl ester (21 mg, 0.056 mmol) was added, the tube was evacuated and refilled with nitrogen again (3×) and heated in the microwave reactor to 105° C. for 45 min. The resin was filtered off and washed with DCM. The combined filtrate and washings were diluted with DCM to ≈50 mL, washed with water and brine, dried over MgSO4, filtered, and concentrated in vacuo. The residue was chromatographed on silica gel [10 g/70 mL prepacked cartridge, eluting with DCM→1% MeOH in DCM→2% MeOH in DCM]. Fractions containing product were combined and dried in vacuo. One obtained the title compound as a yellow solid. 1H NMR (400 MHz, CDCl3): δ=8.30 (d, J=2.4 Hz, 1H), 8.09 (d, J=2.4 Hz, 1), 7.74 (s, 1H), 7.65 (dd, J=7.2, 1.2 Hz, 1H), 7.63 (s, 1H), 7.52 (dd, J=7.0, 1.4 Hz, 1H), 7.41 (ddd, J=1.6, 7.2, 7.2 Hz, 1H), 7.38 (ddd, J=1.4, 7.0, 7.0 Hz, 1H), 5.27 (brs, 2H), 4.37-4.17 (m, 3H), 2.91 (brt, J=11.2 Hz, 2H), 2.18 (brdd, J=2.2, 12.8 Hz, 2H), 1.97 (dq, J=12.4, 4.0 Hz, 2H), 1.48 (s, 9H). MS(ES+): m/z=494.15/496.08 (100/48) [MH+]. HPLC: tR=3.23 min (nonpolar—5 min, ZQ3).
