5-(3-(6-(4,4-difluoropiperidin-1-yl)pyrazin-2-yl)-1-tosyl-1H-indol-5-yl)-N-(4-methoxybenzyl)-1,3,4-oxadiazol-2-amine → 5-(3-(6-(4,4-difluoropiperidin-1-yl)pyrazin-2-yl)-1-tosyl-1H-indol-5-yl)-1,3,4-oxadiazol-2-amine

Participants

Reaction Steps

A solution of 5-(3-(6-(4,4-difluoropiperidin-1-yl)pyrazin-2-yl)-1-tosyl-1H-indol-5-yl)-N-(4-methoxybenzyl)-1,3,4-oxadiazol-2-amine (590 mg) in TFA (5 mL) was heated in a microwave reactor (Personal Chemistry, Biotage AB, Inc., Uppsala, Sweden) at 110° C. for 20 min. The volatiles were removed under reduced pressure. The brown residue was diluted with EtOAc and washed with 0.5 N NaOH. The EtOAc layer was concentrated. The off white solid was stirred with 5 mL Et2O, filtered, rinsed with 2×5 ml of Et2O to give 350 mg of crude material of 5-(3-(6-(4,4-difluoropiperidin-1-yl)pyrazin-2-yl)-1-tosyl-1H-indol-5-yl)-1,3,4-oxadiazol-2-amine that was used without further purification. A glass microwave reaction vessel was charged with the above obtained 5-(3-(6-(4,4-difluoropiperidin-1-yl)pyrazin-2-yl)-1-tosyl-1H-indol-5-yl)-1,3,4-oxadiazol-2-amine (350 mg) in p-dioxane (3 mL) followed by 1 N NaOH (2 mL). The reaction was heated in a microwave reactor (Personal Chemistry, Biotage AB, Inc., Uppsala, Sweden) at 105° C. for 20 min. The mixture was partitioned between 5 mL of H2O and 50 mL of EtOAc. The EtOAc layer was concentrated and the residue purified on a reverse phase HPLC, using a gradient of 10-90% [0.1% TFA in MeCN] in [0.1% TFA in H2O]. The desired fractions were collected, concentrated, the residue was extracted with EtOAc and washed with 0.5 N NaOH to give 5-(3-(6-(4,4-difluoropiperidin-1-yl)pyrazin-2-yl)-1H-indol-5-yl)-1,3,4-oxadiazol-2-amine (20 mg, 5%) as an off white crystalline solid. MS (ESI, pos. ion) 398.1 (M+1); 1H NMR (400 MHz, DMSO-d6) δ ppm 11.93 (1H, br. s.), 8.85 (1H, d, J=1.2 Hz), 8.45 (1H, s), 8.29 (1H, s), 8.19 (1H, s), 7.67 (1H, m), 8.57 (1H, d, J=8.6 Hz), 7.06 (2H, br. s.), 3.89 (4H, t, J=5.6 Hz), 2.12 (4H, m).

Provenance & Evidence