Phthalamide → 5-(3,5-Dicyano-2,6-dimethyl-1,4-dihydro-pyridin-4-yl)-3-[2-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-ethylamino]-indazole-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a stirred solution of crude 5-(3,5-dicyano-2,6-dimethyl-1,4-dihydro-pyridin-4-yl)-3-(2-hydroxy-ethylamino)-indazole-1-carboxylic acid tert-butyl ester (0.6 g), from Synthetic Example 22, in THF (14.3 mL), under Argon, was added sequentially triphenylphosphine (1.08 g, 4.13 mmol), phthalamide (0.21 g, 1.45 mmol), followed by diisopropyl azadicarboxylate (DIAD, 0.31 g, 1.52 mmol) dropwise over 30 minutes. The mixture was stirred overnight at room temperature. The mixture was quenched with saturated sodium hydrogencarbonate solution and extracted with EtOAc. The combined organic extracts were washed with brine, dried and concentrated. The residue was partially purified by chromatography on silica gel, followed by preparative reverse phase HPLC to give 5-(3,5-dicyano-2,6-dimethyl-1,4-dihydro-pyridin-4-yl)-3-[2-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-ethylamino]-indazole-1-carboxylic acid tert-butyl ester (131 mg) which was used directly in the next step.

Provenance & Evidence