2,2-Dimethoxypropane → HCID 66743611, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 5-bromo-3-[(3-nitrobenzyl)amino]thiophene-2-carboxamide (260 mg, 0.730 mmol), 2,2-dimethoxypropane (2.0 mL), CSA (17 mg, 0.073 mmol), MgSO4 (200 mg) and DMA (2 mL) was microwave-irradiated at 120° C. for 1 h. Then, saturated aqueous sodium hydrogen carbonate was added to quench the reaction. The organic materials were extracted with EtOAc. The combined extracts were washed with water and brine, dried over Na2SO4 and filtered. After removal of the solvent at reduced pressure, a yellow crystalline solid was obtained. A flask was charged with this solid, 1,2-dimethoxyethane (4 mL), tert-butyl 3-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole-1-carboxylate (675 mg, 2.19 mmol), sodium carbonate (219 mg, 3.65 mmol) and water (2 mL). The flask was purged with argon. Then, 1,1′-bis(diphenylphosphino) ferrocenepalladium (II) dichloride dichloromethane adduct (60 mg, 0.073 mmol) was added to the mixture. The flask was purged with argon again. After stirring at 100° C. for 2 h, 8 M aqueous NaOH (1.0 mL) was added. After stirring at 100° C. for 1 h, the organic materials were extracted with EtOAc. The combined extracts were washed with brine, dried over Na2SO4 and filtered. After removal of the solvent at reduced pressure, the residue was purified by column chromatography (Purif, silica gel, 80:20 hexane/EtOAc to EtOAc), then crystallized from MeOH/EtOAo/hexane to give the title compound (124 mg, 43%) as a yellow solid:

Provenance & Evidence