1,2-Dimethoxyethane → 7-(2,4-dichloro-phenyl)-2-methyl-2H-indazole-3-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

A mixture of 35a (0.750 g, 2.79 mmol), 2,4-dichlorophenyl boronic acid (1.06 g, 5.57 mmol), 10 mL of ethylene glycol dimethyl ether, tetrakis(triphenylphosphine) palladium(0) (0.097 g, 0.084 mmol), and 10 mL of a 2 M aqueous Na2CO3 solution was stirred at 85° C. overnight, then allowed to cool. Ethyl acetate (50 mL) was added, and the mixture was washed with 30 mL of a saturated aqueous NaCl solution, dried over MgSO4, filtered, and concentrated to a yellow oil. Column chromatography (0→10% EtOAc/hexanes) afforded of 7-(2,4-dichloro-phenyl)-2-methyl-2H-indazole-3-carboxylic acid methyl ester (35b: 0.582 g; 62%; m.p. 128-131) as a white solid:

Provenance & Evidence