p-Toluenesulfonic acid → 1-[((1S,2S)-2-benzyloxy-cyclohexylcarbamoyl)-methyl]-5-(3-fluoro-5-trifluoromethyl-benzyloxy)-1H-pyrazole-3-carboxylic acid ethyl ester

Participants

Reaction Steps

To a solution of 58.5 mg (0.15 mmol) of 1-carboxymethyl-5-(3-fluoro-5-trifluoromethyl-benzyloxy)-1H-pyrazole-3-carboxylic acid ethyl ester (3) in 5 mL of tetrahydrofuran was added 123 mg (0.60 mmol) of (1S, 2S)-2-benzyloxy-cyclohexylamine, 40 mg (0.30 mmol) of 1-hydroxybenzotriazole (HOBt) and 500 mg (0.60 mmol) of PS-carbodiimide resin, and the mixture was shaken at rt overnight. The reaction mixture was then treated with 200 mg (0.60 mmol) of MP-carbonate resin and 225 mg (0.9 mmol) of PS-TsOH resin, and shaken at rt for 4 h. The resulting mixture was filtered and washed with tetrahydrofuran (2×2 mL), and the combined tetrahydrofuran extracts were concentrated to afford crude 1-[((1S, 2S)-2-benzyloxy-cyclohexylcarbamoyl)-methyl]-5-(3-fluoro-5-trifluoromethyl-benzyloxy)-1H-pyrazole-3-carboxylic acid ethyl ester (4) which was used in the next reaction without any further purification.

Provenance & Evidence