Diisopropylethylamine → ethyl 1-methyl-5-(2-phenyl-[1,2,4]triazolo[1,5-a]pyridin-7-ylcarbamoyl)-1H-pyrazole-4-carboxylate

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Reaction Conditions

Reaction Steps

A mixture of 2-phenyl-[1,2,4]triazolo[1,5-a]pyridin-7-amine (945 mg, 4.49 mmol), 4-(ethoxycarbonyl)-1-methyl-1H-pyrazole-5-carboxylic acid (1.07 g, 5.39 mmol), propylphosphonic anhydride (50% in ethyl acetate, 6.62 ml, 11.2 mmol) and diisopropylethylamine (3.93 ml, 22.5 mmol) in tetrahydrofurane (50 ml) is stirred for 2.5 days at 25° C. The crude material is loaded on silicagel and purified by flash chromatography on a 50 g silica column using heptane/ethyl acetate 20-100% and then ethyl acetate/methanol 10-30% as eluent. The fractions containing product are evaporated to dryness and the residue (4.23 g light yellow solid) is dissolved in tetrahydrofurane (20 ml); sodium bicarbonate solution (30 ml) is added and the mixture is stirred for 30 minutes at 25° C. The solid is collected by filtration, washed with water and dried affording ethyl 1-methyl-5-(2-phenyl-[1,2,4]triazolo[1,5-a]pyridin-7-ylcarbamoyl)-1H-pyrazole-4-carboxylate (1.336 g, 76.1%) as an off-white solid. mp.: 242-3° C. MS: m/z=391.2 (M+H+).

Provenance & Evidence