Tricalcium Phosphate → 3-(3-Chlorophenyl)-pyrazolo-[1,5-a]-pyrimidine-5-carboxylic acid ethyl ester

Participants

Reaction Steps

A mixture of 3-bromo-pyrazolo-[1,5-a]-pyrimidine-5-carboxylic acid ethyl ester (18.00 g), 3-chlorophenyl boric acid (12.50 g), calcium phosphate (31.12 g), and 200 ml of dioxane was stirred under a nitrogen atmosphere, added with tetrakis(triphenylphosphine) palladium (0) (1.50 g), and heated at reflux over 3 hours. The reactant was cooled to room temperature, and thereafter poured into 150 ml of water, and extracted with 300 ml of toluene. The extract was washed with saturated saline solution, dried with magnesium sulfate, and concentrated in vacuo. The resulting residue was purified by silica gel column chromatography (ethyl acetate:toluene=8:2) to yield 3-(3-chlorophenyl)-pyrazolo-[1,5-a]-pyrimidine-5-carboxylic acid ethyl ester (18.05 g, 89%) as a brown columnar crystal. mp: 126-129° C.

Provenance & Evidence