Sodium Carbonate → [5-(Tert-butyl-diphenyl-silanyloxymethyl)-2-methyl-pyrazolo[1,5-a]pyridin-3-yl]-oxo-acetic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

In a reaction tube, chloro-oxo-acetic acid methyl ester (2.47 ml, 26.0 mmol, 4.0 equiv) is added to a solution of 5-(tert-butyl-diphenyl-silanyloxymethyl)-2-methyl-pyrazolo[1,5-a]pyridine (2.6 g, 6.49 mmol) in THF (20 ml) under an atmosphere of argon. The tube is sealed under argon, and the reaction mixture is heated under microwave irradiation for 15 minutes at 120° C. After cooling, the reaction mixture is carefully poured into an aqueous solution of sodium carbonate. After three extractions with EtOAc, the combined organic layers are dried over Na2SO4, filtered and concentrated in vacuo. Purification via flash chromatography (hexane/EtOAc 4:1) affords the title compound (2.9 g, 92%). 1H NMR (400 MHz, d6-DMSO): δ=8.76 (d, J=7.8 Hz, 1H), 8.11 (br s, 1H), 7.61-7.59 (m, 4H), 7.44-7.35 (m, 6H), 7.10 (dd, J=7.1/1.9 Hz, 1H), 4.88 (s, 2H), 3.82 (s, 3H), 2.41 (s, 3H), 1.03 (s, 9H). MS (ES+): 487 (M+H)+.

Provenance & Evidence