Triethylamine → 5,5-Dimethyl-2-(5-phenylethynyl-pyridin-2-yl)-pyrazolidin-3-one

Participants

Reaction Conditions

Reaction Steps

Bis-(triphenylphosphine)-palladium(II)dichloride (27 mg, 39 μmol, 0.05 equiv.) was dissolved in 2 ml THF. (210 mg, 770 μmol) 2-(5-Bromo-pyridin-2-yl)-5,5-dimethyl-pyrazolidin-3-one (Example 1, step 2) and phenylacetylene (130 mg, 1.24 mmol, 1.6 equiv.) were added at room temperature. Triethylamine (325 μl, 2.33 mmol, 3 equiv.), triphenylphosphine (6 mg, 23.3 μmol, 0.03 equiv.) and copper(I)iodide (4 mg, 23.3 μmol, 0.03 equiv.) were added and the mixture was stirred for 16 hours at 65° C. The reaction mixture was cooled and extracted with saturated NaHCO3 solution and two times with a small volume of dichloromethane. The crude product was purified by flash chromatography by directly loading the dichloromethane layers onto a silica gel column eluting with an ethyl acetate:heptane gradient 0:100 to 100:0. The desired 5,5-dimethyl-2-(5-phenylethynyl-pyridin-2-yl)-pyrazolidin-3-one (102 mg, 45% yield) was obtained as a white solid, MS: m/e=292.1 (M+H+).

Provenance & Evidence