Stannane, tributyl(1-ethoxyethenyl)- → 1-(7-Amino-3-(6-phenylpyridin-3-yl)-5-(piperidin-4-yl)pyrazolo[1,5-a]pyrimidin-6-yl)ethanone

Participants

Reaction Conditions

Reaction Steps

A degassed mixture of tert-butyl 4-(7-(bis((2-(trimethylsilyl)ethoxy)methyl)amino)-6-bromo-3-(6-phenylpyridin-3-yl)pyrazolo[1,5-a]pyrimidin-5-yl)piperidine-1-carboxylate (Int-91,154 mg, 0.19 mmoL), Pd(PPh3)4 (22 mg, 0.019 mmoL), tributyl(1-ethoxyvinyl)stannane (103 mg, 0.28 mmoL) in dioxane (3 mL) was heated at 100° C. overnight. The reaction mixture was cooled to room temperature, filtered through 9:1 SiO2:KF plug and concentrated in vacuo. The crude tert-butyl 4-(7-(bis((2-(trimethylsilyl)ethoxy)methyl)amino)-6-(1-ethoxyvinyl)-3-(6-phenylpyridin-3-yl)pyrazolo[1,5-a]pyrimidin-5-yl)piperidine-1-carboxylate (Int-9j) was treated with 50% TEA in H2O (4 mL) until the disappearance of starting material in LCMS. Concentration afforded crude 1-(7-amino-3-(6-phenylpyridin-3-yl)-5-(piperidin-4-yl)pyrazolo[1,5-a]pyrimidin-6-yl)ethanone (Int-9k), which was then heated under microwave conditions with N2H4.H2O (800 uL) and NMP (6 mL) first at 100° C. for 30 min and then at 200° C. for 1 h. Purification with prep-LC provided 3-methyl-6-(6-phenylpyridin-3-yl)-4-(piperidin-4-yl)-1H-dipyrazolo[1,5-a:4′,3′-e]pyrimidine (Int-91): LCMS tR=2.49 Min (10 min run, UV254m). Mass calculated for, M+409.2, observed LC/MS m/z 410.6 (M+H).

Provenance & Evidence