Trimethylboroxine → HCID 86704595, compound

Participants

Reaction Conditions

Reaction Steps

A solution of methyl 4-iodo-3-(4-methoxyphenyl)-1-methyl-1H-pyrazole-5-carboxylate (587.8 mg, 1.579 mmol), trimethylboroxine (883 μL, 6.32 mmol) and 1,1′-bis(di-tert-butylphosphino)ferrocene palladium dichloride (103 mg, 0.158 mmol) in THF (2.6 mL) was degassed by bubbling N2 through the solution. 1N K2CO3 (2.6 mL) was added and N2 was bubbled through the mixture for 30 s. The mixture was heated in a sealed tube at 60° C. overnight. Another 4 eq. of trimethylboroxine was added and the reaction was subjected to microwave irradiation (120° C., 30 min). The reaction mixture was filtered through a plug of silica, eluted with EtOAc and the filtrate was washed with 1N aq. NaOH (2×30 mL), dried (Na2SO4) and concentrated in vacuo to afford the crude product. This was purified by flash chromatography (Biotage Horizon, 25M, Si, ˜20 mL/min, 100% hexanes for 144 mL, gradient to 20% EtOAc in hexanes over 2394 mL) to afford methyl 3-(4-methoxyphenyl)-1,4-dimethyl-1H-pyrazole-5-carboxylate, as a colorless solid. Rf=0.33 (20% EtOAc/hexanes). LCMS calc.=261.03. found=261.12 (M+H)+. 1H NMR (600 MHz, CDCl3): δ 7.51 (d, J=8.5 Hz, 2H); 6.96 (d, J=8.5 Hz, 2H); 4.16 (s, 3H); 3.92 (s, 3H); 3.83 (s, 3H); 2.36 (s, 3H).

Provenance & Evidence