Reaction #84789

Reaction equation

4-bromo-1-(tris(4-methoxyphenyl)methyl)-1H-pyrazole

(4-formylphenyl)boronic acid

K2CO3

→

4-(1-(tris(4-methoxyphenyl)methyl)-1H-pyrazol-4-yl)benzaldehyde

Yield 83.7%

Solvents

DME H2O

Conditions

Workup

1. 1
   Otherwas degassed
2. 2
   workup.WAITby alternately putting under house vacuum and argon three times for several minutes
3. 3
   Otherthe mixture was degassed again
4. 4
   Temperaturecooling to room temperature
5. 5
   workup.ADDITIONH2O was added
6. 6
   ExtractionThe mixture was extracted with EtOAc
7. 7
   Washthe combined organics were washed with H2O, saturated aqueous NaHCO3 and brine
8. 8
   Dryingthen dried over Na2SO4
9. 9
   Concentrationconcentrated in vacuo
10. 10
    OtherPurification by chromatography (20-30% EtOAc-hexanes; EtOAc containing 1% Et3N)

Procedure

A mixture of 4-bromo-1-(tris(4-methoxyphenyl)methyl)-1H-pyrazole (1.47 g, 3.1 mmol), (4-formylphenyl)boronic acid (0.94 g, 6.3 mmol), and K2CO3 (0.65 g, 4.7 mmol) in DME-H2O (25 mL, 4:1) was degassed by alternately putting under house vacuum and argon three times for several minutes each. Tetrakis(triphenylphosphine)palladium (0.35 g, 0.3 mmol) was added then the mixture was degassed again. After heating for 16.5 hrs at 80° C. and cooling to room temperature, H2O was added. The mixture was extracted with EtOAc and the combined organics were washed with H2O, saturated aqueous NaHCO3 and brine then dried over Na2SO4 and concentrated in vacuo. Purification by chromatography (20-30% EtOAc-hexanes; EtOAc containing 1% Et3N) gave 4-(1-(tris(4-methoxyphenyl)methyl)-1H-pyrazol-4-yl)benzaldehyde (1.31 g combined from two reactions, 33%).

Source