Reaction #322769

Reaction equation

sodium methoxide

sodium

3,4-difluorobenzamidine hydrochloride

→

5-ethyl-2-(3,4-difluorophenyl)pyrimidine

Yield 106.0%

Solvents

methanol

Conditions

Workup

1. 1
   Temperatureby heating the mixture
2. 2
   Temperatureunder reflux for 6 hours
3. 3
   workup.DISTILLATIONdistilling off methanol at the atmospheric pressure
4. 4
   workup.ADDITIONadding toluene (20 cc) to the reaction residue
5. 5
   Extractionto extract the product
6. 6
   Washwashing the extraction solution with water
7. 7
   Dryingdrying the toluene layer over anhydrous sodium sulfate
8. 8
   Filtrationfiltering off the drying agent
9. 9
   workup.DISTILLATIONdistilling off toluene
10. 10
    Otherrecrystallizing the residue from ethanol (20 cc)

Procedure

To a solution of sodium methoxide prepared by dissolving metallic sodium (2.8 g) dissolved in anhydrous methanol (20 cc) were added 3,4-difluorobenzamidine hydrochloride (11.6 g, 0.06 mol) and α-ethyl-β-dimethylaminoacrolein (8.9 g, 0.066 mol), followed by heating the mixture under reflux for 6 hours, thereafter distilling off methanol at the atmospheric pressure, adding toluene (20 cc) to the reaction residue to extract the product, washing the extraction solution with water, drying the toluene layer over anhydrous sodium sulfate, filtering off the drying agent, distilling off toluene, and recrystallizing the residue from ethanol (20 cc) to obtain the objective 5-ethyl-2-(3,4-difluorophenyl)pyrimidine (7.0 g) having a m.p. of 86.6° C. Its 1H-NMR (proton nuclear magnetic resonance) spectra are shown in FIG. 1.

Source