Réaction #4607

Équation de réaction

butyl lithium

ammonium chloride

methyl 2,4-dichlorobenzoate

5-bromopyrimidine

→

title compound

5-(2',4'-dichlorobenzoyl)pyrimidine

Solvants

hexane

tetrahydrofuran

diethyl ether

Conditions de réaction

Traitement

1. 1
   workup.ADDITIONAfter the addition of 30 g of molecular sieve
2. 2
   Températurecooled to about -120° C
3. 3
   workup.STIRRINGThe reaction mixture is then stirred for 11/2 hours in the temperature range from -100° to -130° C
4. 4
   Températureto increase to room temperature
5. 5
   workup.STIRRINGstirring
6. 6
   Extractionthe reaction mixture is extracted three times with ethyl acetate
7. 7
   SéchageThe organic solution is dried over sodium sulfate
8. 8
   Filtrationfiltered
9. 9
   Concentrationthe filtrate is concentrated
10. 10
    AutreThe resultant crude product is then purified through a flash column
11. 11
    workup.ADDITIONa 3:1 mixture of petroleum ether and ethyl acetate),

Mode opératoire

61.8 g (0.3 mole) of methyl 2,4-dichlorobenzoate and 52.2 g (0.33 mole) of 5-bromopyrimidine are dissolved in a mixture of 400 ml of tetrahydrofuran and 200 ml of diethyl ether. After the addition of 30 g of molecular sieve, the reaction mixture is stirred for 1/2 hour at room temperature and then cooled to about -120° C. 187.2 ml (0.3 mole) of butyl lithium as a 1.6 molar solution in hexane are added dropwise at this temperature. The reaction mixture is then stirred for 11/2 hours in the temperature range from -100° to -130° C. Subsequently, while allowing the temperature to increase to room temperature, stirring is continued until the reaction is complete. 300 ml of 10% ammonium chloride solution are then added dropwise, and the reaction mixture is extracted three times with ethyl acetate. The organic solution is dried over sodium sulfate and then filtered, and the filtrate is concentrated. The resultant crude product is then purified through a flash column packed with silica gel (eluant: a 3:1 mixture of petroleum ether and ethyl acetate), affording 45 g (59.3% of theory) of the title compound with a melting point of 75°-78° C.

Source