Reaktion #343783

Reaktionsgleichung

sodium carbonate

methyl (+)-5-carboxy-2-cyano-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylate

phosphorus pentachloride

isopropyl alcohol

→

5-isopropyl 3-methyl (+)-2-cyano-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

Ausbeute 95.4%

Lösungsmittel

methylene chloride

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooling
2. 2
   workup.ADDITIONis added
3. 3
   workup.STIRRINGthe mixture is stirred at ambient temperature for one hour
4. 4
   SonstigeThe organic layer is separated
5. 5
   Extraktionthe water layer is extracted with methylene chloride
6. 6
   Waschenwashed with aqueous sodium chloride solution
7. 7
   Trocknendried over anhydrous magnesium sulfate
8. 8
   workup.DISTILLATIONdistilled under reduced pressure
9. 9
   Sonstigeto remove the solvent
10. 10
    SonstigeThe residue is purified by silica gel (75 g) column chromatography, elution
11. 11
    SonstigeThe solvent is removed from the eluate under reduced pressure
12. 12
    Sonstigethe residue is crystallized from diisopropyl ether

Vorschrift

In methylene chloride (30 ml) is suspended methyl (+)-5-carboxy-2-cyano-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylate (3.12 g) followed by addition of phosphorus pentachloride (2.46 g) with ice-cooling, and the mixture is stirred for 30 minutes. Then, a solution of isopropyl alcohol (1.4 g) in methylene chloride (10 ml) is added dropwise over a period of 10 minutes. The mixture is stirred for 20 minutes, at the end of which time 5% aqueous sodium carbonate solution (30 ml) is added and the mixture is stirred at ambient temperature for one hour. The organic layer is separated and the water layer is extracted with methylene chloride. The organic layers are combined, washed with aqueous sodium chloride solution, dried over anhydrous magnesium sulfate and distilled under reduced pressure to remove the solvent. The residue is purified by silica gel (75 g) column chromatography, elution being carried out with benzeneethyl acetate (10:1). The solvent is removed from the eluate under reduced pressure and the residue is crystallized from diisopropyl ether to provide 5-isopropyl 3-methyl (+)-2-cyano-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate (3.34 g).

Quelle