Reacción #50537

Ecuación de reacción

2,3-lutidine

p-bromotoluene

magnesium

iodine

phenyl chloroformate

→

1,6-dihydro-2,3-dimethyl-6-(4-methylphenyl)-1-phenoxycarbonyl pyridine

Disolventes

tetrahydrofuran

tetrahydrofuran

tetrahydrofuran

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturathe mixture was refluxed for 1 hour
2. 2
   Otrothe magnesium complex prepared
3. 3
   workup.ADDITIONabove added
4. 4
   Otroat room temperature
5. 5
   Otroovernight
6. 6
   OtroThe solvent was removed under reduced pressure
7. 7
   Otrothe residue partitioned between ether and 200 ml of 20% ammonium chloride
8. 8
   Lavadothe organic layer washed with water
9. 9
   OtroThe solvent was evaporated under reduced pressure
10. 10
    Otrothe residue flash-chromatographed on silica gel
11. 11
    Lavadoeluting with 1% ethyl acetate in heptane

Procedimiento

A solution of p-bromotoluene (13.5 g) in 50 ml of tetrahydrofuran was added to magnesium (1.5 g) and 1 crystal of iodine in a little tetrahydrofuran, and the mixture was refluxed for 1 hour. In a separate flask, a solution of 2,3-lutidine (6.5 g) in 100 ml of tetrahydrofuran was cooled to about -60° C., and the magnesium complex prepared above added, followed by phenyl chloroformate (8 ml). The mixture was stirred for 1 hour at -60° C., then at room temperature overnight. The solvent was removed under reduced pressure, the residue partitioned between ether and 200 ml of 20% ammonium chloride, the organic layer washed with water, followed by dilute hydrochloric acid. The solvent was evaporated under reduced pressure, and the residue flash-chromatographed on silica gel, eluting with 1% ethyl acetate in heptane, to yield 12.4 g of 1,6-dihydro-2,3-dimethyl-6-(4-methylphenyl)-1-phenoxycarbonyl pyridine, m.p. 106° C.

Fuente