Reacción #96165

Ecuación de reacción

phosphorane

(5-hydroxypentanoylmethylene)-triphenylphosphorane

3,5-dimethoxybenzaldehyde

→

1-(3,5-dimethoxyphenyl)-7-hydroxy-1-hepten-3-one

Disolventes

benzene

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturathe solution was maintained under a nitrogen atmosphere
2. 2
   Temperaturarefluxed for 3 days
3. 3
   Otrothe benzene was removed at room temperature under a nitrogen stream
4. 4
   Otroleaving a product mixture
5. 5
   OtroThis mixture was separated chromatographically on a silica column
6. 6
   workup.ADDITIONa mixture of 30 percent by volume of ethyl acetate in benzene

Procedimiento

10 parts of the phosphonium salt produced in Example 16 was dissolved in water containing an amount of potassium carbonate in excess of that necessary to deprotonate the phosphonium chloride. After extracting this solution with methylene chloride, the organic phase was dried over sodium sulfate. After separation of the drying agent, the methylene chloride was removed at room temperature and under a stream of nitrogen, leaving (5-hydroxypentanoylmethylene)-triphenylphosphorane. 7.04 parts of this phosphorane and 3.11 parts of 3,5-dimethoxybenzaldehyde were dissolved in about 135 parts of benzene, and the solution was maintained under a nitrogen atmosphere and refluxed for 3 days. After the reaction mixture was cooled to room temperature, the benzene was removed at room temperature under a nitrogen stream, leaving a product mixture. This mixture was separated chromatographically on a silica column using as the elution solvent a mixture of 30 percent by volume of ethyl acetate in benzene, to yield 1-(3,5-dimethoxyphenyl)-7-hydroxy-1-hepten-3-one which, after recrystallization from a mixture of benzene and cyclohexane, melted at about 78°-80° C.

Fuente