Hexamethylphosphoramide → 5-(2-Formyl-3-hydroxyphenoxy)pentanoic acid

Beteiligte Stoffe

Reaktionsschritte

Ethyl 5-(2-formyl-3-methoxphenoxy)pentanoate (Example 4) (2.0 g, 0.00704 M), sodium thiocresolate (2.06 g, 0.014 M), hexamethylphosphoramide (2.48 ml, 0.014 M) and benzene (10 ml) were placed in a round bottom flask and refluxed for 18 hours. The reaction mixture, containing ethyl 5-(2-formyl-3-hydroxyphenoxy)pentanoate, was then cooled and poured into 2 N sodium hydroxide solution (20 ml). The organic layer was removed, diluted with ether (20 ml), then extracted with 2 N sodium hydroxide solution (2×20 ml). The aqueous layers were combined and extracted with dichloromethane (2×20 ml). The organic layer was discarded and the aqueous layer acidified with concentrated hydrochloric acid. The resulting precipitate was filtered, washed with water and dried in a desiccator over phosphorus pentoxide to give 5-(2-formyl-3-hydroxyphenoxy)pentanoic acid, m.p. 98°-99° C. from ethyl acetate/petrol.

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