Reaktion #54954

Reaktionsgleichung

hydrochloric acid

2-(3-Acetyl-4-hydroxyphenyl)propan-1-ol

sodium hydride

Ethyl propionate

→

2-[4-hydroxy-3-(3-oxapentanoyl)phenyl]propan-1-ol

Lösungsmittel

hexamethylphosphoramide

hexamethylphosphoramide

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto maintain the temperature below 25° C
2. 2
   ExtraktionThe solution was extracted with ether (2×300 ml)
3. 3
   Sonstigethe extracts evaporated

Vorschrift

2-(3-Acetyl-4-hydroxyphenyl)propan-1-ol (15.0 g; 0.077 mol) was dissolved in hexamethylphosphoramide (150 ml) and slowly added to a stirred slurry of sodium hydride (10.0 g; 0.417 mol) in hexamethylphosphoramide (40 ml) at a rate sufficient to maintain the temperature below 25° C. Ethyl propionate (20.0 g; 0.2 mol) was added and the mixture stirred for 2 hours before pouring into 2N hydrochloric acid (600 ml). The solution was extracted with ether (2×300 ml) and the extracts evaporated to give 2-[4-hydroxy-3-(3-oxapentanoyl)phenyl]propan-1-ol as a yellow oil. This was dissolved in ethanol (100 ml) containing concentrated hydrochloric acid (20 ml) and the solution was refluxed for 30 mins. The ethanol was removed in vacuo and the aqueous phase extracted with chloroform (2×150 ml). The combined extracts were washed with saturated sodium bicarbonate solution and dried over magnesium sulphate. The solvent was removed and the resulting oil was chromatographed on a silica gel column using ether as eluent. Recrystallisation of the product using hexane/ether (2:1) furnished a white microcrystalline solid (5.0 g) mp 59.5°-60.5° C.

Quelle