Water → 1-(2-Allyloxyphenoxy)-3-[2-(3-carbamoyl-4-hydroxyphenoxy)-1-methylethylamino]propan-2-ol

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Reaction Steps

A mixture of 11.2 g of 1-(2-allyloxyphenoxy)-3-aminopropan-2-ol and 10.5 g of 5-(2-oxopropoxy)salicylamide is boiled using a water separator in 200 ml of toluene with the addition of a few drops of acetic acid. After the splitting off of water has ceased (after about 2-3 hours), the solution is concentrated by evaporation, the dark red residue is dissolved in 300 ml of ethanol and a total of 5.7 g of sodium borohydride is added in portions whilst stirring. The temperature increases during this operation to 36°. The reaction mixture is stirred for a further 2 hours at 20°-30°, and left to stand overnight. Whilst cooling with ice, it is then brought to pH 3-4 with approximately 6N hydrochloric acid, filtered and concentrated by evaporation. The residue is divided between 100 ml of water and 100 ml of ethyl acetate, the aqueous phase is separated off, rendered alkaline with concentrated ammonia and extracted with 200 ml of ethyl acetate. Working up of the organic phase yields crude oily 1-(2-allyloxyphenoxy)-3-[2-(3-carbamoyl-4-hydroxyphenoxy)-1-methylethylamino]propan-2-ol as an enantiomer mixture. By slow crystallisation from isopropanol the two pure enantiomer pairs having melting points of 123°-125° and 98°-102° respectively are obtained.

Provenance & Evidence