1,2-Dichloroethane → (R)-2-ethoxy-N-(2-hydroxy-(R)-1-phenylethyl)-3-[4-(2-{4-methanesulfonyloxyphenyl}-ethoxy)phenyl]propanoic amide

Participants

Reaction Steps

A solution of 2-ethoxy-3-[4-(2-{4-methanesulfonyloxyphenyl} ethoxy)phenyl]propanoic acid (10.5 g; 25.7 mmole) in dry dichloromethane (150 ml) was cooled on an ice-bath and EDC (5.42 g; 28.3 mmole), diisopropylethylamine (4.8 ml; 28.3 mmole) and HOBtxH2O (3.82 g; 28.3 mmole) were added. After 20 minutes the ice-bath was removed and (R)-phenylglycinol (3.88 g; 28.3 mmole) was added. After stirring at room temperature over night dichloromethane (100 ml), citric acid (60 ml, 10%) and ethyl acetate were added and the phases were separated. The organic phase was washed with citric acid (60 ml), sodium bicarbonate (2×60 ml) and brine (60 ml), dried (sodium sulfate), filtered and the solvent evaporated in vacuo. The crude product was crystallized twice in ethyl acetate/heptan to give 4.43 g of (R)-2-ethoxy-N-(2-hydroxy-(R)-1-phenylethyl)-3-[4-(2-{4-methanesulfonyloxyphenyl}ethoxy)phenyl]propanoic amide. The mother liquids were combined, the solvent was evaporated in vacuo and the residue was purified by chromatography on silica gel using ethyl acetate:heptan (gradient 25 to 100% ethyl acetate) to give 5.14 g (yield 38%) of (S)-2-ethoxy-N-(2-hydroxy-(R)-1-phenylethyl)-3-[4-(2-{4-methanesulfonyloxyphenyl}ethoxy)-phenyl]propanoic amide and 0.51 g (totally 4.94 g, yield 36%) of (R)-2-ethoxy-N-(2-hydroxy-(R)-1-phenylethyl)-3-[4-(2-{4-methanesulfonyloxyphenyl}-ethoxy)phenyl]propanoic amide.

Provenance & Evidence