The absolute configuration of benproperinium dihydrogen phosphate, an antitussive drug |
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Authors: | L Schjelderup A J Aasen |
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Institution: | Department of Pharmacy, University of Oslo, Norway. |
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Abstract: | The (+)- and (-)-enantiomers of benproperinium dihydrogen phosphate, an antitussive drug, have been assigned the R- and S-configurations, respectively, by syntheses of both enantiomers using (S)-2-hydroxypropanoic acid (L-lactic acid) as chiral synthon. The key intermediate, (S)-1-methyl-2-2-(phenylmethyl)phenoxy]ethyl p-toluenesulfonate, was subjected to an SN2-type reaction with piperidine furnishing (+)-(R)-benproperinium dihydrogen phosphate. (-)-(S)-Benproperinium dihydrogen phosphate was obtained by submitting the same tosylate to two consecutive SN2-type reactions with Br- and piperidine, respectively, acting as nucleophiles. |
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Keywords: | stereochemistry stereoselective snthesis (S)-2-hydroxypropanoic acid chiral synthon |
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