Boehringer Ingelheim Kg

Boehringer Ingelheim Pharma Kg

Franz Dietrich Klinger

Rainer Sobotta

Heinrich Schneider

Lienhard Wolter

Wolfgang Dietrich

The present invention relates to an improved process for preparing L-phenylephrine hydrochloride 3 on an industrial scale by asymmetric hydrogenation as the key step and a special sequence of subsequent steps, using &lsqb;Rh(COD)Cl&rsqb;,as catalyst and a chiral, two-pronged phosphine ligand such as (2R,4R)-4-(dicyclohexylphosphino)-2-(diphenylphosphino-methyl)-N-methyl-aminocarbonyl-pyrrolidine as the catalyst system.

Method for preparing of L-phenylephrine hydrochloride

A method of preparing sugar acetonides, such as for example 1,2:5,6-Di-O-isopropylidene-.alpha.-D-glucofuranose, by reacting the corresponding sugar, e.g. D-(+)-glucose, with acetone in the presence of a Lewis acid and a carboxylic acid derivative of general formula ##STR1## wherein X is a leaving group which may be readily replaced by a hydroxyl group.

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Griesheim, Germany

Franz Dietrich Klinger