Zambon S.p.a.

Zambon Group S.p.a.

Silvia Cavicchioli

Claudio Giordano

Graziano Castaldi

Fulvio Uggeri

Marco Villa

Silvio Levi

Maurizio Paiocchi

Francesco Minisci

Carlo Restelli

Intermediates for transforming (2S,3S)-2-amino-3-phenyl-1,3-propanediols into their (2R,3R)-enantiomers are described. The final compounds are useful intermediates for the synthesis of antibiotics like chloramphenicol, Thiamphenicol and Florfenicol.

Process for the stereochemical inversion of

Intermediates for transforming (2S,3S)-2-amino-3-phenyl-1,3-propanediols into their (2R,3R)-enantiomers are described. The final compounds are useful intermediates for the synthesis of antibiotics like Chloramphenicol, Thiamphenicol and Florfenicol.

Intermediates for the stereochemical inversion of

A four step process for transforming (2S,3S)-2-amino-3-phenyl-1,3-propanediols into their (2R,3R)-enantiomers is described. The final compounds are useful intermediates for the synthesis of antibiotics like Chloramphenicol, Thiamphenicol and Florfenicol. The starting products generally are discard products in the synthesis of said antibiotics.

A stereoconvergent process is described for preparing optically active alpha-arylalkanoic acids using as starting substance a diastereoisomeric mixture of ketals of formula ##STR1## in which the substitutents have the meanings given in the description. The described process leads to the formation of a single enantiomer.

Trioxy bicyclic compounds useful for preparing optically active

A stereoselective process is described for preparing optically active alpha,beta-disubstituted carbonyl compounds, comprising forming an acetal between an alpha,beta-unsaturated aldehyde or ketone and tartaric acid or a derivative thereof, halogenating the product thus obtained, and restoring the carbonyl compound.

Stereoselective process for preparing optically active alpha,

A process for the preparation of the compound (2S,3S)(+)-3-hydroxy-2,3-dihydro-2-(4-methoxyphenyl)-5-(2-dimethylaminoeth yl)-1, 5-benzothiazepin-4(5H)-one is described. Said compound is an intermediate useful in the synthesis of Diltiazem.

Process for the preparation of intermediates for the synthesis of

A stereoconvergent process is described for preparing optically active alpha-arylalkanoic acids using as starting substance a diastereoisomeric mixture of ketals of formula ##STR1## in which the substituents have the meanings given in the description. The described process leads to the formation of a single enantiomer.

Stereoconvergent process for preparing optically active carboxylic acids

A new enantioselective process is described for preparing optically active alpha-arylalkanoic acids by:

Process for the preparation of optically active alpha-arylalkanoic acids

Compounds of formula ##STR1## wherein Ar represents an optionally substituted aryl group;

Optically active ketals, processes for their preparation and their use

Process for the preparation of optically active alpha-acrylalkanoic

A process is described for preparing alpha-haloalkyl-aryl-ketones, comprising reacting a substantially anhydrous strong acid with a ketal of formula ##STR1## in which Ar, R, R.sub.1, R.sub.2 and X have the meanings given in the description.

Process for preparing optically active alpha-haloalkyl-aryl-ketones

A process is described for preparing optically active alpha-halogenated carbonyl compounds. This process consists of transforming the carbonyl compound into the corresponding acetal with tartaric acid or a derivative thereof, halogenating this acetal and releasing the carbonyl compound.

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Costermano, Italy

Silvia Cavicchioli