Process for preparing the pure enantiomers of lifibrol and its alkyl esters

US5266721A · kind A · utility

Assignee

• Klinge Pharma GmbH · DE

Inventors

• Friedemann Reiter · Putzbrunn, DE
• Hans-Helmut Henschel · Munich, DE

Key dates

• Filing date: Jun 4, 1992
• Grant date: Nov 30, 1993
• Expiry date: Jun 4, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/367
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The preparation of the pure enantiomers of LIFIBROL and its alkyl esters is achieved with surprisingly good yield by reacting the pure enantiomeric forms of S(-) R(+)-4-(4-tert.butylphenyl)-1,2-epoxy butane with 4-hydroxybenzoic acid alkyl ester at elevated temperature in DMF and in the presence of 4-hydroxybenzoic acid alkyl ester sodium salt. Thereafter, the raw reaction product is separated. Either the stereochemically pure LIFIBROL ester is then recovered by recrystallization or the precipitated LIFIBROL enantiomer is made in pure crystalline form by mild alkaline saponification and subsequent acidification.