Boehringer Ingelheim Pharma Kg

Boehringer Ingelheim Pharma Gmbh & Co Kg

Markus Sauter

Wolfgang Wohlleben

Burkhard Jaeger

Oliver Meyer

Juergen Schroeder

Mark Goehlich

Burkhard Jäger

Mark Göhlich

Jürgen Schröder

The invention relates to a continuous process for preparing dihydropyrones of general formula I, wherein the groups Rand Rhave the meanings described herein.

Continuous process for preparing dihydropyrones

The invention relates to a process for preparing optically active 5-hydroxy-3-ketoesters of formula A1 or A2, or one of the tautomers thereof,the use thereof for preparing optically active dihydropyrones of formula B, and the use of the dihydropyrones of formula B thus prepared as starting compounds for preparing pharmaceutically active compounds, particularly Tipranavir.

Process for preparing optically active dihydropyrones

A process for preparing a compound of formula (II)wherein

Process for preparing zolpidem

The invention relates to an improved process for obtaining highly pure, crystalline betulinic acid from a methanolic extract of ground plane tree cortex and/or plane tree bark, as well as highly pure crystalline betulinic acid which is solvated with one equivalent of ethanol.

Process for obtaining betulinic acid

The invention relates to a new process for preparing optically active dihydropyrones, new intermediate products which may be obtained by this synthesis, and their use as starting compounds in the preparation of pharmaceutically active compounds.

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Gensingen, Germany

Markus Sauter