Boehringer Ingelheim Kg

Boehringer Ingelheim Pharma Gmbh & Co Kg

Hanfried Baltes

Matthias Grauert

Herbert Merz

Rolf Dach

Joerg Brandenburg

Juergen Schnaubelt

The invention relates to a method for producing 1,3-dioxolane-2-ones of general formula (3) in basic reaction conditions by reesterifying the respective ester of general formula (1) in which R1 to R5 have the meanings indicated in the claims and the description. The invention further relates to a method for producing 2-hydroxy carboxylic acid esters of general formula (5) with or without isolation of the intermediate in the form of a derivative of the 1,3-dioxolane-2-one of general formula (3) in basic reaction conditions by reesterifying the respective ester of general formula (1) in which R1, R2, and R6 have the meanings indicated in the claims and the description. The method according to the invention allows the reaction to take place in very gentle basic conditions, causing fewer secondary reactions and providing a greater yield than reactions in highly polar aprotic solvents. Acid-sensitive and/or temperature-sensitive compounds can be synthesized. 

Method for the production of 1,3-dioxolane-2-ones and carboxylic acid esters by means of transacylation in basic reaction conditions

A process for the re-racemisation of a (-)-2-phenylmethyl-3,3-dimethyl-piperidin-4-on derivative wherein a (-)-2-phenylmethyl-3,3-dimethyl-piperidin-4-on derivative of the formula 8.sub.B wherein

Heat-based process for the re-racemisation of a

The present invention relates to new processes for preparing norbenzomorphan, the central intermediate step in the preparation of pharmaceutically useful benzomorphan derivatives of general formula 1 ##STR1## especially (-)-(1R,5S,2'R)-3'-hydroxy-2-(2-methoxypropyl)-5,9,9-trimethyl-6,7-benzomo rphan or [(-)-(2R, 6S,2'R)-3-(2-methoxypropyl)-6,11,11-trimethyl-1,2,3,4,5,6-hexahydro-2,6-me thano-benzo[.alpha.]oxacin-9-ol] (BIII 277).

Method of preparing norbenzomorphane as an intermediate in the

The present invention relates to a new process for preparing norbenzomorphane derivatives of general formula 1 ##STR1##

Process for preparing pharmaceutically useful norbenzomorphane derivative

The present invention relates to new processes for preparing norbenzomorphan, the central intermediate step in the preparation of pharmaceutically useful benzomorphan derivatives of general formula 1 ##STR1## especially (-)-(1R,5S,2'R)-3'-hydroxy-2-(2-methoxypropyl)-5,9,9-trimethyl-6,7-benzomo rphan or [(-)-(2R,6S,2'R)-3-(2-methoxypropyl)-6,11,11-trimethyl-1,2,3,4,5,6-hexahyd ro-2,6-methano-benzo[.alpha.]oxacin-9-ol] (BIII 277).

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Wollstein, Germany

Hanfried Baltes