Abstract: 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.

Abstract: 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.

Abstract: 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.BwhereinR.sub.2 denotes hydrogen C.sub.1 -C.sub.6 -alkyl, halogen, C.sub.1 -C.sub.8 -alkoxy, a benzoyl group bound via an oxygen or an alkylcarboxyl group having a straight chained or branched C.sub.1 -C.sub.6 -lower alkyl group--wherein the alkyl group may optionally be substituted by one or more halogen atoms which may be identical or different;is heated to yield a racemic mixture of compounds of the formulae 8.sub.A and 8.sub.

Abstract: 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).

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

Abstract: 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).

Abstract: The present invention relates to a new process 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-methano-benzo?.alpha.!oxacin-9-ol! (BIII 277).