PROCESS FOR PREPARING ENANTIOPURE E-(2S)-ALKYL-5-HALOPENT-4-ENOIC ACIDS AND ESTERS

A process for preparing enantiopure E-(2S)-alkyl-5-halopent-4-enoic acids and their esters of the formula (I), in which R is a C1-C6-alkyl radical, R1 is H or C1-C4-alkyl and X is chlorine, bromine or iodine, in which the corresponding racemic 2-alkyl-5-halopent-4-enoic acid a) is reacted in a suita...

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Bibliographic Details
Main Authors STEINBAUER, GERHARD, POJARLIEV, PETER, ROESSLER, MARKUS
Format Patent
LanguageEnglish
French
German
Published 21.11.2007
Subjects
ACYCLIC OR CARBOCYCLIC COMPOUNDS
APPARATUS THEREFOR
CHEMISTRY
GENERAL METHODS OF ORGANIC CHEMISTRY
METALLURGY
ORGANIC CHEMISTRY
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Summary:A process for preparing enantiopure E-(2S)-alkyl-5-halopent-4-enoic acids and their esters of the formula (I), in which R is a C1-C6-alkyl radical, R1 is H or C1-C4-alkyl and X is chlorine, bromine or iodine, in which the corresponding racemic 2-alkyl-5-halopent-4-enoic acid a) is reacted in a suitable solvent first with (S)-3-Methyl-2-phenylbutylamine, quinine or with N-methyl-D-glucamine, after which b) the corresponding (S)-3-Methyl-2-phenylbutylamine salt, quinine or glucamine salt of the (R)-pentenoic acid is precipitated and removed, and c) the remaining filtrate is mixed with a second chiral base or an inorganic salt, after which the corresponding salt of the (S)-pentenoic acid is precipitated and d) is then converted into the corresponding E-(2S)-alkyl-5-halo-4-pentenoic acid and subsequently where appropriate into the corresponding ester of the formula (I) in which R1 is C1-C4-alkyl.
Bibliography:Application Number: EP20060707162