TY - JOUR A1 - Attia, Mohamed I. A1 - Herdeis, Claus A1 - Bräuner-Osborne, Hans T1 - GABA(B)-Agonistic Activity of Certain Baclofen Homologues JF - Molecules N2 - Baclofen (1) is a potent and selective agonist for bicuculline-insensitive GABAB receptors and is used clinically as an antispastic and muscle relaxant agent. In the search for new bioactive chemical entities that bind specifically to GABAB receptors, we report here the synthesis of certain baclofen homologues, namely (R,S)-5-amino-3-arylpentanoic acid hydrochlorides (R,S)-1a–h as well as (R,S)-5-amino-3-methylpentanoic acid [(RS)-1i] to be evaluated as GABABR agonists. Compound 1a is an agonist to GABAB receptors with an EC50 value of 46 μM on tsA201 cells transfected with GABAB1b/GABAB2/Gqz5, being the most active congener among all the synthesized compounds. KW - pharmacological evaluation KW - synthesis KW - GABA KW - baclofen homologues KW - GABAB receptor agonists Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129690 VL - 18 IS - 9 ER - TY - JOUR A1 - Heller, Eberhard A1 - Herdeis, Claus T1 - Synthesis of 2S,5S- and 2R,5S-5-Hydroxypipecolic Acid via Amide-Methylenation of S-5-Hydroxy-2-piperidone with Dimethyltitanocene N2 - A route to 2S,5S-and 2R,5S-hydroxypipecolic acid is presented, starting with the enantiopure 5S-5-hydroxy-piperidone 7. The key step of this reaction sequence is the chemoselsctive methylenation of the amide carbonyl group of 8 with dimethyltitanocene 9 to 10. The transformation of the exocyclic enecarbamate double bond to the carboxylic acid group is best accomplished via hydroboration/oxidation to the alcohol 11a,b. Separation and oxidation of the dlastereomers 11a,b, to 148. and 14b, and hydrolysis furnishes the diastereomeric pipecolic acids 15a and 15b in enantiopure form. KW - Chemie KW - Asymmetrie Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-38288 ER -