Thiophene Bioisosteres of Spirocyclic σ Receptor Ligands: Relationships between Substitution Pattern and σ Receptor Affinity
作者:Christoph Oberdorf、Dirk Schepmann、Jose Miguel Vela、Helmut Buschmann、Jörg Holenz、Bernhard Wünsch
DOI:10.1021/jm300302p
日期:2012.6.14
On the basis of the 6',7'-dihydrospiro-[piperidine-4,4'-thieno[3,2-c]pyran] framework, a series of more than 30 sigma ligands with versatile substituents in 1-, 2'-, and 6'-position has been synthesized and pharmacologically evaluated in order to find novel structure-affinity relationships. It was found that a cyclohexylmethyl residue at the piperidine N-atom instead of a benzyl moiety led to increased sigma(2) affinity and therefore to decreased sigma(1)/sigma(2), selectivity. Small substituents (e.g., OH, OCH3, CN, CH2OH) in 6'-position adjacent to the O-atom were well tolerated by the sigma(1) receptor. Removal of the substituent in 6'-position resulted in very potent but unselective a ligands (13). A broad range of substituents with various lipophilic and H-bond forming properties was introduced in 2'-position adjacent to the S-atom without loss of a, affinity. However, very polar and basic substituents in both 2'- and 6'-position decreased the a, affinity considerably. It is postulated that the electron density of the thiophene moiety has a big impact on the sigma(1) affinity.