882994-23-2Relevant academic research and scientific papers
Homologous piperazine-alcanols: Chiral pool synthesis and pharmacological evaluation
Holl, Ralph,Schepmann, Dirk,Wünsch, Bernhard
, p. 673 - 679 (2013/11/06)
Starting with the proteinogenic amino acids (S)-aspartate and (S)-glutamate the homologous piperazine-alcanols 3 and 4 were prepared in a five step synthesis. The diversity was introduced by N-1 alkylation of the piperazinediones 5 and 6 with various alkyl halides. Subsequent LiAlH 4 reduction of the dioxopiperazine-esters 7 and 8 provided the alcohols 3 and 4. The ethanol derivatives 3 show similar σ1 affinity as the methanol derivatives 2, but increased selectivity over the σ2 subtype. The corresponding propanol derivatives 4 are considerably less potent. A benzyl or dimethylallyl residue at N-1 appears to be optimal for high σ1 affinity.
Relationships between the structure of 6-allyl-6,8-diazabicyclo[3.2.2]nonane derivatives and their σ receptor affinity and cytotoxic activity
Holl, Ralph,Schepmann, Dirk,Gruenert, Renate,Bednarski, Patrick J.,Wuensch, Bernhard
body text, p. 777 - 793 (2009/08/07)
A series of bridged piperazine derivatives was prepared and the affinity toward σ1 and σ2 receptors by means of radioligand binding assays as well as the inhibition of the growth of six human tumor cell lines was investigated. All possible stereoisomers of the 2-hydroxy, 2-methoxy, 2,2-dimethoxy, 2-oxo, and 2-unsubstituted 6,8-diazabicyclo[3.2.2]nonanes were prepared in a chiral pool synthesis starting with (S)- and (R)-glutamate. A Dieckmann analogous cyclization was the key step in the synthesis of the bicyclic framework. The configuration in position 2 was established by a diastereoselective LiBH4 reduction and subsequent Mitsunobu inversion. Structure-affinity relationships demonstrate that substituents in position 2 decrease σ1 receptor affinity which might be due to unfavorable interactions with the σ1 receptor protein. Without a substituent in position 2 high σ1 affinity was obtained (23a ((+)-(1S,5S)-6-allyl-8-(4-methoxybenzyl)-6,8-diazabicyclo[3.2.2]nonane): Ki = 11 nM). Experiments with six human tumor cell lines showed a weak but selective growth inhibition of the human small cell lung cancer cell line A-427 by the methyl ethers ent-16b (IC50 = 18.9 μM), 21a (IC50 = 16.4 μM), ent-21a (IC50 = 20.4 μM), and 21b (IC50 = 27.1 μM) and the unsubstituted compounds 23a and 23b (42% inhibition at 20 μM).
Molecular modeling directed synthesis of a bicyclic analogue of the δ opioid receptor agonist SNC 80
Jung, Bettina,Englberger, Werner,Wuensch, Bernhard
, p. 281 - 290 (2007/10/03)
In order to find novel δ opioid receptor agonists, the pharmacophoric benzhydryl moiety of the lead compound SNC 80 (1) was dissected and the phenyl residues were attached to different positions of the 6,8-diazabicyclo[3.2.2] nonane core system (4). The position of the carboxamido group, the stereochemistry, the C3/C4 bond order and the kind and length of the spacer X were considered. The resulting compounds were compared with the four energetically most favourable conformations of SNC 80 by a multifit analysis. These calculations led to the structures 5-10, which fit best to SNC 80. Herein the synthesis of one of these compounds (9) is described. Starting from (S)-glutamate two alternative routes are detailed to obtain the key intermediate 14. A variation of the Dieckmann cyclization, which uses trapping of the first cyclization product with ClSiMe3 provided the mixed acetal 20, which was carefully hydrolyzed to yield the bicyclic ketone 17. Stereoselective addition of phenylmagnesium bromide, dehydration, LiAlH4 reduction and exchange of the N-6 residue afforded the designed compound 9. The affinities of 9 towards δ, μ, κ and ORL1 receptors were determined in receptor binding studies with radioligands. Only moderate receptor affinity was found.
