Stephan Röver

Synthesis of (1S, 3aS)-8-(2,3,3a, 4,5,6-hexahydro-1H-phenalen-1-yl)-1-phenyl-1,3,8-triaza-spiro [4.5]decan-4-one, a potent and selective orphanin FQ (OFQ) receptor agonist with anxiolytic-like properties

The development of 8-(2,3,3a,4,5, 6-hexahydro-1H-phenalen1-yl)-1-phenyl-1,3,8-triaza-spiro[4. 5]decan-4-ones 3 starting from (RS)-8-acenaphten-1-yl-1-phenyl-1,3, 8-triazaspiro[4.5]decan-4-one 1 is reported. The synthesis and the binding affinities at human OFQ and opioid (micro, kappa, delta) receptors of the stereoisomers 3a-f are described. In vitro the most selective compound, (1S,3aS)-8-(2,3,3a,4,5, 6-hexahydro-1H-phenalen1-yl)-1-phenyl-1,3,8-triaza-spiro[4. 5]decan-4-one 3c, was found to act as a full agonist at the OFQ receptor in the GTPgamma(35)S binding test. It turned out to be selective versus a variety of other neurotransmitter systems. When tested in vivo following intraperitoneal injection, compound 3c was found to decrease neophobia in a novel environment and to exhibit dose-dependent anxiolytic-like effects in the elevated plus-maze procedure, thus confirming the effects observed following intracerebroventricular infusion of the OFQ peptide in rat.

Synthesis and applications of fluorous silyl protecting groups with improved acid stability

Abstract Fluorous alkoxysilyl protecting groups have been developed and evaluated for their acid stability. tert -Butylphenyl-1 H ,1 H ,2 H ,2 H -heptadecafluorodecyloxysilyl (BPFOS) ethers in particular were found to be surprisingly acid stable and allow simple protection-purification-deprotection schemes by liquid-liquid extraction with FC-72/CH 3 CN or by solid phase extraction with fluorous reverse phase silica gel.

8-Acenaphthen-1-yl-1-phenyl-1,3,8-triaza-spiro[4.5]decan-4-one derivatives as orphanin FQ receptor agonists

A series of 8-acenaphthen-1-yl-1-phenyl-1,3,8-triaza-spiro[4.5]decan+ ++-4-one derivatives 1 was studied with respect to the binding affinity for the orphanin FQ (OFQ) and opioid (mu, kappa, delta) receptors. The influence of stereochemistry as well as the substitution pattern of the phenyl-ring in position 1 on the affinity for the orphanin FQ receptor and selectivity to opioid (mu, kappa, delta) receptors is discussed. The most interesting compound 1c was tested for its anxiolytic-like properties in vivo.

Cloning and functional expression of human kynurenine 3-monooxygenase

Kynurenine 3‐monooxygenase, an NADPH‐dependent flavin monooxygenase, catalyses the hydroxylation of l‐kynurenine to l‐3‐hydroxykynurenine. By hybridization screening using a cDNA probe encoding the entire exon 2 of Drosophila melanogaster kynurenine 3‐monooxygenase, we isolated a 2.0 kb cDNA clone coding for the corresponding human liver enzyme. The deduced amino acid sequence of the human protein consists of 486 amino acids with a predicted molecular mass of 55 762 Da. Transfection of the human cDNA in HEK‐293 cells resulted in the functional expression of the enzyme with kinetic properties similar to those found for the native human protein. RNA blot analysis of human tissues revealed the presence of a major mRNA species of ∼2.0 kb in liver, placenta and kidney.

Benzodioxoles: Novel Cannabinoid-1 Receptor Inverse Agonists for the Treatment of Obesity

The application of the evolutionary fragment-based de novo design tool TOPology Assigning System (TOPAS), starting from a known CB1R (CB-1 receptor) ligand, followed by further refinement principles, including pharmacophore compliance, chemical tractability, and drug likeness, allowed the identification of benzodioxoles as a novel CB1R inverse agonist series. Extensive multidimensional optimization was rewarded by the identification of promising lead compounds, showing in vivo activity. These compounds reversed the CP-55940-induced hypothermia in Naval Medical Research Institute (NMRI) mice and reduced body-weight gain, as well as fat mass, in diet-induced obese Sprague-Dawley rats. Herein, we disclose the tools and strategies that were employed for rapid hit identification, synthesis and generation of structure-activity relationships, ultimately leading to the identification of (+)-[( R)-2-(2,4-dichloride-phenyl)-6-fluoro-2-(4-fluoro-phenyl)-benzo[1,3]dioxol-5-yl]-morpholin-4-yl-methanone ( R)-14g . Biochemical, pharmacokinetic, and pharmacodynamic characteristics of ( R)-14g are discussed.

ORL1 receptor ligands : Structure-activity relationships of 8-cycloalkyl-1-phenyl-1,3,8-triaza-spiro[4,5]decan-4-ones

We have investigated 8-cycloalkyl-1-phenyl-1,3,8-triaza-spiro[4.5]decan-4-o nes as ligands for the ORL1 receptor. These unsophisticated, achiral compounds show remarkable affinity for the ORL1 receptor. Optimizing for selectivity we show that the maximum of affinity and selectivity versus the other opioid receptors is achieved for 8-cyclodecyl-1-phenyl-1,3,8-triaza-spiro[4.5]decan-4-o ne 2e and 8-(cis-4-isopropyl-cyclohexyl)-1-phenyl-1,3,8-triaza-spiro[4.5] decan-4-one 2q. The identified compounds (2e, 2q) are more or less equipotent to the natural ligand itself, both in the binding assay and in the functional GTPgammaS assay.

5-HT 2C Receptor Agonists for the Treatment of Obesity. Biological and Chemical Adventures

Obesity is a major risk factor in the development of conditions such as hypertension, hyperglycemia, dyslipidemia, coronary artery disease and cancer. There is increasing evidence suggesting an important role for the 5-HT 2 C receptor in appetite control. Collaboration between F. Hoffmann-La Roche Ltd and Vernalis Research Ltd has allowed rapid construction of a solid structure-activity relationship around a pyrroloindole core. A one-pot Sonogashira reaction followed by nucleophilic double cyclisation allows an elegant and expedient route to this central motif. Introduction of a (2S)-aminopropyl group in place of the aminoethyl endogenous ligand side-chain enhanced the affinity at the 5-HT 2 C receptor and reduced affinity towards monoamine oxidase enzymes (MAO). Sulfamidate reagents were found to be very effective for the introduction of the 2-aminopropyl moiety in a stereoselective manner. The substitution at position 5 (indole numbering) was found to be crucial for both affinity and selectivity. Pyrroloindoles bearing an alkoxyether in this position exhibit promising pharmacokinetic parameters in rodent and significant reduction of food intake, after per os application.

Pyrido pyrimidinones as selective agonists of the high affinity niacin receptor GPR109A: optimization of in vitro activity.

Pyrido pyrimidinones are selective agonists of the human high affinity niacin receptor GPR109A (HM74A). They show no activity on the highly homologous low affinity receptor GPR109B (HM74). Starting from a high throughput screening hit the in vitro activity of the pyrido pyrimidinones was significantly improved providing lead compounds suitable for further optimization.

Novel Triazolopyrimidine-Derived Cannabinoid Receptor 2 Agonists as Potential Treatment for Inflammatory Kidney Diseases

The cannabinoid receptor 2 (CB2) system is described to modulate various pathological conditions, including inflammation and fibrosis. A series of new heterocyclic small‐molecule CB2 receptor agonists were identified from a high‐throughput screen. Lead optimization gave access to novel, highly potent, and selective (over CB1) triazolopyrimidine derivatives. A preliminary structure–activity relationship was established, and physicochemical properties in this compound class were significantly improved toward better solubility, lipophilicity, and microsomal stability. An optimized triazolopyrimidine derivative, (3S)‐1‐[5‐tert‐butyl‐3‐[(1‐cyclopropyltetrazol‐5‐yl)methyl]triazolo[4,5‐d]pyrimidin‐7‐yl]pyrrolidin‐3‐ol (39), was tested in a kidney ischemia–reperfusion model, in which it showed efficacy at a dose of 10 mg kg−1 (p.o.). A significant depletion of the three measured kidney markers indicated a protective role of CB2 receptor activation toward inflammatory kidney damage. Compound 39 was also protective in a model of renal fibrosis. Oral treatment with 39 at 3 mg kg−1 per day significantly decreased the amount of fibrosis by ∼40 % which was induced by unilateral ureter obstruction.

6-Alkoxy-5-aryl-3-pyridinecarboxamides, a New Series of Bioavailable Cannabinoid Receptor Type 1 (CB1) Antagonists Including Peripherally Selective Compounds

We identified 6-alkoxy-5-aryl-3-pyridinecarboxamides as potent CB1 receptor antagonists with high selectivity over CB2 receptors. The series was optimized to reduce lipophilicity compared to rimonabant to achieve peripherally active molecules with minimal central effects. Several compounds that showed high plasma exposures in rats were evaluated in vivo to probe the contribution of central vs peripheral CB1 agonism to metabolic improvement. Both rimonabant and 14g, a potent brain penetrant CB1 receptor antagonist, significantly reduced the rate of body weight gain. However, 14h, a molecule with markedly reduced brain exposure, had no significant effect on body weight. PK studies confirmed similarly high exposure of both 14h and 14g in the periphery but 10-fold lower exposure in the brain for 14h. On the basis of these data, which are consistent with reported effects in tissue-specific CB1 receptor KO mice, we conclude that the metabolic benefits of CB1 receptor antagonists are primarily centrally mediated as originally believed.