Novel benzofuran derivatives with dual 5-HT1A receptor and serotonin transporter affinity.

Several benzofuran derivatives linked to a 3-indoletetrahydropyridine through an alkyl chain were prepared and evaluated for serotonin transporter and 5-HT(1A) receptor affinities. Their design, synthesis and structure-activity relationships are described.

Synthesis and structure-activity relationship of novel lactam-fused chroman derivatives having dual affinity at the 5-HT(1A) receptor and the serotonin transporter.

The structure-activity relationship (SAR) for three series of lactam-fused chroman derivatives possessing 3-amino substituents was evaluated. Many compounds exhibited affinities for both the 5-HT(1A) receptor and the 5-HT transporter. Compounds 45 and 53 demonstrated 5-HT(1A) antagonist activities in the in vitro cAMP turnover model.

Synthesis, potency, and in vivo evaluation of 2-piperazin-1-ylquinoline analogues as dual serotonin reuptake inhibitors and serotonin 5-HT1A receptor antagonists.

On the basis of the previously reported clinical candidate, SSA-426 (1), a series of related 2-piperazin-1-ylquinoline derivatives 3-16 were synthesized and evaluated as dual-acting serotonin (5-HT) reuptake inhibitors and 5-HT1A receptor antagonists. In particular, compound 7 exhibits potent functional activities at both the 5-HT transporter and 5-HT1A receptor, good selectivity over the alpha1-adrenergic and dopaminergic receptors, acceptable pharmacokinetic properties, and a favorable in vivo profile.

Advances toward new antidepressants with dual serotonin transporter and 5-HT1A receptor affinity within a class of 3-aminochroman derivatives. Part 2.

Novel compounds combining a 5-HT 1A moiety (3-aminochroman scaffold) and a 5-HT transporter (indole analogues) linked through a common basic nitrogen via an alkyl chain attached at the 1- or 3-position of the indole were evaluated for dual affinity at both the 5-HT reuptake site and the 5-HT 1A receptor. Compounds of most interest were found to have a 5-carbamoyl-8-fluoro-3-amino-3,4-dihydro-2 H-1-benzopyran linked to a 3-alkylindole (straight chain), more specifically substituted with a 5-fluoro (( R)-(-)- 35c), 5-cyano ((-)- 52a), or 5,7-difluoro ((-)- 52g). Several factors contributed to 5-HT 1A affinity, serotonin rat transporter affinity, and functional antagonism in vitro. Although most of our analogues showed good to excellent affinities at both targets, specific features such as cyclobutyl substitution on the basic nitrogen and stereochemistry at the 3-position of the chroman moiety seemed necessary for antagonism at the 5-HT 1A receptor. Branched linkers seemed to impart antagonism even as racemates; however, the potency of these analogues in the functional assay was not desirable enough to further pursue these compounds.

Studies toward the discovery of the next generation of antidepressants. Part 6: Dual 5-HT1A receptor and serotonin transporter affinity within a class of arylpiperazinyl-cyclohexyl indole derivatives.

Based on the previously reported discovery lead, 3-(cis-4-(4-(1H-indol-4-yl)piperazin-1-yl)cyclohexyl)-5-fluoro-1H-indole (2), a series of related arylpiperazin-4-yl-cyclohexyl indole analogs were synthesized then evaluated as 5-HT transporter inhibitors and 5-HT(1A) receptor antagonists. The investigation of the structure-activity relationships revealed the optimal pharmacophoric elements required for activities in this series. The best example from this study, 5-(piperazin-1-yl)quinoline analog (trans-20), exhibited equal binding affinities at 5-HT transporter (K(i)=4.9nM), 5-HT(1A) receptor (K(i)=6.2nM) and functioned as a 5-HT(1A) receptor antagonist.

Novel pyridyl-fused 3-amino chroman derivatives with dual action at serotonin transporter and 5-HT1A receptor.

Structural modifications of the initial lead, 3-aminochroman (4), led to the identification of a novel series of pyridyl-fused amino chroman derivatives (5-8) and the structural isomers (9-12). The compounds described were evaluated for dual 5-HT transporter inhibitory and 5-HT(1A) receptor activities. The design strategy, synthesis, and in vitro biological characterization for these novel compounds are described.

Differential and synergistic effects of selective norepinephrine and serotonin reuptake inhibitors in rodent models of pain.

There is increasing recognition that norepinephrine (NE) and serotonin (5-HT) reuptake inhibitors (NRIs and SRIs) are efficacious in treating some types of pain. To date, studies have not systematically evaluated the relative activity at the NE and/or 5-HT transporter required for maximal efficacy in rodent pain models. Known selective NE and 5-HT reuptake inhibitors reboxetine, desipramine, fluoxetine, and paroxetine were evaluated in both in vitro and in vivo assays. Using the spinal nerve ligation model of neuropathic pain, the compounds differentially reversed tactile allodynia. Evaluation of a broader spectrum of reuptake inhibitors in the para-phenylquinone (PPQ)-induced abdominal constriction model, a model of acute visceral pain, demonstrated that both the SRIs and the NRIs significantly blocked abdominal constrictions. However, the magnitude of this effect was greater following treatment with compounds having greater affinity for NRI compared with SRI affinity. In addition, isobolographic analyses indicated significant synergistic effects for all combinations of desipramine and fluoxetine in the PPQ model of visceral pain. Collectively, the present results support the hypothesis that compounds with greater NRI activity should be more effective for the treatment of pain than compounds having only SRI activity, and this hypothesis is also supported by clinical data. These studies also suggest that the potency and effectiveness of NRIs might be enhanced by the presence of 5-HT activity.

Synthesis and biological evaluation of novel compounds within a class of 3-aminochroman derivatives with dual 5-HT1A receptor and serotonin transporter affinity.

Compounds containing a 5-carbamoyl-8-fluoro-3-amino-3,4-dihydro-2H-1-benzopyran and a 3-alkylindole moiety linked through a common basic nitrogen were prepared and evaluated for 5-HT1A affinity, serotonin rat transporter affinity, and functional antagonist activity in vitro. 26a was found to be the most potent and selective compound in this series and was shown to possess neurochemical activity in vivo by producing acute and rapid increases in 5-HT in the rat frontal cortex.

The effect of mGlu5 receptor positive allosteric modulators on signaling molecules in brain slices.

Positive allosteric modulators of metabotropic glutamate receptor subtype 5 (mGlu5) have promising therapeutic potential. The effects of selective mGlu5 receptor positive allosteric modulators on signaling molecules in brain slices have not been previously reported. The current study demonstrated that the selective mGlu5 receptor positive allosteric modulator, N-{4-chloro-2-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2yl)-methyl]phenyl}-2-hydrobenzamide (CPPHA) potentiated the response to a subthreshold concentration of 3,5-dihydroxy-phenylglycine (DHPG) on extracellular signal-regulated protein kinase (ERK) and cyclic-AMP responsive element-binding protein (CREB) activity, as well as N-methyl d-aspartate (NMDA) receptor subunit NR1 phosphorylation in cortical and hippocampal slices. These results suggest that allosteric modulators of mGlu5 receptor could have physiologically significant effects by potentiating the actions of glutamate.

Studies toward the discovery of the next generation of antidepressants. Part 5: 3,4-Dihydro-2H-benzo[1,4]oxazine derivatives with dual 5-HT1A receptor and serotonin transporter affinity.

The design, synthesis, and structure-activity relationship of two novel classes of benzoxazine derivatives with dual selective serotonin reuptake inhibitors and 5-HT(1A) receptor activities are described.

Synthesis and biological evaluation of benzodioxanylpiperazine derivatives as potent serotonin 5-HT(1A) antagonists: the discovery of Lecozotan.

A series of benzodioxanylpiperazine derivatives possessing a 4-aryl amide substituent was prepared and evaluated for 5-HT(1A) affinity and functional antagonist activity in vitro and in vivo. All of the compounds in this series possessed high affinity for the human 5-HT(1A) receptor and many displayed potent antagonist activity in vitro and varying degrees of intrinsic activity in vivo. Compound 11c (Lecozotan) was selected for further development and is currently in clinical trials.

Studies towards the next generation of antidepressants. Part 4: derivatives of 4-(5-fluoro-1H-indol-3-yl)cyclohexylamine with affinity for the serotonin transporter and the 5-HT1A receptor.

Derivatives of the serotonin reuptake inhibitor 4-(5-fluoro-1H-indol-3-yl)cyclohexylamine, in which serotonin 1A (5-HT(1A)) receptor pharmacophoric elements are incorporated, are reported. Analogs exhibiting affinity for both the serotonin transporter and the 5-HT(1A) receptor are described. Compounds containing 1-(4-indolyl)piperazine and 2-(1H-indol-4-yloxy)ethylamine are promising leads for further SAR studies.

Studies toward the discovery of the next generation of antidepressants. 3. Dual 5-HT1A and serotonin transporter affinity within a class of N-aryloxyethylindolylalkylamines.

N-aryloxylethylindolealkylamines (5) having dual 5-HT transporter and 5-HT(1A) affinity are described. These compounds represent truncated analogues of our previously reported piperidinyl derivatives (3). Compounds in this investigation were found to have more similar affinities and functional activities for the 5-HT(1A) receptor and 5-HT transporter. Though 5-HT(1A) antagonism is not consistently observed throughout series 5, several molecular features were found to be essential to obtain high and balanced activities. The proper placement of a heteroatom in the aryl ring and the length of the linkage used to tether the indole moiety had significant influence on 5-HT(1A) and 5-HT transporter affinities. Introduction of a halogen into the aryl ring usually lowered intrinsic activity and in some cases led to full 5-HT(1A) antagonists. Compounds 33 and 34 were observed to be full 5-HT(1A) antagonists with K(i) values of approximately 30 nM for the 5-HT(1A) receptor and K(i) values of 5 and 0.5 nM for the 5-HT transporter, respectively. Unfortunately, similar to our previous series (3), compounds in this report also had high affinity for the alpha(1) receptor.