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In recent years, multi-targeting directed ligands have attracted great interest as possible new atypical antipsychotics. Combinations of dopamine and serotonin receptor ligands within single molecules might afford new therapeutic opportunities. Herein, we describe the synthesis of a novel series of 6-hydroxypyridazinone benzisoxazoles and their binding behaviors to different receptors in terms of atypical antipsychotic behaviors. The most potent compound (46) exhibited excellent affinities for certain receptors (D 2 , K i = 0.5 ± 0.07 nM; 5-HT 1A , K i = 5.9 ± 0.8 nM; 5-HT 2A , K i = 0.3 ± 0.01 nM; 5-HT 6 , K i = 0.5 ± 0.04 nM) and combined with low affinities for the H 1 , 5-HT 2C , and adrenergic α 1 receptors. In contrast to risperidone, compound 46 exhibited a high cataleptic threshold; this may be useful in the development of a novel class of drugs treating schizophrenia. [ABSTRACT FROM AUTHOR]

To develop safer and potent analgesics, we designed, synthesized, and evaluated a new series of benzylaminofentanyl derivates as bifunctional μ opioid receptor (MOR) and σ 1 receptor (σ 1 R) ligands. Compound 68 (Tao-191) showed desirable MOR agonism (K i = 6.5 nΜ; EC 50 = 48.5 nΜ, E max = 66.3%) and σ 1 R antagonism (K i = 35.7 nM) in vitro , and exerted powerful analgesic effects in the abdominal constriction test (ED 50 = 0.32 mg/kg, in mice), formalin-induced pain test (phase II, ED 50 = 2.26 mg/kg, in rats), and paclitaxel-induced neuropathic pain model (ED 50 = 0.30 mg/kg, in mice). The contributions of MOR and σ 1 R to its antinociceptive effect were verified by combined administration with the MOR antagonist naloxone and the σ 1 R agonist PRE-084, respectively. At equianalgesic doses, compound 68 induced fewer MOR-related side effects—including physical and psychological dependence, respiratory depression, constipation, and acute hyperlocomotion—than fentanyl. The results provide a rationale for further exploration of the action and safety of dual MOR/σ 1 R ligands as a promising avenue for the development of potent and safe analgesics. [Display omitted] • A series of benzylaminofentanyl derivates were synthesized as bifunctional MOR/σ 1 R ligands to develop safer analgesics. • Compound 68 showed desirable MOR agonism (EC 50 = 48.5 nΜ, E max = 66.3%) and σ 1 R antagonism (K i = 35.7 nM) in vitro. • Compound 68 exerted powerful analgesic effects in abdominal constriction test and formalin-induced pain test in rodents. • At equianalgesic doses, compound 68 induced fewer MOR-related side effects than fentanyl in mice. [ABSTRACT FROM AUTHOR]

Human α7 nicotinic acetylcholine receptor (nAChR) is a promising therapeutic target for the treatment of schizophrenia accompanied with cognitive impairment. Herein, we report the synthesis and agonistic activities of a series of indolizine derivatives targeting to α7 nAChR. The results show that all synthesized compounds have affinity to α7 nAChR and some give strong agonistic activity, particularly most active agonists show higher potency than control EVP-6124. The docking and structure–activity relationship studies provide insights to develop more potent novel α7 nAChR agonists. [ABSTRACT FROM AUTHOR]

We report the synthesis of novel, potentially hypnotic fluorine-substituted phenyl acetate derivatives. We describe the structure–activity relationship that led us to the promising derivative: ethyl 2-(4-(2-(diethylamino)-2-oxoethoxy)-5-ethoxy-2-fluorophenyl) acetate ( 55 ). The unique pharmacological features of compound 55 are its relatively high affinity for the GABA A receptor, together with a unique affinity for the NMDA receptor, different to propanidid and AZD3043. In animal models, compound 55 showed stronger hypnotic potency and longer duration of LORR than propanidid and AZD3043, but also maintained a rapid recovery time to walking and behavioral recovery. In particular, compound 55 displayed reflex depression during infusion. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis and sigma-1 receptor (σ 1R) antagonist activity of a new series of 3,4-dihydro-2(1H)-quinolinone derivatives are reported. The new compounds were evaluated in vitro in sigma-1 and sigma-2 receptor-binding assays in guinea pig brain membranes. The structure–activity relationship led us to the promising derivative 7-(3-(piperidin-1-yl)propoxy)-1-(4-fluorobenzyl)-3,4-dihydro-2(1H)-quinolinone (35). The compounds with highest affinity and greatest selectivity were further profiled, and compound 35 had a high binding constant for sigma-1 receptor (K i σ 1 = 1.22 nM) and high sigma-1/2 selectivity (1066-fold). Thus, compound 35, which proved to be an antagonist of sigma-1 receptor, emerged as the most interesting candidate. In addition, compound 35 exerted dose-dependent anti-nociceptive effects in the formalin test. These characteristics suggested that the potent and selective compound 35 could be a potent candidate for pain treatment. [Copyright &y& Elsevier]

Abstract: In this paper, we report the synthesis of novel, potential antipsychotic coumarin derivatives combining potent dopamine D2, D3 and serotonin 5-HT1A, 5-HT2A receptors properties. We describe the structure activity relationship that leads us to the promising derivative: 7-(4-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)butoxy)-6-methyl-2,3-dihydrocyclopenta[c]chromen-4(1H)-one 27. The unique pharmacological features of compound 27 are a high affinity for dopamine D2, D3 and serotonin 5-HT1A, 5-HT2A receptors, together with a low affinity for H1 receptor (to reduce the risk of obesity under chronic treatment). In animal models, compound 27 inhibited apomorphine-induced climbing and MK-801-induced hyperactivity without observable catalepsy at the highest dose tested. In particular, compound 27 was more potent than clozapine. [Copyright &y& Elsevier]

Here, we describe the optimization, synthesis, and associated pharmacological analgesic activities of a new series of bifunctional piperidinamide derivatives as sigma-1 receptor (σ 1 R) antagonists and mu opioid receptor (MOR) agonists. The new compounds were evaluated in vitro in σ 1 R and MOR binding assays. The most promising compound 114 (also called HKC-126), showed superior affinities for σ 1 R and MOR and good selectivity to additional receptors related to pain. Compound 114 showed powerful dose-dependent analgesic effects in the acetic acid writhing test, formalin test, hot plate test, and chronic constriction injury (CCI) neuropathic pain model. In contrast to an equianalgesic dose of fentanyl, compound 114 produced fewer opioid-like side effects, such as reward liability, respiratory depression, physical dependence, and sedation. Lastly, the pharmacokinetic properties of this drug were also acceptable, and these results suggest that compound 114 , as a mixed σ 1 R/MOR ligand, has potential for treating neuropathic pain. [Display omitted] 1. A new series of bifunctional piperidinamide derivatives were synthesized and evaluated biological activity. 2. Compound 114 showed superior affinities for σ 1 R and MOR and good selectivity to additional receptors related to pain. 3. Compound 114 showed powerful dose-dependent analgesic effects in different models. 4. Compound 114 produced fewer opioid-like side effects, such as reward liability, respiratory depression, physical dependence and sedation than fentanyl at an equianalgesic dose. [ABSTRACT FROM AUTHOR]

Opioid analgesics are highly effective painkillers for the treatment of moderate or severe pain, but they are associated with a number of undesirable adverse effects, including the development of tolerance, addiction, constipation and life-threatening respiratory depression. The development of new and safer analgesics with innovative mechanisms of action, which can enhance the efficacy in comparison to available treatments and reduce their side effects, is urgently needed. The sigma-1 receptor (σ 1 R), a unique Ca2+-sensing chaperone protein, is expressed throughout pain-modulating tissues and affects neurotransmission by interacting with different protein partners, including molecular targets that participate in nociceptive signalling, such as the μ-opioid receptor (MOR), N -methyl- d - aspartate receptor (NMDAR) and cannabinoid 1 receptor (CB 1 R). Overwhelming pharmacological and genetic evidence indicates that σ 1 R antagonists induce anti-hypersensitive effects in sensitising pain conditions (e.g. chemically induced, inflammatory and neuropathic pain) and enhance opioid analgesia but not opioid-mediated detrimental effects. It has been suggested that balanced modulation of MORs and σ 1 Rs may improve both the therapeutic efficacy and safety of opioids. This review summarises the functional profiles of ligands with mixed MOR agonist and σ 1 R antagonist activities and highlights their therapeutic potentials for pain management. Dual MOR agonism/σ 1 R antagonism represents a promising avenue for the development of potent and safer analgesics. [Display omitted] • σ 1 R antagonists exhibit anti-hypersensitive effects in sensitising pain conditions. • σ 1 R antagonists enhance opioid analgesia but not opioid-mediated unwanted effects. • Bifunctional MOR and σ 1 R ligands possess wider therapeutic window with fewer adverse effects. • Representative ligands with MOR agonist and σ 1 R antagonist activities were summarised. • Dual MOR-agonism/σ 1 R-antagonism represents a promising avenue for the development of potent and safer analgesics. [ABSTRACT FROM AUTHOR]

In this study, a series of novel Isoquinolinone derivatives were synthesized as potential multi-target antipsychotics. Among these, compound 13 showed high affinity for dopamine D 2 and serotonin 5-HT 1A , 5-HT 2A , 5-HT 6 , and 5-HT 7 receptors, showed low affinity for off-target receptors (5-HT 2C , H 1 , and α 1), and negligible effects on ether-a-gogo-related gene (hERG; i.e., reduced QT interval prolongation). An animal behavioral study revealed that compound 13 reversed APO-induced hyperlocomotion, MK-801-induced hyperactivity, an induced head twitch. Moreover, compound 13 exhibited a high threshold for acute toxicity, a lack of tendency to induce catalepsy, and did not cause prolactin secretion or weight gain when compared to risperidone. Furthermore, in the forced swim test, tail suspension test, and novel object recognition test, treatment with compound 13 resulted in improvements in depression and cognitive impairment. In addition, compound 13 had a favorable pharmacokinetic profile in rats. Thus, the antipsychotic drug-like effects of compound 13 indicate that it may be useful for developing a novel class of drugs for the treatment of schizophrenia. Image 1 [ABSTRACT FROM AUTHOR]

We designed and synthesized a novel series of piperidine propionamide derivatives as potent sigma-1 (σ 1) receptor antagonists and mu (μ) opioid receptor agonists, and measured their affinity for σ 1 and μ receptors in vitro through binding assays. The basic scaffold of the new compounds contained a 4-substituted piperidine ring and N-aryl propionamide. Compound 44, N-(2-(4-(4-fluorobenzyl) piperidin-1-yl) ethyl)-N-(4-methoxy-phenyl) propionamide, showed the highest affinity for σ 1 receptor (K i σ 1 = 1.86 nM) and μ receptor (K i μ = 2.1 nM). It exhibited potent analgesic activity in the formalin test (ED 50 = 15.1 ± 1.67 mg/kg) and had equivalent analgesic effects to S1RA (σ 1 antagonist) in a CCI model. Therefore, Compound 44, which has mixed σ 1 /μ receptor profiles, may be a potential candidate for treating neuropathic pain. Image 1 • A new series of piperidine propionamide derivatives was designed and synthesized. • Compound 44 showed highest affinities to σ 1 receptor and μ receptor with mixed σ 1 /μ receptor profiles. • Compound 44 performed a dose-dependent analgesic effect in the formalin test. • Compound 44 performed equivalent analgesic effect with S1RA. [ABSTRACT FROM AUTHOR]

The α7 nicotinic acetylcholine receptor (α7 nAChR) has emerged as a promising therapeutic target for schizophrenia. In our previous work, a novel series of α7-nAChR agonists bearing scaffold of indolizine were discovered. To explore the effect of aromaticity on the activity and find more active agents, herein, fused heterocyclic carboxamide derivatives were designed and synthesized in this study. Based on the evaluation by two-electrode voltage clamp in Xenopus oocytes, 27 of the synthesized compounds showed obvious agonism of α7 nAChR. Particularly, compounds 10a and 10e showed significantly higher E max than EVP-6124. The result illustrated the importance of aromaticity to the activity of agonism. Compound 10a , which showed EC 50 of 1.88 μM and E max of 72.4%, was further characterized comprehensively, including co-application with type II positive allosteric modulator PNU-120596, selectivity with other closely related ligand-gated ion channel, etc. The results showed that 10a showed moderate selectivity over other subtypes such as α4β2 and α3β4 nAChR. 10a evoked α7-like currents that were inhibited by MLA and enhanced in the presence of the α7 PAM PNU-120596. The analysis of binding mode and understanding of structure-activity relationship provided insights to develop more potent novel α7-nAChR agonists. Schematic representation of the designed fused heterocyclic carboxamide derivatives. Image 1 • Novel fused heterocyclic carboxamide α7 agonists were designed and synthesized. • Compound 10a and 10e showed significant efficacy and higher E max than EVP-6124. • 10a evoked α7-like currents and enhanced in the presence of the α7 PAM. • The aromaticity favored the activity of agonism. [ABSTRACT FROM AUTHOR]