Use of imidazo[1,5-a]quinoline scaffold as the pharmacophore in the design of bivalent ligands of central benzodiazepine receptors.

The imidazo[1,5-a]quinoline scaffold of central benzodiazepine receptor (CBR) ligands was used as the pharmacophore in the design of bivalent ligands bearing spacers showing variable length and different physicochemical features. The newly designed compounds were synthesized along with the corresponding reference monovalent compounds bearing the corresponding spacers terminated with a tert-butoxycarbonyl group. The novel compounds were tested in binding assays with different CBR preparations such as the cerebral cortex from male CD-1 albino mice or the human recombinant α1β3γ2 and α2β3γ2 γ-aminobutyric acid type A receptors (GABARs) stably expressed in mouse L(tk-) cells.

Novel multitarget directed ligands inspired by riluzole: A serendipitous synthesis of substituted benzo[b][1,4]thiazepines potentially useful as neuroprotective agents.

Riluzole, the first clinically approved treatment for amyotrophic lateral sclerosis (ALS), represents a successful example of a drug endowed with a multimodal mechanism of action. In recent years, different series of riluzole-based compounds have been reported, including several agents acting as Multi-Target-Directed Ligands (MTLDs) endowed with neuroprotective effects. Aiming at identical twin structures inspired by riluzole (2a-c), a synthetic procedure was planned, but the reactivity of the system took a different path, leading to the serendipitous isolation of benzo[b][1,4]thiazepines 3a-c and expanded intermediates N-cyano-benzo[b][1,4]thiazepines 4a-c, which were fully characterized.

Novel analgesic/anti-inflammatory agents: 1,5-Diarylpyrrole nitrooxyethyl sulfides and related compounds as Cyclooxygenase-2 inhibitors containing a nitric oxide donor moiety endowed with vasorelaxant properties.

The design of compounds able to combine the selective inhibition of cyclooxygenase-2 (COX-2) with the release of nitric oxide (NO) is a promising strategy to achieve potent anti-inflammatory agents endowed with an overall safer profile and reduced toxicity upon gastrointestinal and cardiovascular systems. With the aim of generating novel and selective COX-2 inhibiting NO-donors (CINOD) and encouraged by the promising results obtained with our nitrooxy- and hydroxyethyl ethers 11 and 12 reported in previous works, we shifted our attention on the synthesis of isosteric thioanalogs nitrooxy- and hydroxy ethyl sulfides 13a-c and 14a-c, respectively, along with their oxidation products nitrooxy- and hydroxyethyl sulfoxides 15a-c and 16a-c, respectively, also referred to as thio-CINOD. Preliminary data and metabolic analysis highlighted how the isosteric substitution of the ethereal oxygen atom of 11a-c with sulfur in compounds 13a-c, independently from the presence and the number of fluorine atoms in N-phenyl ring, leads to new selective and highly potent COX-2 inhibitors, capable to induce vasorelaxant responses in vivo.

Exploring Translocator Protein (TSPO) Medicinal Chemistry: An Approach for Targeting Radionuclides and Boron Atoms to Mitochondria.

Translocator protein 18 kDa [TSPO or peripheral-type benzodiazepine receptor (PBR)] was identified in the search of binding sites for benzodiazepine anxiolytic drugs in peripheral regions. In these areas, binding sites for TSPO ligands were recognized in steroid-producing tissues. TSPO plays an important role in many cellular functions, and its coding sequence is highly conserved across species.

Therapeutic potential for coxibs-nitric oxide releasing hybrids in cystic fibrosis.

This review discusses the rational for further studies of COX-2 inhibitors-NO releaser hybrids (NO-Coxibs) in the pharmacological treatment of the airway inflammation in Cystic Fibrosis (CF). Our research group developed several classes of NO-Coxibs for the pharmacological treatment of arthritis, and among them several compounds showed an outstanding in vivo efficacy and good pharmacokinetic properties. The good antiinflammatory properties displayed by these compounds during the previous screening could, by itself, suggest appropriate candidates for further testing in CF.

Design, synthesis and biological evaluation of 7-substituted 4-phenyl-6H-imidazo[1,5-a]thieno[3,2-f] [1,4]diazepines as safe anxiolytic agents.

A series of 4-phenyl-6H-imidazo[1,5-a]thieno[3,2-f][1,4]diazepine-7-carboxylate esters were synthesized and tested as central benzodiazepine receptor (CBR) ligands by the ability to displace [H]flumazenil from rat cortical membranes. All the compounds showed high affinity with IC values ranging from 5.19 to 16.

Hyaluronan Graft Copolymers Bearing Fatty-Acid Residues as Self-Assembling Nanoparticles for Olanzapine Delivery.

In order to evaluate the potential of a technology platform based on hyaluronan copolymers grafted with propargylated ferulate fluorophores (HA-FA-Pg) in the development of drug delivery systems, the propargyl groups of HA-FA-Pg derivatives were employed with oleic acid (OA) or stearic acid (SA) residues across a biocompatible hexa(ethylene glycol) (HEG) spacer. The designed materials (i.e.

Radiosynthesis and Preclinical Evaluation of C-VA426, a Cyclooxygenase-2 Selective Ligand.

Cyclooxygenase-2 (COX-2) is involved in the inflammatory response, and its recurrent overexpression in cancers as well as in neurodegenerative disorders has made it an important target for therapy. For this reason, noninvasive imaging of COX-2 expression may represent an important diagnostic tool. In this work, a COX-2 inhibitor analogue, VA426 [1-(4-fluorophenyl)-3-(2-methoxyethyl)-2-methyl-5-(4-(methylsulfonil)phenyl)-1-pyrrole], was synthesized and radiolabelled with the C radioisotope.

Synthesis, biological evaluation and molecular modeling of novel selective COX-2 inhibitors: sulfide, sulfoxide, and sulfone derivatives of 1,5-diarylpyrrol-3-substituted scaffold.

A novel series of 1,5-diarylpyrrol-3-sulfur derivatives (10-12) was synthesized and characterized by NMR and mass spectroscopy and x-ray diffraction. The biological activity of these compounds was evaluated in in vitro and in vivo tests to assess their COX-2 inhibitory activity along with anti-inflammatory and antinociceptive effect. Results showed that the bioisosteric transformation of previously reported alkoxyethyl ethers (9a-c) into the corresponding alkyl thioethers (10a-c) still leads to selective and active compounds being the COX-2 inhibitory activity for most of them in the low nanomolar range.

Development of subnanomolar-affinity serotonin 5-HT receptor ligands based on quinoline structures.

Two small series of quinoline derivatives were designed starting from previously published quinoline derivatives and in order to obtain information about their interaction with the 5-HTR binding site. Initially, the structure of and was modified by replacing their basic moiety with that of partial agonist (ML10302) or with that of reference ligand (RS-67-333). Then, the aromatic moieties of 4-quinolinecarboxylates , , and or 4-quinolinecarboxamides , , and were modified into those of 2-quinolinecarboxamides .

In vitro comprehensive analysis of VA692 a new chemical entity for the treatment of osteoarthritis.

Selective cyclooxigenase (COX)-2 inhibitors were developed to prevent traditional non-steroidal anti-inflammatory drugs (tNSAIDs) gastro-intestinal adverse effects. VA692, a recently disclosed selective COX-2 inhibitor, structurally related to well-known marketed coxibs, showed anti-inflammatory, and anti-nociceptive properties. The aim of this study was to analyze the anti-inflammatory effect of VA692, in comparison with celecoxib.

Development of Potent Inhibitors of the Mycobacterium tuberculosis Virulence Factor Zmp1 and Evaluation of Their Effect on Mycobacterial Survival inside Macrophages.

The enzyme Zmp1 is a zinc-containing peptidase that plays a critical role in the pathogenicity of Mycobacterium tuberculosis. Herein we describe the identification of a small set of Zmp1 inhibitors based on a novel 8-hydroxyquinoline-2-hydroxamate scaffold. Among the synthesized compounds, N-(benzyloxy)-8-hydroxyquinoline-2-carboxamide (1 c) was found to be the most potent Zmp1 inhibitor known to date, and its binding mode was analyzed both by kinetics studies and molecular modeling, identifying critical interactions of 1 c with the zinc ion and residues in the active site.

Enantioresolution and stereochemical characterization of two chiral sulfoxides endowed with COX-2 inhibitory activity.

The capacity of nonsteroidal antiinflammatory drugs (NSAIDs) to prevent prostanoids biosynthesis through the inhibition of COX-2 enzyme is related to their structural backbone, based on the fusion of a cis-stilbene unit with a variety of heterocyclic and carbocyclic rings. By this route, a series of new selective COX-2 inhibitors was developed, by maintaining the 4-methylsulfone or 4-methylsulfonamide substituent on the phenyl moiety, essential for their activity. In this frame, two novel propyl sulfoxide derivatives were synthesized, which proved selective and sufficiently potent COX-2 inhibition activity when tested as racemates.

Synthesis and Biological Evaluation of Novel Neuroprotective Pyridazine Derivatives as Excitatory Amino Acid Transporter 2 (EAAT2) Activators.

LDN-212320 (3) was found to be a potent EAAT2 activator at a translational level, restoring the normal clearance of glutamate and providing neuronal protection. Since the pharmacologic activation of EAAT2 represents a valuable strategy to relieve neuropathic pain, we synthesized novel activators (4a-f) of EAAT2. Among them 4f, analyzed in comparison with 3 by different paradigms in a rat model of oxaliplatin-induced neuropathic pain, showed the better antihypersensitive profile being able to fully counteract the oxaliplatin-induced neuropathy.

Multivalent ligands for the serotonin 5-HT receptor.

5-HT receptors are known to form constitutive dimers in membranes. To explore whether multivalency can enhance ligand interactions and/or efficacy in 5-HT receptors, the structure of the partial agonist ML10302 was modified with oligo(ethylene glycol) chains, thus generating, by a gradual approach, short and long tethered bivalent or tetravalent ligands and the corresponding spanner-linked monovalent controls. Both bivalent and tetravalent ligands displayed a 10-20-fold increase in binding affinity compared to appropriate controls, but no multivalent ligand showed greater binding energy than ML10302 itself.

Synthesis and biological evaluation of a new class of benzothiazines as neuroprotective agents.

Neurodegenerative diseases are disorders related to the degeneration of central neurons that gradually lead to various, severe alterations of cognitive and/or motor functions. Currently, for no such diseases does any pharmacological treatment exist able to arrest its progression. Riluzole (1) is a small molecule able to interfere with multiple cellular and molecular mechanisms of neurodegeneration, and is the only approved treatment of amyotrophic lateral sclerosis (ALS), the progression of which proved to significantly slow, thus increasing somewhat average survival.

Phenylindenone isomers as divergent modulators of p38α MAP kinase.

Two new fluorophenylindenone derivatives were designed as potential p38α MAPK modulators by preserving the key interactions of the vicinal pyridine/fluorophenyl pharmacophore with the enzyme protein. Interestingly, these two fluorophenylindenone isomers showed divergent activities, with compound 6 behaving as an inhibitor and 5 as a putative activator. These results were rationalized by docking studies and molecular dynamics simulations in terms of stabilization of DFG loop, by compound 5 in a conformation more accessible to phosphorylation.

Design, Synthesis, and Biological Evaluation of Imidazo[1,5-a]quinoline as Highly Potent Ligands of Central Benzodiazepine Receptors.

A series of imidazo[1,5-a]quinoline derivatives was designed and synthesized as central benzodiazepine receptor (CBR) ligands. Most of the compounds showed high CBR affinity with Ki values within the submicromolar and subnanomolar ranges with interesting modulations in their structure-affinity relationships. In particular, fluoroderivative 7w (Ki = 0.

Synthesis and biological evaluation of fluorinated 1,5-diarylpyrrole-3-alkoxyethyl ether derivatives as selective COX-2 inhibitors endowed with anti-inflammatory activity.

A series of substituted 1,5-diarylpyrrole-3-alkoxyethyl ethers were previously synthesized and the potential anti-inflammatory and antinociceptive activities of these compounds were evaluated in vivo. The compounds displayed a very good activity against both carrageenan-induced hyperalgesia and oedema in the rat paw test. Therefore, in a very preliminary test, compounds (8a,b) showed antiproliferative activity in the HaCaT (aneuploid immortal keratinocyte from adult human skin) cell models.

Chondroprotective effect of three different classes of anti-inflammatory agents on human osteoarthritic chondrocytes exposed to IL-1β.

VA694, a promising cyclooxigenase-2 (COX-2)-inhibiting hybrid drug endowed with nitric oxide (NO) releasing properties (NO-COXIB), showed COX-2-selective inhibitory effects, associated with interesting anti-inflammatory and anti-nociceptive activities. Therefore, we studied the effects of VA694 on cartilage metabolism, in comparison with Naproxcinod, a COX inhibitor and NO donor (CINOD), and Naproxen, a traditional non-steroidal-anti-inflammatory drug (NSAID) on human osteoarthritic chondrocyte cultures. IL-1β-stimulated chondrocytes showed a significant decrease in cell viability (P<0.

Radiosynthesis and Preliminary Biological Evaluation of [18F]VC701, a Radioligand for Translocator Protein.

Positron emission tomography (PET) can be used to monitor in vivo translocator protein (TSPO) expression by using specific radioligands. Recently, several [11C]PK11195 analogues have been synthesized to improve binding stability and brain availability. [18F]VC701 was synthesized and validated in CD healthy rats by biodistribution and inhibition analysis.

Synthesis, biological evaluation and docking analysis of a new series of methylsulfonyl and sulfamoyl acetamides and ethyl acetates as potent COX-2 inhibitors.

We report herein the synthesis, biological evaluation and docking analysis of a new series of methylsulfonyl, sulfamoyl acetamides and ethyl acetates that selectively inhibit cyclooxygenase-2 (COX-2) isoform. Among the newly synthesized compounds, some of them were endowed with a good activity against COX-2 and a good selectivity COX-2/COX-1 in vitro as well as a desirable analgesic activity in vivo, proving that replacement of the ester moiety with an amide group gave access to more stable derivatives, characterized by a good COX-inhibition.

Synthesis of trifluoromethyl-substituted pyrazolo[4,3-c]pyridines - sequential versus multicomponent reaction approach.

A straightforward synthesis of 6-substituted 1-phenyl-3-trifluoromethyl-1H-pyrazolo[4,3-c]pyridines and the corresponding 5-oxides is presented. Hence, microwave-assisted treatment of 5-chloro-1-phenyl-3-trifluoromethylpyrazole-4-carbaldehyde with various terminal alkynes in the presence of tert-butylamine under Sonogashira-type cross-coupling conditions affords the former title compounds in a one-pot multicomponent procedure. Oximes derived from (intermediate) 5-alkynyl-1-phenyl-3-trifluoromethyl-1H-pyrazole-4-carbaldehydes were transformed into the corresponding 1H-pyrazolo[4,3-c]pyridine 5-oxides by silver triflate-catalyzed cyclization.

Dendrimeric tetravalent ligands for the serotonin-gated ion channel.

Multivalency is widely used in nature in specific recognition processes. This paper describes an approach to multivalency in the pentameric 5-HT3 receptor, a ligand-gated ion channel, which constitutes an example of intrinsically multivalent biological receptors. Owing to the picomolar Ki value, TETRA-L represents an outstanding multivalent ligand for the neurotransmitter receptor.

Synthesis and structure-activity relationship studies in serotonin 5-HT4 receptor ligands based on a benzo[de][2,6]naphthridine scaffold.

A small series of serotonin 5-HT4 receptor ligands has been designed from flexible 2-methoxyquinoline compounds 7a,b by applying the conformational constraint approach. Ligands 7a,b and the corresponding conformationally constrained analogues 8a-g were synthesized and their interactions with the 5-HT4 receptor were examined by measuring both binding affinity and the ability to promote or inhibit receptor-G protein coupling. Ester derivative 7a and conformationally constrained compound 8b were demonstrated to be the most interesting compounds showing a nanomolar 5-HT4R affinity similar to that shown by reference ligands cisapride (1) and RS-23,597-190 (4).