Gérard Aimé Pinna

Università degli Studi di Sassari, Sassari, Sardinia, Italy

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Publications (110)195.07 Total impact

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    ABSTRACT: New analogues (3a-l) of the previously described α4β2 selective ligand 3-(6-halopyridin-3-yl)-3,6-diazabicyclo[3.1.1]heptanes (2a,b) have been synthesized and their binding activity for neuronal acetylcholine receptor subtypes α4β2 and α7 were assayed. Six of these compounds (3a,b,c,j,k and l) showed high affinity and selectivity for α4β2 receptors. The phenylpyridyl-diazabicycloheptane 3c displayed Ki value of 11.17 pM for α4β2, in line with that of the halogenated homologues 3a,b, although it was characterized by an improved selectivity (Ki = 17 μM for α7 receptors). The influence of substitutions on the phenylpyridyl moiety on binding at both α4β2 and α7 receptors has been examined through the Topliss decision tree analysis. Substitution with electron-donating groups (as CH3 and OCH3) resulted in a good affinity for α4β2 receptors and substantially no affinity for α7. Amongst all the tested phenyl-substituted compounds, the p-NO2-phenyl substituted analogue 3j exhibited the highest α4β2 affinity, with Ki value comparable to that of 3c. Intrinsic α4β2 receptor mediated activity in [(3)H]-DA release assay was showed by compound 3a as well as by the reference analogue 2a, whereas phenyl substituted derivative 3c exhibited α4β2 antagonist activity.
    European Journal of Medicinal Chemistry 09/2015; 103:429-437. DOI:10.1016/j.ejmech.2015.09.006 · 3.45 Impact Factor
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    ABSTRACT: During the last years, there has been a continuous interest in the development of cannabinoid receptor ligands that may serve as therapeutic agents and/or as experimental tools. This prompted us to design and synthesize analogues of the CB2 receptor antagonist N-fenchyl-5-(4-chloro-3-methyl-phenyl)-1-(4-methyl-benzyl)-1H-pyrazole-3-carboxamide (SR144528). The structural modifications involved the bioisosteric replacement of the pyrazole ring by a pyrrole ring and variations on the amine carbamoyl substituents. Two of these compounds, the fenchyl pyrrole analogue 6 and the myrtanyl derivative 10, showed high affinity (Ki in the low nM range) and selectivity for the CB2 receptor and both resulted to be antagonists/inverse agonists in [(35)S]-GTPγS binding analysis and in an in vitro CB2 receptor bioassay. Cannabinoid receptor binding data of the series allowed identifying steric constraints within the CB2 binding pocket using a study of Van der Waals' volume maps. Glide docking studies revealed that all docked compounds bind in the same region of the CB2 receptor inactive state model. Copyright © 2015 Elsevier Masson SAS. All rights reserved.
    European Journal of Medicinal Chemistry 08/2015; 101:651-667. DOI:10.1016/j.ejmech.2015.06.057 · 3.45 Impact Factor
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    ABSTRACT: Here we report the investigation of diazabicycloalkane cores as potential new scaffolds for the development of novel analogues of the previously reported diazatricyclodecane selective delta (δ) opioid agonists, as conformationally constrained homologues of the reference δ agonist (+)-4-[(αR)-α((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide (SNC80). In particular, we have simplified the diazatricyclodecane motif of δ opioid agonist prototype 1a with bridged bicyclic cores. 3,6-diazabicyclo[3.1.1]heptane, 3,8-diazabicyclo[3.2.1]octane, 3,9-diazabicyclo[3.3.1]nonane, 3,9-diazabicyclo[4.2.1]nonane, and 3,10-diazabicyclo[4.3.1]decane were adopted as core motifs of the novel derivatives. The compounds were synthesized and biologically assayed as racemic (3-5) or diastereoisomeric (6,7) mixtures. All the novel compounds 3-7 showed δ agonism behaviour and remarkable affinity to δ receptors. Amongst the novel derivatives, 3,8-diazabicyclo[3.2.1]octane based compound 4 evidenced improved δ affinity and selectivity relative to SNC80. Published by Elsevier Ltd.
    Bioorganic & medicinal chemistry 07/2015; 23(17). DOI:10.1016/j.bmc.2015.07.036 · 2.79 Impact Factor
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    ABSTRACT: By following a multitarget ligand design approach, a library of 47 compounds was prepared, and they were tested as binders of selected G protein-coupled receptors (GPCRs) and inhibitors of acetyl and/or butyryl cholinesterase. The newly designed ligands feature pyridazinone-based tricyclic scaffolds connected through alkyl chains of variable length to proper amine moieties (e.g., substituted piperazines or piperidines) for GPCR and cholinesterase (ChE) molecular recognition. The compounds were tested at three different GPCRs, namely serotoninergic 5-HT1A , adrenergic α1A , and dopaminergic D2 receptors. Our main goal was the discovery of compounds that exhibit, in addition to ChE inhibition, antagonist activity at 5-HT1A because of its involvement in neuronal deficits typical of Alzheimer's and other neurodegenerative diseases. Ligands with nanomolar affinity for the tested GPCRs were discovered, but most of them behaved as dual antagonists of α1A and 5-HT1A receptors. Nevertheless, several compounds displaying this GPCR affinity profile also showed moderate to good inhibition of AChE and BChE, thus deserving further investigations to exploit the therapeutic potential of such unusual biological profiles. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    ChemMedChem 04/2015; 10(6). DOI:10.1002/cmdc.201500124 · 2.97 Impact Factor
  • Giorgio Chelucci · Gerard A. Pinna · Giansalvo Pinna
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    ABSTRACT: A reagent combination of NaBH4 and TMEDA in the presence of a Pd-catalyst is found to be an efficient system for the regioselective hydrobromination of polybrominated indoles having a N-methyl or N-methoxycarbonyl substituent.
    ChemInform 02/2015; 46(8):no-no. DOI:10.1002/chin.201508177
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    ABSTRACT: Novel pyrazolo[5,1-f][1,6]naphthyridines, pyrazolo[5,1-a][2,6]naphthyridines, pyrazolo[5,1-a][2,7]naphthyridines and pyrazolo[5,1-a]isoquinolines phenylimidazole/benzimidazole ethylene-linked were designed and synthesized for PDE10A interaction. An AgOTf and proline-cocatalyzed multicomponent methodology based on use of o-alkynylaldehydes, tosylhydrazide and ketones was developed and proved to be a convenient route for assembly of most of the novel tricyclic pyrazoles synthesized. Pyrazolo[5,14] [1,6]naphthyridine 43 and 59, pyrazolo[5,1-a][2,6]naphthyridine 66, and pyrazolo[5,1-a][2,7]naphthyridine 42 showed the highest affinity for PDE10A enzyme (IC50 = 40, 42, 40, 55 nM, respectively). (c) 2014 Elsevier Masson SAS. All rights reserved.
    European Journal of Medicinal Chemistry 09/2014; 84:181–193. DOI:10.1016/j.ejmech.2014.07.020 · 3.45 Impact Factor
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    ABSTRACT: A series of dihydrothienocyclopentapyrazole-based derivatives was synthesized and evaluated for the affinity at CB1 and CB2 receptors. The major term, the 6-methyl-1-(1,4-dichlorophenyl)-N-piperidinyl)-1,4-dihydrothieno[2',3'-4,5]cyclopenta[1,2-c]pyrazole-3-carboxamide (6a), displayed a high affinity and good selectivity for CB2 receptors (Ki values of 2.30 nM for CB2 receptor and 440 nM for CB1 receptors respectively). Subsequent analogue preparation resulted in the identification of compounds such as 6b, 6d, 6e, 6k, 6l, 6m, 6s and 6t that showed 1.3-485 fold selectivity for CB2 receptors with potencies in the 1.1-7.2 nM range. These compounds profiled as full agonists at CB2 receptor in an inhibition assay of P-ERK 1/2 up regulation in HL-60 cells.
    European Journal of Medicinal Chemistry 08/2014; 85C:747-757. DOI:10.1016/j.ejmech.2014.08.042 · 3.45 Impact Factor
  • Giorgio Chelucci · Gérard A. Pinna · Giansalvo Pinna
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    ABSTRACT: The mixture of sodium borohydride and N,N,N′,N′- tetramethylethylenediamine in combination with a palladium catalyst is a mild and efficient system for the regioselective hydrodebromination of polybrominated indoles with both N-donating and N-withdrawing substituents [N-methyl- and N-(methoxycarbonyl)indoles, respectively]. The mixture of NaBH 4/N,N,N′,N′-tetramethylethylenediamine in combination with a palladium catalyst is a mild and efficient system for the regioselective hydrodebromination of polybrominated indoles with both N-donating and N-withdrawing substituents [N-methyl- and N-(methoxycarbonyl)indoles].
    European Journal of Organic Chemistry 06/2014; 2014(18). DOI:10.1002/ejoc.201400032 · 3.07 Impact Factor
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    ABSTRACT: A new series of 1H-benzofuro[3,2-c]pyrazole-3-carboxamides was synthesized. The novel compounds (15-24) were evaluated for their affinity to CB2 and CB1 cannabinoid receptors. The synthesis of the title compounds takes advantage of the acid-catalysed thermal cyclization of bicyclic hydrazone ethyl 2-(2-(2,4-dichlorophenyl)hydrazono)-2-(6-methyl-3-oxo-2,3-dihydrobenzofuran-2-yl)acetate to tricyclic ethyl 1-(2,4-dichlorophenyl)-6-methyl-1H-benzofuro[3,2-c]pyrazol-3-carboxylate. All the obtained derivatives showed high affinity to CB2 receptors. Moreover, significant selectivity for CB2 over CB1 receptors was highlighted for lead derivatives amongst the novel series. The best binding profiles were determined for homologues bearing monocyclic and bicyclic monoterpenic substituents at the carbamoyl group at 3 position of the pyrazole ring (KiCB2 < 4 nM). In particular, the isopinocampheyl-substituted derivative 22 exhibited the highest selectivity for CB2 receptors with Ki values of 3.7 and 2398 nM for CB2 and CB1 receptors, respectively. Preliminary functional assays evidenced CB2 agonism behaviour for all the assayed novel derivatives.
    European Journal of Medicinal Chemistry 05/2014; 82C:281-292. DOI:10.1016/j.ejmech.2014.05.055 · 3.45 Impact Factor
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    ABSTRACT: The discovery of phosphodiesterase 10A (PDE10A) enzyme ligands as therapeutic agents in the treatment of central nervous system diseases, especially schizophrenia and Huntington's disease nowadays is a competitive field developing rapidly, with many pharmaceutical companies involved in identifying a huge diversity of chemical scaffolds and molecular architectures for PDE10A interaction. Owing to the importance of this field, the aim of this review is to survey the chemistry and biological properties of linear and angular tricyclic-based heterocycles incorporating valid pharmacophores for PDE10A activity.
    ChemInform 12/2013; 44(52). DOI:10.1002/chin.201352261
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    ABSTRACT: Considering the interesting pharmacological profile of the delta (δ) selective opioid agonist compound SNC-80, conformationally constrained analogs containing two diazatricyclodecane ring systems in place of dimethylpiperazine core motif were synthesized. The compounds showed subnanomolar or low nanomolar δ opioid receptor binding affinity. Depending upon the substituents on the diazatricyclodecane ring, these compounds displayed varying selectivity for δ opioid receptor over μ and κ receptors. Amongst the novel compounds, 1Aa showed the more interesting biological profile, with higher δ affinity and selectivity compared to SNC-80. The δ receptor agonist profile and antinociceptive activity of 1Aa were confirmed using ex-vivo (isolated mouse vas deferens) and in vivo (tail flick) assays.
    European Journal of Medicinal Chemistry 09/2013; 69C:413-426. DOI:10.1016/j.ejmech.2013.09.014 · 3.45 Impact Factor
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    ABSTRACT: Two sensitive and reproducible capillary electrophoresis and high-performance liquid chromatography-fluorescence procedures were established for quantitative determination of L-egothioneine in plasma. After derivatization of L-ergothioneine with 5-iodoacetamidofluorescein, the separation was carried out by HPLC on an ODS-2 C-18 sperisorb column by using a linear gradient elution and by HPCE on an uncoated fused silica capillary, 50 µm id, and 60 cm length. The methods were validated and found to be linear in the range of 0.3 to 10 µmol/l. The limit of quantification was 0.27 µmol/l for HPCE and 0.15 µmol/l for HPLC. The variations for intra- and inter-assay precision were around 6 RSD%, and the mean recovery accuracy close to 100% (96.11%).
    PLoS ONE 07/2013; 8(7):e70374. DOI:10.1371/journal.pone.0070374 · 3.23 Impact Factor
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    ABSTRACT: For the past few decades membrane zinc metallopeptidases have been identified as important therapeutic targets in the control of pain. In particular neutral endopeptidase (NEP) has been shown to play critical roles in the metabolism of the endogenous peptides Met- and Leu- enkephalins. In this study we have evaluated the activity of a new fluorinated peptidase inhibitor NESS002ie in both in vitro and in vivo assays. NESS002ie has been compared to the peptidomimetic compound thiorphan and the previously reported NEP selective thiol inhibitor C20. The metallopeptidases inhibitory activity of NESS002ie was tested in vitro using a highly, sensitive, continuous, fluorometric, enzyme assay. Also, the analgesic propriety of NESS002ie, thiorphan and C20 have been evaluated in vivo, by intraplantar, intravenous and intrathecal administration, through nociception assays based on formalin test in mice. Metallopeptidases assays have shown an inhibitory potency of NESS002ie in the nanomolar range for NEP and angiotensin-converting enzyme (ACE). The new fluorinated inhibitor showed higher analgesic activity and bioavailability compared to thiorphan and C20 when administered by both intravenous and intrathecal injection. More significantly intrathecal injection of NESS002ie reduced both the first and the second phases of the formalin biphasic pain response. In addition, naltrindole and naloxone reversed the analgesic effect of NESS002ie with a diverse profile. This study, shows an improvement in relief of inflamation and pain, in vivo, using NESS002ie compared to reference compounds thiorphan and C20. This significant effect, could be due to the replacement of isobutyl chain of the thiol C20 with the trifluoromethyl group.
    Pharmacology Biochemistry and Behavior 07/2013; 110. DOI:10.1016/j.pbb.2013.06.008 · 2.78 Impact Factor
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    ABSTRACT: In this paper we report the synthesis of new compounds based on the pyrazole and isoxazole framework fused to a cycloalkene unit, and bearing as a substituent the 1-piperidinyl group as new examples of potential antipsychotic molecules. The general synthesis involves the acylation of a chloro-substituted cyclic ketone with a 1-substituted piperidine-4-carboxylate derivative, followed by heterocyclization of the formed 1,3-dioxo compound with a hydrazine or hydroxylamine.
    Molecules 07/2013; 18(7):8147-8159. DOI:10.3390/molecules18078147 · 2.42 Impact Factor
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    ABSTRACT: We have recently synthesized a new series of 4,5-Dihydrobenzo-oxa-cycloheptapyrazole derivatives with the aim to discover novel CB1 antagonist agents characterized by anti-obesity activity comparable to that of SR141716A but with reduced adverse effects such as anxiety and depression. Within the novel class, the CB1 antagonist 8-Chloro-1-(2,4-dichlorophenyl)-N-piperidin-1-yl-4,5-dihydrobenzo-1H-6-oxa-cyclohepta(1,2-c)pyrazole-3-carboxamide (NESS06SM) has been selected as lead compound. We found that NESS06SM is a CB1 neutral antagonist, characterized by poor blood brain barrier permeability. Moreover, NESS06SM chronic treatment determined both anti-obesity effect and cardiovascular risk factor improvement in C57BL/6N Diet Induced Obesity (DIO) mice fed with fat diet (FD mice). In fact, the mRNA gene expression in Central Nervous System (CNS) and peripheral tissues by real time PCR, showed a significant increase of orexigenic peptides and a decrease of anorexigenic peptides elicited by NESS06SM treatment, compared to control mice fed with the same diet. Moreover, in contrast to SR141716A treatment, the chronic administration of NESS06SM did not change mRNA expression of both monoaminergic transporters and neurotrophins highly related with anxiety and mood disorders. Our results suggest that NESS06SM reduces body weight and it can restore the disrupted expression profile of genes linked to the hunger-satiety circuit without altering monoaminergic transmission probably avoiding SR141716A side effects. Therefore the novel CB1 neutral antagonist could represent a useful candidate agent for the treatment of obesity and its metabolic complications.
    Pharmacological Research 06/2013; 74. DOI:10.1016/j.phrs.2013.06.001 · 4.41 Impact Factor
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    ABSTRACT: This review provides an overview of methods that lead to the substitution of halogens from rings of halogenated heterocycles by hydrogen. The first part of the review treats the subject matter from the viewpoint of the method used for the hydrodehalogenation reaction, while the second part is devoted to site selective reductive processes.
    ChemInform 04/2013; 44(17). DOI:10.1002/chin.201317237
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    ABSTRACT: The search of new drugs and targets to treat the pain is an intriguing challenge both for several companies and researchers from academia. In this context, since the modulation of the endocannabinoid system with the non selective phytocannabinoid Δ9-THC produces analgesia and potentiates opioid analgesia in animal models, CB2 ligands studies aimed to explore the involvement of endocannabinoid system in management of pain were started. Several selective CB2 receptor agonists exhibited analgesic activity in preclinical models of acute, inflammatory and neuropathic pain, therefore this class of modulators could be useful as analgesic agents for pain, migraine, inflammation and osteoarthritis. This review is an update of our previously manuscript "A survey of recent patents on CB2 agonists in the management of pain" and provides an overview of patents and advances in CB2 agonist studies in the treatment of pain.
    03/2013; 8(1). DOI:10.2174/15748898112079990016
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    ABSTRACT: A new hydrophilic interaction ultra-performance LC method was established for the whole blood measurement of L-ergothioneine. Chromatographic separation was achieved in a fairly short time, less than 4 min, on a 100 × 2.1 mm Acquity UPLC BEH HILIC 1.7 μm column with a mobile phase consisting of a mixture of 100 mmol/L ammonium acetate/ACN/water (5:85:10, v/v/v) that flowed isocratically at 0.250 mL/min. The LOD and the limit of quantification were 3.85 and 11.67 μmol/L, respectively. The method exhibited linearity in a concentration range of 15.63–1000 μmol/L (R2 > 0.999). Mean recovery was 96.34% whereas intraassay and interassay precision were 1.52 and 1.82% RSD, respectively. On the whole, the developed method is simple, fast, precise, accurate, and sensitive and may be useful for routine analyses.
    Journal of Separation Science 03/2013; 36(6):1002-1006. DOI:10.1002/jssc.201201016 · 2.74 Impact Factor

Publication Stats

954 Citations
195.07 Total Impact Points


  • 1990–2015
    • Università degli Studi di Sassari
      • • Department of Chemistry and Pharmacy
      • • Dipartimento di Scienze Biomediche
      Sassari, Sardinia, Italy
  • 2012
    • Neuroscienze PharmaNess
      Cagliari, Sardinia, Italy
  • 2010
    • University of Milan
      Milano, Lombardy, Italy
  • 2000
    • University of Naples Federico II
      Napoli, Campania, Italy