Salvatore Sanna Coccone

Discovery of a new class of potential multifunctional atypical antipsychotic agents targeting dopamine D3 and serotonin 5-HT1A and 5-HT2A receptors: design, synthesis, and effects on behavior.

Dopamine D(3) antagonism combined with serotonin 5-HT(1A) and 5-HT(2A) receptor occupancy may represent a novel paradigm for developing innovative antipsychotics. The unique pharmacological features of 5i are a high affinity for dopamine D(3), serotonin 5-HT(1A) and 5-HT(2A) receptors, together with a low affinity for dopamine D(2) receptors (to minimize extrapyramidal side effects), serotonin 5-HT(2C) receptors (to reduce the risk of obesity under chronic treatment), and for hERG channels (to reduce incidence of torsade des pointes). Pharmacological and biochemical data, including specific c-fos expression in mesocorticolimbic areas, confirmed an atypical antipsychotic profile of 5i in vivo, characterized by the absence of catalepsy at antipsychotic dose.

Combining 4-aminoquinoline- and clotrimazole-based pharmacophores toward innovative and potent hybrid antimalarials.

Antimalarial agents structurally based on novel pharmacophores, synthesized by low-cost synthetic procedures and characterized by low potential for developing resistance are urgently needed. Recently, we developed an innovative class of antimalarials based on a polyaromatic pharmacophore. Hybridizing the 4-aminoquinoline or the 9-aminoacridine system of known antimalarials with the clotrimazole-like pharmacophore, characterized by a polyarylmethyl group, we describe herein the development of a unique class (4a-l and 5a-c) of antimalarials selectively interacting with free heme and interfering with Plasmodium falciparum (Pf) heme metabolism. Combination of the polyarylmethyl system, able to form and stabilize radical intermediates, with the iron-complexing and conjugation-mediated electron transfer properties of the 4(9)-aminoquinoline(acridine) system led to potent antimalarials in vitro against chloroquine sensitive and resistant Pf strains. Among the compounds synthesized, 4g was active in vivo against P. chabaudi and P. berghei after oral administration and, possessing promising pharmacokinetic properties, it is a candidate for further preclinical development.

Development of antitubercular compounds based on a 4-quinolylhydrazone scaffold. Further structure-activity relationship studies.

A series of 4-quinolylhydrazones was synthesized and tested in vitro against Mycobacterium tuberculosis. At a concentration of 6.25microg/mL, most of the newly synthesized compounds displayed 100% inhibitory activity against M. tuberculosis in cellular assays. Further screening allowed the identification of very potent antitubercular agents. Compound 4c was also tested in a time-course experiment and against mtb clinical isolates, displaying interesting results.

Clotrimazole Scaffold as an Innovative Pharmacophore Towards Potent Antimalarial Agents : Design, Synthesis, and Biological and Structure-Activity Relationship Studies

We describe herein the design, synthesis, biological evaluation, and structure-activity relationship (SAR) studies of an innovative class of antimalarial agents based on a polyaromatic pharmacophore structurally related to clotrimazole and easy to synthesize by low-cost synthetic procedures. SAR studies delineated a number of structural features able to modulate the in vitro and in vivo antimalarial activity. A selected set of antimalarials was further biologically investigated and displayed low in vitro toxicity on a panel of human and murine cell lines. In vitro, the novel compounds proved to be selective for free heme, as demonstrated in the beta-hematin inhibitory activity assay, and did not show inhibitory activity against 14-alpha-lanosterol demethylase (a fungal P450 cytochrome). Compounds 2, 4e, and 4n exhibited in vivo activity against P. chabaudi after oral administration and thus represent promising antimalarial agents for further preclinical development.

Tacrine based human cholinesterase inhibitors: Synthesis of peptidic-tethered derivatives and their effect on potency and selectivity

Tacrine based reversible inhibitors of cholinesterases (ChEIs) containing peptidic tethers were synthesized to interact with specific regions at the gorge level, and their potency was determined with human (h) acetylcholinesterase and butyrylcholinesterase. Analogues 3i,j and 3l,m were identified as promising hits and may pave the way for the development of a new series of tacrine based enzyme selective hChEIs.

Synthesis and Antiplasmodial Activity of Bicyclic Dioxanes as Simplified Dihydroplakortin Analogues

Here we report the synthesis and evaluation of antiplasmodial activity of a novel series of bicyclic peroxides inspired by the marine natural compound dihydroplakortin. We developed a synthetic strategy leading to the dihydroplakortin-related peroxides in only a few steps. The in vitro antiplasmodial potency of the peroxides was similar to, or greater than, that of the reference natural compound, and structure-activity relationship studies revealed several key structural requirements for activity and potency.

Specific targeting of peripheral serotonin 5-HT3 receptors. Synthesis, biological investigation, and structure-activity relationships

The synthesis and the biological characterization of novel highly selective pyrroloquinoxaline 5-HT(3) receptor (5-HT(3)R) ligands are described. In functional and in vivo biological studies the novel quinoxalines modulated cardiac parameters by direct interaction with myocardial 5-HT(3)Rs. The potent 5-HT(3)R ligands 4h and 4n modulate chronotropy (right atrium) but not inotropy (left atrium) at the cardiac level, being antagonist and partial agonist, respectively. Preliminary pharmacokinetic studies indicate that (S)-4n and 4a, representatives of the novel 5-HT(3)R ligands, possess poor blood-brain barrier permeability, being the prototypes of peripherally acting 5-HT(3)R modulators endowed with a clear-cut pharmacological activity at the cardiac level. The unique properties of 4h and 4n, compared to their previously described centrally active N-methyl analogue 5a, are mainly due to the hydrophilic groups at the distal piperazine nitrogen. These analogues represent novel pharmacological tools for investigating the role of peripheral 5-HT(3)R in the modulation of cardiac parameters.

An efficient approach to chiral C8/C9-piperazino-substituted 1,4-benzodiazepin-2-ones as peptidomimetic scaffolds.

A promising way to interfere with biological processes is through the modulation of protein-protein interactions by means of small molecules acting as peptidomimetics. The 1,4-benzodiazepine scaffold has been widely reported as a peptide-mimicking, pharmacogenic system. While several synthetic pathways to C6-8 substituted benzodiazepines have been disclosed, few 1,4-benzodiazepines substituted at C9 have been reported. Herein, we describe a versatile approach to introduce cyclic, protonatable functionality at C8/C9. Introduction of the piperazine system at C8 and C9 gave access to a unique functionalization of the versatile benzodiazepine skeleton, broadening tailoring options on the benzofused side of the molecule, and the possibility of discovering novel peptidomimetics potentially able to modulate protein-protein interactions. Coupling of activated amino acids with poorly reactive anilines under mild conditions, while avoiding racemization, gave easy access to these compounds. Efficient amino acid activation was obtained by exploiting the rapid formation of acid chlorides under low temperature and acid/base free conditions, using triphenylphosphine and hexachloroacetone. This procedure successfully resulted in high reaction yields, did not produce racemization (ee > 98%, as demonstrated by using chiral solvating agents), and was compatible with the acid sensitive protecting groups present in the substrates.

1H-Cyclopentapyrimidine-2,4(1H,3H)-dione-Related Ionotropic Glutamate Receptors Ligands. Structure−Activity Relationships and Identification of Potent and Selective iGluR5 Modulators

(S)-CPW399 ((S)-1) is a potent and excitotoxic AMPA receptor partial agonist. Modifying the cyclopentane ring of (S)-1, we developed two of the most potent and selective functional antagonists (5 and 7) for kainate receptor (KA-R) subunit iGluR5. Derivatives 5 and 7, with their unique pharmacological profile, may lead to a better understanding of the different roles and modes of action of iGluR1-5 subunits, paving the way for the synthesis of new potent, subunit selective iGluR5 modulators.

Exploring clotrimazole-based pharmacophore: 3D-QSAR studies and synthesis of novel antiplasmodial agents

We report herein the generation and validation of a 3D-QSAR model based on a set of antimalarials previously described by us and characterized by a clotrimazole-based pharmacophore. A novel series of derivatives was synthesized and showed activity against Plasmodium falciparum chloroquine-sensitive (CQ-S) and chloroquine-resistant (CQ-R) strains. Gratifyingly, compounds 35a-c showed interesting activity against P. falciparum CQ-R strains with improved predicted physico-chemical properties.