Gabriele Murineddu

Tricyclic Pyrazoles. Part 1: Synthesis and Biological Evaluation of Novel 1,4-Dihydroindeno[1,2-c]pyrazol-based Ligands for CB1and CB2 Cannabinoid Receptors

Cannabinoids receptors, cellular elements of the endocannabinoid system, have been the focus of extensive studies because of their potential functional role in several important physiological and pathological processes. To further evaluate the properties of CB receptors, especially CB(1) and CB(2) subtypes, we have designed, using SR141716A as a benchmark, a new series of rigid 1-aryl-1,4-dihydroindeno[1,2-c]pyrazole-3-carboxamides. Compounds 1 were synthesized from substituted 1-aryl-1,4-dihydroindeno[1,2-c]pyrazole-3-carboxylic acids and requisite amines. The various analogues were assayed for binding both to the brain and peripheral cannabinoid receptors (CB(1) and CB(2)). Seven of the new compounds displayed very high in vitro CB(2) binding affinities, especially 1a, 1b, 1c, 1e, 1g, 1h and 1j which showed K(i) values of 0.34, 0.225, 0.27, 0.23, 0.385, 0.037 and 0.9 nM, respectively. Compounds 1a, 1b, 1c and 1h showed the highest selectivity for CB(2) receptor with K(i)(CB(1)) to K(i)(CB(2)) ratios of 6029, 5635, 5814 and 9810, respectively. Noticeably, 1h exhibited the highest affinity and selectivity for CB(2) receptors.

Synthesis and SAR study of new phenylimidazole-pyrazolo[1,5-c]quinazolines as potent phosphodiesterase 10A inhibitors.

A series of phenylimidazole-pyrazolo[1,5-c]quinazolines 1a-q was designed, synthesized and characterised as a novel class of potent phophodiesterase 10A (PDE10A) inhibitors. In this series, 2,9-dimethyl-5-(2-(1-methyl-4-phenyl-1H-imidazol-2-yl)ethyl)pyrazolo[1,5-c]quinazoline (1q) showed the highest affinity for PDE10A enzyme (IC(50)=16nM).

Synthesis and application in asymmetric copper(I)-catalyzed allylic oxidation of a new chiral 1,10-phenanthroline derived from pinene

Abstract A convenient and rapid method for the preparation of chiral C2-symmetric 1,10-phenanthrolines is reported. As an example of this procedure the synthesis of new 1,10-phenanthroline (+)-7 and its 5,6-dihydro derivative (+)-6 from (−)-β-pinene is described. These ligands have been assessed in asymmetric copper(I)-catalyzed allylic oxidation of cycloalkenes affording enantioselectivities up to 71%.

Chromophore-modified bis-benzo[ g ]indole carboxamides: synthesis and antiproliferative activity of bis-benzo[ g ]indazole-3-carboxamides and related dimers

Tricyclic pyrazole dimers that comprise two kinds of CONH-(CH(2))(n)-N(CH(3))-(CH(2))(n)-NHCO bridges to which are linked potential DNA-intercalating groups such as 1H-benzo[g]indazole, 2H-benzo[g]indazole and 1,4-dihydroindeno[1,2-c]pyrazole were designed, synthesized and some of them evaluated in vitro by NCI (Bethesda, USA) against nine types of cancer cells. Compounds 2a, 2f-i and 2o-r demonstrated significant antiproliferative activity, all with GI(50) values in the low micromolar range. Preliminary analysis of the structure-activity relationship for dimers 2 indicated that: (i) in the ground terms (2a and 2k) antitumor activities were strongly related to the type of chromophore, (ii) in contrast, either 1H-benzo[g]indazole- or 1,4-dihydroindeno[1,2-c]pyrazole-dimers when bore a N(1)-aryl group (2g, 2h, 2i, 2o, 2p, 2q and 2r) generally showed a good level of antitumor potency and (iii) for the most representative compounds (pairs of compounds: 2g,2h; 2o,2p and 2q,2r) the length of the bridges did not significantly contribute to the variations in cytotoxicity. Two members of this series, 2f and 2q, were selected and tested in the hollow fiber cell assay to evaluate in a preliminary fashion their in vivo antitumor activity. Finally, viscosity measurement of 2f with poly(dA-dT)(2), confirmed that these promising compounds behaved as typical DNA-intercalating agents.

Design of a new class of chiral C2-symmetric dipyridylmethane ligands and their application in asymmetric catalysis

A new class of chiral C2-symmetric dipyridylmethane ligands was prepared from naturally occurring monoterpenes, according to a method based on a double Michael–azaannellation–aromatization sequence. These ligands were assessed in the enantioselective palladium-catalyzed allylic alkylation of 1,3-diphenylprop-2-enyl acetate with dimethylmalonate and in the copper-catalyzed cyclopropanation of styrene with ethyl diazoacetate. Enantioselectivity up to 88% ee was obtained.

NESS06SM reduces body weight with an improved profile relative to SR141716A

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.

Pyridazine N-Oxides. III. Synthesis and “in vitro” antimicrobial properties of N-Oxide derivatives based on tricyclic indeno[2,1-c]pyridazine and benzo [f]cinnoline systems

A number of 9H‐indeno[2,1‐c]pyridazine N‐oxides (3a—c) and benzo[f]cinnoline N‐oxides (4,5a—c) have been synthesized and tested for antimicrobial activity. All new products were inactive against Gram negative bacteria and fungi. In contrast, among the compounds synthesized, 3b, 4b and 5b showed a moderate activity against Gram positive Staphylococcus aureus and Staphylococcus epidermidis. Of the present series, the 9‐nitro‐benzo[f]cinnoline N‐oxide 5b possessed the highest activity especially against Trichomonas vaginalis (MIC = 3.9 μg/ml).

A Survey of Recent Patents on CB2 Agonists in the Management of Pain

Pain, a homeostatic and protective mechanism which can go awry in disease states and therefore needs treatment, is a complex and differentiated sensorial perception which may be classified as physiological, inflammatory and neuropathic. Chronic pain represents a major health problem throughout the world, thus several companies and researchers have embarked on the search for new drugs and targets to treat the disease. The different types of receptors in the CNS involved in the mediation of analgesia include the cannabinoid receptors: in particular, CB2 modulators seem to represent a new potential class of analgesic. This review covers recent patents and advances in CB2 agonist studies in the management of pain.

Synthesis and D2-like binding affinity of new derivatives of N-(1-ethyl-2-pyrrolidinylmethyl)-4,5-dihydro-1H-benzo[g]indole-3-carboxamide and related 4H-[1]benzothiopyrano[4,3-b]pyrrole and 5,6-dihydro-4H-benzo[6,7]cyclohepta[b]pyrrole-3-carboxamide analogues

Various new derivatives and structural analogues of N-(1-ethyl-2-pyrrolidinylmethyl)-4,5-dihydro-1H-benzo[g]indole-3-carboxamide (2a), a representative term of a series of 2-aminomethylpyrrolidinyl derived 4,5-dihydrobenzo[g]indolcarboxamides with good D(2)-like affinity, were synthesized and evaluated for their ability to bind to dopamine D(2)-like receptors in vitro. The structural contribution to D(2)-like receptor binding of the 4,5-dihydrobenzo[g]indole portion of the molecule was examined. From these studies, compound 2k, 2-chloro-N-(1-ethyl-2-pyrrolidinylmethyl)-5,6-dihydro-4H-benzo[6,7]cyclohepta[b]pyrrole-3-carboxamide, was found to possess a potent affinity for D(2)-like receptors. Behavioural tests in rats have shown that this compound reduces the hyperactivity induced by amphetamine, a property shared by all antipsychotic drugs, at a dose which failed to induce catalepsy, an effect which is predictive of extrapyramidal side effects in humans. The other compounds demonstrated moderate (2c, 2h, and 2j) or no affinity for D(2)-like receptors.

Tricyclic pyrazoles. Part 6. Benzofuro[3,2-c]pyrazole: a versatile architecture for CB2 selective ligands.

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.