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Monoacylglycerol lipase (MAGL) is the enzyme hydrolyzing the endocannabinoid 2-arachidonoylglycerol (2-AG) to free arachidonic acid and glycerol. Therefore, MAGL is implicated in many physiological processes involving the regulation of the endocannabinoid system and eicosanoid network. MAGL inhibition represents a potential therapeutic target for many diseases, including cancer. Nowadays, most MAGL inhibitors inhibit this enzyme by an irreversible mechanism of action, potentially leading to unwanted side effects from chronic treatment. Herein, we report the discovery of long-chain salicylketoxime derivatives as potent and reversible MAGL inhibitors. The compounds herein described are characterized by a good target selectivity for MAGL and by antiproliferative activities against a series of cancer cell lines. Finally, modeling studies suggest a reasonable hypothetical binding mode for this class of compounds.

The CB2 receptor is a therapeutic target of increasing importance for several diseases, including pain, inflammation, neurodegeneration, cancer and osteoporosis. While several compounds showing CB2-selective agonist or inverse agonist properties have been developed, only few CB2 receptor selective neutral antagonists are actually known. Such type of compounds could be useful to study more in depth the role of the CB2 receptor, because they lack the ability to counteract its “constitutive” activity. Here we describe the synthesis and biological activity of a series of biphenylic carboxamides as a new class of CB2 receptor selective ligands. In binding assays, one of these compounds showed good CB2 receptor affinity and selectivity (Ki = 11.48 nM; Selectivity Index = 130). Furthermore, in functional assays, the same compound showed a very interesting pharmacological profile as CB2 receptor selective neutral antagonist. These results pave the way to further developments, including structural optimization, with the aim to obtain more potent CB2 receptor ligands with this peculiar feature.

Allosteric modulation of the CB1Rs could represent an alternative strategy for the treatment of diseases in which these receptors are involved, without the undesirable effects associated with their orthosteric stimulation. PSNCBAM-1 is a reference diaryl urea derivative that positively affects the binding affinity of orthosteric ligands (PAM) and negatively affects the functional activity of orthosteric ligands (NAM) at CB1Rs. In this work we reported the design, synthesis and biological evaluation of three different series of compounds, derived from structural modifications of PSNCBAM-1 and its analogs reported in the recent literature. Almost all the new compounds increased the percentage of binding affinity of CP55940 at CB1Rs, showing a PAM profile. When tested alone in the [35S]GTPγS functional assay, only a few derivatives lacked detectable activity, so were tested in the same functional assay in the presence of CP55940. Among these, compounds 11 and 18 proved to be functional NAMs at CB1Rs, dampening the orthosteric agonist-induced receptor functionality by approximately 30%. The structural features presented in this work provide new CB1R-allosteric modulators (with a profile similar to the reference compound PSNCBAM-1) and an extension of the structure-activity relationships for this type of molecule at CB1Rs.

Aggressive behavior and diffuse infiltrative growth are the main features of Glioblastoma multiforme (GBM), together with the high degree of resistance and recurrence. Evidence indicate that GBM-derived stem cells (GSCs), endowed with unlimited proliferative potential, play a critical role in tumor development and maintenance. Among the many signaling pathways involved in maintaining GSC stemness, tumorigenic potential, and anti-apoptotic properties, the PDK1/Akt pathway is a challenging target to develop new potential agents able to affect GBM resistance to chemotherapy. In an effort to find new PDK1/Akt inhibitors, we rationally designed and synthesized a small family of 2-oxindole derivatives. Among them, compound 3 inhibited PDK1 kinase and downstream effectors such as CHK1, GS3Kα and GS3Kβ, which contribute to GCS survival. Compound 3 appeared to be a good tool for studying the role of the PDK1/Akt pathway in GCS self-renewal and tumorigenicity, and might represent the starting point for the development of more potent and focused multi-target therapies for GBM.

Starting from the previously developed P-gp ligands 1a and 1b (EC50 = 0.25 μM and 0.65 μM, respectively), new arylmethyloxyphenyl derivatives have been synthesized as P-gp modulators in order to investigate: (i) the effect of small electron-donor groups (OMe) (5–11), (ii) the effect of the replacement of methoxy groups with an electron-withdrawal substituent (Cl) on C-ring (13) (iii) the effect induced by the replacement of C-ring with heteroaromatic cycles such as thiophene and pyrimidine (13, 15, 16), (iv) the effect induced by molecular constriction on C ring (14, 17, 18) on P-gp modulating activity. The results demonstrated that P-gp inhibition potency is strongly correlated to the number of methoxy groups in the A-ring whereas the methoxylation of C-ring seems to poorly affect P-gp activity. The best result was found for compound 10 that displays a nanomolar affinity (EC50 = 7.1 nM) towards P-gp pump and, in the meantime lacks of activity against MRP1 pump.

Targeting type-2 cannabinoid receptor (CB2) is considered a feasible strategy to develop new drugs for the treatment of diseases like neuropathic pain, chronic inflammation, neurodegenerative disorders and cancer. Such drugs are devoid of the undesired central side effects that are typically mediated by the CB1 receptor. In this work we synthesized 18 biphenylic carboxamides as new CB2-selective ligands and evaluated their pharmacological profiles. The functional activity of these compounds is strongly influenced by the nature of the substituent at position 4' and 5 of the biphenyl scaffold. Position 5 seems to be responsible for the agonist or inverse agonist behaviour independently of the substituent in position 4', with the exception of the methoxyl group which transforms both full agonists and inverse agonists into neutral antagonists. This study provides a novel complete toolbox of CB2 functional modulators that derive from the same chemical scaffold. Such probes may be useful to investigate the biological role of CB2 receptors in cellular assays.

Current cancer research is being increasingly focused on the study of distinctive characters of tumour metabolism, resulting in a switch from oxidative phosphorylation to glycolysis (Warburg effect). Isoform 5 of human lactate dehydrogenase (hLDH5), which catalyzes the final step in the glycolytic cascade (pyruvate to lactate), constitutes a relatively new and untapped anti-cancer target. In this study, careful design and synthesis of a selected series of aryl-substituted N-hydroxyindole-2-carboxylates (NHIs) has led to several hLDH5-inhibitors, showing "first-in-class" potency and isoform selectivity. Enzyme kinetics studies indicated that these inhibitors exhibit a competitive mode of inhibition. Some representative examples were tested against two human pancreatic carcinoma cell lines, and displayed a good anti-proliferative activity, which was even more evident under hypoxic conditions.

The relevance of CB2R-mediated therapeutic effects is well-known for the treatment of inflammatory and neuropathic pain and neurodegenerative disorders. In our search for new cannabinoid receptor modulators, we report the optimization of a series of 1,2-dihydro-2-oxopyridine-3-carboxamide derivatives as CB2R ligands. In particular, N-cycloheptyl-5-(4-methoxyphenyl)-1-(4- fluorobenzyl)-pyridin-2(1H)-on-3-carboxamide (17) showed high CB2R affinity (Ki = 1.0 nM), accompanied by interesting Ki(CB1R)/K i(CB2R) selectivity ratio (SI = 43.4). Compound 17 was also identified as a potent CB2R neutral antagonist/weak partial inverse agonist. Finally we found that the functionality activity of the series of 1,2-dihydro-2-oxopyridine is controlled by the presence of a substituent in position 5 of the heterocyclic nucleus. In fact when the hydrogen atom in position 5 of the unsubstituted compound 1 was replaced with a phenyl group (compound 18) the CB2R activity was shifted from agonism to inverse agonism whereas the introduction in the same position of p-methoxyphenyl group lead to compound 17 which showed a behavior as CB2R neutral antagonist/weak partial inverse agonist. © 2013 Elsevier Masson SAS. All rights reserved.

Summary The chiral (S)- and (R)-N-[3-(isopropylamino)-2-hydroxypropylidene](p-chlorophenylmethyloxy)amines ((S)-1a and (R)-1a) and their corresponding N-tert-butyl-substituted analogs ((S)-1b and (R)-1b) were synthesized from optically active precursors of known absolute configuration by procedures which had no effect on the configuration of the asymmetric carbon. Compounds (S)-1a,b and (R)-1a,b were tested for their β-adrenergic properties by radioligand binding experiments and functional tests on isolated preparations. The biopharmacological results show that compounds (S)-1a,b, in which the geometry of the chiral carbon adjacent to the hydroxyl group resembles that of natural catecholamines with the R configuration, interacted better with β-receptors, even if the stereochemical selectivity among enantiomeric pairs is not particularly marked.

The diastereoisomeric N -isopropyl- and N-t -butyl-substituted 2-(5′-(3′-phenyl)- and 2-(5′-(3′-isopropyl)isoxazolidinyl)-ethanolamines ( 5–8 ), which can be viewed as conformationally restrained analogs of the corresponding β-blocking oxime ethers 10 and 11 , were synthesized. The relative configurations of 5–8 were assigned by 1 H-NMR studies and by the determination of the solid-state structure of one of the new compounds ( 6a ). The new isoxazoline derivatives ( 5–8 ) were tested both by radioligand binding assays and by functional tests on isolated preparations. Compounds 5a–8a were found to retain, albeit to a lower extent, the β-blocking properties of the corresponding oxime ethers 10a and 11a , thus indicating that these last compounds may prove to be still capable of interacting with the β-receptors, even if their C = NOCH 2 portion is constrained in a conformationally semi-rigid isoxazoline structure. Possible rationalizations of the results were sought by comparing the conformations and the molecular reactivity of model compounds of the isoxazolines 5–8 and of the oxime ethers 10 and 11 .

The (E)-[2-(4-Methylsulphonylphenyl)-1-cyclopentenyl-1-methyliden](methyloxy)amine (5) and (arylmethyloxy)amines (6–12) were designed in order to verify the effects on the biological properties of the substitution of an aryl of selective diarylcyclopentenyl cyclooxygenase-2 (COX-2) inhibitors of type 3 with a methyleneaminoxymethyl moiety (MAOMM). Compounds 5–12 were tested in vitro for their inhibitory activity towards COX-1 and COX-2 by measuring prostaglandin E2 (PGE2) production in U937 cell lines and activated J774.2 macrophages, respectively. The compound with the highest in vitro activity towards COX-2 (9) was also assayed in vivo for its antiinflammatory activity by means of the carrageenan-induced paw edema test in rats. Some of the new compounds showed an appreciable in vitro COX-2 inhibitory activity, with IC50 values in the μM (6,7,9,10,11) range. Compound 9 also exhibited an appreciable in vivo activity (29% inhibition at a dose of 30 mg kg−1) when administered intraperitoneally. The structural parameters of 9 were determined by X-ray crystallographic analysis.

The molecular parameters of the tetrabutylammonium salt 3 of the monobactam antibiotic 2 were determined by means of X-ray cyrstallographic analysis. Crystals are monoclinic, space group P21 with Z = 4, unit-cell dimensions a = 17.368(3), b = 19.101(4), c = 9.464(2) A , β = 94.25(1)° . In the asymmetric unit of 3 2 independent molecules (3a and b) are present. The structure was solved by direct methods and refined by a least-squares procedure to an R value of 0.049 for 4 346 unique observed reflections. The relevant molecular parameters of 3 compare well with the corresponding ones of sulfazecin 1, the only biologically active monobactam antibiotic subjected to crystal-structure determination.

The 3-aminoxy-( E )-2-methoxyiminopropionyl penicillins 13 and cephalosporins 14 and 15 were synthesized and assayed for their antimicrobial activity on Gram-positive and Gram-negative bacteria whether producers of β-lactamases or otherwise. Compounds 13 , 14 , and 15 exhibited an activity which was generally lower than that of the corresponding phenylacetyl derivative: penicillin G ( 4 ), cephaloram ( 5 ), and phenylacetamidodesacetoxycephalosporanic acid ( 6 ). Furthermore, the comparison of the minimum inhibitory concentration values of some of the new 2-methoxyimino 3-aminoxypropionyl derivatives 13–15 with those of the corresponding ones 1–3 lacking the 2-methoxyimino substituent showed that the introduction of the 2-methoxyimino group of E configuration on the aminoxypropionamido side chain of 1–3 gives compounds ( 13–15 ) which do not generally possess better antimicrobial properties.

Summary Some monocyclic β-lactam derivatives of types II (1a-5a) and III (1b-5b) , designed as analogs of type I derivatives, in which the C-4 aryloxy group of I is replaced by an oximate moiety, were synthesized and tested in vitro for their inhibitory activity towards porcine pancreatic (PPE) and human leukocyte (HLE) elastases. All compounds were found to be inactive on PPE. While 1b-5b did not display any appreciable activity towards HLE, compounds 1a-5a exhibited a marked inhibitory activity on this enzyme. The most active in vitro type- II compound 4a and the derivative 5a , whose molecular structure presents a carboxylic moiety like type- I reference drug 14 , were tested in vivo for their human sputum elastase-inhibitory activity in elastase-induced lung hemorrhage in mice: they proved to possess an appreciable inhibitory activity even if somewhat lower than might have been expected on the basis of their activity indices obtained in the in vitro tests.

The diastereoisomeric 2-(5′-(3′-aryl)isoxazolidinyl)ethanolamines 1c-h-4c-h were synthesized as analogs of the corresponding β-blocking isoxazolines unsubstituted on the aromatic ring 1a-4a , with the aim of checking the effects on the adrenergic properties of the insertion of a methoxy group or a chlorine atom in the ortho, meta or para position of the phenyl ring of 1a-4a . The relative configurations of 1c-h-4c-h were assigned on the basis of their 1 H-NMR spectral characteristics. The new isoxazolines 1c-h-4c-h were tested for their affinity towards β 1 - and β 2 -adrenoceptors by radioligand binding experiments; compounds showing the highest affinity were also assayed for their β-adrenergic activity by functional tests on isolated preparations. The results showed that most of the new compounds ( 1c-h-4c-h ) possess a slightly better capacity to interact with the β-receptors, compared with the corresponding analogs unsubstituted on the phenyl ring ( 1a-4a ), and that the substitution that leads to compounds with the best properties is the one with the chlorine atom. Quantum mechanical calculations carried out in order to look for possible correlations between the β-adrenergic properties and the conformational and electronic characteristics induced by the presence of the substituents on the phenyl ring of compounds of types 1–4 do not suggest any reasonable explanation for the trend of the affinity data.

A series of 3-(methyleneaminoxy)methylpiperidines (5a–h) and their corresponding N-methyl derivatives (6a–h) with a variety of substituents on the imino carbon were synthesized and tested for their potential antidepressant properties; their capacity to inhibit the re-uptake of biogenic amines (NA, 5-HT and DA) in rabbit brain synaptosomal fractions was also evaluated. The biological results obtained for the piperidine derivatives 5a–h and 6a–h and viloxazine 1, the reference drug, on the 3 re-uptake systems revealed that compounds 5 and 6 are generally able to inhibit biogenic amine uptake. The IC50 values for 5 and 6 were often lower than that of viloxazine 1, in particular for the serotonin- and/or dopamine-uptake systems. A higher activity was found for compounds substituted with at least one phenyl ring on the imino carbon with respect to completely aliphatic systems, and for N-unsubstituted compounds with respect to N-methyl-substituted compounds.

Some monocyclic β-lactam derivatives of type 3 (MAOAs) in which the leaving group (LG) on the C(4) is a methyleneaminoxy moiety, were synthesised and tested in vitro and in vivo for their inhibitory activity towards human leukocyte elastase (HLE). Some compounds showed an appreciable in vitro inhibitory activity against this enzyme. Effects on the anti-HLE activity due to the nature of the substituents R and R1 present on their LG were observed and rationalised by means of molecular modelling techniques. The results of in vivo pharmacological tests indicated that MAOAs, while showing an inhibitory activity on the haemorrhage induced by HLE, did not exhibit any effects due to the R and R1 substituents.

In a continuing effort to improve the subtype selectivity and agonist potency of estrogen receptor β (ERβ) ligands, we have designed and developed a thus far unexplored structural series obtained by molecular refinements of monoaryl-substituted salicylaldoximes (Salaldox B). The most interesting compounds in this series (2c, d) show remarkably high ERβ-binding affinities, with Ki values reaching the sub-nanomolar range (Ki = 0.38 nM for 2c and 0.57 nM for 2d), and have very high levels of ERβ-subtype selectivity. Both compounds show a potent full agonist character on ERβ (EC50 = 0.23 nM for 2c and 1.3 nM for 2d). Furthermore, 2d shows a remarkable functional subtype selectivity, with a β/α transcription potency ratio 50-fold higher than that of estradiol.

The tetrahydronaphthalene analogs 4 and 5 of DCI ( 3b ) and of its N -unsubstituted derivative ( 3a ) were synthesized and tested for their β-adrenergic properties by means of both binding tests and functional tests. Compounds 4 and 5 proved to possess a good affinity for β-adrenergic receptors accompanied by an appreciable β-blocking activity, thus indicating that the formal insertion of a β-blocking drug such as DCI into a tetrahydronaphthalene structure is able to provide compounds which still possess a β-blocking activity.

Some new cephem derivatives of types 4 and 5, viewed as analogues of type I esters in which the atomic sequence of the C-2 ester group is formally inverted, were synthesised and tested in vitro for their inhibitory activity towards human leukocyte elastase and porcine pancreatic elastase. An examination of the inhibition data obtained for the new type 4 and 5 derivatives, while exhibiting a considerable reduction in their activity against porcine pancreatic elastase, indicated that these compounds still maintain an appreciable inhibitory activity against human leukocyte elastase. On this basis the new type of C-2 substitution appears to contribute to the research of new, potentially interesting, cephalosporinic human leukocyte elastase inhibitors.