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The present work describes the design, and synthesis of the polyfunctionalized indole derivative Contilistat for the treatment of a broad diversity of cancers, and neurodegenerative diseases such as glioblastoma, and Alzheimer’s disease (AD). Contilistat has been designed as a Multi-Target-Directed (MTD) small molecule, able to inhibit HDAC6, cholinesterase and monoamine oxidase enzymes, and modulate histamine 3, sigma 1, 5-HT6, and dopamine 3 receptors. Contilistat has been submitted to biological evaluation in suitable in vitro and vivo glioblastoma and AD models.

A new series of urea and thiourea derivatives containing benzimidazole group as potential anticancer agents have been designed and synthesized. The structures of the synthesized compounds were characterized and confirmed by spectroscopic techniques such as 1H NMR, 13C NMR, and mass spectrometry. In vitro anticancer assay against two breast cancer (BC) cell lines, MDA-MB-231ER(−)/PR(−) and MCF-7ER(+)/PR(+), revealed that the cytotoxicity of 1-(2-(1H-benzo[d]imidazol-2-ylamino)ethyl)-3-p-tolylthiourea (7b) and 4-(1H-benzo[d]imidazol-2-yl)-N-(3-chlorophenyl)piperazine-1-carboxamide (5d) were higher in MCF-7 with IC50 values of 25.8 and 48.3 µM, respectively, as compared with MDA-MB-231 cells. Furthermore, 7b and 5d were assessed for their apoptotic potential using 4′,6-diamidino-2-phenylindole, acridine orange/ethidium bromide staining, and Caspase-3/7. After incubation with MCF-7, the compounds 7b and 5d induced apoptosis through caspase-3/7 activation. In conclusion, the compounds 7b and 5d are potential candidates for inducing apoptosis in different genotypic BC cell lines.

A novel series of 5-nitroimidazole-piperazines (4a–j) and 5-nitrothiazole-piperazine (7a–j) have been prepared in good yields. The antigiardial and antitrichomonal activities of these new compounds were evaluated. Majority of the compounds was found to be more active against Giardia lamblia as compared to metronidazole at 24 hours of incubation. After 48 hours of incubation, compounds 4b, 4f, 7c and 7j showed better activity against G. lamblia with IC50 of 15.3, 11.4, 5.9, 13.5 μM respectively compared to metronidazole (17.4 μM). Compounds 4a–j and 7a–j exhibited anti-parasitic activity against T. vaginalis with IC50 ranging from 16.4–88.7 μM and 1.2–86.7 μM at 24 hours and 48 hours of incubation respectively. Compounds 4c and 7e were 15 times more potent than the standard drug, metronidazole.

We describe here the synthesis, antioxidant capacity, and biological activities on MAO, ChE, and selected GPCRs, of novel 1-(2,5-dimethoxybenzyl)-4-arylpiperazines 1–10, as well as known N-(2-(2-methyl-5-nitro-1H-imidazol-1-yl))-2-(4-arylpiperazin-1-yl) 11–20 and N-(5-nitrothiazol-2-yl)-2-(4-arylpiperazin-1-yl) 21–29. Some of the new 4-arylpiperazines were found to have low-micromolar affinities for the proteins tested. The most potent MAO inhibitor identified was compound 2-(4-(3-fluorophenyl)-yl)-N-(5-nitrothiazol-2-yl)(27), with an IC50 value of 4.14 ± 0.5 μM, whereas the most potent interaction with a GPCR was 1-(2,5-dimethoxybenzyl)-4-(4-trifluoromethylphenyl) (5) for the 5-HT6 serotonin receptor, with a Ki value of 0.7 μM. Interestingly, some of the compounds described here showed impressive antioxidant potential. Of mention, compounds 1, 6, 7, and 23 had trolox/equivalent ORAC values of 9.10, 8.80, 8.82, and 9.42, respectively, all of them being significantly higher than the TE determined for ferulic acid (3.74), a standard antioxidant. Among all molecules synthesized and tested, compound 23 can be regarded as an interesting low-micromolar MAO−B/5-HT6 dual inhibitor lead with potent antioxidant properties.

Cis lipids can be converted by thiols and free radicals into trans lipids, which are therefore a valuable tell-tale for free radical activity in the cell's lipidome. Our previous studies have shown that polyunsaturated lipids are isomerized by alkahethiy1 radicals (S-center dot) in a cycle propagated by reversible double-bond addition and terminated by radical H-abstraction from the lipid. A critical flaw in this picture has long been that the reported lipid abstraction rate from radiolysis studies is faster than addition-isomerization, implying that the "cycle" must be terminating faster than it is propagating! Herein, we resolved this longstanding puzzle by combining a detailed product analysis, with reinvestigation of the time-resolved kinetics, DFT calculations of the indicated pathways, and reformulation of the radical-stasis equations. We have determined thiol-coupled products in dilute solutions arise mainly from addition to the inside position of the bisallylic followed by rapid intramolecular H-center dot transfer, yielding allylic radicals (L-zz + S-center dot reversible arrow SL center dot SLR'(center dot)) that are slowly reduced by thiol (SL'(center dot) + SH -> SL'H + S-center dot). The first-order grow-in rate of the L--H(center dot). signal (k(exp)(280nm)) may therefore be dominated by the addition-H-translocation rather than slower direct H-center dot-abstraction. Steady-state kinetic analysis of the new mechanism is consistent with products and the rates and trends for polyunsaturated fatty acids (PUFAs), monounsaturated fatty acids (MUFAs), and mixtures, with and without physiological [O-2]. Implications of this new paradigm for the thiol-ene reactivity fall in an interdisciplinary research area spanning from synthetic applications to metabolomics.

Mannose glyco-oligoamide β-D-Man-Py-γ-Py-Ind (β-D-Man, 1) and two new glyco-oligoamides, β-L-Man-Py-γ-Py-Ind (β-L-Man, 2) and 6-deoxy-β-D-Man-Py-γ-Py-Ind (6-deoxy-β-D-Man, 3), have been designed and synthesized to investigate the role of hydrogen-bonding cooperative donor centres of carbohydrates in their recognition by DNA. The free- and bound-state geometries were studied, as were the affinities of the D and L enantiomers of the mannose glyco-oligoamides (1 and 2) for DNA polymers [ct-DNA and poly(dA-dT)2]. TR-NOESY and DF-STD experiments for the diastereomeric complexes formed with DNA allow the asymmetric centres of the sugar residue that are close to the inner and outer regions of the DNA minor grooves to be distinguished. A CN hairpin folding in β-L-Man derivative 2 was observed, with the α face of the sugar close to the indole ring. The C-2 and C-3 centres are orientated towards the inner region of the DNA minor groove. The affinity data for poly(dA-dT)2 indicate that there is a chiral discrimination process, with β-L-Man derivative 2 being the best ligand. 6-Deoxy-β-D-Man derivative 3 forms the least stable complexes with DNA. Molecular dynamics simulations of β-L-Man derivative 2 in complex with a double-strand dodecamer d(AT)12 are in agreement with the experimental NMR spectroscopic data. Thus, the cooperative donor centre 2-OH in the L-mannose enantiomer is a key contributor to the stability of the 2·poly(dA-dT)2 complex.

The search for synthetic selective compounds for G-protein-coupled receptors has provided a myriad of molecules with high selectivity and therapeutic potential. In some cases, however, selectivity is difficult to obtain. For instance, the selectivity ratio is relatively low for compounds acting on D and D dopamine receptors, which are targets of neurodegenerative diseases such as Parkinson's and Huntington's. From a therapeutic point of view, it is of interest the relative recent discovery of biased agonism, which is characterized by different signaling pathways engaged by different compounds acting on a given receptor. The aim of this paper was to investigate whether new piribedil-derived compounds could display higher selectivity for D or D receptor and/or provide biased signaling. The results show that selectivity was not different, but that one of the molecules described here, 5-((4-(pyrimidin-2-yl)piperazin-1-yl)methyl)quinolin-8-ol (10), does engage Gi-mediated signaling via D or D receptors, whereas it does not activate the mitogen-activated-protein kinase pathway, which is usually activated by dopamine receptor agonists.

The reaction of racemic 2-amino-4H-pyrans, such as 3-amino-1-aryl-1H-benzo[f]chromene-2-carbonitriles, with N-bromosuccinimide (NBS), in CH2 Cl2, at room temperature, is a very quick, regio, stereoselective, and high yielding process, affording major racemic (1S,2S)-2-bromo-3-imino-benzo[f]chromene or racemic (1S,2S)-2-bromo-3-(bromoimino)-benzo[f]chromene derivatives, when using 1.0 or 2.2 equivalents of NBS, respectively. This reaction, extended to isomeric 2-amino-4-aryl-4H-benzo[h]chromene-3-carbonitriles, showed an unexpected reactivity, affording racemic (3S,4S)-3-bromo-2-(bromoimino)-benzo[h]chromene-3-carbonitriles or 2-oxo-2H-benzo[h]chromene-3-carbonitriles, when using 2.2 or 1.0 equivalents of NBS, respectively. The reaction of alkyl 6-amino-5-cyano-2-methyl-4H-pyran-3-carboxylates has yielded unstable racemic (3S,4S)-alkyl 3-bromo-2-(bromoimino)-3-cyano-6-methyl-3,4-dihydro-2H-pyran-5-carboxylates. The mechanism of these reactions has been investigated by computational methods.

The design, synthesis, and pharmacological evaluation of donepezil-indolyl based amines 7-10, amides 12-16, and carboxylic acid derivatives 5 and 11, as multipotent ASS234 analogs, able to inhibit simultaneously cholinesterase (ChE) and monoamine oxidase (MAO) enzymes for the potential treatment of Alzheimer's disease (AD), is reported. Theoretical studies using 3D-Quantitative Structure-Activity Relationship (3D-QSAR) was used to define 3D-pharmacophores for inhibition of MAO A/B, AChE, and BuChE enzymes. We found that, in general, and for the same substituent, amines are more potent ChE inhibitors (see compounds 12, 13versus7 and 8) or equipotent (see compounds 14, 15versus9 and 10) than the corresponding amides, showing a clear EeAChE inhibition selectivity. For the MAO inhibition, amides were not active, and among the amines, compound 14 was totally MAO A selective, while amines 15 and 16 were quite MAO A selective. Carboxylic acid derivatives 5 and 11 showed a multipotent moderate selective profile as EeACE and MAO A inhibitors. Propargylamine 15 [N-((5-(3-(1-benzylpiperidin-4-yl)propoxy)-1-methyl-1H-indol-2-yl)methyl) prop-2-yn-1-amine] resulted in the most potent hMAO A (IC50 = 5.5 ± 1.4 nM) and moderately potent hMAO B (IC50 = 150 ± 31 nM), EeAChE (IC50 = 190 ± 10 nM), and eqBuChE (IC 50 = 830 ± 160 nM) inhibitor. However, the analogous N-allyl and the N-morpholine derivatives 16 and 14 deserve also attention as they show an attractive multipotent profile. To sum up, donepezil-indolyl hybrid 15 is a promising drug for further development for the potential prevention and treatment of AD. © 2014 Elsevier B.V.

The reaction of 4-amino-5,5-dimethyl-5H-1,2-oxathiole 2,2-dioxide (1) with 2-(arylidene)malononitriles 2 in ethanol, at reflux, using piperidine as catalyst, afforded 5-amino-3,3-dimethyl-7-aryl-3H-[1,2]oxathiolo[4,3-b]pyridine-6-carbonitrile 1,1-dioxides (3) in moderate chemical yields.

Amyloid beta (Aβ ) aggregation and deposition is a key pathological hallmark of AD. Growing evidence suggests that neurotoxicity of this peptide is related to the formation of toxic oligomeric aggregates. Therefore, a deeply investigated therapeutic strategy comes at present from blocking the formation of these species to non-toxic aggregates. Among other considered strategies, the multi-target approach has been proposed as a more suitable potential therapy, precisely due to the multifactorial nature of AD. In this context, we recently identified ASS234, a novel compound that possesses a significant multipotent profile since it is able to inhibit cholinesterase and monoamine oxidase enzymes as well as to interfere in Aβ aggregation process. In this work, we investigated more in detail the effects of ASS234 on Aβ aggregation and toxicity in vitro as well as we explored its ability to penetrate to the CNS. We report that ASS234 inhibited Aβ 1-42 self-aggregation more efficiently than that of Aβ 1-40 , limiting the formation of fibrillar and oligomeric species. Additionally, ASS234 completely blocked the aggregation mediated by AChE of both Aβ 1-42 and Aβ 1-40 , showing a dual binding site to AChE. Interestingly, ASS234 significantly reduced A β 1-42 -mediated toxicity in SH-SY5Y human neuroblastoma cells through the prevention of the mitochondrial apoptosis pathway activation. Also importantly, we observed a significant ability of ASS234 to capture free-radical species in vitro as well as a potent effect in preventing the Aβ 1-42 -induced depletion of antioxidant enzymes (catalase and SOD-1). Finally, we report the capability of ASS234 to cross the bloodbrain barrier. Overall, our in vitro results show that ASS234 may have an impact on different processes involved in AD pathogenesis and provide evidences that it has encouraging attributes as a therapeutic lead compound.

ITH12246 (ethyl 5-amino-2-methyl-6,7,8,9-tetrahydrobenzo[b][1,8] naphthyridine-3-carboxylate) is a 1,8-naphthyridine described to feature an interesting neuroprotective profile in in vitro models of Alzheimer's disease. These effects were proposed to be due in part to a regulatory action on protein phosphatase 2A inhibition, as it prevented binding of its inhibitor okadaic acid. We decided to investigate the pharmacological properties of ITH12246, evaluating its ability to counteract the memory impairment evoked by scopolamine, a muscarinic antagonist described to promote memory loss, as well as to reduce the infarct volume in mice suffering phototrombosis. Prior to conducting these experiments, we confirmed its in vitro neuroprotective activity against both oxidative stress and Ca2+ overload-derived excitotoxicity, using SH-SY5Y neuroblastoma cells and rat hippocampal slices. Using a predictive model of blood-brain barrier crossing, it seems that the passage of ITH12246 is not hindered. Its potential hepatotoxicity was observed only at very high concentrations, from 0.1 mM. ITH12246, at the concentration of 10 mg/kg i.p., was able to improve the memory index of mice treated with scopolamine, from 0.22 to 0.35, in a similar fashion to the well-known Alzheimer's disease drug galantamine 2.5 mg/kg. On the other hand, ITH12246, at the concentration of 2.5 mg/kg, reduced the phototrombosis-triggered infarct volume by 67%. In the same experimental conditions, 15 mg/kg melatonin, used as control standard, reduced the infarct volume by 30%. All of these findings allow us to consider ITH12246 as a new potential drug for the treatment of neurodegenerative diseases, which would act as a multifactorial neuroprotectant.

Background: The heterogeneity of Alzheimer disease requires the development of multitarget drugs for treating the symptoms of the disease and its progression. Both cholinergic and monoamine oxidase dysfunctions are involved in the pathological process. Thus, we hypothesized that the development of therapies focused on these targets might be effective. We have developed and assessed a new product, coded ASS234, a multipotent acetyl and butyrylcholinesterase/monoamine oxidase A–B inhibitor with a potent inhibitory effect on amyloid-β aggregation as well as antioxidant and antiapoptotic properties. But there is a need to reliably correlate in vitro and in vivo drug release data. Methods: We examined the effect of ASS234 on cognition in healthy adult C57BL/6J mice in a model of scopolamine-induced cognitive impairment that often accompanies normal and pathological aging. Also, in a characterized transgenic APPswe/PS1ΔE9 mouse model of Alzheimer disease, we examined the effects of short-term ASS234 treatment on plaque deposition and gliosis using immunohistochemistry. Toxicology of ASS234 was assessed using a quantitative high-throughput in vitro cytotoxicity screening assay following the MTT assay method in HepG2 liver cells. Results: In vivo, ASS234 significantly decreased scopolamine-induced learning deficits in C57BL/6J mice. Also, reduction of amyloid plaque burden and gliosis in the cortex and hippocampus was assessed. In vitro, ASS234 exhibited lesser toxicity than donepezil and tacrine. Limitations: The study was conducted in male mice only. Although the Alzheimer disease model does not recapitulate all features of the human disease, it exhibits progressive monoaminergic neurodegeneration. Conclusion: ASS234 is a promising alternative drug of choice to treat the cognitive decline and neurodegeneration underlying Alzheimer disease.

We report herein the silver-catalyzed cycloisomerization of readily available N-(prop-2-yn-1-yl)pyridine-2-amines as a new and practical method for the synthesis of differently substituted 3-methylimidazo[1,2-a]pyridines. The isomerization reactions proceeded under mild reactions conditions to give good yields and excellent regioselectivity. A DFT-based mechanistic analysis is also reported.

A simple, quick, and high-yielding microwave-assisted synthesis of 2-(N,N-dimethyl)amine- and 2-aminopyridine derivatives is reported here for the first time in the reaction of 2-chloro substituted pyridines with amide solvents such as dimethylformamide or formamide, without transition-metal catalysts.

The synthesis and pharmacological analyses of a number of pyrazolo[3,4-b]quinoline and benzo[b]pyrazolo[4,3-g][1,8]naphthyridine derivatives are reported. We have synthesized the diversely substituted tacrine analogues 1-6, by Friedländer-type reaction of readily available o-amino-1-methyl-pyrazole-dicarbonitriles with cyclohexanone. The biological evaluation showed that pyrazolotacrines 1-6 are inhibitors of Electrophorus electricus acetylcholinesterase (EeAChE), in the micromolar range, and quite selective in respect to serum horse butyrylcholinesterase (eqBuChE) inhibition; the most interesting inhibitor is N-(5-amino-1-methyl-6,7,8,9-tetrahydro-1H- benzo[b]pyrazolo[4,3-g][1,8]naphthyridin-3-yl)acetamide (5) [IC50 (EeAChE) = 0.069 ± 0.006 μM; IC50 (eqBuChE) = 6.3 ± 0.6 μM]. Kinetic studies showed that compound 5 is a mixed-type inhibitor of EeAChE (Ki = 155 nM). Inhibitor 5 showed a 45% neuroprotection value against rotenone/oligomycin A-induced neuronal death. © 2011 Elsevier Masson SAS. All rights reserved., We thank V. Gómez and L. González-Lafuente for technical support. D. Silva thanks Fundação para a Ciência e Tecnologia do Ministério da Ciência, Tecnologia e Ensino Superior of Portugal for his grant belonging to project PTDC/SAU-NEU/64151/2006. M. Chioua thanks Instituto de Salud Carlos III (MICINN) for a “Sara Borrell” post-doctoral contract. JMC thanks MICINN (SAF2006-08764-C02-01; SAF2009-07271) financial support. MGL thanks MICINN Ref. SAF2009-12150. DS thanks COST Action D34. This work was partly supported by grants RD06/0026/1002 (RENEVAS), ISCIII, MICINN, S/SAL-0275-2006, Comunidad de Madrid, and Fundación CIEN, project 1004040042. JMC thanks Prof. A. García for his continuous interest and support

The synthesis and pharmacological evaluation of racemic 14-aryl-10,11,12,14-tetrahydro-9H-benzo[5,6]chromeno[2,3-b]quinolin-13-amines (19-28), prepared by Friedländer reaction of 3-amino-1-aryl-1H-benzo[f]chromene-2-carbonitriles (10-18) with suitable cycloalkanones is described. These molecules are potent, in the nanomolar range [IC(50) (EeAChE)=7-101 nM], and selective inhibitors of acetylcholinesterase (AChE). The most potent inhibitor, 4-(13-amino-10,11,12,14-tetrahydro-9H-benzo[5,6]chromeno[2,3-b]quinolin-14-yl)phenol (20) [IC(50) (EeAChE)=7±2 nM] is four-fold more active than tacrine. Kinetic studies on compound 20 showed that this is a mixed-type inhibitor of EeAChE with a K(i) of 5.00 nM. However, racemic 20 was unable to displace propidium iodide, suggesting that the inhibitor does not strongly bind to the peripheral anionic site (PAS) of AChE. Docking, molecular dynamics stimulations, and MM-GBSA calculations agree well with this behavior.

The synthesis, biological assessment, and molecular modelling of new tacrine analogues 11–22 is described. Compounds 11–22 have been obtained by Friedlander-type reaction of 2-aminopyridine-3-carbonitriles 1–10 with cyclohexanone or 1-benzyl-4-piperidone. The biological evaluation showed that some of these molecules were good AChE inhibitors, in the nanomolar range, and quite selective regarding the inhibition of BuChE, the most potent being 5-amino-2-(dimethylamino)-6,7,8,9-tetrahydrobenzo[1,8-b]-naphthyridine-3-carbonitrile (11) [IC50 (EeAChE: 14 nM); IC50 (eqBuChE: 5.2 μM]. Kinetic studies on the easily available and potent anticholinesterasic compound 5-amino-2-(methoxy)-6,7,8,9-tetrahydrobenzo[1,8-b]-naphthyridine-3-carbonitrile (16) [IC50 (EeAChE: 64 nM); IC50 (eqBuChE: 9.6 μM] showed that this compound is a mixed-type inhibitor (Ki = 69.2 nM) of EeAChE. Molecular modelling on inhibitor 16 confirms that this compound, as expected and similarly to tacrine, binds at the catalytic active site of EeAChE. The neuroprotective profile of molecules 11–22 has been investigated in SH-SY5Y neuroblastoma cells stressed with a mixture of oligomycin-A/rotenone. Compound 16 was also able to rescue by 50% cell death induced by okadaic acid in SH-SY5Y cells. From these results we conclude that the neuroprotective profile of these molecules is moderate, the most potent being compounds 12 and 17 which reduced cell death by 29%. Compound 16 does not affect ACh- nor K+-induced calcium signals in bovine chromaffin cells. Consequently, tacrine analogues 11–22 can be considered attractive therapeutic molecules on two key pharmacological targets playing key roles in the progression of Alzheimer, that is, cholinergic dysfunction and oxidative stress, as well as in neuronal cerebrovascular diseases.

An unexpected, but simple method for the efficient synthesis of new 2.2′-azopyridine dyes, such as (E)-diethyl 6,6′-(diazene-1,2-diyl)bis(5-cyano-2-methyl-4-phenylnicotinates) (2, 4, 6, 8, 10, and 12), based on the treatment of ethyl 6-amino-5-cyano-2-methyl-4-arylnicotinates (1, 3, 5, 7, 9, and 11) with NBS/benzoyl peroxide, is described. The X-ray diffraction analysis and the UV–vis absorption spectra of dye 2 are reported and discussed.

Various imidates 3 were successfully synthesized from naphthopyrans and ethyl orthoesters in moderate yields. These intermediates undergo rapid condensation with several primary amines to give the corresponding 11-aryl-1,12-dihydro-11H-naphthopyrano[2,3-d] pyrimidin-12-ones 4.

The Sandmeyer reaction on some selected heterocyclesbearing the 2-amino-3-carbonitrile structural moiety has been in-vestigated in order to prepare the corresponding 2-chloro-3-carbo-nitrile derivatives as synthetic useful intermediates for furtherdevelopment. Key words: Sandmeyer reaction, 2-amino(heterocyclic)-3-carbo-nitriles, 2-aminopyrazoles, 2-aminooxazoles, 2-amino-4 H -pyrans,2-amino-1,4-dihydropyridines, 2-aminopyridines, 2-chloro(hetero-cyclic)-3-carbonitriles In the context of a current project in progress in our labo-ratory for the synthesis of pharmacological active com-pounds, 1 we have recently synthesized some differentlysubstituted 2-chloropyridine-3-carbonitrile intermediates I by Sandmeyer reaction 2 of easily available 2-aminopyri-dine derivatives II (Scheme 1). Eventually, intermediates I could also be prepared by reaction with sodium nitrite inhydrochloric acid, 3 or by reaction with phosphorus oxy-chloride from 2-pyridones III . 4 Scheme 1 2-Chloro(heterocyclic)-3-carbonitriles are well known,useful synthetic intermediates in heterocyclic chemistrythat have been transformed into complex and more ad-vanced heterocyclic compounds.

1,8-Naphthyridine derivatives related to 17 (ITH4012), a neuroprotective compound reported by our research group, have been synthesized. In general, they have shown better inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) than most tacrine derivatives previously synthesized in our laboratory. The compounds presented an interesting neuroprotective profile in SH-SY5Y neuroblastoma cells stressed with rotenone/oligomycin A. Moreover, compound 14 (ethyl 5-amino-2-methyl-6,7,8,9-tetrahydrobenzo[b][1,8]naphthyridine-3-carboxylate) also caused protection in cells stressed with okadaic acid (OA) or amyloid beta 1-42 peptide (Abeta(1-42)). Interestingly, compound 14 prevented the OA-induced PP2A inhibition, one of the enzymes implicated in tau dephosphorylation. This compound also exhibited neuroprotection against neurotoxicity elicited by oxygen and glucose deprivation in hippocampal slices. Because these stressors caused neuronal damage related to physiopathological hallmarks found in the brain of Alzheimer's disease (AD) patients, we conclude that compound 14 deserves further in vivo studies in AD models to test its therapeutic potential in this disease.

The synthesis of new 7-azabicyclo[2.2.1]heptane derivatives has been achieved in a four-step synthetic sequence, starting from readily available cyclohex-3-enecarboxylic acid, Curtius reaction, stereoselective bromination leading to major benzyl(cis-3,trans-4-dibromocyclohex-1yl)carbamates (amides or sulfonamides), followed by NaH-mediated intramolecular cyclization. The synthesis and free radical cyclization of precursors 4-7, as well as the synthesis of a conformationally constrained epibatidine analogue 3 exploiting the reactivity of the 7azabicyclo[2.2.1]hept-2-yl radical in intramolecular reactions, are described. The N-sulfonyl functional motif is the only one to afford a cyclized product when incorporated in the radical precursor.

This document is the accepted manuscript version of a Published Work that appeared in final form in ACS Chemical Neuroscience 7.8, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see DOI: 10.1021/acschemneuro.6b00122, A series of multitarget directed propargylamines, as well as other differently susbstituted piperidines have been screened as potential modulators of neuronal nicotinic acetylcholine receptors (nAChRs). Most of them showed antagonist actions on α7 nAChRs. Especially, compounds 13, 26, and 38 displayed submicromolar IC50 values on homomeric α7 nAChRs, whereas they were less effective on heteromeric α3β4 and α4β2 nAChRs (up to 20-fold higher IC50 values in the case of 13). Antagonism was concentration dependent and noncompetitive, suggesting that these compounds behave as negative allosteric modulators of nAChRs. Upon the study of a series of less complex derivatives, the N-benzylpiperidine motif, common to these compounds, was found to be the main pharmacophoric group. Thus, 2-(1-benzylpiperidin-4-yl)-ethylamine (48) showed an inhibitory potency comparable to the one of the previous compounds and also a clear preference for α7 nAChRs. In a neuroblastoma cell line, representative compounds 13 and 48 also inhibited, in a concentration-dependent manner, cytosolic Ca2+ signals mediated by nAChRs. Finally, compounds 38 and 13 inhibited 5-HT3A serotonin receptors whereas they had no effect on α1 glycine receptors. Given the multifactorial nature of many pathologies in which nAChRs are involved, these piperidine antagonists could have a therapeutic potential in cases where cholinergic activity has to be negatively modulated., This work was supported by grants SAF2011-22802 to S.S., SAF2012-33304 to J.M.-C., CSD2008-00005 (the Spanish Ion Channel Initiative-CONSOLIDER INGENIO 2010) to M.C. from the Spanish Ministry of Science and Innovation (Ministerio de Economía y Competitividad).

A careful study of the linoleic acid hydroperoxide (LOOH) profile obtained upon peroxidation of linoleic acid (LA) photosensitized by tiaprofenic acid (TPA) and analogous ketones has been undertaken to distinguish between type-I and type-II photoperoxidation mechanisms. 1,4-Cyclohexadiene and 1,2-dimethylcyclohexa-2,5-dienecarboxylic acid (CHDCA) have also been used as models for LA since they also have double allylic systems. Coirradiation of LA with TPA and decarboxytiaprofenic acid (DTPA) in acetonitrile and micellar media produced significant amounts of conjugated dienic LOOH. The cis,trans to trans,trans ratio depended on the irradiation time; thus, this parameter is an ambiguous tool for mechanistic assignment. An interesting finding was the decrease of the LOOH level after long irradiation times in mixtures photooxidized by DTPA, which is attributed to quenching of the DTPA triplet by the generated dienic LOOH. High-performance liquid chromatography analyses confirmed that the main pathway operating in photodynamic lipid peroxidation sensitized by (D)TPA is a type-I mechanism. However, product studies using CHDCA have clearly shown that a type-II mechanism is also operating and might contribute to the overall photooxidation process in a significant way.

The reaction of 4-amino-5,5-dimethyl-5H-1,2-oxathiole 2,2-dioxide (1) with 2-(arylidene)malononitriles 2 in ethanol, at reflux, using piperidine as catalyst, afforded 5-amino-3,3-dimethyl-7-aryl-3H-[1,2]oxathiolo[4,3-b]pyridine-6-carbonitrile 1,1-dioxides (3) in moderate chemical yields.

On the basis of N-((5-(3-(1-benzylpiperidin-4-yl)propoxy)-1-methyl-1H-indol-2-yl)methyl)-N-methylprop-2-yn-1-amine (II, ASS234) and QSAR predictions, in this work we have designed, synthesized, and evaluated a number of new indole derivatives from which we have identified N-methyl-N-((1-methyl-5-(3-(1-(2-methylbenzyl)piperidin-4-yl)propoxy)-1H-indol-2-yl)methyl)prop-2-yn-1-amine (2, MBA236) as a new cholinesterase and monoamine oxidase dual inhibitor.

The synthesis, biochemical evaluation, ADMET, toxicity and molecular modeling of novel multi-target-directed Donepezil + Propargylamine + 8-Hydroxyquinoline (DPH) hybrids 1-7 for the potential prevention and treatment of Alzheimer's disease is described. The most interesting derivative was racemic α-aminotrile4-(1-benzylpiperidin-4-yl)-2-(((8-hydroxyquinolin-5-yl) methyl)(prop-2-yn-1-yl)amino) butanenitrile (DPH6) [MAO A (IC50 = 6.2 ± 0.7 μM; MAO B (IC50 = 10.2 ± 0.9 μM); AChE (IC50 = 1.8 ± 0.1 μM); BuChE (IC50 = 1.6 ± 0.25 μM)], an irreversible MAO A/B inhibitor and mixed-type AChE inhibitor with metal-chelating properties. According to docking studies, both DPH6 enantiomers interact simultaneously with the catalytic and peripheral site of EeAChE through a linker of appropriate length, supporting the observed mixed-type AChE inhibition. Both enantiomers exhibited a relatively similar position of both hydroxyquinoline and benzyl moieties with the rest of the molecule easily accommodated in the relatively large cavity of MAO A. For MAO B, the quinoline system was hosted at the cavity entrance whereas for MAO A this system occupied the substrate cavity. In this disposition the quinoline moiety interacted directly with the FAD aromatic ring. Very similar binding affinity values were also observed for both enantiomers with ChE and MAO enzymes. DPH derivatives exhibited moderate to good ADMET properties and brain penetration capacity for CNS activity. DPH6 was less toxic than donepezil at high concentrations; while at low concentrations both displayed a similar cell viability profile. Finally, in a passive avoidance task, the antiamnesic effect of DPH6 was tested on mice with experimentally induced amnesia. DPH6 was capable to significantly decrease scopolamine-induced learning deficits in healthy adult mice. © 2014 Elsevier Masson SAS. All rights reserved.

The pharmacological analysis of racemic chromenotacrines (CT) 1-7, bearing the 11-amino-12-aryl-8,9,10,12-tetrahydro-7H-chromeno[2,3-b]quinolin-3-ol ring skeleton, in a series of experiments targeted to explore their potential use for the treatment of Alzheimer's disease (AD), is reported. The toxicological evaluation showed that among all these chromenotacrines, CT6 is much less hepatotoxic than tacrine in a range of concentrations from 1 to 300 μM, measured as cell viability in HepG2 cells. Moreover, CT6 did not significantly increase lactate dehydrogenase, aspartate transaminase, and alanine transaminase release in HepG2 cells. Besides, CT6 treatment exerts a high protective effect against the lipid peroxidation induced after H2O2-treated SH-SY5Y cells, in a concentration-dependent manner. CT6 showed an excellent antioxidant profile in the AAPH test, and protects against the decrease in cell viability induced by respiratory chain inhibitors (Oligomicyn A/Rotenone) and NO donors in neuronal cultures. This effect could be due to a mixed antiapoptotic and antinecrotic neuroprotective effect at low and intermediate CT6 concentrations, respectively. CT1-7 are potent and selective inhibitors of EeAChE in the submicromolar range. CT3 [IC50 (EeAChE) = 0.007 ± 0.003 μM], and CT6 [IC50 (EeAChE) = 0.041 ± 0.001 μM] are the most potent AChE inhibitors. Kinetic studies on the non-toxic chromenotacrine CT6 showed that this compound behaves as a non-competitive inhibitor (Ki = 0.047 ± 0.003 μM), indicating that CT6 binds at the peripheral anionic site, a fact confirmed by molecular modeling analysis. In silico ADMET analysis showed also that CT6 should have a moderate BBB permeability. Consequently, non-toxic chromenotacrine CT6 can be considered as an attractive multipotent molecule for the potential treatment of AD. © 2014 Elsevier Masson SAS. All rights reserved.