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A new set of 5-(2-(pyrrolidin-1-yl)acetamido)- N -butyl-2-(substituted)benzamide and 5-(2-(piperidin-1-yl)acetamido)- N -butyl-2-(substituted) benzamide derivatives were synthesized in which as structural features the 2-(1-pyrrolidinyl)- or 2-(1-piperidyl)acetylamino group or a diphenylether moiety are associated to a benzamide scaffold. Their binding affinity for human PrP C and inhibition of its conversion into PrP Sc were determined in vitro; moreover, the antiprion activity was assayed by inhibition of PrP Sc accumulation in scrapie-infected mouse neuroblastoma cells (ScN2a) and scrapie mouse brain (SMB) cells. The results clearly indicate the benzamide derivatives as attractive lead compounds for the development of potential therapeutic agents against prion disease.

N'-cyanoisonicotinamidine derivatives, linked to an arylpiperazine moiety, were prepared to identify highly selective and potent 5-HT(1A) ligands as potential pharmacological tools in studies of wide spread psychiatric disorders. The combination of structural elements (heterocyclic nucleus, alkyl chain and 4-substituted piperazine) known to be critical in order to have affinity on 5-HT(1A) receptor and the proper selection of substituents led to compounds with high specificity and affinity towards serotoninergic receptors. In binding studies, several molecules showed affinity in nanomolar and subnanomolar range at 5-HT(1A) and moderate to no affinity for other relevant receptors (5-HT(2A), 5-HT(2C), D(1), D(2), alpha(1) and alpha(2)). N'-cyano-N-(3-(4-(pyridin-2-yl)piperazin-1-yl)propyl)isonicotinamidine (4o) with K(i)=0.038 nM, was the most active and selective derivative for the 5-HT(1A) receptor with respect to other serotoninergic, dopaminergic and adrenergic receptors.

Protease-activated receptor-1 (PAR-1) is a G-coupled receptor activated by α-thrombin and other proteases. In this paper we describe the synthesis and the pharmacological evaluation of novel peptide-mimetic antagonists (compounds 1 – 16 ) characterized by the presence of new heterocyclic nuclei such as 2-methyl-indole (5- and 6-substituted) and 1,4-benzodiazepine moiety. The new derivatives, tested in order to evaluate their antagonist potency by using human platelet aggregation induced by PAR-1AP, resulted in some cases (compounds 1 and 4 ) more potent than the reference. The compounds, tested on aortic rings, confirmed the results obtained in the aggregation assay.

1,3 Dipolar cycloaddition of Fmoc-amino azides and acetylenic amides produces under solvent free irradiation a mixture of 1,4 or 1,5 substituted [1,2,3]-triazoles. The presence of copper (I) iodide, plays a central role on regioselectivity. Four Fmoc-amino azides characterized by different steric hindrance in side chains, and three different terminal alkynes, provided only the 1,4 substituted regioisomer under thermal microwave heating. Good yields, low consumption of organic solvents and short reaction times are the main aspects of our procedure. Reactions are compared to regioselective copper (I) catalysed solution synthesis performed at room temperature.

A recombinant dengue 2 virus NS2B-NS3 protease (NS means non-structural virus protein) was compared with human furin for the capacity to process short peptide substrates corresponding to seven native substrate cleavage sites in the dengue viral polyprotein. Using fluorescence resonance energy transfer peptides to measure kinetics, the processing of these substrates was found to be selective for the Dengue protease. Substrates containing two or three basic amino acids (Arg or Lys) in tandem were found to be the best, with Abz–AKRRSQ–EDDnp being the most efficiently cleaved. The hydrolysis of dipeptide substrates Bz–X–Arg–MCA where X is a non-natural basic amino acid were also kinetically examined, the best substrates containing aliphatic basic amino acids. Our results indicated that proteolytic processing by dengue NS3 protease, tethered to its activating NS2B co-factor, was strongly inhibited by Ca2+ and kosmotropic salts of the Hofmeister’s series, and significantly influenced by substrate modifications between S4 and View the MathML source. Incorporation of basic non-natural amino acids in short peptide substrates had significant but differential effects on Km and kcat, suggesting that further dissection of their influences on substrate affinity might enable the development of effective dengue protease inhibitors.

Background: Green chemistry is a discipline of great interest in medicinal chemistry. It involves all fields of chemistry and it is based on the principle to conduct chemical reactions protecting the environment at the same time, through the use of chemical procedures able to avoid pollution. In this context, water as solvent is a good choice because it is abundant, nontoxic, non-caustic, and non-combustible. Even if microwave assisted organic reactions in conventional solvents have quickly progressed, in the recent years medicinal chemists have focused their attention to processes deemed not dangerous for the environment, using nanotechnology and greener solvents as water. Objective: Several reports of reaction optimizations and selectivities, demonstrating the capability of microwave to allow the obtaining of increased yields have been recently published using water as solvent. In this review, we selected the available knowledge related to microwave assisted organic synthesis in aqueous medium, furnishing examples of the newest strategies to obtain useful scaffolds and novel derivatives for medicinal chemistry purposes. Conclusion: The intention of this review is to demonstrate the exclusive ability of MAOS in water as solvent or as co-solvent. For this purpose we report here the most representative applications of MAOS using water as solvent, focusing on medicinal chemistry processes leading to interesting nitrogen containing heterocycles with potential pharmaceutical applications.

Background: Protease activated receptor-1 (PAR1) is a G-coupled receptor activated by α-thrombin and other proteases. Several reports have demonstrated the PAR1 involvement in tumorigenesis and tumor progression. In order to investigate on potential use of PAR1 antagonists as antiproliferative agents. Aims: We have identified a series of arylpiperazine derivatives acting as PAR1 antagonists; the selected molecules have been evaluated for their antiproliferative properties. Method: All the compounds inhibited the growth of a panel of cell lines expressing PAR1; two of them, compounds 13 and 15, were able to inhibit, in a dose dependent manner, the growth of the selected cell lines with the lowest IC50 values, and were further characterized to define the mechanism responsible for the observed antiproliferative effect. Result: This study directed us to the identification of two interesting leads that may help to further validate PAR1 as an important therapeutic target for cancer treatment.

A series of protease activated receptor 2 activating peptide (PAR2-AP) derivatives (1–15) were designed and synthesized. The obtained compounds were tested on a panel of human kallikreins (hKLK1, hKLK2, hKLK5, hKLK6, and hKLK7) and were found completely inactive toward hKLK1, hKLK2, and hKLK7. Aiming to investigate the mode of interaction between the most interesting compounds and the selected hKLKs, docking studies were performed. The described compounds distinguish the different human tissue kallikreins with compounds 1 and 5 as the best hKLK5 and hKLK6 inhibitors, respectively.

H(2)S functions as a neuromodulator and exerts anti-inflammatory activities. Recent data indicate that irritable bowel syndrome (IBS) is linked to inflammation of the gastrointestinal tract. In this study, we have investigated the role of a novel H(2)S-releasing derivative of mesalamine (5-amino-2-hydroxybenzoic acid 4-(5-thioxo-5H-[1,2]dithiol-3yl)-phenyl ester, ATB-429) in modulating nociception to colorectal distension (CRD), a model that mimics some features of IBS, in healthy and postcolitic rats. Four graded (0.4-1.6 ml of water) CRDs were produced in conscious rats, and colorectal sensitivity and pain were assessed by measuring the abdominal withdrawal response and spinal c-Fos expression. In healthy rats, ATB-429 dose dependently (25, 50, or 100 mg/kg) attenuated CRD-induced hypersensitivity and significantly inhibited CRD-induced overexpression of spinal c-FOS mRNA, whereas mesalamine had no effect. ATB-429-induced antinociception was reversed by glibenclamide, a ATP-sensitive K(+) (K(ATP)) channel inhibitor. The antinociceptive effect of ATB-429 was maintained in a rodent model of postinflammatory hypersensitivity (4 weeks after colitis induction). At a dose of 100 mg/kg, ATB-429 reversed the allodynic response caused by CRD in postcolitic rats. Colonic cyclooxygenase-2 and interkeukin-1beta mRNA and spinal c-FOS mRNA expression were significantly down-regulated by ATB-429, but not by mesalamine. ATB-429, but not mesalamine, increased blood concentrations of H(2)S in both healthy and postcolitic rats. Taken together, these data suggest that ATB-429 inhibits hypersensitivity induced by CRD in both healthy and postcolitic, allodynic rats by a K(ATP) channel-mediated mechanism. This study provides evidence that H(2)S-releasing drugs might have beneficial effects in the treatment of painful intestinal disorders.

Heterocyclic compounds hold a special place among pharmaceutically important natural and synthetic materials. The remarkable ability of heterocyclic nuclei to serve both as biomimetics and reactive pharmacophores has largely contributed to their unique value as traditional key elements of numerous drugs. In both lead identification and optimization processes there is an acute need for new organic small molecules. Traditional methods of organic synthesis are orders of magnitude too slow to satisfy the demand for these compounds; so, the fields of combinatorial and automated medicinal chemistry have been developed to meet the increasing requirement of new compounds for drug discovery, within these fields, speed is of the essence. The efficiency of microwave flash-heating chemistry in dramatically reducing reaction times (reduced from days and hours to minutes and seconds) has recently been proven in several different fields of organic chemistry. We believe that the time saved by using focused microwaves is potentially important in traditional organic synthesis but could be of even greater importance in high-speed combinatorial and medicinal chemistry. In this review, it is impossible to cover all significant developments in the area of microwave-assisted organic synthesis (MAOS). Rather, outlines the basic principles behind the technology and summarizes the areas in which microwave technology has made an impact, to date. Specific attention is given to application of microwave technology in Combinatorial Organic Synthesis of several representative biologically interesting nuclei obtained both in liquid systems and in the solid state.

An efficient, facile, and practical parallel combinatorial synthesis of substituted-benzoxazines under microwave irradiation was described. The procedure involved the use of a microwave oven especially designed for organic synthesis suitable for parallel synthesis of solution libraries. A demonstration 19-membered library of substituted N,N-dimethyl- and N-methyl-benzoxazine amide derivatives, structurally related to the potassium channel opener cromakalim, was generated by both conventional and microwave procedures, achieving a reduction from 7 h to 30-36 min in library generation time for the microwave approach. All the synthesized compounds were tested using the in vitro models of rat aorta and guinea pig trachea rings pre-contracted with phenylephrine and carbachol, respectively. All N,N-dimethyl amide derivatives showed a relaxant activity higher on guinea pig trachea rings than on rat aorta rings.

In the present paper, the role played by Na+/Ca2+ exchanger (NCX) in focal cerebral ischemia was investigated. To this aim, permanent middle cerebral artery occlusion (pMCAO) was performed in male rats. The effects on the infarct volume of some inhibitors, such as tyrosine-6 glycosylated form of the exchanger inhibitory peptide (GLU-XIP), benzamil derivative (CB-DMB) and diarylaminopropylamine derivative (bepridil), and of the NCX activator, FeCl3, were examined. FeCl3, CB-DMB, bepridil and GLU-XIP, a modified peptide synthesized in our laboratory in order to facilitate its entrance into the cells through the glucose transporter, were intracerebroventricularly (icv) infused. FeCl3 (10 μg/kg) was able to reduce the extenson of brain infarct volume. This effect was counteracted by the concomitant icv administration of CB-DMB (120 μg/kg). All NCX inhibitors, GLU-XIP, CB-DMB and bepridil, caused a worsening of the brain infarct lesion. These results suggest that a stimulation of NCX activity may help neurons and glial cells that are not irreversibly damaged in the penumbral zone to survive, whereas its pharmacological blockade can compromise their survival.

A novel and convenient microwave-assisted synthesis of an active metabolite (EXP-3174) of losartan is described. Room temperature and microwave irradiation of the reactions are compared. Synthesis by microwave irradiation gave the desired compound in higher yields and in shorter reaction times than those obtained at room temperature. © 2003 Elsevier Science Ltd. All rights reserved.

A novel and convenient microwave-assisted dimerization of an active peptide compound using the DKPs as scaffold is described. The key reaction giving rise to the diketopiperazine scaffold is the intermolecular coupling. No epimerization was detected in the reactions used. Conventional and microwave heating of the reactions are compared. Synthesis by microwave irradiation gave the desired compounds in higher yields and in shorter reaction times than those obtained by conventional heating. © 2003 Elsevier Science Ltd. All rights reserved.

Research in the nitric oxide (NO) field has enormously extended in the past 20 years and maintaining an overview of NO research has become very difficult. NO biology has been extensively studied and several aspects of its role in physiology and pathology have been clarified. The final outcome of these researches is that NO is a double edge sword mediator in that it can exert beneficial or detrimental effect depending on the physiopathological context. However, the development of drugs based on these new knowledge has been strongly impaired by these double face of NO. The purpose of this review is to briefly outline the role of this almost ubiquitous mediator and give a state of the art on the development of new drugs based on the NO concept rather than summarising the large number of NO donors that have been synthesised since there are several specific review dealing with this matter. The final picture that comes out by our analysis is that it goes without any doubt that much has still to be done to develop new drugs. Thus, the development of new drugs still represents a challenging task. There has been an enormous interest on nitric oxide (NO) since its discovery and its involvement in many physiological and pathological events has been demonstrated or postulated. Drugs which acts through NO such as the organic nitrates have been used in therapy since many years and it would have been predicted that due to the enormous effort profuse in understanding the biology of NO, new drugs based on all these new findings would have been ready developed. So far this matter has resulted in a challenging task since, as it is summarised below, NO has multiple action that are linked to both beneficial and pathological effect. Thus, in some cases we want to prevent NO production while in other cases we want deliver or increase NO production. This review will briefly addresses some of the major areas of biology where NO has been involved and give an overview of what is the state of the art in developing drugs that works through NO.

KLK7 substrate specificity was evaluated by families of fluorescence resonance energy transfer (FRET) peptides derived from Abz-KLFSSK-Q-EDDnp (Abz=ortho-aminobenzoic acid and Q-EDDnp=glutaminyl-N-[2,4-dinitrophenyl] ethylenediamine), by one bead-one peptide FRET peptide library in PEGA resin, and by the FRET peptide libraries Abz-GXX-Z-XX-Q-EDDnp (Z and X are fixed and random natural amino acids, respectively). KLK7 hydrolyzed preferentially F, Y or M, and its S1' and S2' subsites showed selectivity for hydrophilic amino acids, particularly R and K. This set of specificities was confirmed by the efficient kininogenase activity of KLK7 on Abz-MISLM(↓)KRPPGFSPF(↓)RSSRI-NH2 ((↓)indicates cleavage), hydrolysis of somatostatin and substance P and inhibition by kallistatin. The peptide Abz-NLY(↓)RVE-Q-EDDnp is the best synthetic substrate so far described for KLK7 [kcat/Km=455 (mMs)(-1)] that was designed from the KLK7 substrate specificity analysis. It is noteworthy that the NLYRVE sequence is present in human semaphorin 6B. KLK7 is activated by GAGs, inhibited by neutral salts, and activated by high concentration of kosmotropic salt. Pyroglutamic acid inhibited KLK7 (Ki=33mM) and is present in skin moisturizing factor (124mM). The KLK7 specificity described here and elsewhere reflects its participation in patho-physiological events in skin, the gastrointestinal tract and central nervous system, where KLK7 is significantly expressed.

The serotonin receptor subtype 5-HT(1A) was one of the first serotonin receptor subtypes pharmacologically characterized. This receptor subtype has long been object of intense research and is implicated in the pathogenesis and treatment of anxiety and depressive disorders. In recent years, new chemical entities targeting the 5-HT(1A) receptor (alone or in combination with other molecular targets) have been proposed for novel therapeutic uses in neuroprotection, cognitive impairment, Parkinson's disease, pain treatment, malignant carcinoid syndrome, and prostate cancer. This Perspective compares existing data on expression and signaling activity of the 5-HT(1A) receptor to a ligand with an intrinsic agonist or antagonist profile. Our purpose is also to make a complete overview, useful for underlining the features needed to select a specific pharmacological profile rather than another one. This aspect could be really interesting to consider and justify the 5-HT(1A) receptor as a new attractive target for drug discovery.

2-Methyl-1,4-benzodiazepin-5-ones were synthesized from isatoic anhydrides via cyclization of N-allyl-2-aminobenzamides with application of microwave irradn. Conventional heating and microwave irradn. of the reactions were compared. Synthesis by microwave irradn. gave the desired compds. in better yields than by conventional heating. Overall times for the syntheses were considerably reduced.

Peptide T (ASTTTNYT), a fragment corresponding to residues 185-192 of gp120, the coat protein of HIV, is endowed with several biological properties in vitro, notably inhibition of the binding of both isolated gp120 and HIV-1 to the CD4 receptor, and chemotactic activity. Based on previous nuclear magnetic resonance (NMR) studies performed in our laboratory, which were consistent with a regular conformation of the C-terminal pentapeptide, and SAR studies showing that the C-terminal pentapeptide retains most of the biological properties, we designed eight hexapeptides containing in the central part either the TNYT or the TTNY sequence, and charged residues (D/E/R) at the two ends. Conformational analysis based on NMR and torsion angle dynamics showed that all peptides assume folded conformations, albeit with different geometries and stabilities. In particular, peptides carrying an acidic residue at the N-terminus and a basic residue at the C-terminus are characterized by stable helical structures and retain full chemotactic activity. The solution conformation of peptide ETNYTR displays strong structural similarity to the region 19-26 of both bovine pancreatic and bovine seminal ribonuclease, which are endowed with anti-HIV activity. Moreover, the frequent occurrence, in many viral proteins, of TNYT and TTNY, the two core sequences employed in the design of the hexapeptides studied in the present work, hints that the sequence of the C-terminal pentapeptide TTNYT is probably representative of a widespread viral recognition motif. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.

In lieu of H-Dmt-Tic-OH, H-Dmt-analogues included 2-amino-3(1H-benzoimidazol-2-yl)-propionic acid, N(Bzl)Gly, L-octahydroindole-2-carboxylic acid, [3S-(3alpha,4abeta, 8abeta)]-decahydro-3-isoquinoline carboxylic acid, benzimidazole-, pyridoindole- or spiroinden-derivatives, or C-terminally modified. L- or D-Ala, Sar, or Pro were spacers between aromatic nuclei. Only H-Dmt-(Xaa-)-pyridoindole exhibited high affinities with delta and mu antagonism. The peptides competed equally against [3H]DPDPE (delta agonist) or [3H]N,N(CH3)2-Dmt-Tic-OH (delta antagonist) signaling a single delta binding site. The data confirm the importance of Tic for delta affinity and antagonism, while heterocyclic or heteroaliphatic nuclei, or spacer exert effects on mu- and delta-receptor properties.

Anumber of 1- and 2-(4-arylpiperazinylalkyl)-4-(benzoyl)-1,2,3-triazole derivatives (1–4) were prepared in order to obtain compounds with a high affinity and selectivity for 5-HT 1A receptors. 5-HT 1A, 5-HT 2A and 5-HT 2C affinities were determined by radioligand binding experiments and the most active compounds were also tested for binding affinities on dopaminergic D-1, D-2 and adrenergic α 1 , α 2 receptors. The modification of aromatic substituents, the length of the alkyl chain and its position on the 4-benzoyl-1,2,3-triazole ring were explored. Most of the considered compounds generally showed moderate to high affinity for the 5-HT 1A receptor binding site. Three derivatives 2c , 3c and 3e bind to 5-HT 1A receptors in the nanomolar range (IC 50 values = 2, 7.2 and 2.6 nM respectively). The most active compound, 2c , presented a high degree of selectivity versus all considered receptors. It was found that the benzoyltriazole derivatives 1h and 4c are new selective ligands for 5-HT 2A (IC 50 = 89 nM) and 5-HT 2C receptors (IC 50 = 17 nM), respectively.

Hydrogen sulphide is endogenously synthesized mainly by two pyridoxal-5′-phosphate-dependent enzymes involved in L-cysteine metabolism: cystathionine-ß-synthase (CBS) and cystathionine-γ-lyase (CSE) [1], [2] and [3]. The H2S pathway has been proposed to be involved in the pathophysiology of several diseases. At the present stage the research in this field is impaired by the lack of pharmacological tools such as selective enzymatic inhibitors [2], [3] and [4]. The goal of our study is the development of compounds that selectively regulate enzymatic activity. Here we present the synthesis and the activity of a selective CSE inhibitor. We preliminarily selected and tested commercially available cysteine surrogates because of the unavailability of a pharmacophoric model as a lead for rational design of targeted enzyme inhibitors. The catalytic profiles of recombinant CBS and CSE were assessed in the presence of the selected compounds. On the basis of the results obtained were designed new compounds aiming to obtain novel molecular entities embodying the structural features of both cysteine and the well known CSE inhibitor, DL-propargylglycine. The synthetically modified compounds, obtained in our laboratory, were tested in vitro by using rat aortic rings. The compound showing maximal inhibitory effects in this test was an oxothiazolidine derivative, dubbed ‘compound VII’. The effects of this compound on the enzyme kinetics were further tested on the purified enzymes using a metabolomic approach based on nuclear magnetic resonance techniques. These studies clearly showed that ‘compound VII’ is a potent enzyme inhibitor of CSE, without affecting the CBS kinetics. The identification of this highly selective CSE inhibitor may help to better define the role of CSE vs CBS in the pathophysiology of the diseases where a role for the H2S pathway has been proposed.

Two new peptides, tailored after Ac-Thr-D-Trp(CHO)-Phe-NMeBzl (TRI), namely, Ac-Thr-D-Trp(CHO)-Phe-NMe alpha MeBzl (TRA) and Ac-Thr-D-Trp(CHO)-Oic-NMeBzl (TOI), in which Phe is replaced by (3aS, 7aS)-octahydroindole-2-carboxylic acid, proved more potent and selective NK1 antagonists. The conformational properties of all three compounds were investigated in solution by NMR spectroscopy and those of TRI analyzed in greater detail by means of systematic computer-assisted modeling. All conformers whose energy differs by less than 9 kcal/mol from the absolute minimum are different from the conformer proposed in a previous molecular modeling study by the discovers of TRI. Parallel calculations for TRA and TOI yield low-energy conformers similar to those of TRI but in a slightly different order. Comparison of the shapes of low-energy conformers of all three peptides with those of four typical rigid NK1 antagonists shows that putative bioactive conformations are indeed present in solution.

We designed, synthesized and tested novel 2,6-disubstituted-anthraquinones able to bind dynamic secondary structures of nucleic acids, such as TAR RNA and its reverse transcript cTAR, leading to inhibition of the chaperone activities of the nucleocapsid NCp7, a highly conserved viral protein implied in crucial steps of HIV-1 replication.

Previous studies have demonstrated that the knockdown or knockout of the three Na(+)/Ca(2+) exchanger (NCX) isoforms, NCX1, NCX2, and NCX3, worsens ischemic brain damage. This suggests that the activation of these antiporters exerts a neuroprotective action against stroke damage. However, drugs able to increase the activity of NCXs are not yet available. We have here succeeded in synthesizing a new compound, named neurounina-1 (7-nitro-5-phenyl-1-(pyrrolidin-1-ylmethyl)-1H-benzo[e][1,4]diazepin-2(3H)-one), provided with an high lipophilicity index and able to increase NCX activity. Ca(2+) radiotracer, Fura-2 microfluorimetry, and patch-clamp techniques revealed that neurounina-1 stimulated NCX1 and NCX2 activities with an EC(50) in the picomolar to low nanomolar range, whereas it did not affect NCX3 activity. Furthermore, by using chimera strategy and site-directed mutagenesis, three specific molecular determinants of NCX1 responsible for neurounina-1 activity were identified in the α-repeats. Interestingly, NCX3 became responsive to neurounina-1 when both α-repeats were replaced with the corresponding regions of NCX1. In vitro studies showed that 10 nM neurounina-1 reduced cell death of primary cortical neurons exposed to oxygen-glucose deprivation followed by reoxygenation. Moreover, in vitro, neurounina-1 also reduced γ-aminobutyric acid (GABA) release, enhanced GABA(A) currents, and inhibited both glutamate release and N-methyl-d-aspartate receptors. More important, neurounina-1 proved to have a wide therapeutic window in vivo. Indeed, when administered at doses of 0.003 to 30 μg/kg i.p., it was able to reduce the infarct volume of mice subjected to transient middle cerebral artery occlusion even up to 3 to 5 hours after stroke onset. Collectively, the present study shows that neurounina-1 exerts a remarkable neuroprotective effect during stroke and increases NCX1 and NCX2 activities.

To obtain information about the structure-activity relationships of analgesic peptides, we modified the previously reported tripeptide, H-Lys-Pro-Thr-OH (C). The proline part in C was replaced with various analogues of unconventional amino acids {(3aS, 7aS)-octahydroindole-2-carboxylic acid (Oic), (S,S,S,)-2-azabiciclo [3.3.0] octane-3-carboxylic acid (Aoc), D-Aoc, and (2S, 4R)-hydroxyproline (Hyp)} with varying lipophilic, steric, and conformational properties, and alternatively with Lys and Orn in the lysine part. Moreover, the threonine part was changed to various natural amino acids (Ser, Thr, Val, Leu). All the compounds were screened in vivo for their analgesic effects in mouse writhing test. Compound 24 (H-Orn-Hyp-Val-OH), the most active compound within the series, showed an ED50 value of 10 mg/kg, which is comparable with the ED50 values exhibited by indometacin (4.1 mg/kg) and the dipeptide H-Lys-D-Pro-OH (6.9 mg/kg), both used as reference drugs. © 1997 John Wiley & Son's, Inc. Biopoly 40: 479–484, 1996

Summary A number of benzotriazole derivatives have been assayed in radioligand binding experiments involving the following recombinant human serotonin receptors: 5-HT 2A , 5-HT 1A , 5-HT 1Dβ and 5-HT 2C . Several of the compounds tested show interesting selectivity profiles. In particular, the affinities of 3d, 4a and 4d for teh 5-HT 2A subtype (with p K i values of 7.4, 7.4 and 8.0, respectively) are between 100 and 1000 times higher than for the other investigated receptors. Compound 51 , characterized by a p K i value of 7.4 on the 5-HT 1A receptor, binds with 100- to 1000-fold lower potencies on the other receptors. Our benzotriazole derivatives are generally weak ligands of the 5-HT 1Dβ and 5-HT 2C receptors. Structure—affinity relationship data suggest that not all the compounds exhibit the same binding mode at the 5-HT 2A and 5-HT 1A receptors.

Summary A set of N -[2-(alkylamino)ethyl]benzotriazol- X -yl isobutyramides have been synthesized and assayed in vivo for their local anesthetic activity and acute toxicity. Some of them showed a more favorable pharmacological profile than that of the reference drug lidocaine. QSAR studies have delineated the influence of overall lipophilicity on surface and infiltration anesthetic activities.

One pot microwave-assisted synthesis of substituted 1,2,4-oxadiazoles I (R = H. NO2, OEt), in solvent and under solvent free condition, was performed exploring the importance of some coupling reagents. Good yields and short reactions time were the main aspects of the methods.

Here, we report the chemical characterization and identification of the possible sources of particulate matter (fraction PM10) at two different sites in Naples. PM10 concentration and its chemical composition were studied using the crustal enrichment factor (EF) and principal component analysis (PCA). In all of the seasons, the PM10 levels, were significantly higher (p < 0.01) in the urban-traffic site (denominated NA02) than in the urban-background site (denominated NA01). In order to reconstruct the particle mass, the components were classified into seven classes as follows: mineral dust (MD), trace elements (TE), organic matter (OM), elemental carbon (EC), sea salt (SS), secondary inorganic aerosol (SIA) and undetermined parts (unknown (UNK)). According to the chemical mass closure obtained, the major contribution was OM, which was higher (p < 0.01) during summer than in other seasons. In both sites, a good correlation (R2 > 0.8) was obtained between reconstructed mass and gravimetric mass. PCA analysis explained 76% and 79% of the variance in NA01 and NA02, respectively. The emission sources were the same for both sites; but, the location of the site, the different distances from the sources and the presence and absence of vegetation proved the different concentrations and compositions of PM10.

Kallikrein-related peptidases (known as KLKs) constitute a single family of 15 secreted, highly conserved serine proteases with tryptic or chymotryptic activity. KLKs share a wide range of expression in different tissues; examples of KLK co-expression, are certain groups expressed in the prostate (KLKs 2-4, 11, and 15), skin (KLKs 1, 4-11, 13, and 14), breast (KLKs 5, 6, 10, and 13), and the central nervous system (KLKs 6-9, 14). Aberrant regulation of KLKs has been associated with several diseases such as hypertension, renal dysfunction, skin desquamation, inflammation, neurodegeneration, and tumor-promotion or -inhibition. However, despite their widespread expression in diseased tissues, the exact mechanisms by which this enzyme family regulates cellular function are not clear and their potential endogenous targets in vivo are only beginning to be revealed. Tumor marker prostate-specific antigen (PSA/KLK3), for example, is the most widely known KLK due to its application in diagnosis and monitoring of prostate cancer, nevertheless the biological role of this enzyme in cancer progression is unclear. Accumulating evidences suggest that KLKs signal via proteinase activated receptors (PARs), a family which has been implicated in several pathways of cell signaling. PARs are G-protein-coupled receptors with seven transmembrane domains, which are activated by a unique mechanism dependent on proteolytic cleavage. KLKs can regulate multiple signaling pathways triggered by PARs 1, 2, and 4, resulting in calcium release, platelet aggregation and vascular relaxation, and they can cause murine inflammation. KLK-derived regulation of PARs would be critical for many pathological conditions affecting different tissues, where distinct groups of KLKs are expressed. Via the PARs, KLKs can regulate processes including cell migration, inflammation, nociception, as well as angiogenesis, cell apoptosis, adhesion, proliferation, metastasis, and invasion. Therefore, the kallikrein-PAR axis may be considered as an attractive target for drug development.

(Z)-2-(2-phenylbenzylidene)-3-quinuclidinone, C20H19NO,M r =300.47D crystallizes in the monoclinicP21/c space group witha = 6.9809(2) A,b=19.0523(2) A,c = 11.7733(1) A,β=100.92(2)°,V=1537.5(3) A3,Z=4,D c = 1.298 g/cm3,D x =1.29 g/cm3 (flotation). Diffractometric data, using CuKα radiation,λ=1.54178 A, were collected on plate-like crystals. The structure, solved by direct methods was refined to a final R value of 0.037 for the 2645 observed reflections withF o >3.0σ(F o ). The molecule shows a trans conformation around the double bond. The quinuclidine and the diphenyl moieties present deformations in their geometric and conformational parameters due to the need of releasing intramolecular strains and/or nonbonded interactions.

A series of 1- and 2-[3-[4-( X )-1-piperazinyl]-propyl]benzotriazoles were prepared and evaluated for their trazodone-like pharmacological profile; as preliminary pharmacological screening, the compounds were tested for their antiserotonergic, antiadrenergic and antihistaminic in vitro activity as well as for their analgesic in vivo action. Structure-activity relationships showed that among the synthesized compounds, the analogues bearing on the 4-piperazine nitrogen either an unsubstituted phenyl ring or a 2- or 3-chloro phenyl moiety show a pharmacological profile similar to that of the antidepressant trazodone.

The difficult coupling of a-aminoisobutyric acid (Aib), during the synthesis of dipeptides [Z-Aib-Val-OMe, Z-Val-Aib-OMe, Z-Aib-Ile-OMe, Boc-Ile-Aib-OMe, Z-Aib-Aib-OMe, Boc-Aib-Aib-OMe, (Z = benzyloxycarbonyl, Boc = tert-butoxycarbonyl)], was carried out using PyBOP/HOBt and HBTU/HOBt reagents by application of microwave energy in the presence of solvent. Room temp., conventional heating (oil bath) and microwave irradn. of the reactions are compared. Synthesis by microwave irradn. gave the desired compds. in higher yields and in shorter reaction times than those obtained by conventional heating or at room temp.

Serotonin (5-hydroxytryptamine, 5-HT) is one of the most important neuromediator involved in numerous physiological and pathophysiological processes. In addition it is well established that 5-HT acts as a growth factor on several types of non-tumoral and tumoral cells, and recently it was also related to oncogenes. 5-HT1A receptor expression was identified in prostatic tumor cell lines (PC3 cells) and in human hormone refractory prostate cancer tissue. Based on these observations, development of 5-HT1A antagonists could be useful in inhibiting the growth of cancer cells. In order to investigate on potential use of 5-HT1A ligands as antiproliferative agents, we have analyzed a new set of 1-naphtylpiperazine derivatives. In binding studies, several molecules showed affinity in nanomolar and subnanomolar range at 5-HT1A and moderate to no affinity for other relevant receptors (5-HT2A, 5-HT2C, D1, D2, α1 and α2). All compounds were then evaluated in order to assess their antiproliferative activity using PC3 cells and the most active compounds (1 and 2) were fully characterized to define the mechanism responsible for the observed antiproliferative effect.

Gaseous transmitters are a growing family of regulatory molecules involved in multilevel regulation of physiological and pathological functions in mammalian tissues. Hydrogen sulfide (H2S) is best known for its characteristic smell of rotten eggs. It is now widely recognized that H2S, along with nitric oxide (NO) and carbonmonoxide (CO), is involved in a multitude of physiological functions. The generation of H2S bymammalian tissues is likely to occur in a slow and constant rate, and it appears to be involved in several processes including neuromodulation, hypertension, inflammation, edema, hemorrhagic shock, pain perception, gastric mucosal integrity, and vascular tone. This Perspective has been designed in order to give to the reader an updated overview on the physiology and biochemistry of H2S. In particular we have summarized the effects of H2S inhibitors and H2S donors in animal models of disease ordered for apparatus. Finally there is a section that addresses the potential for therapeutic exploitation ofH2S and provides an update on the patents so far filed.

An easy and convenient microwave-assisted synthesis of a small library of indolic arylpiperazine derivatives is described. Parallel and mixed pool combinatorial methods are reported and compared. The described reactions are nucleophilic substitutions of several aromatic piperazines in presence of K(2)CO(3). Good yields and short reaction times are the main aspect of these procedures. Binding assays shed additional light on the influence of the LCAPs on the 5-HT(1A), 5-HT(2A) and 5-HT(2C) receptors affinity and allowed to disclose three interesting compounds as 5-HT(2C), mixed 5-HT(2A)/5-HT(2C) and 5-HT(1A)/5-HT(2C) ligands (4i, 4l and 4d, respectively), with potential antiepileptic, anxiolytic or atypical antipsychotic agent therapeutical profiles.

Several studies have been published on discovering involvement of PARs receptors in a number of disease states, including cancer and inflammation of the cardiovascular, respiratory, musculoskeletal, gastrointestinal and nervous systems. This mini-review will focus on recent advances in the synthesis of PAR ligands highlighting their therapeutic potential in the treatment of various inflammatory diseases.

A series of 4-substituted piperazine derivatives bearing a norbornene nucleus have been prepared and their affinity for serotonin 5-HT1A, 5-HT2A and 5-HT2C receptors has been evaluated. Compounds showing the highest affinity have been selected and evaluated on dopaminergic (D1 and D2) and adrenergic (alpha1 and alpha2) receptors. The combination of structural elements (heterocyclic nucleus, oxyalkyl chain and 4-substituted piperazine) known to be critical in order to have affinity on serotonin receptors and the proper selection of substituents led to compounds with higher receptor specificity and affinity. In binding studies, several molecules showed affinity in nanomolar range towards 5-HT1A, 5-HT2A and 5-HT2C receptors and moderate to no affinity for other relevant receptors (D1, D2, alpha1 and alpha2). Compound 2q 4-[2-[4-(3,4-dichlorophenyl)piperazin-1-yl]ethoxy]-4-aza-tricyclo[5.2.1.02,6]dec-8-ene-3,5-dione (Ki = 1.13 nM), was the most active and selective derivative for the 5-HT2C receptor with respect to other serotonin, dopaminergic and adrenergic receptors. Moreover, compound 3p showed mixed 5-HT2A/5-HT2C activity with affinity values in nanomolar range.

The interest in the microwave assisted organic synthesis has been growing during the recent years. It results from an increasing knowledge of fundamentals of the dielectric heating theory, availability of an equipment designed especially for the laboratory use as well as the discovery of the special techniques of the microwave syntheses. The efficiency of microwave flash-heating chemistry in dramatically reducing reaction times (reduced from days and hours to minutes and seconds) has recently been proven in several different fields of organic chemistry and this aspect is of great importance in high-speed combinatorial and medicinal chemistry. In this contribution, the current state of the art is summarized providing examples of the most recent applications in the field of microwave assisted synthesis of biologically active compounds both in heterocyclic and in peptide and peptidomimetic optimization.

Irritable bowel syndrome (IBS) is characterized by dysfunction of the afferent pathways that may lead to visceral hypersensitivity. Trimebutine is a weak μ opioid receptor agonist used in the treatment of IBS. We report on the effects of a novel derivative in which trimebutine has been salified with nitro-arginine (NO2-Arg-Trim), in modulating nociception to colorectal distension (CRD) in intact and post-colitis rats, an animal model that mimics some features of IBS. Colorectal sensitivity and pain were assessed by measuring the abdominal withdrawal score (AWR) during CRD. Healthy rats were treated with vehicle, trimebutine (10 mg/kg i.p.) or NO2-Arg-Trim (4, 8 and 16 mg/kg i.p.). Post-colitis, allodynic rats were investigated 4 weeks after colitis induction. Treating healthy rats with NO2-Arg-Trim resulted in a dose-dependent attenuation of CRD-induced nociception and in an inhibition of CRD-induced overexpression of spinal cFOS mRNA. NO2-Arg-Trim-induced antinociception was reversed by the opioid receptor antagonist naloxone and by the NO synthase-cGMP pathway inhibitor methylene blue, while L-NAME had no effect. The antinociceptive effect of NO2-Arg-Trim was maintained in a rodent model of post-inflammatory allodynia. In this setting, NO2-Arg-Trim but not trimebutine, significantly down-regulated the spinal cFOS mRNA expression and increased blood concentrations of NO2 + NO3. Moreover, the expression of several genes involved in inflammation and pain, as IL-1β, TNFα, COX2 and iNOS, was up-regulated in colonic tissue from post-colitis rats and NO2-Arg-Trim, but not trimebutine, effectively reversed this effect. In summary, these data suggest that NO2-Arg-Trim inhibits nociception induced by CRD in both healthy and post-colitis, allodynic rats. The NO2-arginine moiety interacts with the opioid agonist trimebutine to potentiate its analgesic activity. This study provides evidence that NO2-arginine derivative of trimebutine might have beneficial effect in the treatment of painful intestinal disorders. © 2009 Elsevier Ltd. All rights reserved.

In this paper, we describe the synthesis of conformationally constrained dipeptide mimetic derivatives. Microwave flash heating was used in several synthetic steps providing the opportunity to perform the reactions in dramatically shortened time as well as to increase the obtained yields. The efficiency of the methodology makes it useful in order to prepare other dipeptides containing the 4-amino-tetrahydro-2- benzazepin-3-one motif.

The 5-[2-ethoxy-5-(4-methylpiperazin-1-ylsulfonyl)phenyl]-1-methyl-3-propyl-1,6-dihydro-7 H-pyrazolo[4,3-d]pyrimidin-7-one, sildenafil, is a cGMP-specific phosphodiesterase-5 (PDE5) inhibitor used for penile erectile dysfunction. In the search for more potent and selective PDE5 inhibitors, new sildenafil analogues (6a-v), characterized by the presence on the sulfonyl group in the 5' position of novel N-4-substituted piperazines or ethylenediamine moiety, were prepared by traditional and microwave-assisted synthesis and tested in rabbit isolated aorta and corpus cavernosum. Similarly to sildenafil, several analogues showed IC50 values in the nanomolar range. In the in vitro studies, all the tested compounds caused concentration-dependent relaxations in both rabbit isolated aorta and corpus cavernosum. All sildenafil analogues potentiated the nitric oxide-dependent vasodilation in endothelium-intact rabbit aorta. Compound 6f exhibited great pEC50 value in corpus cavernosum, and compounds 6r and 6u in isolated aorta were found as potent as sildenafil for inhibiting PDE5. Because several analogues were significantly more lipophilic than sildenafil, these compounds may offer a new lead for development of new sildenafil analogues.

This paper reports the microwave-assisted synthesis and the binding assays on the 5-HT(1A), 5-HT(2A) and 5-HT(2C) receptors of new benzotriazinone derivatives, in order to identify selective ligands for the 5-HT(1A) subtype receptor. Conventional and microwave heating of the reactions were compared. Good yields and short reaction times are the main advantages of our synthetic route. More active compounds were selected and further evaluated for their binding affinities on D(1), D(2) dopaminergic and alpha(1), alpha(2) adrenergic receptors. The 3-(2-(4-(naphthalen-1-yl)piperazin-1-yl)ethyl)benzo[d][1,2,3]triazin-4(3H)-one 5 with K(i)= 0.000178 nM was the most active and selective derivative for the 5-HT(1A)receptor with respect to other serotonin receptors and the most selective derivative compared to dopaminergic and adrenergic receptors.

Increase of VPAC receptor s binding to the (16)gamma-glutamyl diaminopropane vasoactive intestinal peptide (VIP-DAP) agonist, a vasoactive intestinal polypeptide (VIP) structural analogue containing a positive charge at position 16, has confirmed the importance of a positive charge at this site. By investigating the effect of distance from the peptide backbone Calpha of a positive charge in position 16, data are reported here concerning: (i) a novel chemical method used for the synthesis of a new family of (16)gamma-glutamyl diamine VIP derivatives differing among them for single carbon atoms and including diaminoethane (VIP-DAE2), diaminopropane (VIP-DAP3), diaminobutane (VIP-DAB4), diaminopentane (VIP-DAP5), and diaminohexane (VIP-DAH6); (ii) functional characterization of these compounds on human VPAC1 and VPAC2 receptors. In more detail, the EC50 and IC50 values, when measured as a function of the alkylic chain length, show in more detail, that the use of VIP-DAB4 derivative changes the IC50 but not the EC50, thus indicating on hVPAC2 receptor an unexpected relationship between binding and activity that differs from that obtained on hVPAC1.

We report microwave-assisted synthetic routes, the pharmacokinetic profile along with results from ulcerogenicity and mutagenicity studies of atenolol aspirinate, and an already described derivative, in which acetyl salicylic acid (aspirin®) was connected to atenolol by an ester linkage. Atenolol aspirinate was stable towards aqueous hydrolysis but rapidly hydrolyzed in plasma (t 1/2 = 7.6 min). The results showed that the rapid and complete hydrolysis generates atenolol salicylate, which assumes a conformation stabilized by two intramolecular H-bonds, avoiding its further hydrolysis to salicylic acid and atenolol.

Three series of compounds characterized by biphenylic structure were synthesized in order to develop new scaffolds able to induce β-sheet folding in the peptides. Microwave flash heating was used in order to shorten reaction times and to enhance the obtained yields. Simulated annealing molecular dynamics simulations demonstrated that some of the compounds were capable of adopting a 15-membered intramolecularly hydrogen-bonded conformation, which supports an antiparallel β-sheet structure.

Peptide T (ASTTTNYT), a segment corresponding to residues 185–192 of gp120, the coat protein of HIV, has several important biological properties in vitro that have stimulated the search for simpler and possibly more active analogs. We have previously shown that pseudocyclic hexapeptide analogs containing the central residues of peptide T retain considerable chemotactic activity. We have now extended the design of this type of analogs to peptides containing different aromatic residues and/or Ser in lieu of Thr. The complex conformation-activity relationship of these analogs called for a reexamination of the basic conformational tendencies of peptide T itself. Here, we present an exhaustive NMR conformational study of peptide T in different media. Peptide T assumes a γ-turn in aqueous mixtures of ethylene glycol, a type-IV β-turn conformation in aqueous mixtures of DMF, and a type-II β-turn conformation in aqueous mixtures of DMSO. The preferred conformations for the analogs were derived from modeling, starting from the preferred conformations of peptide T. The best models derived from the γ-turn conformation of peptide T are those of peptides XII (DSNYSR), XIII (ETNYTK) and XVI (ESNYSR). The best models derived from the type-IV β-turn conformation of peptide T are those of peptides XIV (KTTNYE) and XV (DSSNYR). No low-energy models could be derived starting from the type-II β-turn conformation of peptide T. The analogs with the most favored conformations are also the most active in the chemotactic test. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.

Fifteen analogues of the C-terminal CA1A2X motif were synthesized and evaluated for their inhibition potency against farnesyltransferase (FTase). Replacement of the A2 residue by phenylalanine or tyrosine-derived analogues, in which a different number of methyl groups were introduced on the aromatic ring, resulted in compounds less active than the reference compound CVFM against FTase except for compounds I and VI (IC50 = 1 μM and 2.5 μM, respectively) that were comparable to CVFM and compound IV (IC50 = 0.1 μM), which was 6-fold more active than the reference compound. Because pseudopeptidic derivatives I-IX were inactive in the cellular assays, the N-formyl- and methyl-ester derivatives (compounds X-XV) were synthesized and tested on different cell lines, showing, in some cases, activity and appreciable selectivity against transformed cells. To rationalize the obtained results, molecular modeling experiments were carried out suggesting the molecular basis of FTase inhibition by these products. © 2006 American Chemical Society.

In this study, the mutagenicity of the anti-inflammatory parsalmide [5-amino-N-butyl-2-(2-propynyloxy)-benzamide] analogues PA7 [5-amino-N-butyl-2-cyclohexyloxy-benzamide], PA10 [5-amino-N-butyl-2-phenoxy-benzamide] and PA31 [5-amino-N-butyl-2-(p-tolyloxy)-benzamide] was determined by an Ames Salmonella assay. The experiments were performed by preincubating the compounds in the absence and presence of a post-mitochondrial fraction (S9) of rat liver homogenate from phenobarbital/beta-naphtoflavone treated rats. No mutagenic effect was observed after direct testing (no S9 added) in Salmonella typhymurium strains TA98, TA100, TA102, TA1535 and TA1537. However, in the presence of S9, the test substances triggered mutagenic responses in strains TA100 and TA98. PA31 presented the strongest mutagenic potential. The reversion rates in the presence of PA31 were about 2-19 fold higher than spontaneous mutation rates. In the presence of PA7, the reversion increased 2-14-fold over spontaneous rates. While PA10 showed a relatively mild mutagenic potential, as the number of revertants did not exceed 2.5 times the number of spontaneous mutations. Mass spectrometric analysis of the in vitro biotransformation showed that S9 converted (%), regioselectively, PA7 (19%), PA10 (7%) and PA31 (12%) into hydroxy-derivatives.