Synthesis and Broad-Spectrum Antiviral Activity of Some Novel Benzo-Heterocyclic Amine Compounds

A series of novel unsaturated five-membered benzo-heterocyclic amine derivatives were synthesized and assayed to determine their in vitro broad-spectrum antiviral activities. The biological results showed that most of our synthesized compounds exhibited potent broad-spectrum antiviral activity. Notably, compounds 3f (IC50 = 3.21–5.06 μM) and 3g (IC50 = 0.71–34.87 μM) showed potent activity towards both RNA viruses (influenza A, HCV and Cox B3 virus) and a DNA virus (HBV) at low micromolar concentrations. An SAR study showed that electron-withdrawing substituents located on the aromatic or heteroaromatic ring favored antiviral activity towards RNA viruses

Development of radiosynthesis methods for 18F-labelled radiopharmaceuticals : General considerations and production of a dopamine transporter radioligand

Positron emission tomography (PET) is a molecular imaging technique that utilises radiopharmaceuticals (radiotracers) labelled with a positron-emitting radionuclide, such as fluorine-18 (18F). Development of a new radiotracer requires an appropriate radiosynthesis method: the most common of which with 18F is nucleophilic substitution with [18F]fluoride ion. The success of the labelling reaction is dependent on various factors such as the reactivity of [18F]fluoride, the structure of the target compound in addition to the chosen solvent. The overall radiosynthesis procedure must be optimised in terms of radiochemical yield and quality of the final product. Therefore, both quantitative and qualitative radioanalytical methods are essential in developing radiosynthesis methods. Furthermore, biological properties of the tracer candidate need to be evaluated by various pre-clinical studies in animal models. In this work, the feasibility of various nucleophilic 18F-fluorination strategies were studied and a labelling method for a novel radiotracer, N-3-[18F]fluoropropyl-2beta-carbomethoxy-3beta-4-fluorophenyl)nortropane ([18F]beta-CFT-FP), was optimised. The effect of solvent was studied by labelling a series of model compounds, 4-(R1-methyl)benzyl R2-benzoates. 18F-Fluorination reactions were carried out both in polar aprotic and protic solvents (tertiary alcohols). Assessment of the 18F-fluorinated products was studied by mass spectrometry (MS) in addition to conventional radiochromatographic methods, using radiosynthesis of 4-[18F]fluoro-N-[2-[1-(2-methoxyphenyl)-1-piperazinyl]ethyl-N-2-pyridinyl-benzamide (p-[18F]MPPF) as a model reaction. Labelling of [18F]beta-CFT-FP was studied using two 18F-fluoroalkylation reagents, [18F]fluoropropyl bromide and [18F]fluoropropyl tosylate, as well as by direct 18F-fluorination of sulfonate ester precursor. Subsequently, the suitability of [18F]beta-CFT-FP for imaging dopamine transporter (DAT) was evaluated by determining its biodistribution in rats. The results showed that protic solvents can be useful co-solvents in aliphatic 18F-fluorinations, especially in the labelling of sulfonate esters. Aromatic 18F-fluorination was not promoted in tert-alcohols. Sensitivity of the ion trap MS was sufficient for the qualitative analysis of the 18F-labelled products; p-[18F]MPPF was identified from the isolated product fraction with a mass-to-charge (m/z) ratio of 435 (i.e. protonated molecule [M+H]+). [18F]beta-CFT-FP was produced most efficiently via [18F]fluoropropyl tosylate, leading to sufficient radiochemical yield and specific radioactivity for PET studies. The ex vivo studies in rats showed fast kinetics as well as the specific uptake of [18F]beta-CFT-FP to the DAT rich brain regions. Thus, it was concluded that [18F]beta-CFT-FP has potential as a radiotracer for imaging DAT by PET.Positroniemissiotomografia (PET) on kuvantamismenetelmä, jossa hyödynnetään lyhytikäisillä positronisäteilijöillä, kuten fluori-18:lla, leimattuja radioaktiivisia yhdisteitä, ns. radiolääkeaineita. PET:n ja 18F-leimattujen radiolääkeaineiden tärkeitä sovellutuskohteita on mm. neurologiassa, esimerkkinä dopamiinin kuljetusproteiinien (DAT) diagnostinen kuvantaminen: DAT:n toiminnan on osoitettu muuttuneen monissa neurologisissa ja psykiatrisissa sairauksissa kuten Parkinsonin taudissa. Uusien, spesifisten radiolääkeaineiden tuottaminen edellyttää sopivan radioleimausmenetelmän kehittämistä ja leimattujen yhdisteiden biologisten ominaisuuksien määrittämistä eläinmalleissa. Tyypillinen leimausreaktio 18F:lla perustuu nukleofiiliseen substituutioon [18F]fluoridilla. Leimausreaktion onnistumiseen voidaan vaikuttaa monilla tekijöillä, joita ovat mm. [18F]fluoridin reaktiivisuus, kohdemolekyylin rakenne sekä valittu liuotin. Tavoitteena on tuottaa puhdas lopputuote mahdollisimman hyvällä radioaktiivisella saannolla ja riittävän korkealla spesifisellä radioaktiivisuudella, näin ollen myös asianmukaiset analyysimenetelmät ovat ensisijaisen tärkeitä valmistusmenetelmän kehityksessä. Tämän väitöskirjatyön tarkoituksena oli tutkia erilaisia nukleofiilisiä 18F-fluorausmenetelmiä ja optimoida valmistusmenetelmä uudelle DAT -merkkiaineelle, N-3-[18F]fluoripropyyli)-2beta-karbometoksi-3beta-4-fluorifenyyli)nortropaanille ([18F]beta-CFT-FP). Liuottimen ja lähtöaineen rakenteen vaikutusta leimausreaktion onnistumiseen tutkittiin radioleimaamalla erilaisia malliyhdisteitä, 4-(R1-metyyli)bentsyyli R2-bentsoaatteja, sekä yleisesti käytetyissä aproottisissa että uusissa proottisissa liuottimissa. Tulokset osoittivat, että tertiääriset alkoholit soveltuvat alifaattisten yhdisteiden, erityisesti sulfonaattiesterien leimaukseen, mutta aromaattisissa 18F-fluorausreaktioissa ne eivät toimineet. Serotoniinireseptori 5HT1A -ligandin, 4-[18F]fluori-N-[2-[1-(2-metoksifenyyli)-1-piperatsinyyli]etyyli-N-2-pyridinyyli-bentsamidi (p-[18F]MPPF), valmistuksessa käytettiin leimautuneiden tuotteiden analysointiin perinteisten kromatografisten menetelmien rinnalla massaspektrometriaa (MS). Ioniloukku-MS:n todettiin olevan riittävän herkkä menetelmä leimatun lopputuotteen tunnistamiseen reaktioseoksesta. [18F]beta-CFT-FP:n radioleimausta tutkittiin käyttäen kahta, 18F-fluoroalkylointiin pohjautuvaa menetelmää sekä suoraa yksivaiheista leimausmenetelmää, joista [18F]fluoripropyyli tosylaatti leimausreagenssina osoittautui toimivimmaksi: optimoitu leimausmenetelmä mahdollistaa [18F]beta-CFT-FP:n valmistamisen potilastutkimuksiin. Lisäksi [18F]beta-CFT-FP -merkkiaineen biologisia ominaisuuksia tutkittiin rotilla ex vivo. Tulokset osoittivat, että yhdiste kulkeutuu nopeasti ja spesifisesti aivoalueille, joissa DAT-proteiineja on runsaasti. Johtopäätöksenä todetaan, että [18F]beta-CFT-FP soveltuu DAT:n kuvantamiseen PET:lla

Design, synthesis and biological characterization of novel inhibitors of CD38

Human CD38 is a novel multi-functional protein that acts not only as an antigen for B-lymphocyte activation, but also as an enzyme catalyzing the synthesis of a Ca 2+ messenger molecule, cyclic ADP-ribose, from NAD +. It is well established that this novel Ca 2+ signaling enzyme is responsible for regulating a wide range of physiological functions. Based on the crystal structure of the CD38/NAD + complex, we synthesized a series of simplified N-substituted nicotinamide derivatives (Compound1-14). A number of these compounds exhibited moderate inhibition of the NAD + utilizing activity of CD38, with Compound4 showing the highest potency. The crystal structure of CD38/Compound4 complex and computer simulation of Compound7 docking to CD38 show a significant role of the nicotinamide moiety and the distal aromatic group of the compounds for substrate recognition by the active site of CD38. Biologically, we showed that both Compounds4 and 7 effectively relaxed the agonist-induced contraction of muscle preparations from rats and guinea pigs. This study is a rational design of inhibitors for CD38 that exhibit important physiological effects, and can serve as a model for future drug development. © 2011 The Royal Society of Chemistry.postprin

Design and Synthesis of New A2B Adenosine Receptor Antagonists

Starting from chemical structure of N-benzo-[1,3]dioxol-5-yl-2-[5-(2,6dioxo-1,3-dipropyl-2,3,6,7-tetrahydro-1H-purin-8-yl)-1-methyl-1H-pyrazol3-yloxy]-acetamide, MRE2029F20* various structural modifications were realized to afford a new series of A2B antagonists. The bioisosteric replacement of the anilide moiety with benzimidazole or quinazoline rings, the effect of the substitution of pyrazole with isoxazole moiety were investigated. Amide bond has been also replaced with the 5phenyl-1,2,4-oxadiazole nucleus on the basis of other adenosine pharmacophores reported previously. In this context the effect of the nitrogen at the 9-position has been also studied preparing four 9-deaza direct analogs of 8pyrazol-xanthine compounds to compare affinity and selectivity at A2B adenosine receptor. The most significant result was obtained by bioisosteric replacement of the anilide moiety with benzimidazole, achieving antagonists with high affinity and selectivity toward the A2BAR. In particular compound 8-[5-(4-Chloro-6-trifluoromethyl-1H-benzoimidazol-2-ylmethoxy)-2methyl-2H-pyrazol-3-yl]-1,3-dipropyl-3,7-dihydro-purine-2,6-dione (hA1 Ki = 2530 nM, hA2A Ki > 1000 nM, hA2B Ki = 9.4 nM, hA3 Ki > 1000 nM) and compound 8-[5-(4,6-Bis-trifluoromethyl-1H-benzoimidazol-2-ylmethoxy)-2methyl-2H-pyrazol-3-yl]-1,3-dipropyl-3,7 dihydro-purine-2,6-dione (hA1 Ki = 4462 nM, hA2A Ki > 1000 nM, hA2B Ki = 25 nM, hA3 Ki > 1000 nM), showed the best biological data. These new selective and potent A2B antagonists will aid in the elucidation of the physiological role of this receptor and possibily lead to therapeutilally useful agents for treating asthma, diabetes and other diseases

Development of novel fluorine-18 labeled PET radioligands for monoamine oxidase B (MAO-B)

Monoamine oxidases (MAO-A and MAO-B) are important enzymes regulating the levels of monoaminergic neurotransmitters. Selectiv e and irreversible MAO-B inhibitors such as L -deprenyl and rasagiline are clinically used for the t reatment of psychiatric and neurological disorders. Positron em ission tomography (PET) is a non- invasive imaging technique which has widely been util ized to visualize the localization of MAO-B in monkey and human brains and thereby has b een useful for studying neurodegenerative diseases and epilepsy. This thesi s deals with the synthesis and evaluation of novel fluorine-18 labeled PET radioligan ds for detection of MAO-B activity. The present thesis demonstrates that nine fluorinat ed propargyl amines were synthesized and tested for inhibition of MAO-B. In o rder to label those compounds with fluorine-18 seven chloro-precursors and two sulph amidate-precursors were also synthesized by multi step organic synthesis. Radiola beling of six chloro-precursors with fluorine-18 was accomplished by a one-step nucl eophilic substitution reaction. Radiolabeling of two sulphamidate-precursors with fl uorine-18 was performed in two steps, compromising a nucleophilic substitution foll owed by the removal of the protecting group. The incorporation yield of the fluo rination reactions varied from 40- 70%. The radiochemical purity was >99% and the specif ic radioactivities were in a range of 190-240 GBq/μmol at the time of administrat ion. In vitro MAO inhibition and/or autoradiography (ARG) experimen ts demonstrated a high selectivity for MAO-B over MAO-A for five of the compounds namely [ 18 F]fluorodeprenyl, [ 18 F]fluororasagiline, [ 18 F]fluoro- N ,4-dimethyl- N -(prop-2-ynyl) pentan-2-amine, [ 18 F]fluorodeprenyl-D 2 and [ 18 F]fluororasagiline-D 2 . All five compounds were examined by PET and showed a high initial brain uptake in known MAO-B rich regions in cynomolgus monkey. [ 18 F]Fluorodeprenyl showed a kinetic behavior similar to [ 11 C]deprenyl where its fast irreversible binding to th e enzyme renders the distribution of this radioligand in tissue limited by blood flow rather than the MAO-B enzyme concentration. [ 18 F]Fluororasagiline and [ 18 F]fluoro- N ,4-dimethyl- N -(prop-2-ynyl)pentan-2-amine showed continuous increase of the radioactivity throughout the PET measurement that might be an indic ation of a blood-brain barrier penetrating radiometabolite which might in turn compl icate a reliable quantification. Only [ 18 F]fluorodeprenyl-D 2 and [ 18 F]fluororasagiline-D 2 showed fast wash-out from the brain and less accumulation in cortical and sub- cortical regions. Radiometabolite studies demonstrated that both deuterated analogues were more stable measured in monkey plasma when compared to the non-deuterated a nalogues. These results together suggest that both [ 18 F]fluorodeprenyl-D 2 and [ 18 F]fluororasagiline-D 2 may be improved PET radioligands and potential mole cular imaging biomarker candidates for PET studies in neuroi nflammation and neurodegeneration, accompanied with astrocyte activat ion

Bioinorganic Chemistry

This book covers material that could be included in a one-quarter or one-semester course in bioinorganic chemistry for graduate students and advanced undergraduate students in chemistry or biochemistry. We believe that such a course should provide students with the background required to follow the research literature in the field. The topics were chosen to represent those areas of bioinorganic chemistry that are mature enough for textbook presentation. Although each chapter presents material at a more advanced level than that of bioinorganic textbooks published previously, the chapters are not specialized review articles. What we have attempted to do in each chapter is to teach the underlying principles of bioinorganic chemistry as well as outlining the state of knowledge in selected areas. We have chosen not to include abbreviated summaries of the inorganic chemistry, biochemistry, and spectroscopy that students may need as background in order to master the material presented. We instead assume that the instructor using this book will assign reading from relevant sources that is appropriate to the background of the students taking the course. For the convenience of the instructors, students, and other readers of this book, we have included an appendix that lists references to reviews of the research literature that we have found to be particularly useful in our courses on bioinorganic chemistry

A New Class of Benzo[b]thiophene-chalcones as Cholinesterase Inhibitors: Synthesis, Biological Evaluation, Molecular Docking and ADME Studies

In this study, heterocyclic compounds containing a benzothiophene scaffold were designed and synthetized, and their inhibitory activity against cholinesterases (ChE) and the viability of SH- SY5Y cells have been evaluated. Benzothiophenes 4a–4i and benzothiophene-chalcone hybrids 5a–5i were tested against both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), revealing interesting structure–activity relationships. In general, benzothiophene–chalcone hybrids from series 5 proved to be better inhibitors of both enzymes, with compound 5f being the best AChE inhibitor (IC50 = 62.10 μM) and compound 5h being the best BChE inhibitor (IC50 = 24.35 μM), the last one having an IC50 similar to that of galantamine (IC50 = 28.08 μM), the reference compound. The in silico ADME profile of the compounds was also studied. Molecular docking calculations were carried out to analyze the best binding scores and to elucidate enzyme–inhibitors’ interactions

Fungal cyclooligomer depsipeptides: From classical biochemistry to combinatorial biosynthesis

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.This review surveys the biological activities and the iterative and recursive biosynthetic mechanisms of fungal cyclooligomer depsipeptides, and their structural diversification by various combinatorial biosynthetic methods

Identification of A Novel Class of Benzofuran Oxoacetic Acid-Derived Ligands that Selectively Activate Cellular EPAC1

Cyclic AMP promotes EPAC1 and EPAC2 activation through direct binding to a specific cyclic nucleotide-binding domain (CNBD) within each protein, leading to activation of Rap GTPases, which control multiple cell responses, including cell proliferation, adhesion, morphology, exocytosis, and gene expression. As a result, it has become apparent that directed activation of EPAC1 and EPAC2 with synthetic agonists may also be useful for the future treatment of diabetes and cardiovascular diseases. To identify new EPAC agonists we have developed a fluorescent-based, ultra-high-throughput screening (uHTS) assay that measures the displacement of binding of the fluorescent cAMP analogue, 8-NBD-cAMP to the EPAC1 CNBD. Triage of the output of an approximately 350,000 compound screens using this assay identified a benzofuran oxaloacetic acid EPAC1 binder (SY000) that displayed moderate potency using orthogonal assays (competition binding and microscale thermophoresis). We next generated a limited library of 91 analogues of SY000 and identified SY009, with modifications to the benzofuran ring associated with a 10-fold increase in potency towards EPAC1 over SY000 in binding assays. In vitro EPAC1 activity assays confirmed the agonist potential of these molecules in comparison with the known EPAC1 non-cyclic nucleotide (NCN) partial agonist, I942. Rap1 GTPase activation assays further demonstrated that SY009 selectively activates EPAC1 over EPAC2 in cells. SY009 therefore represents a novel class of NCN EPAC1 activators that selectively activate EPAC1 in cellulae