ANALYTICAL CHEMISTRY/MEDICINAL CHEMISTRY427 doi:10.2533/chimia.2007.427 CHIMIA 2007, 61,No. 7/8

Analytical Chemistry 41 Analytical Chemistry 42

Sensor Arrays forthe Analysis of in Aqueous Solution Investigation of Hypericum species by LC/MS

Friederike Zaubitzer,Kay Severin G. Sibailly,K.Ndjoko,A.Marston, andK.Hostettmann* Institutdes Sciences et Ingénerie Chimiques, Ecole Polytechnique Fédérale LaboratoryofPharmacognosyand Phytochemistry, School of de Lausanne (EPFL),CH-1015 Lausanne, Switzerland Pharmaceutical Sciences,University of Geneva, University of Lausanne, Fluorescence sensors for sugars havereceived enormous interestinrecent Quai Ernest-Ansermet 30,CH-1211 Geneva 4, Switzerland years. Most efforts have focused on the development of sensors with a highly selectivityfor aparticular . This is generally accomplished with thehelp of synthetic receptors, which display ahigh specificity. An interest- Acharacteristic of plant species fromthe genus Hypericum (Hypericaceae) ing alternative is the utilization of asensor array technology. In asensor is the presence of pigments belonging to the class of naphthodianthrones. array, severalnon-specific sensorsare combined and the analyteisthen Theseplants havemany traditional uses and, notably, Hypericum perfora- identified with patternrecognition tools. This technique has successfully tum is employedfor the treatment of mild depression. Severalstudiesdeal been appliedfor different analytical problems [1], but the utilization of sen- with the activitiesofthe numerous constituentsofthe genus or compare sor arrays for sugars is virtually unexplored [2]. We describeasensor array, different Hypericum species [1,2]. Thegenus is alsoreputed forcases of which is based on the reversible coupling of fluorescent hydrazides with the poisoningincattle(hypericism) which alsohave their origin in the presence aldehyde group of reducing sugars. of thesecompounds.Morerecently, the naphthodianthrones have assumed importance forthe photodynamic therapy of cancer. O O N In order to determine the relative contents of and pseudohypericin Fluorophore NH NH + O Sugar Fluorophore N Sugar 2 H Fluorophore in theseplants,extraction of several species of St.-John's wortwas per- Fig.1.: Schematic representation of afluorescence sensor for sugars formedbydifferent proceduresinordertooptimizethe yield of the active constituents. Discrimination is achieved by exploitation of differences in fluorescence HPLC-UV/DAD and HPLC-MS methods werethen developed forthe emission intensities whichdependonthe nature of the dye-sugar derivate analysis of naphthodianthrones in the plants. It was found that Hypericum and the reaction equilibria in solution. calycinum L. does not contain this classofcompounds.

[1]K.J.Albert, N. S. Lewis, C. L. Schauer, G. A. Sotzing, S. E. Stitzel, [1] FicoG., VitaliniS., Colombo N.,TomeF., L.,H. T.P. Vaid,D.R.Walt, Chem.Rev. 2000,100, 2595. maculatum Crantz. ,H.calycinum L .and H. pulchrum L .: phytochemical [2] J. W. Lee, J.-S. Lee, Y.-T. Chang, Angew. Chem. Int. Ed. 2006,45, andmorphological studies., 2006,1,1129-1132. 6485. [2]OzturkY., Testing the andipressant effects of Hypericum specieson animal models,Pharmacopsychiatry, 1998,31, 37.

Medicinal Chemistry 43 Medicinal Chemistry 44

Thermodynamic and KineticConsiderations of theBinding Processof Novelguanidine-type 5-HT5A receptorantagonists MAG-Antagonists Jens-Uwe Peters ,* Alexander Alanine,AndreAlker,Francesca Blasco, StefanieMesch,DanielStrasser, Morena Spreafico, BrianCutting, Arnulf Dorn, Alain Gast, Luca Gobbi,Sabine Kolczewski, Nicole SachinShelke, Oliver Schwardt,Beat Ernst Kratochwil,Thomas Lübbers, PariMalherbe, Eric Prinssen, Diana Schuhbauer,Lucinda Steward Institute of MolecularPharmacy,University of Basel, Klingelbergstr. 50, 4050 Basel, Switzerland *Discovery Chemistry, F. Hoffmann-La Roche Ltd, CH-4070 Basel

Theinjured adult mammalian central nervous system is an inhibitoryenvi- ronment foraxon regeneration due to specific inhibitoryproteins.The mye- Cl Cl lin-associated glycoprotein (MAG)[1] wasidentified as oneoftheseneurite NH Cl NH NH outgrowth inhibitory proteins [2]. It belongs to the siglec family (sialic-acid N N F H N NH N N bindingimmunoglobulin-like lectin). In earlier studies,weidentified the 2 H F lead structure 1 [3], which was further optimized yielding antagonists with 1 2 3 nM affinities. K i (5-HT 5A)=160 nM K i (5-HT 5A)=2nM K i (5-HT 5A)=3nM screening hit brain/plasma ~0.2 brain/plasma ~4 Cl H N OH COOH Theexpression of the 5-HT receptor in the limbic brain areas suggestsa OH 5A potential role in the modulation of psychiatric diseases. 1 Howeveruntil re- O O O AcHN cently, no selective 5-HT5A receptor ligands were available to study its HO in detail. We screened the Roche compound librarytoiden- tifyselective antagonists forthis target, and found several guanidines such 1 as 1 among the mostselective compounds.Asystematic exploration of small substituents (Cl, Me,MeO,F)around the core structureled to 2 with

Thekinetic and thermodynamic propertiesofthese high affinity ligands potent 5-HT5A antagonistic affinity in vitro ,and improved selectivity, apart wereelucidatedbyBiacorestudies.Inaddition, the binding mode wasex- from5-HT 7 .Compound 2 had good PK properties, however alow brain- amined through STDNMR experiments and docking studies. plasma ratio. Thebrain penetration was improved by the introduction of electron-withdrawing substituents,which afforded acompound with in- [1]Quarles, R. H., J. Neurochem. 2007, 100,1431. creased lipophilicity,and reduced basicity, 3 .The series refinement and [2]Crocker,R.H., Curr.Opin. Struct.Biol. 2002, 12,609. structure activity relationship elucidatedinprogressing from the initialhit 1 [3]Shelke, S.,Gao,G-P., Mesch, S.,Gäthje, H.,Kelm, S.,Schwardt, O., to lead compound 3 will be furtherdescribed in the presentation. Ernst, B., Bioorg. Med. Chem, in press . [1]Thomas,D.R. Pharmacol.Ther. 2006, 111(3), 707-714. MEDICINAL CHEMISTRY428 CHIMIA 2007, 61,No. 7/8

Medicinal Chemistry 45 Medicinal Chemistry 46

Identification of NovelMulti-functional Compounds for the Treatment Medicinal chemistryefforts towardsthe identificationand development of some Aging Related NeurodegenerativeDiseases of inhibitorsofphosphatidylinositol 3-kinases (PI3Ks)and related proteinkinases forcancer treatment. Juan Bravo,Saviana Di Giovanni,Delphine Cressend, Francesca Bertolini; Laura Novaroli,Antoine Daina,Marianne Reist, Pierre-Alain Carrupt Frédéric Stauffer ,CarlosGarcia-Echeverria, Pascal Furet, Hans-GeorgCapraro,Philipp Holzer,Christian Schnell, Unité de Pharmacochimie, Section dessciences pharmaceutiques, ChristineM.Fritsch &MichelMaira. Université de Genève,Université de Lausanne, Quai Ernest-Ansermet 30, CH-1211 Genève 4, Suisse Novartis Institutes forBioMedical Research, Klybeckstrasse 141, 4057 Basel, Switzerland. Aging related neurodegenerative disorders such as Parkinsondisease (PD) and Alzheimer’s disease(AD) arethe result of multiple pathophysi- Constitutive activation of the PI3K-pathwayseemstobeaprerequisite for a ological pathways that contribute to theneurodegenerativecascade. Hence, wide spectrumofcancers, either by loss /mutationsofPTEN,acquisition of multi-functionaldrug candidatesabletointeract with severaltargets areof activating in the PI3K catalytic subunit, or amplification /over- great interest forthe treatment of such diseases.Therefore,anexperimental expression of receptor tyrosine kinases upstream of PI3K.Inthisrespect, andvirtualscreening pathwaytogeneratemulti-functionalhits promising components of the PI3K/PKB/mTor pathway such as membersofthe classI forthe treatment of PD or AD was suggested[1]. PI3Ks represent wellvalidated therapeutic targetsfor thediscoveryand de- Among the numerous potentialtargets,fivewereselected; two are velopment of new anticancer drugs.Although theyhave sub-optimal phar- common to both diseases,namely monoamine oxidaseB(MAO B) and oxi- maceutical properties,PI3Kinhibitors like the fungal metabolite wortman- dativestress, and threeare specificfor onlyone of thetwo disorders, nin and the morpholino derivative LY294002 have shown that this classof catechol-O-methyltransferase (COMT) forPDand acetylcholinesterase lipid kinasesis"drug-able".Inactivators of the TORC1 complex- (AChE)aswellas -amyloid deposition forAD, respectively. mTor/Raptor-, such as the rapamicinederivative RAD001, have shown anti- Suitable experimental and virtual screening methods to rapidly test cancer activity in clinical trials.Inaddition to TORC1,the TORC2 complex pre-focused compound librariesweredeveloped and validated. Thepro- -mTor/Rictor-has recently been linked to PKBphosphorylation and activa- posed rationalscreening strategy wasappliedtoalibrary of naturalcom- tion.1 pounds and some focusedsynthetic libraries, leading to some interesting Our medicinalchemistry efforts using the privilege kinaseinhibitor scaffold multi-functionalhits.Refinedmolecularmodelling approaches were also imidazo[4,5-c]quinoline to identify andoptimizenew inhibitors of the used to identifytheir binding modes and to suggestsome guidelinesfor the PI3K/PKB/mTor-pathwaywill be disclosed.From this chemotype,aclinical pharmacomodulation of retained hits in order to obtain multifunctional vir- candidatehas been selected. This inhibitor,which has suitablepharmacol- tual lead compounds. ogical properties forclinical development, shows an efficient controlofthe PI3K-pathway in tumor cells by inhibiting the phosphorylation and activa- tion of PKB in cellularand in vivo settings. [1]L.Novaroli et al, Chimia. 2005, 59,315-320. [1] Sarbassov, D. D.;Guertin, D. A.,; Ali,S.M.; Sabatini, D. M.; Science 2005, 307,1098.

Medicinal Chemistry 47 Medicinal Chemistry 48

Receptor-MediatedTargetingofMetastaticMelanomawith VesicleFormation in Aqueous Solution Radiolabeled DOTA- -MSH Analogs Driven by Selective Non-Covalent Interactions

Jean-Philippe Bapst ,Martine Calame-Christe,Heidi Tanner JessicaGrun a ,Corinne Vebert*b ,Matteo Conzaa , and Alex N. Eberle Wolfgang Meierb ,Helma Wennemers* a

University HospitalBasel,Department of Research,Hebelstrasse 20, a OrganicChemistry,University of Basel, St.Johanns-Ring 19,CH-4056 Basel, Switzerland CH-4031 Basel, Switzerland b Physical Chemistry, UniversityofBasel,Kingelbergstr.80, CH-4056 Basel, Switzerland

Melanotic andamelanoticmelanomas expressreceptorsfor -melanocyte- TheWennemersgroup has recently developedtwo-armed diketopiperazine stimulating hormone ( -MSH;receptor name: MC1R) .Radiolabeled - receptorsthat bind with high bindingselectivities andaffinities.[1] MSHanalogs arepotentialcandidates forreceptor-mediated melanomatar- Thehighly selective intermolecularinteraction between the diketopiperazine geting (diagnosis and therapy).Several short -MSH peptides werede- receptor 1 and the ,Ac-D -Val- D -Val- D -His-resin, was used to induce signed and testedinthe past, which showed high affinity forthe MC1R in supramolecular assemblies by functionalizingthe peptidewith aPEG-chain. vitro ,aswell as agood incorporation in tumor xenografts in vivo,but also In chloroform, diketopiperazine receptor 1 mixed with the peptide-PEG considerable uptake by the kidneys. conjugate 2 [2], formsagel. In aqueous solution, the formation of vesicles 4 5 7 was observed and studied using dynamic lightscattering(DLS),transmis- We now investigate glycosylated analogs of [Nle ,Asp ,D-Phe ]- -MSH4-11 (NAPamide) [1], as glycosylation had been showntoimprove tumor-to- sion electron (TEM)and atomic forcemicroscopy (AFM), surface pressure kidney ratios in the caseofsomatostatin. Carbohydrate moieties such as measurements, as well as,NMR titration. glucose, galactoseand maltotriosewereintroduced at various positions on Phe Tyr(Dye) O O H H the MSHpeptide carrying the metalchelatorDOTA(1,4,7,10- N N N N 111 H H tetraazacyclododecane-1,4,7,10-tetraacetic acid) forlabeling with In.The O O Gln(Trt) N H O O H H peptides wereevaluated in vitro forMC1Rbindingand cellular localization, 1 O O N N (OCH CH ) -OCH N N 2 2 16 3 H N Gln(Trt) H H and in vivo fortissuedistribution. Thetumor-to-kidneyratio forGal- O O O O H H N N N 2 NAPamide(1.85),bearinganN-terminal galactosemoiety, wascomparable N N H H N O O with that of NAPamide (1.92).Other glycopeptides showed verygood bind- Phe Tyr(Dye) H ing affinitiesbut lowerselectivity in vivo. This workisthe firstexample of vesicle formationbased on selective non- Additionally, aclassofnon-glycosylated dimericderivatives,bearing one or covalentinteractions. We envisionthis concepttobeofinterest for encapsu- two moietiesofthe chelator complex, was developedand is currently being lation and drug delivery. tested. [1] (a)H.Wennemers,M.Conza, M. Nold, P. Krattiger, Chem.Eur.J. 2001, 7 ,3342; (b) M. Conza, H. Wennemers, J. Org. Chem. 2002, 67,2696; (c)M.Conza, H. Wennemers, [1]Froidevaux S, Calame-Christe M, Tanner H, Sumanovski L, Eberle Chem. Commun. 2003,866;(d) P. Krattiger,H.Wennemers, Synlett 2005, 4 ,706. AN. JNuclMed. 2002, 43,1699 [2]J.Grun, J. D. Revell,M.Conza, H. Wennemers, Bioorg. Med.Chem. 2006, 14,6197. MEDICINAL CHEMISTRY429 CHIMIA 2007, 61,No. 7/8

Medicinal Chemistry 49 Medicinal Chemistry 50

HypermodifiedEpothilone Analogs as New LeadStructures forAnti- Synthesis of aC-linked Disaccharide Analogue of theThomsen- Cancer DrugDiscovery Friedenreich (TF)-Epitope andFormationofaClustery form as aPotential Anticancer Vaccine ChristianKuzniewski ,Karl-HeinzAltmann Loay Awad,and Pierre Vogel*

Department of Chemistryand Applied Biosciences,ETH Zürich, LGSA, BCH,EPFL, CH-1015 Lausanne, Switzerland Wolfgang-Pauli-Strasse 10, HCI, CH-8093 Zurich, Switzerland TheThomsen-Friedenreich antigen (T antigen) is acancer-associated disac- Epothilones aremicrotubule-stabilizing agents with potent in vitro and in charide whichplays an important role in tumor cell-cellrecognition. The vivo antitumor activity. Although the SAR of thishighly promising com- immunodominant partofthe Tantigen consists of the disaccharide poundclasshas been extensively investigated, specific aspectsstill remain Gal 1 3GalNAc Olinked to serine or threonine. Thegreat potential of unaddressed [1] .Benzimidazole-basedanalogsofepothilonesexhibit en- clusteredantigenmotifs such as 1 forantitumorvaccines has been demon- hanced antiproliferative activity againstdrug-sensitive cancer cells;however strated. [1] they alsoshow increasedsusceptibility to P-gp170-mediated drug efflux[1,2] . In contrast, the corresponding cyclopropane analogs arepoor substrates for P-gp-mediateddrugefflux[3] .The major objective of this project is the de- velopment of an efficient synthesis forepothilone analogues of type 1 ,that allow for the combinedexploitation of the potent biological activity of the 3-deoxy trans-epothilone Ascaffold and an activity-enhancing dimethyl- benzimidazole side chain. To circumvent drug efflux, the epoxide moiety is C-linked disaccharide analogues offerstability towards hydrolysis which is replaced by an isostericcyclopropane ring. Thesestructuralchanges lead to catalysed by ubiquitous glycosidases.Wewishtopresent here the extension hypermodifiedanalogues with little structural resemblance to the original of our previous efforts [2] towards the synthesis of C-disaccharide analogues epothilone scaffold. Thesynthesis of 1 is based on the assembly of frag- of the Tantigen based on aBaylis-Hillman type of condensationbetween a [3-4] ments 2 and 3 via an esterification/ring-closing-metathesis sequence. The D -galactose-derived aldehydeand isolevoglucosenone. preparation of thesebuilding blocks andtheir elaboration into targetstruc- ture 1 willbedescribed in detail. [1]S.D.Kuduk, J. B. Schwarz, X.-T.Chen,P.W.Glunz, D. Sames,G.Ra- gupathi, P. O. Livingston, S. J. Danishefsky, J. Am.Chem. Soc. 1998, 120, 12474. HO N TBSO N [2]Y.-H. Zhu, P. Vogel, Synlett 2001,79 . O OH N [3]Y.-H. Zhu, P. Vogel, Tetrahedron Lett. 1998, 39,31; Y.-H.Zhu, R. De- N O mange, P. Vogel, Tetrahedron: Asymmetry 2000, 11,263; O O OH [1]F.Cachoux et al. , Angew. Chem. Int. Ed. 2005, 44,7469. O [2]F.Cachoux et al., ChemBioChem 2006, 7 ,54. [3]K.C.Nicolaou et al. , J. Am.Chem. Soc. 2001, 123,9313.

Medicinal Chemistry 51 Medicinal Chemistry 52

Vitamin B as a“trojan-horse”intherapy 12 From ASAtoSAM: Introducing the PAMPAdiagnostic mode

PilarRuiz-Sánchez,BernhardSpingler,Roger Alberto Frank Senner University of Zürich,Winterthurerstr.190, CH-8057Zürich, Switzerland F. Hoffmann-La Roche Ltd.,Grenzacherstrasse,4070 Basel, Switzerland We have synthesized and characterized aseriesofPt(II)complexes contain- PAMPA is a1st line permeability screen forpharmaceutical drugs [1-7]. ing vitamin B as aligand.1 Theprecursors [PtCl L]- {L=NH ,antibiotics 12 3 3 When introduced firstin1998 it has been used to predict oral absorption in (norfloxacin, ciprofloxacin) or fluorescentmarkers (dansylimidazole,dan- humans. Later on its application area hasbeen extended to blood brain bar- syl-L-lysine )}, react with thecyanide of vitamin B to form the{Co- 12 rier (BBB) penetrationand even skin permeation[8]. CN-Pt} conjugates, with abehaviour similartothatofcisplatin (example: Nowadays ashift from“AllScreenAll (ASA)” to “Selected Assays and compound 1 ). Molecules (SAM)” is becoming moreand moreimportant in order to sup- Enzymatic corrinoid adenosylation assays2 of theseadducts showed recogni- tion andconversion to adenosylcobalamin and releaseofPt(II)species. portfasterdecisionmaking in early drug development (LI, LO,CLS). Thesenovel derivatives can be used forspecific targeting of cancer cells or PAMPA diagnostic mode is such an examplefor “SAM”. By applying a donor pH profile and acceptor sink conditions (blood pH 7.4, protein bind- bacterialinfections,since fast proliferationcells arehighB12 consumers. Preliminary bacterialand cancer celluptake studieswill be discussed. ingeffects) lowpermeableand lowsolublemolecules arecharacterized in detail. Further extensions arepossible. Thekeywords are: excipient screen- Cl L ing and reduction of sample consumption (DiFi plates). LCPt l H NOC 2 N CONH 2 H NOC CH 2 3 NH3 anticanceractivity C CH3 H C [1]Kansy, Manfred; Senner,Frank; Gubernator,Klaus,J.ofMed.Chem. 3 CONH N N 2 O H 3 C H Co F COOH 1998,41(7),1007. N N H NOC CH3 N N [2]Avdeef,Alex, Cur.Top.inMed.Chem. 2001,1(4), 277. 2 N antibiotic activity CH3 H 3 C [3]Wohnsland, Frank; Faller, Bernard, J. of Med. Chem. 2001,44(6),923. CH3 Norfloxacin [4]Sugano Kiyohiko; Nabuchi Yoshiaki; Machida Minoru; AsoYoshinori, CONH 2 O CH HN N 3 N H C Int. J. of Pharm. 2003,257(1-2), 245. 3 HO O N CH H 3 N S fluorescent [5]Kansy, Manfred; Avdeef,Alex; Fischer,Holger, Drug Disc. Today: O O N O P O Dansylimidazole Tech. 2004,1(4), 349. O O OH [6]Avdeef,Alex, Exp. Op.onDrugMet.&Tox. 2005,1(2), 325. 1 [7] Bendels,Stefanie; Tsinman, Oksana; Wagner, Bjoern; Lipp, Dana;Par- [1]Mundwiler,S.; Spingler,B.; Kurz, P.;Kunze, S.;Alberto,R. Angew. rilla,Isabelle;Kansy,Manfred; Avdeef,Alex, Pharm.Res. 2006, Chem.Int.Edit. 2005, 11,4089. 23(11),2525. [2]Fonseca, M.V.;Escalante-Semerena, J.C. J. Biol.Chem. 2001, 276, [8]Ottaviani, Giorgio; Martel, Sophie; Carrupt,Pierre-Alain, J. of Med. 32101. Chem. 2006,49(13),3948. MEDICINAL CHEMISTRY430 CHIMIA 2007, 61,No. 7/8

Medicinal Chemistry 53 Medicinal Chemistry 54

Orexin Receptor Antagonists:ANew TherapeuticPrinciple in Efficient ligand affinity calculations using Neurology and Psychiatry? novelcomputational methods

Hamed Aissaoui, Christoph Boss, Thierry Sifferlen,Markus Gude, Thomas HolmfridurB.Thorsteinsdottir,Michael Podvinec, Weller,Catherine Brisbare-Roch, François Jenck, John Gatfield, Roberto Torsten Schwede, Markus Meuwly Bravo, Ralf Koberstein University of Basel, Klingelbergstrasse 50/70,CH-4056 Basel, Switzerland Drug Discovery, ActelionPharmaceuticalsLtd., Gewerbestrasse16, 4123 Allschwil, Switzerland

Orexins arehypothalamic peptides that play an importantrole in main- In recent yearsvirtual screening toolsare becomingincreasinglyimportant taining wakefulness in mammals.Permanent deficit in orexinergic function forthe drug discoveryprocess. However,the scoring functions many of is apathophysiological hallmarkofrodent, canine and human narcolepsy. thesemethods useare often found to be lacking in accuracy. Previously a Herewereportthat in ,somnolencewithout cataplexy is induced by MM-GBSA method to calculate binding freeenergies has been validated usingthe well characterized HIV-1proteaseand 16 known ligands as atest pharmacological blockade of both OX1 andOX 2 receptors. We de- scribe the medicinalchemistry efforts thatled fromthe initiallead structure system [1]. We would like to extend this methodtoimprove poses gener- ( 1 )tothe clinical candidate ACT-078573 ( 2 ). ated fromvirtual screening methods by molecular dynamics simulations and O O useMM-GBSAasamore advanced scoring technique to obtain better rank- O O N N ing of ligands. O N N ON O H H One of the main obstaclesinthe routine application of molecular dynamics O LEAD simulations in large-scalevirtualscreening projectsisthe calculation time 1 DRUG that is required.GRIDcomputing is apossible solution to this problem, but CF3 2 molecularsimulations arenot well adaptedtothe parallelization requiredfor Thespecific challenge in this project was to find acompound, which crosses calculations on aGRID. This workaims to develop amethod forparalleli- theblood-brain-barrier (BBB) in order to interact with theorexinreceptors zation andshow that parallelized molecular dynamics is able to reproduce in the brain. It alsoneeded to be devoid of cytochrome inhibition and to binding freeenergies in acomparable way to classical molecular dynamics exhibit appropriate pharmacokinetic properties. Objective is to improve simulations and can thereforebeapplied to virtual screening projects. next-day performance that is often impaired with other insomniadrugs.The results found during preclinical and clinical investigations open new per- spectives forstudying the role of endogenous orexinsinsleep-wake regula- [1] HB.Thorsteinsdottir, T. Schwede,V.Zoete,M.Meuwly, Proteins. tion. 2006,65, 407 [1]Catherine Brisbare-Roch et al, NatureMedicine 2007, 13,150-155. [2] Ralf Koberstein et al, Chimia 2003, 57,270.

Medicinal Chemistry 55 Medicinal Chemistry 56

Ruthenium(II) 6 -AreneImidazoleComplexes: ThePreorganization of theTrisaccharide Core of Sialyl Lewisx ANew Promising ClassofOrganometallic Compounds in Anticancer Is Essential for Binding to E-selectin Therapy Alexander Titz,Beatrice Wagner,Beat Ernst Carsten A. Vock† and Paul J. Dyson† Institute of MolecularPharmacy,University of Basel †Institut desSciences et IngénierieChimiques, Ecole Polytechnique Klingelbergstrasse 50, CH-4056 Basel FédéraledeLausanne (EPFL), CH-1015 Lausanne, Switzerland Theselectins playakeyrole in theinflammatory process. Sincethe physio- Duringthe last decade, ruthenium-based anticancer drugs have becomean logical ligands of theselectinsall containthe tetrasaccharideepitope sialyl important fieldofresearch in organometallic chemistry. Ruthenium(III) Lewis x (sLex ), this epitope served as lead structureinthe search forE- complexeslike NAMI-A[1] or KP1019[2] have shown promising antimeta- selectin antagonists.Ithas been shown that the preorganization of the core static activity andhavesuccessfully completedphase Iclinical trials.Al- in the bioactive conformation [ 1 ] contributessubstantially to the affinity of though imidazole ligands arefrequently used with ruthenium(III) drugs, E-selectin antagonists [ 2 ] . onlyafew examples of ruthenium(II) 6 -arene imidazole complexesare In additiontothe exoanomeric effects, thereare twofactorsthatstabilizethe known, and none of them has been biologically evaluatedsofar. coreconformation of sLe x :(i) by steric compression with sterically demand- ingsubstituents of the GlcN Ac moiety and (ii) by lipophilic interaction be- Therefore, with theintentiontocombine aspectsofbothruthenium(III) and tween thealpha-face of fucosewith thebeta-face of galactose. ruthenium(II) 6 -arene anticancer drugs,our research has focussedonthe synthesis,characterisation and biological evaluation of ruthenium(II) 6 - areneimidazole complexes.[3] Furthermore,the “imidazole strategy” has been used to attach bioactiveorganicligands to ruthenium(II) 6 -arene fragments in order to obtain newand morepowerfuldrugs. [4] Thepresenta- tion will give asummary of ourresearch in this field.

x [1]J.M.Rademaker-Lakhai, D. van denBongard, D. Pluim, J. H. Beijnen, Stabilizing interactions of the bioactive conformation of sLe J. H. Schellens, Clin. Cancer Res. 2004, 10,3717–3727. [2]M.A.Jakupec, V. B. Arion, S. Kapitza, E. Reisner, A. Eichinger, M. In order to verifythe above considerations,aseries of E-selectin antagonists Pongratz, B. Marian, N. Graf von Keyserlingk, B. K. Keppler, Int. J. weresynthesized and biologically evaluated. Clin. Pharm. Ther. 2005, 43,595–596. [3] C. A. Vock, C. Scolaro,A.D.Phillips, R. Scopelliti, G. Sava,P.J. [ 1 ] Scheffler,L.; Ernst, B. et al. Angew. Chem. Int. Ed. 1995, 34,1841. Dyson, J. Med. Chem. 2006, 49,5552–5561. Rinnbauer,M.; Ernst, B. et al.Glycobiology 2003, 13,435. [4]C.A.Vock, W. H. Ang, C. Scolaro, A. D. Phillips,L.Lagopoulos,G. [ 2 ] Kolb, H. C.;Ernst,B. Chem. Eur. J. 1997,3,1571. Thoma, G. et al. Sava,L.Juillerat-Jeanneret, P. J. Dyson, J. Med. Chem.,ASAP. Angew. Chem.lnt.Ed. 2001,40 ,1941. MEDICINAL CHEMISTRY431 CHIMIA 2007, 61,No. 7/8

Medicinal Chemistry 57 Medicinal Chemistry 58

NVP-AEB071: Oral and Specific InhibitorofTcell Activation forthe Structural and Functional Studiesofthe N-terminal domain Prevention of GraftRejectionand theTreatment of of theY4GPCR Autoimmune Diseases Chao Zou ,Stefan Markovic, Reto Walser,OliverZerbe* Rainer Albert, Marc Bigaud, Nigel Cooke, Sylvain Cottens,Jean-Pierre Evenou, Randall Morris,Charles Pally,RichardSedrani, Walter Schuler, Institute of Organic Chemistry, 8057 Zurich, Switzerland Maurice van Eis, Jürgen Wagner,Gerhard Zenke, Peter von Matt G-protein coupled receptors(GPCRs)comprises 2% of the , ATDA andGlobalDiscovery Chemistry, Novartis Institutesfor BioMedical andalmostone thirdofthe drugs on the markettargetGPCRs. Research, Postfach, 4002 Basel, Switzerland Y(NPY) receptors(Yreceptors) areimportant in the regulation of blood pressure,memoryretention and food intake[1]. In human organisms func- tional Y1, Y2, Y4 and Y5 subtypes have been identified. While NPY and Immunosuppressants with an improved therapeuticwindow represent ahigh PYY targetall subtypeswith nanomolaraffinities, the pancreatic peptide medicalneed. Thesearch fornovel approaches to blockT-cell activation led (PP) preferentially binds to the Y4 receptor.Wehaveproposed that peptides to NVP-AEB071, aselective and potent inhibitor of classicaland novel pro- from the NPY family associatewith themembrane prior to binding to the tein kinase C(PKC)isoforms with K valuesinthe low nM range. i receptor[2]. Herein, we have structurally characterized theN-terminal ex- H N tracellulardomainofthe Y4 (N-Y4) receptor and determined whether the OO hormones bind to the isolated domain:

N N N H N

N NVP-AEB071

T-cellactivation is effectively blockedasdetermined by inhibition of IL-2 N-Y4 wasproduced both by solid phasepeptide synthesis and recombinant production (IC50 ~5nM).Incontrast,IL-2-dependent Tcell proliferation is not affected. NVP-AEB071 dose-dependently prolongs Brown-Norway techniques in 15N-labeledin E.coli .Wecomparedthe structureofN-Y4in heartgraftsinLewis rats with all animals reaching28days without clinical solution in the presence and absence of phospholidmicelles by NMR. Bind- adverse events at an oral doseof30mg/kg bid. ing affinitiesofpeptidesfrom the NPY family to N-Y4 have been measured by SPR and mutagenesis experiments revealed the interaction sites. This lecturedescribes the medicinal chemistry programthatled to NVP- AEB071 and highlights its effectivenessasanovel immunosuppressant in [1]Grundemar,L., and Bloom, S. R. (eds). Neuropeptide Yand drug de- animalmodels of transplantation andits tolerabilityinaPh Iclinical trial. velopment, 1997,Academic Press. [2]Bader,R., Zerbe, O. ChemBioChem, 2005,6,1520-1534.

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Non-phosphate inhibitorsofIspE, akinaseinthe non-mevalonate TheRole of Sphingosine-1-PhosphateReceptor Modulators in the pathway andapotentialtargetfor antimalarial therapy Prevention of Transplant Rejectionand Autoimmunity

Anna K. H. Hirsch ,S.Lauw, P. Gersbach, W. BerndSchweizer,F.Rohdich, R. Albert, C. Beerli, M. Bigaud, V. Brinkmann, C. Bruns,N.Cooke, N. W. Eisenreich, A. Bacher,F.Diederich Gray, D. Guerini,K.Hinterding, B. Nüsslein-Hildesheim, C. Pally,S.Pan, C. Spanka,MStreiff, F. Zécri Laboratorium fürOrganischeChemie,ETH Zurich,8093 Zurich, Switzerland Novartis Institutesfor BioMedical Research, Autoimmune Disease&Transplantation, CH-4002 Basel, Switzerland Malaria remains the mostimportant and devastating tropical disease known with 300-500 millionclinical cases and around one million deaths ayear. FTY720 is anovel immunomodulator which is highly effective in animal Theemergence of drug and insecticideresistance theneed formedicines models of organtransplantation andautoimmunity.Phase III clinical trials with anovel mode of action has become increasingly important. for de novo kidneytransplantationwererecently discontinued, while Plasmodium parasites,the causative agents of malaria,use the non- FTY720 successfully completed PhaseIIclinical trials forrelapsing- mevalonate pathway forthe biosynthesisofthe common isoprenoid precur- remitting multiple sclerosis and recently entered PhaseIII forthisindica- sors,whichisdistinctfrom thatusedbyhumans.Hence, the enzymesofthis tion. FTY720-phosphate, the activemetabolite generated upon in vivo phos- pathwayare ideal targets in thefight againstthis important infectious dis- phorylation, acts as apotent agoniston4ofthe 5known sphingosine-1- ease[1]. phosphate (S1P)receptors. ThekinaseIspE, at the center of thenon-mevalonate pathway, was chosen as thetargetofastructure-based drug designproject leading to potent com- H O H O F F OH F petitive inhibitors with K i values in the nanomolar range [2]. Thesyntheses H N H N 2 2 O N and biological activities of thesecompounds will be presented. H OH C H O(CH ) C F 8 17 2 3 2 5 S

FTY720 NIBR713 AUY954

NIBR713,showsselectivity overthe S1P3 receptor while retaining its abil- ity to reduce peripheral lymphocyte counts both in rats and monkeys after p.o. application. AUY954,isamonoselective S1P1agonistwith nanomolar potency and good pharmacokinetic properties both in rats and monkeys in- [1]H.Jomaa et al. , Science 1999, 285,1573. ducing aprofound and reversible reduction of lymphocyte countsand pro- [2]A.K.H.Hirsch, S. Lauw, P. Gersbach, W. B. Schweizer,F.Rohdich, longed survival of cardiac allografts in rats.This demonstrates that targeting W. Eisenreich, A. Bacher,F.Diederich, ChemMedChem 2007,DOI: S1P1 is sufficient to achieve immunomodulation in vivo. 10.1002/cmdc.200700014 MEDICINAL CHEMISTRY432 CHIMIA 2007, 61,No. 7/8

Medicinal Chemistry 61 Medicinal Chemistry 62

Structure-guided OptimizationofAminobenzoquinolizines Towards Ruthenium-PorphyrinCompounds forPhotodynamicCancer Therapy LowNanomolar DPP-IV Inhibitors Bruno Therrien Markus Böhringer,Holger Fischer,Luca Gobbi, Michael Hennig, Jörg Huwyler, BerndKuhn,Bernd Löffler,ThomasLübbers, Patrizio Institut de Chimie, Université de Neuchâtel,CasePostale 158, CH-2009 Mattei, RobertNarquizian, Jörgen Nielsen, Hans PeterWessel, Pierre Wyss Neuchâtel, Switzerland.

F. Hoffmann-LaRoche Ltd.,PharmaceuticalsDivision, Preclinical Research Porphyrin derivatives areknown to concentrate in cancer cells and they are PRBD,CH-4070 Basel, Switzerland used as photosensitising agents in the photochemotherapy of cancer.Ruthe- nium possesses severalfavourable properties suited to rational anticancer Theserineproteasedipeptidyl peptidaseIV(DPP-IV) is aclinically vali- drug design. It is thought that ruthenium complexes reduce tumour growth dated target forthe treatment of type II and has received great in- by amechanismofinteraction with DNAalthough non-genomic targets also terestfromthe pharmaceutical industryoverthe last years[1].Concomitant appear to be important. Therefore, we wereinterestedincoordinating arene- with alarge variety of published smallmolecule DPP-IV inhibitorsacon- ruthenium units to porphyrin moiety to combine thephotodynamic action of siderable number of co-crystalstructures have been solved providing asolid porphyrin with the cytotoxicity of arene-rutheniumcomplexes.Aseries of basis forthe understanding of molecularrecognitioninthis enzyme. organo-ruthenium modifiedporphyrin compounds has been prepared and Glu 206 Tyr662 the in vitro tumourcellgrowth inhibition effectsassessed. Glu 205 NH + NH + O 3 3 R Cl R M Cl M R O N N Cl H Cl O MeO MeO N R N N H = O S1 pocket N N H MeO MeO N Cl Cl N N 1 2 M Cl M Cl R M=Ru, Rh ,Ir, Os We describeour multidisciplinaryapproach to optimize the aminobenzo- R quinolizine HTShit 1 to potent DPP-IV inhibitorsofthe general structure 2 They show astrong photodynamic activityonmelanomasafter exposureto (R =aryl, heteroaryl, 2-oxopyrrolidin-1-yl).The focus of this presentation is light. In particular,two of the eight complexeswereonly slightly cytotoxic placed in theanalysis of thecentralmolecular interactions and theirexploi- towards two metastatic cancer cell lines,unlessexposed to light. These tation by structure-based designmethods. complexesofferaconsiderablepotentialinterms of future drug andirradia- tion leveloptimisation [1]. [1]D.Hunziker,M.Hennig, J.-U. Peters, Curr. Top. Med. Chem. 2005, 5 , 1623-1637 [1]B.Therrien, P. Govindaswamy, G. Süss-Fink, W. H. Ang, P. J. Dyson, F. Schmitt, L. Juillerat-Jeanneret, submitted .

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Enzymatic Functionalizationand Radiolabeling of aTumorAffine Structural studies of fragments of Ste2p,aG-proteincoupled receptor Monoclonal Antibody Using Transglutaminase from yeast, in membrane-mimicking environments

1,2 2 2 1,2 Simone Jeger ,Alexander Hohn ,JürgenGrünberg and Roger Schibli A. Neumoin1 ,L.S.Cohen2 ,B.Arshava2 ,J.Becker3 ,F.Naider 2 1 1 Department of Chemistryand Applied Biosciences, ETHZ, 8093 Zurich, and O. Zerbe * Switzerland. 2 Center forRadiopharmaceutical Science ETH-PSI-USZ,PSI, 5232 Villigen, Switzerland 1 Institute of Organic Chemistry,University of Zurich, 2 College of Staten Island, CUNY, 3 University of Knoxville, Tennessee Antibodies (mAb) functionalized with the chelatordeferoxamine (DF) and radiolabeled with 89Zr showedpromising clinical results [1]. However, the Structural studies of G-protein coupled receptorsare often hampered by five-step coupling of DF to the lysine(Lys) side chains of the mAb by problems in expressing, purifying and reconstituting the receptorsaswell as chemical methods is laborious (see Figure, route B). Using the enzymatic activity of bacterialtransglutaminase (BTGase) we in the spectroscopy of theselarge systems.Tocircumvent some of these wereable to link the primary pentyl amino residue of unmodifiedDFto problems we have looked at fragments comprisingthe transmembrane (TM) glutamine(Gln) side chains of the tumoraffinemAb chCE7agl, via forma- segments.Hereinwereportonthe structureand dynamics of alarge seg- tion of isopeptide bonds under physiological conditions in asingle step mentsofSte2p, the G-protein coupled -factor receptorfromyeast[1],us- (route A).The ligand-to-protein ratio wasdeterminedtobebetween 2and 3, ing solution NMRspectroscopy. We investigatedthe 73-residue peptide whereas forthe chemical method the ratio was foundtobe1only. TM7consisting of the thirdextracellular loop, the 7th transmembrane helix Theimmunoconjugate was radiolabeled with 67Ga. Addition of excessDFto [ 67Ga-DF]-chCE7agl showed only slight transchelation of 67Ga, proving the and40residuesfrom the cytosolic C-terminaldomain [2] in stability andspecificity of the radiolabeling. dodecylphosphocholine (DPC)micelles.The structurereveals the presence Theimplementation of the procedurefor the functionalization of chCE7agl of an -helix forresidues 10 to 30, which is perturbed around the internal with other chelating systems suitable forradiolabeling with 67Cu (e.g. Pro24 residue. Spin-label data indicate that the -helix integratesinto DPC CPTA,DOTA),aswellasinvitro andinvivostudiesare in progress. micelles so that residues 22 to 26 arepartially exposed to solution. Moreover,the data reveal asecond site of interaction with the micelle within thecytosolic portion[3].Our present effortsare concentratedonthe structural studies of the 80-residue peptide TM1-TM2consisting of the 19 residuesfrom N-terminaldomain, the 1sttransmembrane helix, the first cytoplasmic loop, the second transmembrane helix and 7residues fromthe firstendoplasmic loop in lyso-palmitoylphosphatidylglycerol(LPPG) mi- celles. [1] N. Nakayama,A.Miyajima,K.Arai, EMBO J. 1985,10, 2643-2648. [2]R.Estephan, J. Englander,B.Arshava, K. Samples, J. Becker,F. Naider, Biochemistry 2005,44, 11795-11810. [1]Verel et al. JNucl Med , 2003, 44,1271-1281. [3]A.Neumoin, B. Arshava, J. Becker,O.Zerbe,F.Naider, Biophys.J. 2007,inpress MEDICINAL CHEMISTRY433 CHIMIA 2007, 61,No. 7/8

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Synthesis, Crystallography and BiologicalEvaluationofMonocationic Strucure baseddiscoveryofpotentselective inhibitors Complexes[Ru( 6 - p -cymene)(Racac)(PTA)][X] of Leishmnia sirtuin

(Racac =DifferentSymmetric 1,3-Diketonates; X=BPh 4 ,BF 4 ) Rameshwar U. Kadam1 ,Joana Tavares2 ,Kiran V. M 1 ,AnabelaCordeiro 2 , Carsten A. Vock,† Anna K. Renfrew , † Hervé Pittet,† Ali Ouaissi3 ,and Nilanjan Roy 1 * Lucienne Juillerat-Jeanneret †† and Paul J. Dyson† Centre of Pharmacoinformatics 1 ,National Institute of Pharmaceutical Edu- † cation and Research, S.A.SNagar-160062,India; Faculdade de Farmacia da Institut desSciences et IngénierieChimiques, Ecole Polytechnique 2 3 Fedérale de Lausanne (EPFL), CH-1015 Lausanne Universidade do Porto ,Portugal and "Pathogeniedes Trypanosomatides ", 34394 Montpellier Cedex 5, France †† University Institute of Pathology, CHUV,Rue de Bugnon 25, CH-1011 Lausanne,Switzerland. In the recent yearsvisceral leishmaniasisisrapidly emerging as an oppor-

6 tunistic infection in HIV patients,inpregnancy andorgan transplant. Glob- Thedevelopmentofnew ruthenium(II) -arene complexesaspotential alizationand consequent travel of peopleacrossthe world has increased the [1,2] anticancer agentshas gainedconsiderableinterestduringthe last years. chances of spreading theinfection. Since theavailabletreatment for RAPTAcomplexeswith PTAligands (PTA =1,3,5-triaza-7-phospha- leishmaniasis poses many problems,researchersare looking fornovel tar- [1] adamantane)haveshown promising antimetastatic activity, and complexes gets in ordertodevelop newdrugs.Inthisquest,wehavebuilt homology [2] with acetylacetone ligands exhibit strong cytotoxic effects. model of LmSir2,anemergingtargetand didcomparativeanalysis of co- factor and substrate binding site of leishmania and human Sir2. Our finding indicates fewsubtle structural deference in NAD binding and catalytic do- main of LmSir2and human Sir2.1 In abid to identifycompounds selective to LmSir2, we have screened 2x10 5 NCIcompounds based on nicotina- mide fingerprintfollowed by docking in boththe active site. Thecom- pounds showed selectivity in docking study is subjected to in-vitro enzy- matic and cell killing assay. We have successfully identified fewcom- In ordertocombine both moieties, we willpresent synthetic andcrystallo- pounds which areselective against LmSir2and cankill axenic amastigotes graphic aspects forthe novel monocationic complexes [Ru( 6 - p -cymene) in culture.Our result indicates thatthis strategy canbeusedfor screening of more selective LmSir2 inhibitors. (Racac)(PTA)][X] (Racac =different symmetric 1,3-diketonates;X=BPh4 , 1400 AD- BF4 ). Results of biological in vitro studieswill be included. -N 1200 1000 NAD+

800 Control

340/460 600 2,5mMNCI 7 at [1]W.H.Ang, P. J. Dyson, Eur. J. Inorg. Chem. 2006,4003–4018. 400 200

0 [2]A.Habtemariam, M. Melchart, R. Fernandez, S. Parsons,I.D.H. Fluorescence Oswald, A. Parkin, F. P. A. Fabbiani, J. E. Davidson, A. Dawson, R. E. [1]Kadam, R. U.;Kiran,V.M.; Roy, N, Bioorg. Med. Chem. Lett. 2006, Aird,D.I.Jodrell, P. J. Sadler, J. Med. Chem. 2006 , 49,6858–6868. 16, 6013-8 .

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Nuclear targeted therapyusing 99mTc-intercalatingcomplexes Natural Product-Like Furo[3,4-c ]pyranones as Lead Structure for Novel Anticancer Agents Patricia Antunes ,Eszter Boros, Roger Alberto Cyril A. Fuhrer a ,Stephan Ruetzb ,Alina Nussbaumer a ,Fabian Wengera and Institute of Inorganic Chemistry,University of Zurich, RobertHänera Winterthurerstrasse 190, 8057 Zurich, Switzerland a Department of Chemistry, University of Bern,CH-3012 Bern,Switzerland Beside its usefulnessfor radioimaging the potential application of 99mTc for b Novartis Institutes of Biomedical Research, CH-4002 Basel, Switzerland therapeutic purposes is basedonits radiotoxicity as caused by low energy and high LETAuger electrons.Nevertheless, thetherapeutic potentialof New drugs arerequired to combat drug resistance, forthe improvement in this Auger-emitting radionuclide is critically dependent on the cellular local- the treatment of existing diseases,the treatment of newly identified diseases isation. An intranuclear decayiscrucial to provoke cellular catabolism and the production of saferdrugs by the reduction or removal of adverse through DNA damage. Forthis purpose, the conjugation of DNA targeting side effects. andbinding molecules in theligands designiscrucial.Wehave recently We have shown that natural product-like compounds can improve the drug proved theprinciple that intercalatorscan be used as carriersfor 99mTc into discovery namely the hit/lead identification process.1 In connection with this the nucleus.[1,2] In extending thisprinciple to ourwork, DNA intercalators strategy we recently reported the synthesisofdifferent natural product-like like acridine orange and Hoechstare attached to mono/bidentate ligands in furo[3,4- c ]pyranones. 2 Thesecompounds like 1 ,containing a cis -stilbene ordertotarget nuclear DNA with the corresponding Re/99mTc-complexes. motif,exhibited interesting anticancer properties in different human cancer Theremaining position should then be occupied with acell specific recep- celllines.3 Afteridentification of the cis -stilbene as pharmacophorewenow tor-targeting agent. This [2+1] methodology is used with avariety of investigate how thesubstitution pattern of this motif correlatestothe bio- monodentate ligands,including amodel dipeptide. The in vitro studies of logical activity. Ashort summary of this structure-activity relationships 99m thesenew Re/ Tc-intercalatingagentswill be presented. (SAR)study will be presented.

a) b) N N N R''' R O 4 R' O 1 HN O O H N (+/-) H HN N R'' OH N H N N O O N O Acridine Orange a) andHoechst b) basedligands [1]R.Messer,C.A.Fuhrer,R.Häner, Curr. Opin.Chem. Biol. 2005, 9 , 259-265. [1]P.Haefliger,N.Agorastos,A.Renard, G. Giambonini-Brugnoli, [2]C.A.Fuhrer,R.Messer,R.Häner, Tetrahedron Lett. 2004, 45,4297- C. Marty, and R. Alberto, Bioconjugate Chem. 2005 , 16,582. 4300. [2]N.Agorastos,L.Borsig, A. Renard, P. Antoni, G. Viola, B. Spingler, [3]C.A.Fuhrer,E.Grüter, S. Ruetz,R. Häner, ChemMedChem 2007, 2 , P. Kurz,and R. Alberto, Chem. Eur. J. 2007,000. 441-444. MEDICINAL CHEMISTRY434 CHIMIA 2007, 61,No. 7/8

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Combinatorial Variation of BranchingLengthand Multivalency in a FactorsModulating Time-Dependent DistributionofChlorin Deriva- Large (390'625 Member) Glycopeptide DendrimerLibrary: tivesinPhospholipid Membranes Ligands forFucose-specificLectins MartinaVermathen,Peter Bigler Emma M. V. Johansson ,Tamis Darbre,Jean-LouisReymond* University of Berne,Department of Chemistry andBiochemistry, Freiestrasse 3, 3012 Bern,Switzerland Department of Chemistryand Biochemistry, University of Berne, Freiestrasse 3, 3012 Berne, Switzerland Membranepenetration of porphyrinic drugs is believed to be one of the cru- cial factorsfor theirefficiency in Photodynamic Therapy (PDT)ofdiseased Theantibiotic-resistant pathogenic pseudomonas aeruginosa bacterium tissues,since singlet oxygen, the actual cytotoxic species,unfolds its effect causes lethal respiratorytract infections in cystic fibrosis patients.The fu- mainly in the immediate surrounding of the location whereitisgenerated, cose specific lectin PA-IIL (LecB)mediatestissueattachment andbiofilm [1] i.e. the location of the excited photosensitizer [1]. In this study previous formation and can be inhibited by fucose. We have discovered high- NMR-spectroscopic kinetic studies of chlorin e6 (CE) and mono-L-aspartyl affinity ligands forPA-IILbyscreening combinatorialfucosyl-peptide den- chlorin e6 (MACE) transition across the phospholipid (PL)-bilayer [2]were drimerlibraries.[2] Here we reportastudy of multivalency effects in these [3] extended to further determine the factorswhich modulatethis distribution ligandsusing an innovative combinatorial approach. process. Addition of CE or MACE resultedincharacteristic changesinthe 1 HNMR spectrum of dioleoylphosphatidyl choline(DOPC)vesicles,most (X) (X) (X) n (X)n n n pronounced being asplit of the PL-choline resonances.Atneutral pH CO2 H (X) n (X)n (X)n MACE remained surface attached while CE slowlydistributed acrossthe H C O (X)n + 3 OH bilayer[2].For CE an exponential relationship wasfound between the tran- (X)n OH OH (X) n (X) n sition rate constant and the pH of the surrounding medium, while forMACE (X) (X) 1 (= ) n n reduction of the pH hadonly little effect.Inaddition, the rate constant was (X) n Tripod library (X) (390'536 structures) n found to depend on chlorin concentration. Increase in membranerigidity reduced the transition rate of CE as was derived fromstudies performed bis- to penta-valentglycodendrimers with cholesterol containing DOPC vesicles. In conclusion, the above results demonstrate that membranelocalization anddistribution of the porphyrinic [1]D.Tielker et al., Microbiol. 2005, 151,1313. compound canbeverysensitive to small changesinthe physico-chemical [2] E. Kolomiets, E. M. V. Johansson, O. Renaudet, T. Darbre, propertiesofthe chlorin vesicle system. J.–L.Reymond, Org. Lett. 2007, 9 ,1465-1468. [3]E.M.V.Johansson, E. Kolomiets, D. Tielker,K.-M. Bartels, [1]A.Castano, T.N.Demidova, M.R. Hamblin, Photodiagnosis and Pho- F. Rosenau, K.-E.Jäger,T.Darbre, J.-L.Reymond, N. J. Chem. 2007, todynamic Therapy 2004, 1 ,279. DOI:10.1039/b616051b. [2]M. Vermathen, U. Simonis, P. Bigler, J. Porphyrins Phthalocyanines 2006, 10,519.

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AComputational Study on theDimerization of Studies on theTotal Synthesis of Resorcyclic Lactone LE-783,277 – ANew Lead Structure for KinaseInhibition Manuela Koch,Markus Meuwly Tatjana Hofmann,Karl-Heinz Altmann University of Basel, Klingelbergstrasse 80, CH-4056 Basel,Switzerland Institute of Pharmaceutical Sciences,ETH Zurich, In recent years the number of social diseases has steadily increased. Dia- Wolfgang-Pauli-Strasse 10, 8093 Zurich,Switzerland betes mellitus is one of thebiggest impacts on adults of working age and is reaching epidemic proportions in industrial countries.1 , 2 Kinaseshave emerged as important drug targets in cancer andinflammatory Patients suffering from Diabetes mellitus are not able to either produce diseaseand several low-molecular-weight kinaseinhibitorshave now been or to assimilate insulin and have to be treated with insulin shots. Insulin introduced into clinical practice.[1]The natural product L-783,277 ( 1 ) is apeptide hormone whichcontrols the concentration of glucose in the belongs to the family of resorcyclic acid lactones (RALs),which includes compounds such as zearalenone, C292 (LL-Z1640-2),hypothemycin,or blood stream. In its nativeform insulin aggregates immediately into a Radicicol,and whichexhibit adiverserange of biological activities.[2] hexamer under physiological conditions. In the human body only the L-783,277 ( 1 )isapotent inhibitor of the Ser/Thr kinase MEK.[3] No total monomeric form binds to the receptor what causes severe problems in synthesis of 1 has been reported so farand the biological activity of the insulin therapy. Experimentally,itwas found that mutations at theend compound has not been characterized beyond itsability to inhibit afew of the Bchainofthe protein, especially at position B243 have asignifi- selected kinases.The development of an efficient enantioselectivesynthesis cant influence on thereceptor binding potency. 4 of 1 and amoredetailedcharacterizationofits biological effectsare the primarygoals of this research project. Thesynthesis of macrolactone 1 is In this study twoB24-insulin monomer anddimer mutants were investi- based on theconsecutive assembly of thekey fragments A and B ,whose gated using atomistically detailed computer simulations. Moleculardy- synthesis is already implemented. Thepreparationofthe advanced interme- namics simulations forthe nativeand the twomutatedforms showed diate C as well as their ongoing assembly will be described in detail. This differences in flexibilityinparticular at thedimerization interface. As approach will enable the synthesisofanalogsfor SAR studiesand also ameasure for aggregation potency the dimerization energies were calcu- biophysical investigations,inorder to assess its usefulnessasapotential lated andwerecompared to the calculated energy of thenativeform and lead structurefor drug discovery. to the experimentrespectively.

[1] World Health Org. http://www.who.int/diabetes/facts/en.2006 [2] WicoxG., Clin. Biochem. Rev , 2005, 26,19. [3] Hua Q. X., Shoelson S. E.,InouyeK., Weiss M., Proc.Natl. Acad. Sci., 1993, 90,582. [4] DeFelippis M.R., Chance R. E., Frank B. H., Critical Reiews [1]Krause, D. S. and Van Etten, R. H. N. Engl.J.Med. 2005,353, 172-187. in TherapeuticalDrug Carrier Systems, 2001, 18,201. [2]Winssinger,N.and Barluenga, S. Chem. Commun. 2007, 1 ,22-36. [3] Zhao,A.; Lee, S. H.;Mojena,M.; Jenkins,R.G.; Patrick, D. R.;Huber, H. E.; Goetz, M. A.;Hensens,O.D.; Zink,D.L.; Vilella, D.;Dombrowski, A. W.;Lingham, R. B.;Huang, L. J. Antibiot. 1999,52 (12),1086-1094 MEDICINAL CHEMISTRY435 CHIMIA 2007, 61,No. 7/8

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Interactions of abacterial lipopolysaccharide with antibacterial Novel BisubstrateInhibitors of Catechol- O -Methyltransferase peptides (COMT): Investigation of theRiboseStructural Unit

Jiˇr ´ı Mareˇs ,Sowmini Kumaran, Oliver Zerbe ManuelEllermann[a] ,Ralph Paulini[a] ,Edilio Borroni[b] ,Gerhard Zürcher [b] , Roland Jakob-Roetne[b] ,FrançoisDiederich *[a] UniversityofZ¨u rich, Winterthurerstr. 190, CH-8057 Z¨urich, Switzerland

[a] The action of manyantibacterial (ATB) peptides starts by interacting with Laboratorium fürOrganischeChemie,ETH Zürich, Wolfgang- lipopolysaccharide (LPS), whichlargely forms the outer membrane of gram- Pauli-Str. 10,8093 Zürich [b] negativebacteria. We purified isotopically labelled LPS from the deep rough Pharma Division, Präklinische Forschung, F. Hoffman-La Roche AG, mutantofEscherichia coli D31m4 [1] for NMR studies. Incorporation of LPS Grenzacherstr.124, 4070 Basel into dodecylphosphocholine (DPC) micelles provided asuitable model of a bacterial membrane. Heteronuclear 2D and 3D spectroscopytechniques were Catechol-O -Methyltransferase (COMT) is one of thekey enzymes involved employedfor assignmentpurposes. Interactions of LPS with ATBpeptide in catecholamine catabolism. Therefore it is avaluabletargetfor the treat- were studied by chemical shift mapping experiments using proton-carbon cor- ment of CNSdisorderssuch as Parkinson’sdisease [1]. Highly potent bi- relation experiments. Moreover, contacts were additionally directly probed substrate Inhibitors(e.g. 1 )have been developed by de novo design [2], but by isotopeedited and isotope-filtered NOESY experiments The data allowto the exact binding motif at the ribosemoiety still requiresfurtherexplanation describeATB peptide-LPS interactions at atomic resolution. [3]. In our ongoing workwesynthesizenovel bisubstrate inhibitorsinorder to investigate these interactions in detail.

[1]P.T.Männistö,S.Kaakola, Pharmacol.Rev. 1999,51, 593-628. [2]C.Lerner,A.Ruf,V.Gramlich, B. Masjost, G. Zürcher,R.Jakob- Roetne, E. Borroni, F. Diederich, Ang. Chem.Int.Ed. 2001,40, 4040- 4042. [3]R.Paulini, C. Trindler,C.Lerner, L. Brändli, W. B. Schweizer,R.Ja- kob-Roetne, G. Zürcher,E.Borroni,F.Diederich, ChemMedChem [1] Qureshi, J. Biol. Chem., 1988, 263,11971. 2006,1,340-357.

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Synthesisofconformationaly constrainednucleotideswith improved Antisense mechanisms of tc-DNA modifiedoligonucleotides lipophilicity DamianIttig1 ,Daniel Schümperli2 ,Christian J. Leumann1 Samuel Luisier, Christian Leumann 1 Department of Chemistry and Biochemistry, Freiestrasse 3, 3012 Bern, Department of chemistryand biochemistry,University of Bern, 2 Department of Cell Biology, Baltzerstrasse 4, 3012Bern, Freiestrasse 3, 3012 Bern,Switzerland University of Bern,Switzerland

Tricyclo (tc)-and bicycle (bc)-DNA show promisingproperties as antisense High potential in terms of antisense properties is given to the classofcon- oligonucleotides1,2 .Due to the anionic character of the sugar-phosphate formationally constrainedoligonucleotide analoguessuch as forexample backbone, oligonuclceotides and modifiedoligonucleotides show restricted LNAortricyclo (tc)-DNA [1](Fig.), which show signifcantly enhanced cellular uptake. Theattachment of alipophilic rest to the sugaranalogue of targetbinding propertiesand enhanced biological stability. bc-DNAisexpected to increasethe membranepermeability of the modified We investigated different antisense mechanisms(steric block, RNase Hin- oligo-nucleotide3 .Inthis context,wesynthesized two different bicyclo- ducedmRNAdegradation and siRNA) of afully modifiedtc- DNA analogues,with lipophilic side chains at the carbocyclic rings. oligonucleotide, 5-8-5tc-DNA gapmer and sensestrandmodifiedsiRNAs that weredirected to thecoding region of theEnhanced Green Fluorescent -O -O -O Protein(EGFP) mRNA. Adual fluorescence reporter assaywas used [2] P P P -O P consisting of two plasmids carrying EGFP and RedFluorescent Protein O O H O O H O O H O H O O O O O (RFP, as acontrol) that werecotransfected with variable amounts of an- base base RON base base tisenseoligonucleotides into HeLacells. Theantisenseeffect was quantified RO C O O O 2 O on the protein level by Fluorescence Activated Cell Sorting (FACS) and on the RNAlevel by quantitative PCR. tc-DNA tc-DNA obc-DNA abc-DNA

R=alkyl, aryl, steroid O P O OOP O P O O O O Base H Base O O O Base

O O O O

1 D. Ittig,S.Liu,D.Renneberg, D. Schümperli, C. J. Leumann, Nucleic DNA Tricyclo-DNA LNA AcidsRes. , 2004, 32, 346 2 D. Renneberg, C. Leumann, J. Am.Chem. Soc, 2002, 124,5993 3 P. Chaltin, A. Margineanu, D. Marchand, A. VanAerschot, J. Rozenski, [1]D.Ittig,S.Liu,D.Renneberg, D. Schümperli,C.J.Leumann, Nucleic F. C. De Schryver, F. Herrmann, K. Müllen, R. Juliano, M. Fisher, AcidsRes, 2004, 32,346-353. H. Kang, S. De Feyter,P.Herdewijn, Bioconjugate Chem., 2005, 16,827 [2]Y.-L.Chiu, T. M. Rana, Mol. Cell, 2002, 10,549-561. MEDICINAL CHEMISTRY436 CHIMIA 2007, 61,No. 7/8

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Stereoselectiveblock of hERG channelby(S)-methadone and Synthesisofnew prodrugsofcyclosporin Aapplying chemical and detailedstudies of mechanisms of interaction. enzymatic triggering of O,N-acyl migrations in situ

Liliana Sintra Grilo (1,2), Pierre-Alain Carrupt (1), Hugues Abriel(2) J. Bérard,E.Condemi, R. Lysek, M. Mutter

(1)Pharmacochemistry, School of Pharmaceutical Sciences,University of SwissFederal Institute of Technology (EPFL), CH-1015 Lausanne Geneva, University of Lausanne, Switzerland.(2) Department of Pharma- cology andToxicology,University of Lausanne, Switzerland. Thecyclosporin family is composedofcyclic undecapeptidesamong the cy- closporin A(CsA) is the most important representative due to its well known im- Methadone, awidely used opioid μ -receptor ,blocks the hERG munosuppressive,anti-inflammatory, antifugaland antiparasitic activities. The potassium channelessentialincardiacrepolarization. As aresult, metha- biological efficiency of the molecule is limitedbyits poor solubility thatinduces done prolongs the QT interval and can triggerpotentially lethal arrhythmias forexample loworal absorption. To overcome this problem, the synthesis of pro- [1]. Methadone is given as aracemate, even though (R)-methadone has a drugs of CsAand its synthetic analogueshas been amajor topic of research over manyyears [1]. Here, we apply the conceptofswitch-peptides[2] in transforming higher μ -receptor activity [2]. CsAtoits N(Y)-protected Iso-CsAderivative (Soff-state), whichundergoesby We investigated how thehERGcurrent (IhERG) is stereoselectively chemicalorenzymatic cleavage of Yspontaneous O,N-acyl migration to native blocked by one enantiomer and investigated the state-dependency of the CsA(Son).The chemicalsynthesis, the kineticsofcleavage, physico-chemical and block. IhERGwererecorded fromHEK293 cells expressing the wild type biological propertiesofaseries of Y-protected Iso-CsAderivativesare investi- channel or mutants,using the patch-clamp technique at 37° Cor25° C. gated. It will be shown, thatthe prodrugs (Soff state)are devoid of biological activ- Methadone-induced block of IhERGwas found to be stereoselective ity, exhibit high chemical stabilityatphysiological conditions andshow signifi- under both recording temperatures.At37° C, we found that (S)-methadone cantly increased solubility.

is ~3.5-fold more potentinblockingIhERG than the(R)-form (IC 50=2μ M and 7 μ Mrespectively).Block is the contribution of both closed and open HO states,and stereoselectivity seemstohappen in theopen state. Residue F656 O O O O 1 1 - Y 1 is important forthe binding of methadoneasthe mutant F656A shows de- pH >7 N N H 2 N O O creased block. Theses findings provide new insights into stereoselectivity in Y O O the field of drug-induced Long QT syndrome.

N-(Y) -Iso-CsA (Soff) Iso-CsA CsA (Son) [1]PearsonEC, Woosley RL, Pharmacoepidemiol. Drug Saf. 2005, 14, In modulating Y, the transformation of the CsAprodrugs to their bioactive state 747-53 (Son) proceeds smoothly overatimescaleuptoseveral hours. Results on thede- [2]Kristensen K, ChristensenCB, ChristrupLL, LifeSci. 1995, 56,L45- sign andsynthesis of protecting groups Yexhibiting highsolubilising power in L50 waterwill also be presented. [1]a)R.Oliyai, TJ.Siahaan,VJ. Stella, Pharm. Res ., 12,323 (1995).b)A.Hamel, F. Hublerand M. Mutter, J. Pept. Res ., 65(3),364-374 (2005). [2]a)M.Mutter, et al., Angew. Chem.Int. Ed., 43, 4172 (2004).b)S.Dos Santos, et al., J. Am. Chem.Soc., 127, 11888 (2005).

Medicinal Chemistry 79 Medicinal Chemistry 80

Screeningfor antioxidant propertiesbydifferent in vitro assays Rapid IdentificationofProteaseSubstratesbyDirect On-bead Assayof Peptide Combinatorial Libraries DelphineCressend,Marianne Reist, Pierre-Alain Carrupt Ewelina Minta,Jacob Kofoed,Jean-Louis Reymond* Unité de Pharmacochimie, Sectiondes sciences pharmaceutiques, Université de Genève,Université de Lausanne, Quai Ernest-Ansermet 30, Department of Chemistry &Biochemistry, CH-1211 Genève 4, Suisse Freiestrasse 3, 3012 Bern,Switzerland

Oxidativestress, contributing to the pathophysiology of many diseases Proteolyticpathways have acrucialimportance to biological regulation of with ahigh incidenceinthe population, is resulting fromanimbalance bet- the fundamental aspectsofcell behaviour.Proteases areinvolved in differ- ween thegeneration and detoxification of reactiveoxygen species (ROS). ent pathological processessuchascancer,neurodegenerative and cardiovas- To protect biomolecules form ROS,efficient antioxidantsare needed. cular diseases,i.e., thus theseenzymes areimportant biomarkersand poten- Twocomplementary in vitro microplateassays wereusedtoscreenfor tialdrug targets.Asaresult, specific andsensitive assays to monitor the newchemical entities(NCE) with antioxidant properties. One wasa activity of proteases areofthe great interest.Activity-based proteinprofil- fluorimetric test[1] to assess the antioxidant capacity of compounds to pro- ing is achemical proteomic method that characterizes proteasespecificity tect proteins fromlossofactivity caused by ROS, using alkaline phospha- fromthe sequence of shortpeptidic or peptidomimetic substrates [1,2,3] tase(ALP) as model protein. EC50(prot),i.e.requiredconcentrations to pro- Herewereportamethod forthe rapid discoveryofselective proteasesub- tect ALPto50% from maximalactivity decrease, were determined. The strates by screening a65'536 member octapeptidesplit-and-mix combina- other assaywas aspectrophotometric test[2] to evaluate theradical scaven- torial library.Proteolysis is carried out directly on-bead, followed by che- ging capacity of compounds able to participate in hydrogen transferreac- moselective staining of proteolyzed sequencesand high-throughput decod- tions,based on the scavenging of the stable radical 2,2-diphenyl-1- ing [4] .The method correctly identifies reactive subtrates forsolution assays, and deliversoriginal new reactive sequencestoguide the designofinhibi- picrylhydrazyl (DPPH).Results wereexpressedasEC 50(DPPH),the effec- tive concentration to scavenge 50% of DPPH, and as log Z, akinetic pa- tors. rameter derived from initial second-order rate constants and antioxi- dant/DPPH ratios. [1] O. Schilling,C.M.Overall, Curr Opin Chem Biol. 2007, 11, 36. Theseantioxidant parametersallowed to characterizethe antioxidant [2]M.J.Evans,B.F.Cravatt, Chem Rev 2006, 106,3279. properties of NCEand to comparethem with thoseofknown reference anti- [3]Y.Yang, J.-L.Reymond, MolBioSys 2005, 1 ,57. oxidants. [4]J.Kofoed, PhDdissertation 2006,University of Bern.

[1]BertoliniF,Novaroli L, Carrupt PA,Reist M, J. Pharm. Sci. 2007, in press. [ 2] Ancerewicz J, Migliavacca E, Carrupt PA,Testa B, Brée F, Zini R, Til- lement JP,Labidalle S, Guyot D, Chauvet-Monges AM,Crevat A, Le Ridant A, Free RadBiolMed. 1998. 25,113-120. MEDICINAL CHEMISTRY437 CHIMIA 2007, 61,No. 7/8

Medicinal Chemistry 81 Medicinal Chemistry 82

NeoglycopeptideDendrimer Libraries as aSource of Lectin Binding Development of anovel BNA biosensorbased on DNA-core-shell Ligands nanoparticles

ElenaKolomiets,Tamis Darbre, Jean-Louis Reymond* Caroline Fraysse-Ailhas a ,Sandrine Pouxa ,Cornelia Palivana , Franck Vazquezb ,Wolfgang Meiera Department of Chemistryand Biochemistry, University of Berne, Freiestrasse 3, 3012 Berne, Switzerland a University Basel, Klingelbergstrasse 80,4056 Basel, Switzerland b FriedrichMiescherInstitute for Biomedical Research,Maulbeerstrasse 66, Amicroballectin PA-IIL involvedinbiofilm formation in the opportunistic 4058 Basel, Switzerland pathogen P seudomonas aeruginosa responsible forlethal infections in cystic fibrosis patients.Micromolar affinity binding of this lectin to fucoseinhibits Theincreasing demand of DNA biosensing formedical applications in- attachment of the bacterium to its hostcelland mayblockinfection.[1] creased dramatically since some years, and lead to thedevelopment of dif- High-affinity ligands forPA-IILlectin wererevealed by screening of 2 nd ferent systems 1, 2 .Wepresent thedesignand development of anew DNA generation fucosylated peptide dendrimerlibrary.[2]Under investigation of biosensor system based on core-shell nanoparticles 3 . the structure-activity relationship in one of the most potent ligand FD2 ,the

nanomolarligand was find out with IC50 =25nM.Incontinuation, the impor- tance of sequence wasshown and multivalency effect was stud- ied.[3]

HO NH2

HO OH HO O O H HO N N HN OH O HN O O O O O N HN O

NH2 HN FD2 H O N O H 2 N HN N O H O O NH H O Thesystemisacting as aDNA biosensor perse ,inaqueous solution and NH O O Lectin IC50 (ELLA) N N NH NH N NH H O UEA-I 11 μ M O H O withoutany disturbance from the polymer particles.Asthey allow recovery O N O N H O O NH PA-IIL 0.14 μ M NH O 2 HN O NH H of both the DNA biosensor and the precious DNA sample after measure- N H N N NH2 2 O NH OH O O ment,for re-use andfurther analysis,respectively,our particles have ahigh NH O N H N O 2 OH potentialfor medical applications. OH OH HO OH 1. Brown, P. O.;Botstein,D. NatureGenetics 1999, 21, 33-37. [1]D.Tielker,S.Hacker,R.Loris,M.Strathmann,K.-E. Jaeger, Mic- 2. McGlennen, R. C. Clinical Chemistry 2001, 47, (3), 393-402. robiology. 2005, 151,1313. 3. Kong,X.Z.; Ruckenstein, E. Journal Of AppliedPolymer Science [2]E.Kolomiets, E. M. V. Johansson, O. Renaudet, T. Darbre, J.-L. 1999, 73,(11), 2235-2245. Reymond, Org. Lett. 2007, 9 ,1465. [3]E.Kolomiets,T.Darbre, J.-L.Reymond, unpublished results.

Medicinal Chemistry 83 Medicinal Chemistry 84 Lipophilicity determination by RP-LC: Preparation andcharacterizationofNaYF4 :Yb,Er nanoparticles thecomplexcaseofzwitterionic compounds Mireille Crittin,Michel J. Rossi,Hubertvan den Bergh

SwissFederal Institute of Technology,Air and Soil Pollution Laboratory, Amandine Guillot,Sophie Martel, Pierre-Alain Carrupt CH-1015 Lausanne, Switzerland Unité de Pharmacochimie, Sectiondes sciences pharmaceutiques, Up-converting phosphors, which emit visible light upon infraredexcitation, Université de Genève,Université de Lausanne, Quai Ernest-Ansermet 30, have agreat potential in biological labellingand imaging. Thepurposeof CH-1211 Genève 4, Suisse. this project is to prepareultrasensitive up-converting nanoparticles forcell

biologicalstudies.NaYF4 hasbeen reportedasthe mostefficient hostmate- Lipophilicity, akey parameter in thestudy of pharmacokinetic behav- rial forgreen (Yb/Er)up-conversion phosphors[1].Water-soluble iour of NCEmustbemeasured by rapidand accurateexperimental methods

NaYF4 :Yb,Er nanoparticles have been prepared using the hydrothermal in early stagesofdrugdevelopment. In this context, RP-LCmethods,based method [2]. We will focus on the details of the preparation as well as the on correlation between log Pand log k w (measured or extrapolated retention characteristic properties of thesenanoparticles such as morphology, pho- factors),werelargely used forthe determinationoflog Poct of neutral, toemission yield and structureinrelation to relevant parametersoftheir acidic and basiccompounds [1,2]. However,16%of drugs areampholytes preparationmethod. Images of theseup-converting nanoparticles upon (compounds containing abasic and an acidicfunction) and number of them Near-IR excitation within cells will also be presented. acidic basic arezwitterionic compounds (pK a

1. Lombardo F, Shalaeva MY,Tupper KA,Gao F, Abraham MH. J.Med.Chem. 2000, 43,2922-2928 2. Nasal A, Siluk D, Kaliszan A. Curr.Med.Chem. 2003, 10,381-426. MEDICINAL CHEMISTRY/COMPUTATIONAL CHEMISTRY438 doi:10.2533/chimia.2007.438 CHIMIA 2007, 61,No. 7/8

Medicinal Chemistry 85 Medicinal Chemistry 86

NewC-glucosylxanthones from theleaves of Arrabidaea patellifera Analyses andbioactivitiesofwildpopulations of Rhodiola rosea L. (Bignoniaceae) (Crassulaceae) from Switzerland

F. Martina ,A.E.Haya ,S.Vargas a ,L.Vivasb ,M.P.Guptac and D. van Diermen, A. Marston, K. Ndjoko and K. Hostettmann K. Hostettmanna,* LaboratoryofPharmacognosyand Phytochemistry, School of Pharmaceuti- a LaboratoryofPharmacognosyand Phytochemistry, School of Pharmaceuti- cal Sciences,University of Geneva, University of Lausanne, Quai Ernest- cal Sciences,University of Geneva, University of Lausanne, Quai Ernest- Ansermet30, CH-1211 Geneva 4, Switzerland Ansermet30, CH-1211 Geneva 4, Switzerland. b London School of Hygiene and Tropical Medicine, Department of Infec- tious and Tropical Diseases,Keppel Street, LondonWC1E7HT,UK Rhodiola rosea L.,alsoknown as “Golden root”, hasbeen used forcenturies c Center forPharmacognostic Research on Panamanian Flora in the traditionalmedicine of EasternEurope and Asia. It has been classed (CIFLORPAN), College of Pharmacy,University of Panama,Panama as an adaptogenbyRussian researchersdue to its ability to increaseresis- tance in humans to avariety of stressors. As apartofour ongoing investigations on Panamanian Bignoniaceae [1], According to the Soviet Pharmacopoeia(RFMHMI 1983),extracts of sevenmethanolic extractsfrom sixplantsweresubmittedtoa -hematin Rhodiola rosea L. arenow standardized in both rosavin (min. 3%)and sa- polymerization inhibition test[2].This reaction is one of the possible targets lidroside(min.1%) content [1]. in the fight againstparasites of the genus Plasmodium,responsible forma- Theefficacy observed in clinical studies is due to thesynergistic activity of laria. Theextract fromthe leaves of Arrabidaeapatellifera (Schlecht) these two metabolitesand otheractive ingredients. Sandw.,aliana which grows fromlowlands to mountainforest, wasselected An efficient analytical method by HPLC-UV/DADwas developedtoquan- becauseofits good activity, corroborated by an in vitro test against Plasmo- tifyrosavin and salidrosideinthe roots of four wild populations of R. rosea dium falciparum.Moreover,this plant has never been investigated before. L. comingfromthe same area in Switzerland. Theanalyses wereperformed Theextract was firstfractionated by vacuumliquidchromatography (VLC) in order to observe the variability in the populations,and to establishthe and then by medium pressure liquid chromatography (MPLC).Itafforded dynamicsoftheir rosavin and salidroside content over aone year period. directly mangiferin and four of its derivatives,new C-glucosylxanthones, all Theresults obtainedafter the analysis of 20 sampleswill be useful in the active in vitro against P. falciparum.Further chromatographic separations selection of the mostappropriate population forlarge scale cultivation. gave other compounds,ofwhich theidentificationisunderway. Acetylcholinesterase-inhibitory activity was observed due to the presence in Thestructures were determined by meansofspectrometric methods,includ- theplant of linoleic acidand cinnamic alcohol. ing 1D and 2D NMRexperiments and MS analysis. Further investigations on R. rosea areunderwayinorder to discover new biological activities, especially in the area of depression (inhibition of [1] F. Martin, A.E. Hay, L. Corno, M. P. Gupta,K.Hostettmann, Phyto- monoamine-oxidase). chemistry. 2007,inpress [2]K.K.Ncokazi, T. J. Egan, Anal.Biochem. 2005, 338 ,306-319 [1]Khanum F.,BawaA.S., Singh B ., Comp RevFood Sci Food Safety, 2005, 4 ,55-62.

Medicinal Chemistry 87 Computational Chemistry 88

ANew Protocol to theSyntheses of , -Diamino Acids DFT Study of Jahn-Teller Effect in Cobaltocene

Y. Liu 1 ,P.Schmutz1 ,M.Bauwens2 ,J.Mertens2 ,R.Alberto1 Matija Zlatar1 , 2 ,Emmanuel PenkaFowe1 ,Carl-Wilhelm Schlapfer1 , Claude Daul1 1 Institute of Inorganic Chemistry, University of Zurich Winterthurerstr. 190, 1 CH-8057 Zurich,Switzerland 2 Radiopharmaceutical Chemistry, DepartmentofChemistry,UniversityofFribourg, Chemin de Mus´e e9, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussel, Belgium CH-1700, Fribourg, Switzerland 2 Center for Chemistry,IHTM, UniversityofBelgrade, Njegoˇs eva12, P.O. Box815, 11001 Belgrade, Serbia , -Diamino Acids have attracted the interests from both organic chemists and biochemists through years,becauseofits unique structural and ubiqui- The detailed analysis of Jahn-Teller (JT) effect in bis -cyclopentadyenyl- tous role playing in biologically active compounds.Moreover,ithas been cobalt(II) -cobaltocene (CoCp2 ), is given. Descentinsymmetry goes from demonstratedthatthe , -diamino acid can be used as efficient tripodal D 5 h (eclipsed conformation of the two rings) to C 2 v .The electronic ground ligand forthe labelling of Re(I)/Tc(I) tricarbonyl,the corresponding hydro- 2 2 2 state, E 1 ,splits into A 2 and B 1 .Wehave used the methoddeveloped by philic compound of which is stable to air and competition fromcysteine or Daul et al. [1] for the calculation of the ground-state JT stabilization energy histidine. However,inthe radiopharmaceutical context, only after being ( E JT)and the resulting properties of aJT-activemolecules by DFT. The adi- coupled to otherbiomolecules,could , -diaminoacids be feasible for the abatic potential energy surface is described by three parameters ( E JT,Δand further application[1]. R JT)whichare related to the Bersuker’s description [2] of E ⊗ e problem ( K E , Herewereportanew method forthe preparation of , -diamino acid, F E , G E -force constant, first and second order vibronic coupling constants − 1 which entails alsothe convenientsynthesesof , -diamino acids derivat- respectively). We obtained E JT =750 − 850 cm (depending on the basis ized at -position. Thedeprotected 2 formedstableRe(I)/Tc(I)tricarbonyl set and functional used) whichisinagreementwith experimentally estimated complex, whichcan be recognized and transported into acell by LAT1 [2]. value of 1010 cm− 1 [3]. There is no second order JT effect. The geometry changed mainly in the Cp rings. The results are interpreted by group theory, NHCbz NHCbz in both, the high, D ,and the low, C 2 v ,symmetry.In D ,the problem NHBoc 5 h 5 h a) CN MsO COOEt a) wasconsidered as amultimode E ⊗ ( e )and in a C as amultimode BocHN COOEt i i 2 v b) 2 2 AcHN COOEt AcHN COOEt AcHN COOEt ( A 2 + B 1 ) ⊗ ( i a i )vibronic interactions. The contribution of the totally 1 2 symmetrical vibrations in C to the E wasanalysed. o 2 v JT a) NaBH4 ,NiCl 2 ,Boc2 O, MeOH,0C; b) NaOEt, EtOH,reflux [1] R. Bruyndockx, C. Daul, P. T. Manoharan, E. Deiss, Inorg. Chem., [1]R.Alberto, Top. Curr. Chem., 2005, 252,1-44. 1997, 36,4251-4256. [2]Y.Liu,J.K.Pak,P.Schmutz,M.Bauwens, J. Mertens, H. Knight,R. [2] I. B. Bersuker, The Jahn-Teller Effect,Cambridge University Alberto, J. Am.Chem. Soc., 2006, 128, 15996-15997. Press, 2006. [3] R. Bucher, ESR-Untersuchungen an Jahn-Teller-Aktiven Sand- witchkomplexen,PhD Thesis, ETH Zuerich, 1977.