{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T18:44:31Z","timestamp":1782758671532,"version":"3.54.5"},"reference-count":49,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2022,7,25]],"date-time":"2022-07-25T00:00:00Z","timestamp":1658707200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004329","name":"Slovenian Research Agency (ARRS)","doi-asserted-by":"publisher","award":["P1-0179"],"award-info":[{"award-number":["P1-0179"]}],"id":[{"id":"10.13039\/501100004329","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004329","name":"Slovenian Research Agency (ARRS)","doi-asserted-by":"publisher","award":["P1-0140"],"award-info":[{"award-number":["P1-0140"]}],"id":[{"id":"10.13039\/501100004329","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004329","name":"Slovenian Research Agency (ARRS)","doi-asserted-by":"publisher","award":["P1-0201"],"award-info":[{"award-number":["P1-0201"]}],"id":[{"id":"10.13039\/501100004329","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>In silico evaluation of various regioisomeric 5- and 3-hydroxy-substituted alkyl 1-aryl-1H-pyrazole-4-carboxylates and their acyclic precursors yielded promising results with respect to their binding in the active site of dihydroorotate dehydrogenase of Plasmodium falciparum (PfDHODH). Consequently, four ethyl 1-aryl-5-hydroxy-1H-pyrazole-4-carboxylates and their 3-hydroxy regioisomers were prepared by two-step syntheses via enaminone-type reagents or key intermediates. The synthesis of 5-hydroxy-1H-pyrazoles was carried out using the literature protocol comprising acid-catalyzed transamination of diethyl [(dimethylamino)methylene]malonate with arylhydrazines followed by base-catalyzed cyclization of the intermediate hydrazones. For the synthesis of isomeric methyl 1-aryl-3-hydroxy-1H-pyrazole-4-carboxylates, a novel two-step synthesis was developed. It comprises acylation of hydrazines with methyl malonyl chloride followed by cyclization of the hydrazines with tert-butoxy-bis(dimethylamino)methane. Testing the pyrazole derivatives for the inhibition of PfDHODH showed that 1-(naphthalene-2-yl)-5-hydroxy-1H-pyrazole-4-carboxylate and 1-(naphthalene-2-yl)-, 1-(2,4,6-trichlorophenyl)-, and 1-[4-(trifluoromethyl)phenyl]-3-hydroxy-1H-pyrazole-4-carboxylates (~30% inhibition) were slightly more potent than a known inhibitor, diethyl \u03b1-{[(1H-indazol-5-yl)amino]methylidene}malonate (19% inhibition).<\/jats:p>","DOI":"10.3390\/molecules27154764","type":"journal-article","created":{"date-parts":[[2022,7,26]],"date-time":"2022-07-26T00:17:27Z","timestamp":1658794647000},"page":"4764","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Regioselective Synthesis of 5- and 3-Hydroxy-N-Aryl-1H-Pyrazole-4-Carboxylates and Their Evaluation as Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase"],"prefix":"10.3390","volume":"27","author":[{"given":"Luka","family":"Vah","sequence":"first","affiliation":[{"name":"Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ve\u010dna pot 113, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tadej","family":"Medved","sequence":"additional","affiliation":[{"name":"Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ve\u010dna pot 113, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5186-9879","authenticated-orcid":false,"given":"Uro\u0161","family":"Gro\u0161elj","sequence":"additional","affiliation":[{"name":"Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ve\u010dna pot 113, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3079-4492","authenticated-orcid":false,"given":"Marina","family":"Klemen\u010di\u010d","sequence":"additional","affiliation":[{"name":"Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ve\u010dna pot 113, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8429-0273","authenticated-orcid":false,"given":"\u010crtomir","family":"Podlipnik","sequence":"additional","affiliation":[{"name":"Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ve\u010dna pot 113, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8709-9853","authenticated-orcid":false,"given":"Bogdan","family":"\u0160tefane","sequence":"additional","affiliation":[{"name":"Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ve\u010dna pot 113, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jernej","family":"Wagger","sequence":"additional","affiliation":[{"name":"Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ve\u010dna pot 113, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1824-1649","authenticated-orcid":false,"given":"Marko","family":"Novinec","sequence":"additional","affiliation":[{"name":"Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ve\u010dna pot 113, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3339-3595","authenticated-orcid":false,"given":"Jurij","family":"Svete","sequence":"additional","affiliation":[{"name":"Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ve\u010dna pot 113, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,7,25]]},"reference":[{"key":"ref_1","unstructured":"Patrick, G.L. (2020). History of malaria and its treatment. Antimalarial Agents Design and Mechanism of Action, Elsevier. [1st ed.]."},{"key":"ref_2","unstructured":"Patrick, G.L. (2020). Antimalarial Agents Design and Mechanism of Action, Elsevier. [1st ed.]."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1038\/nrd1416","article-title":"Antimalarial drug discovery: Efficacy models for compound screening","volume":"3","author":"Fidock","year":"2004","journal-title":"Nat. Rev. Drug Disc."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"999","DOI":"10.1586\/eri.09.68","article-title":"Discovery, mechanisms of action and combination therapy of artemisinin","volume":"7","author":"Cui","year":"2009","journal-title":"Expert Rev. Anti-Infect. Ther."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"9219","DOI":"10.3390\/molecules18089219","article-title":"Amazonian Plant Natural Products: Perspectives for Discovery of New Antimalarial Drug Leads","volume":"18","author":"Pohlit","year":"2013","journal-title":"Molecules"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1186\/1475-2875-11-11","article-title":"A review of malaria vaccine clinical projects based on the WHO rainbow table","volume":"11","author":"Schwartz","year":"2012","journal-title":"Malar. J."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"O2","DOI":"10.1186\/1475-2875-13-S1-O2","article-title":"Phenotypic divergence among the members of the African malaria mosquitoes and strategies of persistence throughout the dry season. In Challenges in Malaria Research: Core Science and Innovation","volume":"13","author":"Lehmann","year":"2014","journal-title":"Malar. J."},{"key":"ref_8","unstructured":"Patrick, G.L. (2020). Drugs targeting mitochondrial functions. Antimalarial Agents Design and Mechanism of Action, Elsevier. [1st ed.]."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1039","DOI":"10.2174\/138955711797247707","article-title":"Recent Developments in the Medicinal Chemistry and Therapeutic Potential of Dihydroorotate Dehydrogenase (DHODH) Inhibitors","volume":"11","author":"Vyas","year":"2011","journal-title":"Mini-Rev. Med. Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1573","DOI":"10.4155\/fmc.13.121","article-title":"Targeting the mitochondrial electron transport chain of Plasmodium falciparum: New strategies towards the development of improved antimalarials for the elimination era","volume":"5","author":"Nixon","year":"2013","journal-title":"Future Med. Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1853","DOI":"10.4155\/fmc-2017-0250","article-title":"Plasmodium falciparum dihydroorotate dehydrogenase: A drug target against malaria","volume":"10","author":"Hoelz","year":"2018","journal-title":"Future Med. Chem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1021\/jm060687j","article-title":"Design and Synthesis of Potent Inhibitors of the Malaria Parasite Dihydroorotate Dehydrogenase","volume":"50","author":"Ramsey","year":"2007","journal-title":"J. Med. Chem."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1945","DOI":"10.1016\/j.bmc.2005.01.017","article-title":"Synthesis of brequinar analogue inhibitors of malaria parasite dihydroorotate dehydrogenase","volume":"13","author":"Boa","year":"2005","journal-title":"Bioorg. Med. Chem."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2683","DOI":"10.1021\/jm800963t","article-title":"Structure-based design, synthesis and characterization of inhibitors of human and Plasmodium falciparum dihydroorotate dehydrogenase","volume":"52","author":"Davies","year":"2009","journal-title":"J. Med. Chem."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1864","DOI":"10.1021\/jm801343r","article-title":"Identification of a Metabolically Stable Triazolopyrimidine-Based Dihydroorotate Dehydrogenase Inhibitor with Antimalarial Activity in Mice","volume":"52","author":"Gujjar","year":"2009","journal-title":"J. Med. Chem."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"708","DOI":"10.1021\/ml200143c","article-title":"Optimization of Potent Inhibitors of P. falciparum Dihydroorotate Dehydrogenase for the Treatment of Malaria","volume":"2","author":"Skerlj","year":"2011","journal-title":"ACS Med. Chem. Lett."},{"key":"ref_17","unstructured":"Joule, J.A., and Mills, K. (2010). Heterocyclic Chemistry, Wiley-Blackwell. [5th ed.]."},{"key":"ref_18","unstructured":"Patrick, G.L. (2013). An Introduction to Medicinal Chemistry, Oxford University Press. [5th ed.]."},{"key":"ref_19","first-page":"725","article-title":"Molecular Design and Combinatorial Compound Libraries","volume":"Volume 2","author":"Nicolaou","year":"2002","journal-title":"Handbook of Combinatorial Chemistry. Drugs, Catalysts, Materials"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"226","DOI":"10.1016\/j.bioorg.2018.11.029","article-title":"Synthesis and biological evaluation of 7-(aminoalkyl)pyrazolo [1,5-a]pyrimidine derivatives as cathepsin K inhibitors","volume":"84","author":"Petek","year":"2019","journal-title":"Bioorg. Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1039\/C9MD00479C","article-title":"An epigrammatic status of the \u2018azole\u2019-based antimalarial drugs","volume":"11","author":"Sharma","year":"2020","journal-title":"RSC Med. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Shamsuddin, M.A., Ali, A.H., Zakaria, N.H., Mohammat, M.F., Hamzah, A.S., Shaameri, Z., Lam, K.W., Mark-Lee, W.F., Agustar, H.K., and Razak, M.R.H.A. (2021). Synthesis, Molecular Docking, and Antimalarial Activity of Hybrid 4-Aminoquinoline-pyrano[2,3-c]pyrazole Derivatives. Pharmaceuticals, 14.","DOI":"10.3390\/ph14111174"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1016\/j.ejmech.2018.01.082","article-title":"Pyrazole-pyrazoline as promising novel antimalarial agents: A mechanistic study","volume":"149","author":"Kumar","year":"2018","journal-title":"Eur. J. Med. Chem."},{"key":"ref_24","first-page":"6225","article-title":"Novel Dual Acting Antimalarial Antileishmanial Agents Derived from Pyrazole Moiety","volume":"12","author":"Bekhit","year":"2022","journal-title":"Biointerface Res. Appl. Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"194","DOI":"10.2174\/1386207321666180213092911","article-title":"Pyrazole Schiff Base Hybrids as Anti-Malarial Agents: Synthesis, In Vitro Screening and Computational Study","volume":"21","author":"Aggarwal","year":"2018","journal-title":"Comb. Chem. High Throughput Screen."},{"key":"ref_26","first-page":"15","article-title":"Pyrazoles","volume":"Volume 12","author":"Neier","year":"2002","journal-title":"Science of Synthesis, Houben-Weyl Methods of Molecular Transformations"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"607","DOI":"10.1016\/S0040-4020(01)89994-4","article-title":"A direct preparation of 2-aryl-4-ethoxycarbonyl-3-pyrazolin-5-ones from aryl hydrazines","volume":"43","author":"Taylor","year":"1987","journal-title":"Tetrahedron"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"897","DOI":"10.3987\/COM-06-10682","article-title":"3-(Dimethylamino)propenoate-based regioselective synthesis of 1,4-disubstituted 5-hydroxy-1H-pyrazoles","volume":"68","author":"Kralj","year":"2006","journal-title":"Heterocycles"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1020","DOI":"10.1002\/cber.190704001154","article-title":"\u00dcber die Darstellung des 1-Phenyl-3-pyrazolons","volume":"40","author":"Michaelis","year":"1907","journal-title":"Chem. Ber."},{"key":"ref_30","unstructured":"(2021, April 27). Downloaded from RSCB PDB Protein Data Bank. Available online: https:\/\/www.rcsb.org\/structure\/1TV5."},{"key":"ref_31","first-page":"312","article-title":"Structure of Plasmodium falciparum dihydroorotate dehydrogenase with a bound inhibitor","volume":"D62","author":"Hurt","year":"2006","journal-title":"Acta Cryst."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/S0169-409X(00)00129-0","article-title":"Experimental and computational approaches to estimate solubility and permeability in drug discovery and development settings","volume":"46","author":"Lipinski","year":"2001","journal-title":"Adv. Drug Del. Rev."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1021\/cc9800071","article-title":"A knowledge-based approach in designing combinatorial or medicinal chemistry libraries for drug discovery. 1. A qualitative and quantitative characterization of known drug databases","volume":"1","author":"Ghose","year":"1999","journal-title":"J. Comb. Chem."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1114","DOI":"10.1002\/anie.201105840","article-title":"Lead-oriented synthesis: A new opportunity for synthetic chemistry","volume":"51","author":"Nadin","year":"2012","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"314","DOI":"10.1002\/anie.201006781","article-title":"Systematic Investigation of Halogen Bonding in Protein\u2013Ligand Interactions","volume":"50","author":"Hardegger","year":"2011","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_36","first-page":"314","article-title":"Orthogonal Multipolar Interactions in Structural Chemistry and Biology","volume":"50","author":"Paulini","year":"2011","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"5900","DOI":"10.1021\/jm050101d","article-title":"Discovery of the Novel Antithrombotic Agent 5-Chloro-N-({(5S)-2-oxo-3- [4-(3-oxomorpholin-4-yl)phenyl]-1,3-oxazolidin-5-yl}methyl)thiophene- 2-carboxamide (BAY 59-7939): An Oral, Direct Factor Xa Inhibitor","volume":"48","author":"Roehrig","year":"2005","journal-title":"Med. Chem."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"220","DOI":"10.1055\/s-1971-21705","article-title":"A New Reagent for the Synthesis of Diethyl Arylaminomethylenemalonates","volume":"1971","author":"Harris","year":"1971","journal-title":"Synthesis"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2829","DOI":"10.1016\/0040-4020(77)80276-7","article-title":"Heterodiene syntheses\u2013XIX1: Correlation of the kinetic data with lumo energies in the reaction between 1-aryl-4-benzylidene-5-pyrazolones and isopropyl vinyl ether","volume":"33","author":"Desimoni","year":"1977","journal-title":"Tetrahedron"},{"key":"ref_40","first-page":"191074","article-title":"1-Aryl-4-nitropyrazole. DE 3501323 A1 19860717 (1986)","volume":"105","author":"Gehring","year":"1986","journal-title":"Chem. Abstr."},{"key":"ref_41","first-page":"316911","article-title":"Preparation of pyrazole amides as cannabinoid receptor ligands. WO 2007026215A1 20070308 (2007)","volume":"146","author":"Kundu","year":"2007","journal-title":"Chem. Abstr."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"11213","DOI":"10.1016\/j.tet.2007.07.052","article-title":"A simple synthesis of 4-(2-aminoethyl)-5-hydroxy-1H-pyrazoles","volume":"63","author":"Kralj","year":"2007","journal-title":"Tetrahedron"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"382","DOI":"10.1002\/prac.19733150306","article-title":"Tautomerie und Nomenklatur der \u201cPyrazolone\u201d und Aminopyrazole","volume":"315","author":"Dorn","year":"1973","journal-title":"J. Prakt. Chem."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"329","DOI":"10.3987\/REV-90-421","article-title":"Prototropic tautomerism of heteroaromatic compounds","volume":"32","author":"Katritzky","year":"1991","journal-title":"Heterocyles"},{"key":"ref_45","first-page":"1","article-title":"Pyrazoles","volume":"Volume 4","author":"Katritzky","year":"2008","journal-title":"Comprehensive Heterocyclic Chemistry III"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1739","DOI":"10.1021\/jm0306430","article-title":"Glide: A New Approach for Rapid, Accurate Docking and Scoring. 1. Method and Assessment of Docking Accuracy","volume":"47","author":"Friesner","year":"2004","journal-title":"J. Med. Chem."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1007\/s10822-013-9644-8","article-title":"Protein and ligand preparation: Parameters, protocols, and influence on virtual screening enrichments","volume":"27","author":"Sastry","year":"2013","journal-title":"J. Comput.-Aided Mol. Des."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"6177","DOI":"10.1021\/jm051256o","article-title":"Extra Precision Glide:\u2009 Docking and Scoring Incorporating a Model of Hydrophobic Enclosure for Protein\u2212Ligand Complexes","volume":"49","author":"Friesner","year":"2006","journal-title":"J. Med. Chem."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"21847","DOI":"10.1074\/jbc.M501100200","article-title":"High-throughput Screening for Potent and Selective Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase","volume":"280","author":"Baldwin","year":"2005","journal-title":"J. Biol. Chem."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/27\/15\/4764\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:56:22Z","timestamp":1760140582000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/27\/15\/4764"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,7,25]]},"references-count":49,"journal-issue":{"issue":"15","published-online":{"date-parts":[[2022,8]]}},"alternative-id":["molecules27154764"],"URL":"https:\/\/doi.org\/10.3390\/molecules27154764","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,7,25]]}}}