{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T03:59:36Z","timestamp":1788321576394,"version":"build-2803163510"},"reference-count":35,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2020,2,2]],"date-time":"2020-02-02T00:00:00Z","timestamp":1580601600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004486","name":"Fondazione Cassa di Risparmio di Perugia","doi-asserted-by":"publisher","award":["2018.0423.021"],"award-info":[{"award-number":["2018.0423.021"]}],"id":[{"id":"10.13039\/501100004486","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>In the present work, we illustrate the ability of high-performance liquid chromatography (HPLC) analysis to assist the synthesis of chiral imidazolines within our medicinal chemistry programs. In particular, a Chiralpak\u00ae IB\u00ae column containing cellulose tris(3,5-dimethylphenylcarbamate) immobilized onto a 5 \u03bcm silica gel was used for the enantioselective HPLC analysis of chiral imidazolines synthesized in the frame of hit-to-lead explorations and designed for exploring the effect of diverse amide substitutions. Very profitably, reversed-phase (RP) conditions succeeded in resolving the enantiomers in nine out of the 10 investigated enantiomeric pairs, with \u03b1 values always higher than 1.10 and RS values up to 2.31. All compounds were analysed with 50% (v) water while varying the content of the two organic modifiers acetonitrile and methanol. All the employed eluent systems were buffered with 40 mM ammonium acetate while the apparent pH was fixed at 7.5. Based on the experimental results, the prominent role of \u03c0-\u03c0 stacking interactions between the substituted electron-rich phenyl groups outside of the polymeric selector and the complementary aromatic region in defining analyte retention and stereodiscrimination was identified. The importance of compound polarity in explaining the retention behaviour with the employed RP system was readily evident when a quantitative structure-property relationship study was performed on the retention factor values (k) of the 10 compounds, as computed with a 30% (v) methanol containing mobile phase. Indeed, good Pearson correlation coefficients of retention factors (r - log k1st = \u22120.93; r - log k2nd = \u22120.94) were obtained with a water solubility descriptor (Ali-logS). Interestingly, a n-hexane\/chloroform\/ethanol (88:10:2, v\/v\/v)-based non-standard mobile phase allowed the almost base-line enantioseparation (\u03b1 = 1.06; RS = 1.26) of the unique compound undiscriminated under RP conditions.<\/jats:p>","DOI":"10.3390\/molecules25030640","type":"journal-article","created":{"date-parts":[[2020,2,3]],"date-time":"2020-02-03T01:25:51Z","timestamp":1580693151000},"page":"640","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Enantioselective HPLC Analysis to Assist the Chemical Exploration of Chiral Imidazolines"],"prefix":"10.3390","volume":"25","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2438-0792","authenticated-orcid":false,"given":"Bruno","family":"Cerra","sequence":"first","affiliation":[{"name":"Department of Pharmaceutical Sciences, University of Perugia, Via Fabretti 48, 06123 Perugia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antonio","family":"Macchiarulo","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Sciences, University of Perugia, Via Fabretti 48, 06123 Perugia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6097-3996","authenticated-orcid":false,"given":"Andrea","family":"Carotti","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Sciences, University of Perugia, Via Fabretti 48, 06123 Perugia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8529-0849","authenticated-orcid":false,"given":"Emidio","family":"Camaioni","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Sciences, University of Perugia, Via Fabretti 48, 06123 Perugia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ina","family":"Varfaj","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Sciences, University of Perugia, Via Fabretti 48, 06123 Perugia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9856-0230","authenticated-orcid":false,"given":"Roccaldo","family":"Sardella","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Sciences, University of Perugia, Via Fabretti 48, 06123 Perugia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0240-2006","authenticated-orcid":false,"given":"Antimo","family":"Gioiello","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Sciences, University of Perugia, Via Fabretti 48, 06123 Perugia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,2,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"4152","DOI":"10.2174\/0929867325666180129094955","article-title":"Analytical and preparative scale separation of enantiomers of chiral drugs by chromatography and related methods","volume":"25","author":"Gumustas","year":"2018","journal-title":"Curr. Med. Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1016\/j.jpba.2018.06.045","article-title":"Liquid chromatographic enantiomer separations applying chiral ion-exchangers based on Cinchona alkaloids","volume":"159","author":"Ilisz","year":"2018","journal-title":"J. Pharm. Biomed. Anal."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"26","DOI":"10.1016\/j.chroma.2012.10.033","article-title":"Recent developments on polysaccharide-based chiral stationary phases for liquid-phase separation of enantiomers","volume":"1269","author":"Chankvetadze","year":"2012","journal-title":"J. Chromatogr. A"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"626","DOI":"10.1021\/ac202892w","article-title":"Chiral separations: A review of current topics and trends","volume":"84","author":"Ward","year":"2012","journal-title":"Anal. Chem."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2593","DOI":"10.1039\/b808881k","article-title":"Chiral HPLC for efficient resolution of enantiomers","volume":"37","author":"Okamoto","year":"2008","journal-title":"Chem. Soc. Rev."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1094","DOI":"10.1021\/acs.chemrev.5b00317","article-title":"Efficient separation of enantiomers using stereoregular chiral polymers","volume":"116","author":"Shen","year":"2016","journal-title":"Chem. Rev."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"51","DOI":"10.1016\/j.chroma.2014.06.042","article-title":"Synthesis and application of immobilized polysaccharide-based chiral stationary phases for enantioseparation by high-performance liquid chromatography","volume":"1363","author":"Shen","year":"2014","journal-title":"J. Chromatogr. A"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"882","DOI":"10.1016\/j.jpba.2007.06.008","article-title":"Cellulose tris(3,5-dichlorophenylcarbamate) immobilised on silica: A novel chiral stationary phase for resolution of enantiomers","volume":"46","author":"Zhang","year":"2008","journal-title":"J. Pharm. Biomed. Anal."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"762","DOI":"10.1002\/jssc.200500372","article-title":"Impact of immobilized polysaccharide chiral stationary phases on enantiomeric separations","volume":"6","author":"Ali","year":"2006","journal-title":"J. Sep. Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1881","DOI":"10.1002\/elps.201800493","article-title":"Recent studies of docking and molecular dynamics simulation for liquid-phase enantioseparations","volume":"40","author":"Peluso","year":"2019","journal-title":"Electrophoresis"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1392","DOI":"10.1016\/j.talanta.2011.06.047","article-title":"Synthesis and chromatographic enantioresolution of anti-HIV quinolone derivatives","volume":"85","author":"Natalini","year":"2011","journal-title":"Talanta"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1016\/j.jpba.2013.10.039","article-title":"Chromatographic separation and biological evaluation of benzimidazole derivative enantiomers as inhibitors of leukotriene biosynthesis","volume":"89","author":"Sardella","year":"2014","journal-title":"J. Pharm. Biomed. Anal."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1016\/j.chroma.2017.11.049","article-title":"Enantioselective separation of racemates using CHIRALPAK IG amylose-based chiral stationary phase under normal standard, non-standard and reversed phase high performance liquid chromatography","volume":"1532","author":"Ghanem","year":"2018","journal-title":"J. Chromatogr. A"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1465","DOI":"10.1002\/jssc.201601386","article-title":"Chiral separation of novel diazenes on a polysaccharide-based stationary phase in the reversed-phase mode","volume":"40","author":"Galewski","year":"2017","journal-title":"J. Sep. Sci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"909","DOI":"10.1007\/s10337-014-2804-8","article-title":"Immobilized polysaccharide-based stationary phases for enantioseparation in normal versus reversed phase HPLC","volume":"78","author":"Geryk","year":"2015","journal-title":"Chromatographia"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1016\/j.chroma.2014.06.040","article-title":"Enantioselective potential of chiral stationary phases based on immobilized polysaccharides in reversed phase mode","volume":"1363","author":"Geryk","year":"2014","journal-title":"J. Chromatogr. A"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"6942","DOI":"10.1016\/j.chroma.2010.08.075","article-title":"Reversed-phase chiral HPLC and LC\/MS analysis with tris(chloromethylphenylcarbamate) derivatives of cellulose and amylose as chiral stationary phases","volume":"1217","author":"Peng","year":"2010","journal-title":"J. Chromatogr. A"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"178","DOI":"10.1016\/j.chroma.2012.09.071","article-title":"Complementary enantiorecognition patterns and specific method optimization aspects on immobilized polysaccharide-derived chiral stationary phases","volume":"1269","author":"Zhang","year":"2012","journal-title":"J. Chromatogr. A"},{"key":"ref_19","unstructured":"Gioiello, A. Unpublished work, manuscript in preparation."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1048","DOI":"10.1016\/j.chroma.2009.11.040","article-title":"Reversed-phase screening strategies for liquid chromatography on polysaccharide-derived","volume":"1217","author":"Zhang","year":"2010","journal-title":"J. Chromatogr. A"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1016\/j.chroma.2005.09.081","article-title":"Immobilized versus coated amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phases for the enantioselective separation of cyclopropane derivatives by liquid chromatography","volume":"1101","author":"Ghanem","year":"2006","journal-title":"J. Chromatogr. A"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1016\/j.jchromb.2008.07.044","article-title":"Comparative study of coated and immobilized polysaccharide-based chiral stationary phases and their applicability in the resolution of enantiomers","volume":"875","author":"Thunberg","year":"2008","journal-title":"J. Chromatogr. B Analyt. Technol. Biomed. Life Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1021\/ac00179a013","article-title":"Methanol-water association and its effect on solute retention in liquid chromatography","volume":"61","author":"Katz","year":"1989","journal-title":"Anal. Chem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"814","DOI":"10.1016\/j.chroma.2009.10.022","article-title":"Chiral recognition by enantioselective liquid chromatography: Mechanisms and modern chiral stationary phases","volume":"1217","year":"2010","journal-title":"J. Chromatogr. A"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1365\/s10337-004-0491-6","article-title":"Reversed-phase liquid chromatographic separation, on cellulose chiral stationary phases, of the stereoisomers of methoxytetra-hydronaphthalene derivatives, new agonist and antagonist ligands for melatonin receptors","volume":"61","author":"Lipka","year":"2005","journal-title":"Chromatographia"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"309","DOI":"10.1002\/chir.20040","article-title":"Reversed-phase liquid chromatographic enantioseparation by cycloalkylcarboxylates of cellulose and amylose","volume":"16","author":"Kubota","year":"2004","journal-title":"Chirality"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1016\/S0021-9673(00)00501-X","article-title":"Polysaccharide-based chiral stationary phases for high-performance liquid chromatographic enantioseparation","volume":"906","author":"Yashima","year":"2001","journal-title":"J. Chromatogr. A"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"727","DOI":"10.1002\/1520-636X(2000)12:10<727::AID-CHIR5>3.0.CO;2-T","article-title":"HPLC enantiomeric resolution of novel aromatase inhibitors on cellulose- and amylose-based chiral stationary phases under reversed phase mode","volume":"12","author":"Ali","year":"2000","journal-title":"Chirality"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1007\/BF02493623","article-title":"Reversed-phase separations on cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phase","volume":"50","author":"Hou","year":"1999","journal-title":"Chromatographia"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1002\/(SICI)1520-636X(1996)8:1<153::AID-CHIR23>3.0.CO;2-L","article-title":"Direct enantioselective separation of some propranolol analogs by HPLC on normal and reversed cellulose chiral stationary phases","volume":"8","author":"Bakr","year":"1996","journal-title":"Chirality"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"3289","DOI":"10.1246\/bcsj.68.3289","article-title":"Chiral discrimination on polysaccharides derivatives","volume":"68","author":"Eiji","year":"1995","journal-title":"Bull. Chem. Soc. Jpn."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1016\/j.chroma.2005.08.028","article-title":"Impact of methanol and acetonitrile on separations based on pi-pi interactions with a reversed-phase phenyl column","volume":"1097","author":"Yang","year":"2005","journal-title":"J. Chromatogr. A"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1016\/0021-9673(96)00208-7","article-title":"Mechanistic investigation into the enantioselective separation of mexiletine and related compounds, chromatographed on an amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phase","volume":"741","author":"Booth","year":"1996","journal-title":"J. Chromatogr. A"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"42717","DOI":"10.1038\/srep42717","article-title":"SwissADME: A free web tool to evaluate pharmacokinetics, drug-likeness and medicinal chemistry friendliness of small molecules","volume":"7","author":"Daina","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_35","unstructured":"(2019, December 19). The R Project for Statistical Computing. Available online: http:\/\/www.R-project.org."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/25\/3\/640\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T08:53:52Z","timestamp":1760172832000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/25\/3\/640"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,2,2]]},"references-count":35,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2020,2]]}},"alternative-id":["molecules25030640"],"URL":"https:\/\/doi.org\/10.3390\/molecules25030640","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,2,2]]}}}