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Theoretical study of nimetazepam, a real-life chiral molecule without an asymmetric carbon atom. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.132720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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2
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Low Temperature Dynamic Chromatography for the Separation of the Interconverting Conformational Enantiomers of the Benzodiazepines Clonazolam, Flubromazolam, Diclazepam and Flurazepam. Symmetry (Basel) 2021. [DOI: 10.3390/sym13061012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Benzodiazepines (BZDs) are an important class of psychoactive drugs with hypnotic-sedative, myorelaxant, anxiolytic and anticonvulsant properties due to interaction with the GABAa receptor in the central nervous system of mammals. BZDs are interesting both in clinical and forensic toxicology for their pharmacological characteristics and potential of abuse. The presence of a non-planar diazepine ring generates chiral conformational stereoisomers, even in the absence of stereogenic centers. A conformational enrichment of BZD at the binding sites has been reported in the literature, thus making interesting a stereodynamic screening of a wide range of BZDs. Herein, we report the investigation of three stereolabile 1,4-benzodiazepine included in the class of “designer benzodiazepines” (e.g., diclazepam, a chloro-derivative of diazepam, and two triazolo-benzodiazepines, flubromazolam and clonazolam) and a commercially available BZD known as flurazepam, in order to study the kinetic of the “ring-flip” process that allows two conformational enantiomers to interconvert at high rate at room temperature. A combination of low temperature enantioselective dynamic chromatography on chiral stationary phase and computer simulations of the experimental chromatograms allowed us to measure activation energies of enantiomerization (ΔG‡) lower than 18.5 kcal/mol. The differences between compounds have been correlated to the pattern of substitutions on the 1,4-benzodiazepinic core.
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Sabia R, Ciogli A, Pierini M, Franzini R, Iazzetti A, Villani C. Chromatographic separation of the interconverting enantiomers of imidazo- and triazole-fused benzodiazepines. J Chromatogr A 2021; 1647:462148. [PMID: 33957345 DOI: 10.1016/j.chroma.2021.462148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/25/2021] [Accepted: 04/03/2021] [Indexed: 10/21/2022]
Abstract
The toolbox of medicinal chemists includes the 1,4-benzodiazepine scaffold as a "privileged scaffold" in drug discovery. Several biologically active small molecules containing a 1,4-benzodiazepine scaffold have been approved by the FDA for the treatment of various diseases, with most of them being used for their psychotropic effects. The therapeutic potential of 1,4-benzodiazepines has stimulated the interest of synthetic chemists in developing new synthetic strategies to a range of substituted analogues for biological evaluation. A structural variation of the classical benzodiazepine skeleton is observed e.g. in alprazolam, midazolam, and related benzodiazepines, which contain a 1,2,4-triazole or an imidazole ring fused to the benzodiazepine core. Irrespective of the presence of the fused heterocyclic ring, the seven-membered diazepine ring is far from planar, and its shape resembles a twist chair. Then, the unsymmetrical substitution pattern around the seven membered cycle renders these molecules chiral, as they lack any reflection-type symmetry element. However, chirality of this molecules is labile at room temperature, becausea simple ring flipping process converts one enantiomer into the other, and 1,4-benzodiazepines exist as a mixture of rapidly interconverting conformational enantiomers in solution at or near room temperature. Physical separation of the interconverting enantiomers of diazepam and of other related 1,4-benzodiazepin-2-ones can be accomplished by low temperature HPLC on chiral stationary phases (CSPs). If the HPLC column is cooled down to temperatures where the interconversion rate is sufficiently low, compared to the chromatographic separation rate, distinct separated peaks can be observed, provided the CSP is sufficiently enantioselctive. The apparent rate constants for the on-column enantiomerization and the corresponding free energy activation barriers were obtained by simulation of exchange-deformed HPLC profiles using a computer program based on the stochastic model. Here we report on the dynamic HPLC investigations carried out on a set of fused imidazo and triazolo-benzodiazepines (alprazolam, midazolam, triazolam and estazolam) The experimental dynamic chromatograms and the corresponding interconversion barriers reported in this paper show that the third fused heterocyclic ring increase the energy barrier by 2 kcal/mol.
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Affiliation(s)
- Rocchina Sabia
- SapienzaUniversità di Roma, Dipartimento di Chimica e Tecnologie del Farmaco, P.le A. Moro 5, 00185Rome, Italy.
| | - Alessia Ciogli
- SapienzaUniversità di Roma, Dipartimento di Chimica e Tecnologie del Farmaco, P.le A. Moro 5, 00185Rome, Italy
| | - Marco Pierini
- SapienzaUniversità di Roma, Dipartimento di Chimica e Tecnologie del Farmaco, P.le A. Moro 5, 00185Rome, Italy
| | - Roberta Franzini
- SapienzaUniversità di Roma, Dipartimento di Chimica e Tecnologie del Farmaco, P.le A. Moro 5, 00185Rome, Italy
| | - Antonia Iazzetti
- SapienzaUniversità di Roma, Dipartimento di Chimica e Tecnologie del Farmaco, P.le A. Moro 5, 00185Rome, Italy
| | - Claudio Villani
- SapienzaUniversità di Roma, Dipartimento di Chimica e Tecnologie del Farmaco, P.le A. Moro 5, 00185Rome, Italy.
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Franzini R, Pierini M, Mazzanti A, Iazzetti A, Ciogli A, Villani C. Molecular Recognition of the HPLC Whelk-O1 Selector towards the Conformational Enantiomers of Nevirapine and Oxcarbazepine. Int J Mol Sci 2020; 22:ijms22010144. [PMID: 33375681 PMCID: PMC7796420 DOI: 10.3390/ijms22010144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/16/2020] [Accepted: 12/23/2020] [Indexed: 01/19/2023] Open
Abstract
The presence of stereogenic elements is a common feature in pharmaceutical compounds, and affording optically pure stereoisomers is a frequent issue in drug design. In this context, the study of the chiral molecular recognition mechanism fundamentally supports the understanding and optimization of chromatographic separations with chiral stationary phases. We investigated, with molecular docking, the interactions between the chiral HPLC selector Whelk-O1 and the stereoisomers of two bioactive compounds, the antiviral Nevirapine and the anticonvulsant Oxcarbazepine, both characterized by two stereolabile conformational enantiomers. The presence of fast-exchange enantiomers and the rate of the interconversion process were studied using low temperature enantioselective HPLC and VT-NMR with Whelk-O1 applied as chiral solvating agent. The values of the energetic barriers of interconversion indicate, for the single enantiomers of both compounds, half-lives sufficiently long enough to allow their separation only at critically sub-ambient temperatures. The chiral selector Whelk-O1 performed as a strongly selective discriminating agent both when applied as a chiral stationary phase (CSP) in HPLC and as CSA in NMR spectroscopy.
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Affiliation(s)
- Roberta Franzini
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (A.I.); (A.C.)
- Correspondence: (R.F.); (C.V.)
| | - Marco Pierini
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (A.I.); (A.C.)
| | - Andrea Mazzanti
- Dipartimento di Chimica Industriale “Toso Montanari”, Università di Bologna, V. Risorgimento 4, 40136 Bologna, Italy;
| | - Antonia Iazzetti
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (A.I.); (A.C.)
| | - Alessia Ciogli
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (A.I.); (A.C.)
| | - Claudio Villani
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (A.I.); (A.C.)
- Correspondence: (R.F.); (C.V.)
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Pertejo P, Corres N, Torroba T, García-Valverde M. Reversal of Diastereoselectivity in the Synthesis of Peptidomimetic 3-Carboxamide-1,4-benzodiazepin-5-ones. Org Lett 2015; 17:612-5. [DOI: 10.1021/ol503628r] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Pablo Pertejo
- Chemistry Department, Faculty
of Science, University of Burgos, 09001 Burgos, Spain
| | - Nazaret Corres
- Chemistry Department, Faculty
of Science, University of Burgos, 09001 Burgos, Spain
| | - Tomás Torroba
- Chemistry Department, Faculty
of Science, University of Burgos, 09001 Burgos, Spain
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Sabia R, Ciogli A, Pierini M, Gasparrini F, Villani C. Dynamic high performance liquid chromatography on chiral stationary phases. Low temperature separation of the interconverting enantiomers of diazepam, flunitrazepam, prazepam and tetrazepam. J Chromatogr A 2014; 1363:144-9. [DOI: 10.1016/j.chroma.2014.07.097] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 07/25/2014] [Accepted: 07/28/2014] [Indexed: 10/24/2022]
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Secci F, Frongia A, Rubanu MG, Sechi ML, Sarais G, Arca M, Piras PP. From (Phenylsulfanyl)cycloalkanecarbaldehydes to Optically Active Spirocyclic Tetrahydrofurans: Stereospecific Resolution of Symmetric Aldehydes through (S)-Proline-Catalysed Aldol Reaction. European J Org Chem 2014. [DOI: 10.1002/ejoc.201402653] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Ramig K. Stereodynamic properties of medium-ring benzo-fused nitrogenous heterocycles: benzodiazepines, benzazepines, benzazocines, and benzazonines. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.10.023] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Qian-Cutrone J, Dasgupta B, Kozlowski ES, Dalterio R, Wang-Iverson D, Vrudhula VM. Separation of maxi-K channel opening 3-substitued-4-arylquinolinone atropisomers by enantioselective supercritical fluid chromatography. J Pharm Biomed Anal 2008; 48:1120-6. [DOI: 10.1016/j.jpba.2008.08.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 07/24/2008] [Accepted: 08/23/2008] [Indexed: 11/25/2022]
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Caccamese S, Caruso C, Parrinello N, Savarino A. High-performance liquid chromatographic separation and chiroptical properties of the enantiomers of naringenin and other flavanones. J Chromatogr A 2005; 1076:155-62. [PMID: 15974082 DOI: 10.1016/j.chroma.2005.04.024] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The HPLC enantiomeric separation of naringenin, eriodictyol, hesperetin and pinocembrin was accomplished in the normal-phase mode using two polysaccharide-derived chiral stationary phases (Chiralcel OD-H and Chiralpak AS-H) and various n-hexane/alcohol mobile phases. The 3',4' substituents pattern affect the enantioselectivity of these phases. Single enantiomers of naringenin were isolated by semipreparative HPLC and their CD spectra were measured and related to the absolute configuration by the exciton-coupling method. Online coupling HPLC/spectropolarimeter afforded the CD sign of the eluted peaks at a single wavelength, and the complete CD spectra of the eluted enantiomers were obtained by trapping them in the spectropolarimeter cell through a switching valve.
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Affiliation(s)
- Salvatore Caccamese
- Dipartimento di Scienze Chimiche, Università di Catania, Vale A. Doria 6, 95125 Catania, Italy.
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Chuang VT, Otagiri M. Flunitrazepam, a 7-nitro-1,4-benzodiazepine that is unable to bind to the indole-benzodiazepine site of human serum albumin. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1546:337-45. [PMID: 11295439 DOI: 10.1016/s0167-4838(01)00151-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Benzodiazepine (BDZ) is generally thought to bind to site II of human serum albumin (HSA), also known as the indole-BDZ site, which is located at subdomain III A of the molecule. However, differences in the binding characteristics of BDZ drugs with HSA have been reported. The photolabeling profiles of HSA with [(3)H]flunitrazepam (FNZP) in the presence and absence of diazepam (DZP) were shown to be identical, suggesting that each drug primarily binds to different regions. The results of fluorescent probe displacement experiments showed that FNZP failed to decrease the fluorescence of dansylsarcosine to an extent similar to that of DZP. In the photoinhibition experiment, site I and site II ligands failed to inhibit the photoincorporation of [(3)H]FNZP to HSA. In order to evaluate the photolabeling specificity of FNZP, an attempt was made to photolabel alpha(1)-acid glycoprotein (AGP) which also binds BDZ with similar affinity as HSA. The effect of myristate (MYR) and DZP on the FNZP photolabeling of these two major drug binding plasma proteins was examined. Photoincorporation was inhibited when HSA was photolabeled with [(3)H]FNZP in the presence of MYR but not in the presence of DZP. Conversely, DZP inhibited the photolabeling of [(3)H]FNZP to AGP. These results suggest that FNZP interacts with HSA at regions which are not located in the preformed binding pocket of subdomain III A.
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Affiliation(s)
- V T Chuang
- Faculty of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, 862-0973, Kumamoto, Japan
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Di Bari L, Pintacuda G, Salvadori P. Stereochemistry and Near-Infrared Circular Dichroism of a Chiral Yb Complex. J Am Chem Soc 2000. [DOI: 10.1021/ja994290z] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lorenzo Di Bari
- Contribution from the Dipartimento di Chimica e Chimica Industriale, Centro di Studio del CNR per le Macromolecole Stereoordinate ed Otticamente Attive, Via Risorgimento 35, I-56126 Pisa, Italy, and Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | - Guido Pintacuda
- Contribution from the Dipartimento di Chimica e Chimica Industriale, Centro di Studio del CNR per le Macromolecole Stereoordinate ed Otticamente Attive, Via Risorgimento 35, I-56126 Pisa, Italy, and Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | - Piero Salvadori
- Contribution from the Dipartimento di Chimica e Chimica Industriale, Centro di Studio del CNR per le Macromolecole Stereoordinate ed Otticamente Attive, Via Risorgimento 35, I-56126 Pisa, Italy, and Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
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Abstract
The binding of drugs known to interact with area I on human serum albumin (HSA) was investigated using a chiral stationary phase obtained by anchoring HSA to a silica matrix. In particular, this high-pressure affinity chromatography selector was employed to study the binding properties of the individual enantiomers of warfarin. The pH and composition of the mobile phase modulate the enantioselective binding of warfarin. Displacement chromatography experiments evidenced significant differences in the binding of the warfarin enantiomers to site I. The (S)-enantiomer was shown to be a direct competitor for (R)-warfarin, while (R)-warfarin was an indirect competitor for the (S)-enantiomer. Salicylate directly competed with (R)-warfarin and indirectly with (S)-warfarin. This behavior was confirmed by difference CD experiments, carried out with the same [HSA]/[drug] system in solution.
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Affiliation(s)
- C Bertucci
- Centro Studio CNR Macromolecole Stereordinate ed Otticamente Attive, Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Pisa, Italy.
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