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Harris CM, Harris TM, Stec DF, Schley ND, Johnson JL, Covington CL, Polavarapu PL. Synthesis, characterization and absolute configurations of methyl ladderanoates. Chirality 2023; 35:49-57. [PMID: 36367323 DOI: 10.1002/chir.23515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/20/2022] [Accepted: 10/23/2022] [Indexed: 11/13/2022]
Abstract
Methyl esters of [5]-ladderanoic acid and [3]-ladderanoic acid were prepared by esterification of the acids isolated from biomass at a wastewater treatment plant. Optical rotations at six different wavelengths (633, 589, 546, 436, 405 and 365 nm) and vibrational circular dichroism (VCD) spectra in the 1800-900 cm-1 region were measured in CDCl3 solvent and compared with quantum chemical (QC) predictions using B3LYP functional and 6-311++G(2d,2p) basis set with polarizing continuum model representing the solvent. QC predictions gave negative optical rotations at all six wavelengths for (R)-methyl [5]-ladderanoate and positive optical rotations for (R)-methyl [3]-ladderanoate, the same signs as previously reported for the corresponding acids. The crystal structure of (-)-methyl [5]-ladderanoate independently confirmed (R) configuration. The QC-predicted VCD spectra using Boltzmann population weighted spectra of individual conformers did not provide satisfactory quantitative agreement with the experimental VCD spectra. An improved quantitative agreement for VCD spectra could be obtained when conformer populations were optimized to maximize the similarity between experimental and predicted VCD spectra, but more improvements in VCD predictions are needed.
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Affiliation(s)
- Constance M Harris
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Thomas M Harris
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Donald F Stec
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Nathan D Schley
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Jordan L Johnson
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Cody L Covington
- Department of Chemistry, Austin Peay State University, Clarksville, Tennessee, USA
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2
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Puente AR, Nagabhushanam K, Ganjihal S, Majeed M, Polavarapu PL. Chiroptical spectroscopic studies for the absolute configuration determination of hexahydrocurcumin and octahydrocurcumin. Chirality 2022; 34:1515-1525. [DOI: 10.1002/chir.23511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/07/2022] [Accepted: 10/13/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Andrew R. Puente
- Department of Chemistry Vanderbilt University Nashville Tennessee USA
| | | | | | - Muhammed Majeed
- Sabinsa Corporation East Windsor New Jersey USA
- Sami‐Sabinsa Group Bangalore India
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3
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Identification of chiral lansoprazole drugs using THz fingerprint spectroscopy. CHEMICAL PAPERS 2022. [DOI: 10.1007/s11696-022-02529-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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4
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Ge R, Zhu Y, Wang H, Gu S. Methods and Application of Absolute Configuration Assignment for Chiral Compounds. CHINESE J ORG CHEM 2022. [DOI: 10.6023/cjoc202108047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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5
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Johnson JL, Polavarapu PL. Chiral Molecular Structure Determination for a Desired Compound Just from Its Molecular Formula and Vibrational Optical Activity Spectra. J Phys Chem A 2021; 125:8000-8013. [PMID: 34478311 DOI: 10.1021/acs.jpca.1c06369] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A novel proof-of-concept model for chiral molecular structure determination using just the molecular formula and vibrational optical activity (VOA) spectra is presented. To verify this concept, the molecular formula of a desired compound is used to generate all possible chiral structural isomers and their VOA spectra are predicted. The similarity analyses of predicted VOA spectra were then carried out in two different ways: (a) similarity between VOA spectrum of one structural isomer with those of the rest, referred to as cross-correlations; (b) similarity between VOA spectra of all chiral structural isomers with the experimental VOA spectra of the desired compound. Three different molecular formulae, C4H8O, C3H5ClO, and C6H10O, and their chiral structural isomers (6, 9, and 75 respectively), were investigated. In each case, the correct chiral molecular structure of the desired compound was identified without ambiguity. Cross-correlation analysis revealed the uniqueness of VOA spectra in deducing the chiral molecular structure solely from its molecular formula. Different chiral structural isomers associated with the molecular formula CH3NO2 were also found to have no significant cross-correlations between their VOA spectra, opening a pathway to detect and identify the elusive chiral N-hydroxyoxaziridine from its VOA spectra.
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Affiliation(s)
- Jordan L Johnson
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Prasad L Polavarapu
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
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6
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Johnson JL, Santoro E, Zatout R, Petrovic AG, Cimmino A, Superchi S, Evidente A, Berova ND, Polavarapu PL. Absolute configuration of seco-eudesmanolide inuloxin D from experimental and predicted chiroptical studies of its 4-O-acetyl derivative. Chirality 2021; 33:233-241. [PMID: 33598968 DOI: 10.1002/chir.23301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 12/12/2022]
Abstract
Sesquitepenoids inuloxins A-D, belonging to different subgroups, were isolated from Dittrichia viscosa and showed potential biocontrol of some parasitic plants as Pelipanche, Orobanche, and Cuscuta species. The absolute configurations of the first three inuloxins A-C were previously determined by using experimental and computational chiroptical spectroscopic methods. The absolute configuration of inuloxin D remains to be established. The bioactive inuloxin E, closely related to inuloxin D, was recently isolated from the same plant organic extract. The same relative configuration of inuloxin D was assigned to inuloxin E by comparison of their NMR spectroscopic data. The absolute configurations of inuloxin D and inuloxin E are suggested in this work by analysis of the experimental and predicted chiroptical properties of the 4-O-acetyl derivative of inuloxin D.
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Affiliation(s)
- Jordan L Johnson
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Ernesto Santoro
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Roukia Zatout
- Department of chemical Sciences, University of Naples Federico II, Naples, Italy
- Laboratoire de Mycologie, de Biotechnologie et de l'Activité Microbienne (LaMyBAM), Département de Biologie Appliquée, Université des Frères Mentouri, Constantine, Algeria
| | - Ana G Petrovic
- Department of Chemical and Biological Sciences, New York Institute of Technology, New York, New York, USA
| | - Alessio Cimmino
- Department of chemical Sciences, University of Naples Federico II, Naples, Italy
| | | | - Antonio Evidente
- Department of chemical Sciences, University of Naples Federico II, Naples, Italy
| | - Nina D Berova
- Department of Chemistry, Columbia University, New York, New York, USA
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7
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New Techniques of Structure Elucidation for Sesquiterpenes. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 2021; 114:253-311. [PMID: 33792862 DOI: 10.1007/978-3-030-59444-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The most significant new techniques that have been used in the twenty-first century for the structure elucidation of sesquiterpenes and some derivatives are reviewed in this chapter. A distinctive feature of these methodologies is the combination of accurate experimental measurements with theoretical data obtained by molecular modeling calculations that allow to visualize, understand, and quantify many structural characteristics. This has been the case for NMR spectroscopy, which has expanded its potential for solving complex structural problems by means of comparison with quantum mechanical molecular models. Ab initio and density functional theory calculations of chemical shifts, coupling constants, and residual chemical shift anisotropies have played important roles in the solution of many structures of sesquiterpenes. The assignments of their absolute configurations by evaluation of calculated and experimental chiroptical properties as electronic and vibrational circular dichroism are also reviewed. This chapter also includes the use of X-ray diffraction analysis with emphasis on calculations of the Flack and Hooft parameters, which are applicable to all molecules that crystallize in non-centrosymmetric space groups. The accurate molecular models of sesquiterpenes, validated by concordance with their experimental properties, are nowadays essential for the interpretation of the effects of these natural products on biological systems.
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8
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Polavarapu PL, Santoro E, Covington CL, Johnson JL, Puente AR, Schley ND, Kallingathodi Z, Prakasan PC, Haleema S, Thomas AA, Ibnusaud I. How important are the intermolecular hydrogen bonding interactions in methanol solvent for interpreting the chiroptical properties? SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 247:119094. [PMID: 33142265 DOI: 10.1016/j.saa.2020.119094] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/10/2020] [Accepted: 10/12/2020] [Indexed: 06/11/2023]
Abstract
Two crispine A analogs and tetrahydrofuro[2,3-b]furan-3,3a(6aH)-diol, endowed with hydroxyl groups that can participate in intramolecular hydrogen bonding, have been synthesized and experimental vibrational circular dichroism (VCD) spectra and optical rotatory dispersion (ORD) data have been measured in CD3OD/CH3OH solvents. The absolute configurations (ACs) of these compounds have been determined using their synthetic schemes, supplemented wherever possible with X-ray diffraction data. The ACs are also analyzed with quantum chemical (QC) calculations of VCD and ORD utilizing implicit solvation as well as explicit solvation models, with the later employing classical molecular dynamics (MD) simulations. It is found that VCD calculations with implicit solvation model are adequate for determining the ACs, despite propensity of studied compounds for intermolecular hydrogen bonding between solute and solvent molecules. This observation is important because time-consuming MD simulations may not be necessary in the type of situations studied here. Additionally, it is found that the QC predicted VCD spectra provided enough diastereomer discrimination for determining the correct AC of studied compounds independently. The same observation did not apply to ORD.
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Affiliation(s)
| | - Ernesto Santoro
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
| | - Cody L Covington
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA; Department of Chemistry, Austin Peay State University, Clarksville, TN 37044, USA
| | - Jordan L Johnson
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
| | - Andrew R Puente
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
| | - Nathan D Schley
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA.
| | - Zabeera Kallingathodi
- Institute for Integrated Programmes and Research in Basic Sciences, Mahatma Gandhi University, Kottayam 686560, India
| | - Prasanth C Prakasan
- Institute for Integrated Programmes and Research in Basic Sciences, Mahatma Gandhi University, Kottayam 686560, India
| | - Simimole Haleema
- Institute for Integrated Programmes and Research in Basic Sciences, Mahatma Gandhi University, Kottayam 686560, India
| | - Annu Anna Thomas
- Institute for Integrated Programmes and Research in Basic Sciences, Mahatma Gandhi University, Kottayam 686560, India
| | - Ibrahim Ibnusaud
- Institute for Integrated Programmes and Research in Basic Sciences, Mahatma Gandhi University, Kottayam 686560, India.
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9
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Scholten K, Engelage E, Merten C. Basis set dependence of S[double bond, length as m-dash]O stretching frequencies and its consequences for IR and VCD spectra predictions. Phys Chem Chem Phys 2020; 22:27979-27986. [PMID: 33290469 DOI: 10.1039/d0cp05420h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Benchmarking functionals and basis sets for the computational prediction of molecular properties is usually done on very small model systems. Larger organic molecules containing heavier second row atoms are not the typical model structures. We herein present the first survey of basis sets and functionals for the prediction of the IR and VCD spectra of chiral tosylates and sulfinates as we noted drastic deviations between computed harmonic frequencies obtained at B3LYP/6-311++G(2d,p) level of theory and those observed in experimental solution phase IR and VCD spectra. We show that the harmonic frequencies of the asymmetric and symmetric S[double bond, length as m-dash]O stretching modes of tosylates are predicted at significantly too low vibrational frequencies if the employed basis set does not provide higher order polarization functions. The results of our benchmarks show that at least the 6-311G(3df,2dp) basis (or equivalent Dunning and Ahlrichs variants) should be used.
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Affiliation(s)
- Kevin Scholten
- Ruhr-Universität Bochum, Fakultät für Chemie und Biochemie, Organische Chemie II, Universitätsstraße 150, 44801 Bochum, Germany.
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10
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Polavarapu PL, Santoro E, Covington CL, Raghavan V. Enhancement of the chiroptical response of α-amino acids via N-substitution for molecular structure determination using vibrational circular dichroism. Chirality 2020; 32:564-578. [PMID: 32115784 DOI: 10.1002/chir.23205] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/23/2020] [Accepted: 02/14/2020] [Indexed: 11/12/2022]
Abstract
The chiroptical response in the form of vibrational circular dichroism (VCD) in the midinfrared region is found to be enhanced when a hydrogen of amino group of l-tryptophan is substituted with acetyl, acryloyl, or maleyl group. The order of preference for VCD enhancement is found to be acryloyl > acetyl > maleyl group. The resulting experimental VCD spectra are also found to be satisfactorily reproduced by the quantum mechanical (QM) predicted spectra. The QM predicted spectra were simulated using the conformer populations, (a) predicted by Gibbs energies and (b) optimized to maximize the similarity between experimental and predicted VCD spectra. It is found that the conformer populations predicted by Gibbs energies do not yield the maximum possible similarity between experimental and the QM predicted spectra. This work identifies the N-substitution of α-amino acids and determining the conformer populations that best reproduce the experimental spectra as two new approaches for molecular structure determination.
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Affiliation(s)
| | - Ernesto Santoro
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee
| | - Cody L Covington
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee.,Department of Chemistry, Austin Peay State University, Clarksville, Tennessee
| | - Vijay Raghavan
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee
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11
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Rojo-Portillo T, Reyes-López E, Hernández-Huerta E, Quiroz-García B, Joseph-Nathan P, Sánchez-Castellanos M, Cuétara-Guadarrama F, Cuevas G. Is the VCD spectrum a fingerprint of the conformational population? The conformation of perezone in the spotlight. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.127273] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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12
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Deol KK, Muller G. Luminescent and Chiroptical Properties of 1 : 1 Eu (III) : Tetracycline Species Probed by Circularly Polarized Luminescence. Chempluschem 2020; 84:1796-1804. [PMID: 31943861 DOI: 10.1002/cplu.201900627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/05/2019] [Indexed: 11/08/2022]
Abstract
This study investigates the significantly different luminescent and chiroptical properties of tetracycline (TC) when coordinated to Eu(III). The approach involves understanding the 1) speciation of TC and 2) conformation and species formed between Eu(III) and TC in a ratio of 1 : 1 in a dimethylformamide (DMF) solution and as a function of the pH value. By identifying the conformational changes of the various 1 : 1 Eu(III) : TC species, the results from this study explain information on the local microenvironment about the Eu(III) metal center. In particular, 5 D0 ←7 F0 Eu(III) laser excitation spectroscopy was employed to distinguish the different types of species found in solution in order to understand the interaction between Eu(III) and TC. On the other hand, circularly polarized luminescence (CPL) spectroscopy was used to understand the structural changes within the 1 : 1 Eu(III) : TC complex that could be related to the chirality of the Eu(III)-containing species. The CPL spectrum serves as a "fingerprint" to indicate the conformational changes within the 1 : 1 Eu(III) : TC complex as a result of the chiroptical signal arising from the various Eu(III) : TC species.
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Affiliation(s)
- Kirandeep K Deol
- Department of Chemistry, San José State University, One Washington Square, San José, CA 95192-0101, USA
| | - Gilles Muller
- Department of Chemistry, San José State University, One Washington Square, San José, CA 95192-0101, USA
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13
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Polavarapu PL, Santoro E. Vibrational optical activity for structural characterization of natural products. Nat Prod Rep 2020; 37:1661-1699. [DOI: 10.1039/d0np00025f] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review presents the recent progress towards elucidating the structures of chiral natural products and applications using vibrational optical activity (VOA) spectroscopy.
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14
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Merten C, Golub TP, Kreienborg NM. Absolute Configurations of Synthetic Molecular Scaffolds from Vibrational CD Spectroscopy. J Org Chem 2019; 84:8797-8814. [PMID: 31046276 DOI: 10.1021/acs.joc.9b00466] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Vibrational circular dichroism (VCD) spectroscopy is one of the most powerful techniques for the determination of absolute configurations (AC), as it does not require any specific UV/vis chromophores, no chemical derivatization, and no growth of suitable crystals. In the past decade, it has become increasingly recognized by chemists from various fields of synthetic chemistry such as total synthesis and drug discovery as well as from developers of asymmetric catalysts. This perspective article gives an overview about the most important experimental aspects of a VCD-based AC determination and explains the theoretical analysis. The comparison of experimental and computational spectra that leads to the final conclusion about the AC of the target molecules is described. In addition, the review summarizes unique VCD studies carried out in the period 2008-2018 that focus on the determination of unknown ACs of new compounds, which were obtained in its enantiopure form either through direct asymmetric synthesis or chiral chromatography.
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Affiliation(s)
- Christian Merten
- Ruhr Universität Bochum , Organische Chemie II , Universitätsstraße 150 , 44780 Bochum , Germany
| | - Tino P Golub
- Ruhr Universität Bochum , Organische Chemie II , Universitätsstraße 150 , 44780 Bochum , Germany
| | - Nora M Kreienborg
- Ruhr Universität Bochum , Organische Chemie II , Universitätsstraße 150 , 44780 Bochum , Germany
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15
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Johnson J, Nair DS, Pillai SM, Johnson D, Kallingathodi Z, Ibnusaud I, Polavarapu PL. Dissymmetry Factor Spectral Analysis Can Provide Useful Diastereomer Discrimination: Chiral Molecular Structure of an Analogue of (-)-Crispine A. ACS OMEGA 2019; 4:6154-6164. [PMID: 31459760 PMCID: PMC6648312 DOI: 10.1021/acsomega.8b03678] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 03/20/2019] [Indexed: 06/10/2023]
Abstract
(1R,10bR)-1'-((R)-1,2-Dihydroxyethyl)-1-hydroxy-8,9-dimethoxy1,5,6,10b-tetrahydropyrrolo [2,1-a]isoquinolin-3(2H)-one, an analogue of (-)-crispine A, with three stereogenic centers is synthesized and its absolute configuration (AC) established using the combined information derived from the synthetic scheme and single crystal X-ray diffraction data. The experimental chiroptical spectra (namely, optical rotatory dispersion (ORD), electronic circular dichroism (ECD), and vibrational circular dichroism (VCD)) and the corresponding quantum chemical (QC) predicted spectra for all diastereomers are used to evaluate the AC. The AC of the synthesized compound could be correctly established using any one of the three chiroptical spectroscopic methods (ORD, ECD, or VCD) when the relative configuration is constrained to be that derived from X-ray data or when the ACs of two of the chiral centers are constrained to be those derived from the synthetic scheme. In the absence of this outside information, the QC predicted ORD, ECD, and VCD for incorrect diastereomers are also found to satisfactorily reproduce the corresponding experimental spectra. Nevertheless, incorrect diastereomers could be eliminated when combined electronic dissymmetry factor (EDF) and vibrational dissymmetry factor (VDF) spectral analyses are included, leaving the correct diastereomer as the sole choice. Thus, the combined EDF and VDF spectral analysis is seen to be a helpful diastereomer discrimination tool.
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Affiliation(s)
- Jordan
L. Johnson
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Divya Sadasivan Nair
- Institute
for Intensive Research in Basic Sciences, Mahatma Gandhi University, P.D. Hills P. O., Kottayam, Kerala 686560, India
| | - Sarath Muraleedharan Pillai
- Institute
for Intensive Research in Basic Sciences, Mahatma Gandhi University, P.D. Hills P. O., Kottayam, Kerala 686560, India
| | - Didimos Johnson
- Institute
for Intensive Research in Basic Sciences, Mahatma Gandhi University, P.D. Hills P. O., Kottayam, Kerala 686560, India
| | - Zabeera Kallingathodi
- Institute
for Intensive Research in Basic Sciences, Mahatma Gandhi University, P.D. Hills P. O., Kottayam, Kerala 686560, India
| | - Ibrahim Ibnusaud
- Institute
for Intensive Research in Basic Sciences, Mahatma Gandhi University, P.D. Hills P. O., Kottayam, Kerala 686560, India
| | - Prasad L. Polavarapu
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
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16
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Johnson J, Polavarapu PL. Chiral Molecular Structures of Substituted Indans: Ring Puckering, Rotatable Substituents, and Vibrational Circular Dichroism. ACS OMEGA 2019; 4:4963-4976. [PMID: 31459680 PMCID: PMC6648482 DOI: 10.1021/acsomega.8b03628] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 02/21/2019] [Indexed: 05/06/2023]
Abstract
The chiral molecular structures of four different substituted indans, namely, (S)-1-methylindan, (R)-1-methylindan-1-d, (R)-1-aminoindan, and (S)-1-indanol, were investigated using experimental vibrational absorption and vibrational circular dichroism spectra and corresponding spectra predicted using quantum chemical (QC) calculations. All of these molecules possess two ring puckering conformations, with ring puckering leading to the pseudoequatorial substituent being approximately four times more abundant over that leading to the pseudoaxial substituent. The amino group in 1-aminoindan has three conformations arising from the rotation of NH2 group, for each ring puckering conformation, resulting in a total of six conformations. Whereas 1-indanol in the nonhydrogen-bonding solvent CCl4 also has six conformations similar to those of 1-aminoindan, 1-indanol in the hydrogen-bonding solvent DMSO-d 6 adopts numerous conformations, of which 30 conformers are considered to have at least ∼1% or more population. In DMSO solution, ring puckering leading to pseudoequatorial substituent accounts for 77% population and 23% for pseudoaxial substituent. The QC spectra predicted for the geometry optimized conformers are found to be in excellent quantitative agreement with corresponding experimental spectra in all of the molecules considered. The procedures suggested in this work are hoped to provide successful pathways for future chiral molecular structural analyses.
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17
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Mándi A, Kurtán T. Applications of OR/ECD/VCD to the structure elucidation of natural products. Nat Prod Rep 2019; 36:889-918. [DOI: 10.1039/c9np00002j] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OR, ECD and VCD are powerful methods to determine the absolute configuration of natural products either applied independently or in combination.
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Affiliation(s)
- Attila Mándi
- Department of Organic Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - Tibor Kurtán
- Department of Organic Chemistry
- University of Debrecen
- Debrecen
- Hungary
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18
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Cao F, Sun TT, Yang JK, Zhao GZ, Liu QA, Hu LD, Ma ZY, Zhu HJ. The absolute configuration of anti-Vibrio citrinin dimeric derivative by VCD, ECD and NMR methods. Nat Prod Res 2018; 33:2192-2199. [DOI: 10.1080/14786419.2018.1493590] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Fei Cao
- Key Laboratory of Medicinal Chemistry and Molecular Diagnostics of Education Ministry of China, Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, People’s Republic of China
| | - Tian-Tian Sun
- Key Laboratory of Medicinal Chemistry and Molecular Diagnostics of Education Ministry of China, Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, People’s Republic of China
| | - Jian-Kun Yang
- Key Laboratory of Medicinal Chemistry and Molecular Diagnostics of Education Ministry of China, Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, People’s Republic of China
| | - Guo-Zheng Zhao
- Key Laboratory of Medicinal Chemistry and Molecular Diagnostics of Education Ministry of China, Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, People’s Republic of China
| | - Qing-Ai Liu
- Shandong Provincial Key Laboratory for Biosensors, Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Lian-Dong Hu
- Key Laboratory of Medicinal Chemistry and Molecular Diagnostics of Education Ministry of China, Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, People’s Republic of China
| | - Zheng-Yue Ma
- Key Laboratory of Medicinal Chemistry and Molecular Diagnostics of Education Ministry of China, Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, People’s Republic of China
| | - Hua-Jie Zhu
- Key Laboratory of Medicinal Chemistry and Molecular Diagnostics of Education Ministry of China, Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, People’s Republic of China
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