1
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Dhaked DK, Nicklaus MC. What impact does tautomerism have on drug discovery and development? Expert Opin Drug Discov 2024:1-6. [PMID: 39014878 DOI: 10.1080/17460441.2024.2379873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Accepted: 07/10/2024] [Indexed: 07/18/2024]
Affiliation(s)
- Devendra K Dhaked
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), Kolkata, India
| | - Marc C Nicklaus
- Computer-Aided Drug Design Group, Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, USA
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2
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Synthesis of a new pyrimidine-based sorbent for indium(III) removal from aqueous solutions – Application to ore leachate. Sep Purif Technol 2023. [DOI: 10.1016/j.seppur.2023.123514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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3
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Fatahiyan L, Taghva Manesh A, Masnabadi N. Tautomerization reactions of thiobarbituric acid: A detailed kinetic study using combined canonical variational transition state theory and QTAIM approach. INT J CHEM KINET 2023. [DOI: 10.1002/kin.21632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Affiliation(s)
- Leila Fatahiyan
- Department of Chemistry, Central Tehran Branch, Islamic Azad University Tehran Iran
| | - Afshin Taghva Manesh
- Department of Chemistry, Central Tehran Branch, Islamic Azad University Tehran Iran
| | - Nasrin Masnabadi
- Department of Chemistry, Roudehen Branch, Islamic Azad University Roudehen Iran
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4
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Zwitterionic or Not? Fast and Reliable Structure Determination by Combining Crystal Structure Prediction and Solid-State NMR. Molecules 2023; 28:molecules28041876. [PMID: 36838863 PMCID: PMC9966216 DOI: 10.3390/molecules28041876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/06/2023] [Accepted: 02/10/2023] [Indexed: 02/18/2023] Open
Abstract
When it comes to crystal structure determination, computational approaches such as Crystal Structure Prediction (CSP) have gained more and more attention since they offer some insight on how atoms and molecules are packed in the solid state, starting from only very basic information without diffraction data. Furthermore, it is well known that the coupling of CSP with solid-state NMR (SSNMR) greatly enhances the performance and the accuracy of the predictive method, leading to the so-called CSP-NMR crystallography (CSP-NMRX). In this paper, we present the successful application of CSP-NMRX to determine the crystal structure of three structural isomers of pyridine dicarboxylic acid, namely quinolinic, dipicolinic and dinicotinic acids, which can be in a zwitterionic form, or not, in the solid state. In a first step, mono- and bidimensional SSNMR spectra, i.e., 1H Magic-Angle Spinning (MAS), 13C and 15N Cross Polarisation Magic-Angle Spinning (CPMAS), 1H Double Quantum (DQ) MAS, 1H-13C HETeronuclear CORrelation (HETCOR), were used to determine the correct molecular structure (i.e., zwitterionic or not) and the local molecular arrangement; at the end, the RMSEs between experimental and computed 1H and 13C chemical shifts allowed the selection of the correct predicted structure for each system. Interestingly, while quinolinic and dipicolinic acids are zwitterionic and non-zwitterionic, respectively, in the solid state, dinicotinic acid exhibits in its crystal structure a "zwitterionic-non-zwitterionic continuum state" in which the proton is shared between the carboxylic moiety and the pyridinic nitrogen. Very refined SSNMR experiments were carried out, i.e., 14N-1H Phase-Modulated (PM) pulse and Rotational-Echo Saturation-Pulse Double-Resonance (RESPDOR), to provide an accurate N-H distance value confirming the hybrid nature of the molecule. The CSP-NMRX method showed a remarkable match between the selected structures and the experimental ones. The correct molecular input provided by SSNMR reduced the number of CSP calculations to be performed, leading to different predicted structures, while RMSEs provided an independent parameter with respect to the computed energy for the selection of the best candidate.
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5
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The Relevance of Crystal Forms in the Pharmaceutical Field: Sword of Damocles or Innovation Tools? Int J Mol Sci 2022; 23:ijms23169013. [PMID: 36012275 PMCID: PMC9408954 DOI: 10.3390/ijms23169013] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/01/2022] [Accepted: 08/05/2022] [Indexed: 12/22/2022] Open
Abstract
This review is aimed to provide to an “educated but non-expert” readership and an overview of the scientific, commercial, and ethical importance of investigating the crystalline forms (polymorphs, hydrates, and co-crystals) of active pharmaceutical ingredients (API). The existence of multiple crystal forms of an API is relevant not only for the selection of the best solid material to carry through the various stages of drug development, including the choice of dosage and of excipients suitable for drug development and marketing, but also in terms of intellectual property protection and/or extension. This is because the physico-chemical properties, such as solubility, dissolution rate, thermal stability, processability, etc., of the solid API may depend, sometimes dramatically, on the crystal form, with important implications on the drug’s ultimate efficacy. This review will recount how the scientific community and the pharmaceutical industry learned from the catastrophic consequences of the appearance of new, more stable, and unsuspected crystal forms. The relevant aspects of hydrates, the most common pharmaceutical solid solvates, and of co-crystals, the association of two or more solid components in the same crystalline materials, will also be discussed. Examples will be provided of how to tackle multiple crystal forms with screening protocols and theoretical approaches, and ultimately how to turn into discovery and innovation the purposed preparation of new crystalline forms of an API.
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6
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Grześkiewicz AM, Kubicki M. Two Tautomers of Thiobarbituric Acid in One Crystal: The Experimental Charge Density Perspective. MATERIALS (BASEL, SWITZERLAND) 2021; 15:223. [PMID: 35009369 PMCID: PMC8745894 DOI: 10.3390/ma15010223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/20/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
High-quality crystals of a certain polymorphic form of thiobarbituric acid containing both keto and enol tautomers in the asymmetric unit were obtained. High-resolution X-ray diffraction data up to sinθ/λ = 1.0 Å-1 were collected and subsequently successfully used for the refining of the multipolar model of electron density distribution. The use of a crystal containing both ketone and enol forms allowed a direct comparison of the topological analysis results and a closer look at the differences between these two forms. The similarities and differences between the deformation densities, electrostatic potentials, Laplacian maps and bond characteristics of the tautomers were analysed. Additionally, the spectrum of the intermolecular interactions was identified and studied from classical, relatively strong N-H···O and O-H···O hydrogen bonds through weaker N-H···S hydrogen bonds to weak interactions (for instance, C-H···O, C-H···S and N···O). The results of these studies point toward the importance of including both the geometrical features and the details of the electron density distribution in the analysis of such weak interactions.
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7
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Bravetti F, Bordignon S, Alig E, Eisenbeil D, Fink L, Nervi C, Gobetto R, Schmidt MU, Chierotti MR. Solid-State NMR-Driven Crystal Structure Prediction of Molecular Crystals: The Case of Mebendazole. Chemistry 2021; 28:e202103589. [PMID: 34962330 DOI: 10.1002/chem.202103589] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Indexed: 11/06/2022]
Abstract
Among all possible NMR crystallography approaches for crystal-structure determination, crystal structure prediction - NMR crystallography (CSP-NMRX) has recently turned out to be a powerful method. In the latter, the original procedure exploited solid-state NMR (SSNMR) information during the final steps of the prediction. In particular, it used the comparison of computed and experimental chemical shifts for the selection of the correct crystal packing. Still, the prediction procedure, generally carried out with DFT methods, may require important computational resources and be quite time-consuming, especially if there are no available constraints to use at the initial stage. Herein, the successful application of this combined prediction method, which exploits NMR information also in the input step to reduce the search space of the predictive algorithm, is presented. Herein, this method was applied on mebendazole, which is characterized by desmotropism. The use of SSNMR data as constraints for the selection of the right tautomer and the determination of the number of independent molecules in the unit cell led to a considerably faster process, reducing the number of calculations to be performed. In this way, the crystal packing was successfully predicted for the three known phases of mebendazole. To evaluate the quality of the predicted structures, these were compared to the experimental ones. The crystal structure of phase B of mebendazole, in particular, was determined de novo by powder diffraction and is presented for the first time in this paper.
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Affiliation(s)
- Federica Bravetti
- Department of Chemistry, Università degli Studi di Torino, via Pietro Giuria 7, 10125, Torino, Italy
| | - Simone Bordignon
- Department of Chemistry, Università degli Studi di Torino, via Pietro Giuria 7, 10125, Torino, Italy
| | - Edith Alig
- Institute of Inorganic and Analytical Chemistry, Goethe University, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
| | - Daniel Eisenbeil
- Institute of Inorganic and Analytical Chemistry, Goethe University, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
| | - Lothar Fink
- Institute of Inorganic and Analytical Chemistry, Goethe University, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
| | - Carlo Nervi
- Department of Chemistry, Università degli Studi di Torino, via Pietro Giuria 7, 10125, Torino, Italy
| | - Roberto Gobetto
- Department of Chemistry, Università degli Studi di Torino, via Pietro Giuria 7, 10125, Torino, Italy
| | - Martin U Schmidt
- Institute of Inorganic and Analytical Chemistry, Goethe University, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
| | - Michele R Chierotti
- Department of Chemistry, Università degli Studi di Torino, via Pietro Giuria 7, 10125, Torino, Italy
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8
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Mechanochemical Synthesis and Physicochemical Characterization of Previously Unreported Praziquantel Solvates with 2-Pyrrolidone and Acetic Acid. Pharmaceutics 2021; 13:pharmaceutics13101606. [PMID: 34683899 PMCID: PMC8540171 DOI: 10.3390/pharmaceutics13101606] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/24/2021] [Accepted: 09/28/2021] [Indexed: 12/26/2022] Open
Abstract
Two new solvates of the widely used anthelminthic Praziquantel (PZQ) were obtained through mechanochemical screening with different liquid additives. Specifically, 2-pyrrolidone and acetic acid gave solvates with 1:1 stoichiometry (PZQ-AA and PZQ-2P, respectively). A wide-ranging characterization of the new solid forms was carried out by means of powder X-ray diffraction, differential scanning calorimetry, FT-IR, solid-state NMR and biopharmaceutical analyses (solubility and intrinsic dissolution studies). Besides, the crystal structures of the two new solvates were solved from their Synchrotron-PXRD pattern: the solvates are isostructural, with equivalent triclinic packing. In both structures acetic acid and 2-pyrrolidone showed a strong interaction with the PZQ molecule via hydrogen bond. Even though previous studies have shown that PZQ is conformationally flexible, the same syn conformation as the PZQ Form A of the C=O groups of the piperazinone-cyclohexylcarbonyl segment is involved in these two new solid forms. In terms of biopharmaceutical properties, PZQ-AA and PZQ-2P exhibited water solubility and intrinsic dissolution rate much greater than those of anhydrous Form A.
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9
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Abstract
Sublimation is an effective and ‘green’ method to prepare and identify new polymorphs, cocrystals, ionic cocrystals and molecular salts.
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Affiliation(s)
- Patrick McArdle
- School of Chemistry, National University of Ireland, Galway, Ireland
| | - Andrea Erxleben
- School of Chemistry, National University of Ireland, Galway, Ireland
- Synthesis and Solid State Pharmaceutical Centre (SSPC), Limerick, Ireland
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10
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Saez Talens V, Davis J, Wu CH, Wen Z, Lauria F, Gupta KBSS, Rudge R, Boraghi M, Hagemeijer A, Trinh TT, Englebienne P, Voets IK, Wu JI, Kieltyka RE. Thiosquaramide-Based Supramolecular Polymers: Aromaticity Gain in a Switched Mode of Self-Assembly. J Am Chem Soc 2020; 142:19907-19916. [PMID: 33191746 PMCID: PMC7705886 DOI: 10.1021/jacs.0c02081] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Despite a growing understanding of factors that drive monomer self-assembly to form supramolecular polymers, the effects of aromaticity gain have been largely ignored. Herein, we document the aromaticity gain in two different self-assembly modes of squaramide-based bolaamphiphiles. Importantly, O → S substitution in squaramide synthons resulted in supramolecular polymers with increased fiber flexibility and lower degrees of polymerization. Computations and spectroscopic experiments suggest that the oxo- and thiosquaramide bolaamphiphiles self-assemble into "head-to-tail" versus "stacked" arrangements, respectively. Computed energetic and magnetic criteria of aromaticity reveal that both modes of self-assembly increase the aromatic character of the squaramide synthons, giving rise to stronger intermolecular interactions in the resultant supramolecular polymer structures. These examples suggest that both hydrogen-bonding and stacking interactions can result in increased aromaticity upon self-assembly, highlighting its relevance in monomer design.
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Affiliation(s)
- Victorio Saez Talens
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
| | - Joyal Davis
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
| | - Chia-Hua Wu
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Zhili Wen
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Francesca Lauria
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
| | - Karthick Babu Sai Sankar Gupta
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
| | - Raisa Rudge
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
| | - Mahsa Boraghi
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Alexander Hagemeijer
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
| | - Thuat T Trinh
- Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Pablo Englebienne
- Process & Energy Laboratory, Delft University of Technology, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands
| | - Ilja K Voets
- Laboratory of Self-Organizing Soft Matter and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MD, Eindhoven, The Netherlands
| | - Judy I Wu
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Roxanne E Kieltyka
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
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11
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Verma V, Bordignon S, Chierotti MR, Lestari M, Lyons K, Padrela L, Ryan KM, Lusi M. Cortisone and cortisol break hydrogen-bonding rules to make a drug-prodrug solid solution. IUCRJ 2020; 7:1124-1130. [PMID: 33209323 PMCID: PMC7642785 DOI: 10.1107/s2052252520013263] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 10/03/2020] [Indexed: 06/11/2023]
Abstract
Multidrug products enable more effective therapies and simpler administration regimens, provided that a stable formulation is prepared, with the desired composition. In this view, solid solutions have the advantage of combining the stability of a single crystalline phase with the potential of stoichiometry variation of a mixture. Here a drug-prodrug solid solution of cortisone and cortisol (hydrocortisone) is described. Despite the structural differences of the two components, the new phase is obtained both from solution and by supercritical CO2 assisted spray drying. In particular, to enter the solid solution, hydrocortisone must violate Etter's rules for hydrogen bonding. As a result, its dissolution rate is almost doubled.
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Affiliation(s)
- Vivek Verma
- Department of Chemistry and Bernal Institute, University of Limerick, Limerick, Ireland
| | | | | | - Monica Lestari
- Department of Chemistry and Bernal Institute, University of Limerick, Limerick, Ireland
| | - Kieran Lyons
- Department of Chemistry and Bernal Institute, University of Limerick, Limerick, Ireland
| | - Luis Padrela
- Department of Chemistry and Bernal Institute, University of Limerick, Limerick, Ireland
| | - Kevin M. Ryan
- Department of Chemistry and Bernal Institute, University of Limerick, Limerick, Ireland
| | - Matteo Lusi
- Department of Chemistry and Bernal Institute, University of Limerick, Limerick, Ireland
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12
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Hodgkinson P. NMR crystallography of molecular organics. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 118-119:10-53. [PMID: 32883448 DOI: 10.1016/j.pnmrs.2020.03.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 02/25/2020] [Accepted: 03/13/2020] [Indexed: 06/11/2023]
Abstract
Developments of NMR methodology to characterise the structures of molecular organic structures are reviewed, concentrating on the previous decade of research in which density functional theory-based calculations of NMR parameters in periodic solids have become widespread. With a focus on demonstrating the new structural insights provided, it is shown how "NMR crystallography" has been used in a spectrum of applications from resolving ambiguities in diffraction-derived structures (such as hydrogen atom positioning) to deriving complete structures in the absence of diffraction data. As well as comprehensively reviewing applications, the different aspects of the experimental and computational techniques used in NMR crystallography are surveyed. NMR crystallography is seen to be a rapidly maturing subject area that is increasingly appreciated by the wider crystallographic community.
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Affiliation(s)
- Paul Hodgkinson
- Department of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, UK.
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13
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Wróblewska A, Śniechowska J, Kaźmierski S, Wielgus E, Bujacz GD, Mlostoń G, Chworos A, Suwara J, Potrzebowski MJ. Application of 1-Hydroxy-4,5-Dimethyl-Imidazole 3-Oxide as Coformer in Formation of Pharmaceutical Cocrystals. Pharmaceutics 2020; 12:pharmaceutics12040359. [PMID: 32326428 PMCID: PMC7238160 DOI: 10.3390/pharmaceutics12040359] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/08/2020] [Accepted: 04/10/2020] [Indexed: 12/20/2022] Open
Abstract
Two, well defined binary crystals with 1-Hydroxy-4,5-Dimethyl-Imidazole 3-Oxide (HIMO) as coformer and thiobarbituric acid (TBA) as well barbituric acid (BA) as Active Pharmaceutical Ingredients (APIs) were obtained by cocrystallization (from methanol) or mechanochemically by grinding. The progress of cocrystal formation in a ball mill was monitored by means of high-resolution, solid state NMR spectroscopy. The 13C CP/MAS, 15N CP/MAS and 1H Very Fast (VF) MAS NMR procedures were employed to inspect the tautomeric forms of the APIs, structure elucidation of the coformer and the obtained cocrystals. Single crystal X-ray studies allowed us to define the molecular structure and crystal packing for the coformer as well as the TBA/HIMO and BA/HIMO cocrystals. The intermolecular hydrogen bonding, π-π interactions and CH-π contacts responsible for higher order organization of supramolecular structures were determined. Biological studies of HIMO and the obtained cocrystals suggest that these complexes are not cytotoxic and can potentially be considered as therapeutic materials.
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Affiliation(s)
- Aneta Wróblewska
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland; (A.W.); (J.Ś.); (S.K.); (E.W.); (A.C.); (J.S.)
| | - Justyna Śniechowska
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland; (A.W.); (J.Ś.); (S.K.); (E.W.); (A.C.); (J.S.)
| | - Sławomir Kaźmierski
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland; (A.W.); (J.Ś.); (S.K.); (E.W.); (A.C.); (J.S.)
| | - Ewelina Wielgus
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland; (A.W.); (J.Ś.); (S.K.); (E.W.); (A.C.); (J.S.)
| | - Grzegorz D. Bujacz
- Institute of Technical Biochemistry, Lodz University of Technology, Stefanowskiego 4/10, 90-924 Lodz, Poland;
| | - Grzegorz Mlostoń
- Department of Organic and Applied Chemistry, University of Lodz, Tamka 12, 91-403 Lodz, Poland;
| | - Arkadiusz Chworos
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland; (A.W.); (J.Ś.); (S.K.); (E.W.); (A.C.); (J.S.)
| | - Justyna Suwara
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland; (A.W.); (J.Ś.); (S.K.); (E.W.); (A.C.); (J.S.)
| | - Marek J. Potrzebowski
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland; (A.W.); (J.Ś.); (S.K.); (E.W.); (A.C.); (J.S.)
- Correspondence: ; Tel.: +48-42-680-3240
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14
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Sacchi P, Lusi M, Cruz-Cabeza AJ, Nauha E, Bernstein J. Same or different – that is the question: identification of crystal forms from crystal structure data. CrystEngComm 2020. [DOI: 10.1039/d0ce00724b] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
An analysis of the CSD with structural comparison tools shows that differentiating between polymorphism and redeterminations is not always straight forward and requires of complementary tools at the hands of an expert practitioner.
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Affiliation(s)
- Pietro Sacchi
- Department of Chemical Engineering and Analytical Science
- University of Manchester
- Manchester
- UK
| | - Matteo Lusi
- SSPC
- The SFI Research Centre for Pharmaceuticals
- Bernal Institute
- Department of Chemical Sciences
- University of Limerick
| | - Aurora J. Cruz-Cabeza
- Department of Chemical Engineering and Analytical Science
- University of Manchester
- Manchester
- UK
| | - Elisa Nauha
- New York University Abu Dhabi
- Abu Dhabi
- United Arab Emirates
| | - Joel Bernstein
- New York University Abu Dhabi
- Abu Dhabi
- United Arab Emirates
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15
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Affiliation(s)
- Tomislav Friščić
- Department of Chemistry McGill University 801 Sherbrooke St. W. H3A 0B8 Montreal Canada
- Laboratoire SPCMIB, CNRS UMR 5068 Université de Toulouse UPS 118 Route de Narbonne 31062 Toulouse Cedex 09 France
| | - Cristina Mottillo
- Department of Chemistry McGill University 801 Sherbrooke St. W. H3A 0B8 Montreal Canada
| | - Hatem M. Titi
- Department of Chemistry McGill University 801 Sherbrooke St. W. H3A 0B8 Montreal Canada
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16
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Friščić T, Mottillo C, Titi HM. Mechanochemistry for Synthesis. Angew Chem Int Ed Engl 2019; 59:1018-1029. [DOI: 10.1002/anie.201906755] [Citation(s) in RCA: 392] [Impact Index Per Article: 78.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Indexed: 01/01/2023]
Affiliation(s)
- Tomislav Friščić
- Department of Chemistry McGill University 801 Sherbrooke St. W. H3A 0B8 Montreal Canada
- Laboratoire SPCMIB, CNRS UMR 5068 Université de Toulouse UPS 118 Route de Narbonne 31062 Toulouse Cedex 09 France
| | - Cristina Mottillo
- Department of Chemistry McGill University 801 Sherbrooke St. W. H3A 0B8 Montreal Canada
| | - Hatem M. Titi
- Department of Chemistry McGill University 801 Sherbrooke St. W. H3A 0B8 Montreal Canada
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17
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Sigalov MV, Afonin AV, Sterkhova IV, Shainyan BA. 2 H-Indazole Tautomers Stabilized by Intra- and Intermolecular Hydrogen Bonds. J Org Chem 2019; 84:9075-9086. [PMID: 31241332 DOI: 10.1021/acs.joc.9b01021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
2-[(2H-Indazol-3-yl)methylene]-1H-indene-1,3(2H)-dione 6 and (E)-2-[(2H-indazol-3-yl)methylene]-2,3-dihydro-1H-inden-1-one 7 have been synthesized. In the crystal, the NH hydrogen atom of 6 is disordered between the N(1) and N(2) atoms with the population ratio of 0.69:0.31. Molecule 7 crystallizes in two tautomeric polymorphs: 7-1H tautomer (yellow) and 7-2H tautomer (red). Both 6 and 7 form centrosymmetric dimers in the crystal with the monomeric units linked by C═O···H···N bifurcated hydrogen bonds in 6 and N-H···N hydrogen bonds in 7. According to 1H and 13C NMR data, in DMSO-d6 solution, the 6-1H tautomer predominates, whereas in less polar CDCl3 or CD2Cl2, the 6-2H tautomer is stabilized by a strong N-H···O═C intramolecular hydrogen bond. Compound 7 in dimethyl sulfoxide (DMSO) or ethanol solutions exists in the form of 7-1H and 7-2H tautomers. On the example of the 7-2H tautomer, it was shown for the first time that the 2H tautomers of 3-substituted indazoles can be stabilized by an intermolecular hydrogen bond and may remain in aprotic solvents almost indefinitely. However, in the open air or in water, fast 2H → 1H tautomerization occurs. As follows from density functional theory calculations, the high stability of the 2H form in solution is due to the formation of centrosymmetric dimers, which are more stable than the corresponding dimers of the 1H tautomer.
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Affiliation(s)
- Mark V Sigalov
- Department of Chemistry , Ben-Gurion University of the Negev , 84105 Beer-Sheva , Israel
| | - Andrey V Afonin
- Siberian Division of Russian Academy of Sciences , A. E. Favorsky Irkutsk Institute of Chemistry , 664033 Irkutsk , Russia
| | - Irina V Sterkhova
- Siberian Division of Russian Academy of Sciences , A. E. Favorsky Irkutsk Institute of Chemistry , 664033 Irkutsk , Russia
| | - Bagrat A Shainyan
- Siberian Division of Russian Academy of Sciences , A. E. Favorsky Irkutsk Institute of Chemistry , 664033 Irkutsk , Russia
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18
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Ivanova B, Spiteller M. Noncentrosymmetric organic crystals of barbiturates as potential nonlinear optical phores: experimental and theoretical analyses. CHEMICAL PAPERS 2019. [DOI: 10.1007/s11696-019-00835-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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19
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Filo J, Tisovský P, Csicsai K, Donovalová J, Gáplovský M, Gáplovský A, Cigáň M. Tautomeric photoswitches: anion-assisted azo/azine-to-hydrazone photochromism. RSC Adv 2019; 9:15910-15916. [PMID: 35521389 PMCID: PMC9064339 DOI: 10.1039/c9ra02906k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 05/15/2019] [Indexed: 11/21/2022] Open
Abstract
The photoswitching behaviour of isatin 4-nitrophenylhydrazones in presence of anions was investigated.
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Affiliation(s)
- Juraj Filo
- Institute of Chemistry
- Faculty of Natural Sciences
- Comenius University
- SK-842 15 Bratislava
- Slovakia
| | - Pavol Tisovský
- Institute of Chemistry
- Faculty of Natural Sciences
- Comenius University
- SK-842 15 Bratislava
- Slovakia
| | - Klaudia Csicsai
- Institute of Chemistry
- Faculty of Natural Sciences
- Comenius University
- SK-842 15 Bratislava
- Slovakia
| | - Jana Donovalová
- Institute of Chemistry
- Faculty of Natural Sciences
- Comenius University
- SK-842 15 Bratislava
- Slovakia
| | - Martin Gáplovský
- Department of Pharmaceutical Chemistry
- Faculty of Pharmacy
- Comenius University
- SK-832 32 Bratislava
- Slovakia
| | - Anton Gáplovský
- Institute of Chemistry
- Faculty of Natural Sciences
- Comenius University
- SK-842 15 Bratislava
- Slovakia
| | - Marek Cigáň
- Institute of Chemistry
- Faculty of Natural Sciences
- Comenius University
- SK-842 15 Bratislava
- Slovakia
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20
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Crystallographic, thermal and spectroscopic characterization of the anhydrous thiourea−barbituric acid and thiourea−2-thiobarbituric acid co-crystals. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2018.09.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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21
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Sharma A, Zamisa SJ, Noki S, Almarhoon Z, El-Faham A, Torre BGDL, Albericio F. Crystal structure, spectroscopic studies and theoretical studies of thiobarbituric acid derivatives: understanding the hydrogen-bonding patterns. ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2018; 74:1703-1714. [PMID: 30516155 DOI: 10.1107/s2053229618015516] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 11/02/2018] [Indexed: 11/10/2022]
Abstract
In addition to their wide-ranging applications in the pharmaceutical industry, thiobarbituric acid (TBA) derivatives are also known to possess applications in engineering and materials science. 20 TBA derivatives, with diversity at the N and C-5 positions through acylation, Schiff base formation, Knoevenagel condensation, thioamide and enamine formation, were studied. The absolute configurations for six derivatives, namely 5-acetyl-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione, C10H14N2O3S, A01, 1,3-diethyl-5-propionyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione, C11H16N2O3S, A02, tert-butyl [1-(1,3-diethyl-4,6-dioxo-2-thioxohexahydropyrimidin-5-yl)-3-methyl-1-oxobutan-2-yl]carbamate, C18H29N3O5S, A06, 1,3-diethyl-4,6-dioxo-2-thioxo-N-(p-tolyl)hexahydropyrimidine-5-carbothioamide, C16H19N3O2S2, A13, 5-(1-aminoethylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione, C10H15N3O2S, A17, and 5-(1-aminopropylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione, C11H17N3O2S, A18, were confirmed by single-crystal X-ray crystallography, which indicates the formation of intramolecular hydrogen bonding in all six cases and intermolecular hydrogen bonding for A17. In A13, the presence of two intramolecular hydrogen bonds was observed. The stabilization of the enol form over the keto form was confirmed by computation. In order to convert the keto form to the enol form, an energy barrier of 55.05 kcal mol-1 needs to be overcome, as confirmed by transition-state calculations.
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Affiliation(s)
- Anamika Sharma
- School of Health Sciences, University of KwaZulu Natal, University Road, Westville, Durban, 4000, South Africa
| | - Sizwe J Zamisa
- School of Chemistry and Physics, University of KwaZulu Natal, Private bag X54001, Westville campus, Durban, 4000, South Africa
| | - Sikabwe Noki
- School of Chemistry and Physics, University of KwaZulu Natal, Private bag X54001, Westville campus, Durban, 4000, South Africa
| | - Zainab Almarhoon
- Department of Chemistry, College of Science, King Saud University, 2455 Riyadh, 11451, Saudi Arabia
| | - Ayman El-Faham
- Department of Chemistry, College of Science, King Saud University, 2455 Riyadh, 11451, Saudi Arabia
| | - Beatriz G de la Torre
- KRISP, College of Health Sciences, University of KwaZulu Natal, Durban, 4001, South Africa
| | - Fernando Albericio
- School of Chemistry and Physics, University of KwaZulu Natal, Private bag X54001, Westville campus, Durban, 4000, South Africa
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22
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Wang Q, Xue J, Wang Y, Jin S, Zhang Q, Du Y. Investigation into tautomeric polymorphism of 2-thiobarbituric acid using experimental vibrational spectroscopy combined with DFT theoretical simulation. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 204:99-104. [PMID: 29909217 DOI: 10.1016/j.saa.2018.06.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/04/2018] [Accepted: 06/10/2018] [Indexed: 06/08/2023]
Abstract
Vibrational modes of 2-thiobarbituric acid (TBA) tautomeric polymorphs (form I, II and IV) were characterized by terahertz time-domain spectroscopy (THz-TDS) and Raman spectral techniques. The experimental results indicate that both vibrational spectroscopy techniques could be used to recognize the above TBA three tautomeric forms clearly. Experimental THz spectral results show that each of TBA tautomeric polymorphs has distinctive fingerprint peaks in the terahertz region. Raman spectra also show similar results about differences of TBA tautomeric polymorphs, but not significant as that of terahertz spectra since Raman-active vibrational modes are mostly from intra-molecular interaction of various functional groups within the specific molecule while that of terahertz region is more sensitive to inter-molecular interaction within crystalline unit cells. In addition, density functional theory (DFT) was used to simulate the optimized structures and vibrational modes of these three TBA tautomeric forms above. The characteristic vibrational modes of TBA polymorphs are assigned comparing the simulated DFT results with experimental vibrational spectra. The results provide fundamental benchmark for the study of pharmaceutical polymorphism based on both Raman and terahertz vibrational spectroscopic techniques combined with theoretical simulations.
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Affiliation(s)
- Qiqi Wang
- Centre for THz Research, China Jiliang University, Hangzhou 310018, China
| | - Jiadan Xue
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Yaguo Wang
- Centre for THz Research, China Jiliang University, Hangzhou 310018, China
| | - Shunji Jin
- Centre for THz Research, China Jiliang University, Hangzhou 310018, China
| | - Qi Zhang
- Centre for THz Research, China Jiliang University, Hangzhou 310018, China
| | - Yong Du
- Centre for THz Research, China Jiliang University, Hangzhou 310018, China.
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23
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Rozatian N, Ashworth IW, Sandford G, Hodgson DRW. A quantitative reactivity scale for electrophilic fluorinating reagents. Chem Sci 2018; 9:8692-8702. [PMID: 30595834 PMCID: PMC6263395 DOI: 10.1039/c8sc03596b] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 09/13/2018] [Indexed: 11/21/2022] Open
Abstract
Through kinetic studies we provide a quantitative reactivity scale for ten electrophilic fluorination reagents.
Electrophilic N–F fluorination agents underpin the introduction of fluorine in aliphatic systems across drug and academic research. The choice of N–F reagent is currently determined through empirical experimentation in the absence of quantitative values for electrophilicities. Here we report an experimentally-determined kinetic reactivity scale for ten N–F fluorinating reagents, including Selectfluor™, NFSI, Synfluor™ and several N-fluoropyridinium salts, in CH3CN. The reactivity scale, which covers eight orders of magnitude, employs para-substituted 1,3-diaryl-1,3-dicarbonyl derivatives to measure relative and absolute rate constants. The para-substituted 1,3-diaryl-1,3-dicarbonyl scaffold delivers a convenient, sensitive spectrophotometric reporter of reactivity that also led to the discovery of a unique form of tautomeric polymorphism.
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Affiliation(s)
- Neshat Rozatian
- Chemistry Department , Durham University , South Road , Durham , DH1 3LE , UK .
| | - Ian W Ashworth
- AstraZeneca , Pharmaceutical Technology & Development , Macclesfield , SK10 2NA , UK
| | - Graham Sandford
- Chemistry Department , Durham University , South Road , Durham , DH1 3LE , UK .
| | - David R W Hodgson
- Chemistry Department , Durham University , South Road , Durham , DH1 3LE , UK .
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24
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Du Y, Xue J, Cai Q, Zhang Q. Spectroscopic investigation on structure and pH dependent Cocrystal formation between gamma-aminobutyric acid and benzoic acid. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 191:377-381. [PMID: 29055755 DOI: 10.1016/j.saa.2017.10.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/25/2017] [Accepted: 10/04/2017] [Indexed: 06/07/2023]
Abstract
Vibrational spectroscopic methods, including terahertz absorption and Raman scattering spectroscopy, were utilized for the characterization and analysis of gamma-aminobutyric acid (GABA), benzoic acid (BA), and the corresponding GABA-BA cocrystal formation under various pH values of aqueous solution. Vibrational spectroscopic results demonstrated that the solvent GABA-BA cocrystal, similar as grinding counterpart, possessed unique characteristic features compared with that of starting parent compounds. The change of vibrational modes for GABA-BA cocrystal comparing with starting components indicates there is strong inter-molecular interaction between GABA and BA molecules during its cocrystallization process. Formation of GABA-BA cocrystal under slow solvent evaporation is impacted by the pH value of aqueous solution. Vibrational spectra indicate that the GABA-BA cocrystal could be stably formed with the solvent condition of 2.00≤pH≤7.00. In contrast, such cocrystallization did not occur and the cocrystal would dissociate into its parent components when the pH value of solvent is lower than 2.00. This study provides experimental benchmark to discriminate and identify the structure of cocrystal and also pH-dependent cocrystallization effect with vibrational spectroscopic techniques in solid-state pharmaceutical fields.
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Affiliation(s)
- Yong Du
- Centre for THz Research, China Jiliang University, Hangzhou 310018, China.
| | - Jiadan Xue
- Department of Chemisty, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Qiang Cai
- Centre for THz Research, China Jiliang University, Hangzhou 310018, China
| | - Qi Zhang
- Centre for THz Research, China Jiliang University, Hangzhou 310018, China
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25
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Tan D, Loots L, Friščić T. Towards medicinal mechanochemistry: evolution of milling from pharmaceutical solid form screening to the synthesis of active pharmaceutical ingredients (APIs). Chem Commun (Camb) 2018; 52:7760-81. [PMID: 27185190 DOI: 10.1039/c6cc02015a] [Citation(s) in RCA: 198] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This overview highlights the emergent area of mechanochemical reactions for making active pharmaceutical ingredients (APIs), and covers the latest advances in the recently established area of mechanochemical screening and synthesis of pharmaceutical solid forms, specifically polymorphs, cocrystals, salts and salt cocrystals. We also provide an overview of the most recent developments in pharmaceutical uses of mechanochemistry, including real-time reaction monitoring, techniques for polymorph control and approaches for continuous manufacture using twin screw extrusion, and more. Most importantly, we show how the overlap of previously unrelated areas of mechanochemical screening for API solid forms, organic synthesis by milling, and mechanochemical screening for molecular recognition, enables the emergence of a new research discipline in which different aspects of pharmaceutical and medicinal chemistry are addressed through mechanochemistry rather than through conventional solution-based routes. The emergence of such medicinal mechanochemistry is likely to have a strong impact on future pharmaceutical and medicinal chemistry, as it offers not only access to materials and reactivity that are sometimes difficult or even impossible to access from solution, but can also provide a general answer to the demands of the pharmaceutical industry for cleaner, safer and efficient synthetic solutions.
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Affiliation(s)
- Davin Tan
- Department of Chemistry, McGill University, 801 Sherbrooke St. W, H3A 0B8 Montreal, Canada.
| | - Leigh Loots
- Department of Chemistry, McGill University, 801 Sherbrooke St. W, H3A 0B8 Montreal, Canada.
| | - Tomislav Friščić
- Department of Chemistry, McGill University, 801 Sherbrooke St. W, H3A 0B8 Montreal, Canada.
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26
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Shemchuk O, Braga D, Grepioni F. Alloying barbituric and thiobarbituric acids: from solid solutions to a highly stable keto co-crystal form. Chem Commun (Camb) 2018; 52:11815-11818. [PMID: 27722256 DOI: 10.1039/c6cc06615a] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Alloying isomorphous crystals of barbituric acid (BA) and thiobarbituric acid (TBA) yields solid solutions of general formula BAxTBA1-x (x < 0.8); for x = 0.5 the stable co-crystal BA0.5TBA0.5, isomorphous with the parent keto forms, is observed, which melts at 265 °C, i.e. ca. 10 and 20 °C higher than the melting points of BA and TBA, respectively. While the BAxTBA1-x solid solutions with x > 0.5 are stable, those with x < 0.5 convert, with time or temperature, to the BA0.5TBA0.5 co-crystal.
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Affiliation(s)
- O Shemchuk
- Dipartimento di Chimica Giacomo Ciamician, Università degli Studi di Bologna, Via Selmi 2, 40126 Bologna, Italy.
| | - D Braga
- Dipartimento di Chimica Giacomo Ciamician, Università degli Studi di Bologna, Via Selmi 2, 40126 Bologna, Italy.
| | - F Grepioni
- Dipartimento di Chimica Giacomo Ciamician, Università degli Studi di Bologna, Via Selmi 2, 40126 Bologna, Italy.
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27
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Lusi M. A rough guide to molecular solid solutions: design, synthesis and characterization of mixed crystals. CrystEngComm 2018. [DOI: 10.1039/c8ce00691a] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent literature on molecular solid solutions is reviewed and general empirical rules to help synthesize mixed crystals are summarised.
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Affiliation(s)
- Matteo Lusi
- Department of Chemical Sciences
- Bernal Institute
- University of Limerick
- Limerick
- Ireland
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28
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Thiobarbiturate and barbiturate salts of pefloxacin drug: Growth, structure, thermal stability and IR-spectra. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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29
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Gelbrich T, Griesser UJ. Buthalital and methitural - 5,5-substituted derivatives of 2-thio-barbituric acid forming the same type of hydrogen-bonded chain. Acta Crystallogr E Crystallogr Commun 2017; 73:1908-1912. [PMID: 29250413 PMCID: PMC5730250 DOI: 10.1107/s205698901701653x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 11/16/2017] [Indexed: 12/02/2022]
Abstract
The mol-ecule of buthalital, (I) [systematic name: 5-(2-methyl-prop-yl)-5-(prop-2-en-1-yl)-2-sulfanyl-idene-1,3-diazinane-4,6-dione], C11H16N2O2S, exhibits a planar pyrimidine ring, whereas the pyrimidine ring of methitural, (II) [systematic name: 5-(1-methyl-but-yl)-5-[2-(methyl-sulfan-yl)eth-yl]-2-sulfanyl-idene-1,3-diazinane-4,6-dione], C12H20N2O2S2, is slightly puckered. (I) and (II) contain the same hydrogen-bonded chain structure in which each mol-ecule is connected, via four N-H⋯O=C hydrogen bonds, to two other mol-ecules, resulting in a hydrogen-bonded chain displaying a sequence of R22(8) rings. The same type of N-H⋯O=C hydrogen-bonded chain has previously been found in several 5,5-disubstituted derivatives of barbituric acid which are chemically closely related to (I) and (II).
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Affiliation(s)
- Thomas Gelbrich
- University of Innsbruck, Institute of Pharmacy, Innrain 52, 6020 Innsbruck, Austria
| | - Ulrich J. Griesser
- University of Innsbruck, Institute of Pharmacy, Innrain 52, 6020 Innsbruck, Austria
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30
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Kumar V, Pilati T, Quici S, Chierotti MR, Nervi C, Gobetto R, Resnati G. Proton in a Confined Space: Structural Studies of H + ⊂Crypt-111 Iodide and Some Halogen-Bonded Derivatives. Chemistry 2017; 23:14462-14468. [PMID: 28657685 DOI: 10.1002/chem.201701699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 06/27/2017] [Indexed: 11/06/2022]
Abstract
Experimental observations and modeling data are reported on the solid-state structural features of crypt- 111⋅HI (1) and the three-component co-crystals that 1 forms with α,ω-diiodoperfluoroalkanes 2 a-d. X-ray analyses indicate that, in all five systems and at low temperature, the caged proton is covalently bonded to a single nitrogen atom and is involved in a network of intramolecular hydrogen bonds. In contrast, room-temperature, solid-state 15 N NMR spectroscopy suggests magnetic equivalency of the two N atoms of crypt-111 in both 1 and co-crystals of 1 with diiodoperfluoroalkanes. Computational modelling confirms that the acidic hydrogen inside the cavity preferentially sits along the internitrogen axis and is covalently bonded to one nitrogen. The computed energy barriers suggest that the hopping of the encapsulated proton between the two N atoms of the cage can occur in the halogen-bonded co-crystals of 1⋅2, but it is hardly possible in the pure H+ ⊂crypt-111 iodide 1. These different pictures of the proton position and dynamics obtained by using different techniques and conditions confirm the unique characteristics of the confined space within the cavity of crypr-111 and the distinctive features of processes occurring therein.
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Affiliation(s)
- Vijith Kumar
- Nanostructured Fluorinated Materials Laboratory (NFMLab), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via L. Mancinelli 7, 20131, Milan, Italy
| | - Tullio Pilati
- Nanostructured Fluorinated Materials Laboratory (NFMLab), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via L. Mancinelli 7, 20131, Milan, Italy
| | - Silvio Quici
- CNR, Istituto di Scienze e Tecnologie Molecolari, Via C. Golgi 19, 20133, Milan, Italy
| | - Michele R Chierotti
- Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy
| | - Carlo Nervi
- Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy
| | - Roberto Gobetto
- Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy
| | - Giuseppe Resnati
- Nanostructured Fluorinated Materials Laboratory (NFMLab), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via L. Mancinelli 7, 20131, Milan, Italy
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31
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Golovnev NN, Molokeev MS, Sterkhova IV, Vereshchagin SN, Golovneva II. Crystal structure and properties of polymeric hexaaqua-hexakis-(2-thiobarbiturato)-disamarium(III). J STRUCT CHEM+ 2017. [DOI: 10.1134/s0022476617030155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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32
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Carletta A, Spinelli F, d'Agostino S, Ventura B, Chierotti MR, Gobetto R, Wouters J, Grepioni F. Halogen-Bond Effects on the Thermo- and Photochromic Behaviour of Anil-Based Molecular Co-crystals. Chemistry 2017; 23:5317-5329. [PMID: 28240437 DOI: 10.1002/chem.201605953] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/23/2017] [Indexed: 11/11/2022]
Abstract
N-Salicilideneanilines are among the most studied thermo- and photochromic systems in the solid state. Although thermochromism is a general property of crystalline N-salicilideneanilines, photochromism is known in a limited number of cases. As a method for the construction of thermo- and photo-responsive molecular architectures, the co-crystallisation of 1,2,4,5-tetrafluoro-3,6-diiodobenzene (I2F4) with three selected imines of o-vanillin, named 1, 2 and 3, obtained through a condensation reaction with 3-aminopyridine, 4-bromoaniline and 4-iodoaniline, respectively, is reported herein. All crystals and co-crystals have been characterised by means of solid-state complementary techniques (X-ray diffraction, solid-state NMR spectroscopy, absorption and emission spectroscopy). The role of halogen bonding and crystal packing in the optical and chromic properties of all solid materials is discussed. All solids exhibit thermochromic behaviour, and three of them (2, 22 ⋅I2F4 and 32 ⋅I2F4) are also photochromic. Imine derivative 3 crystallises in two different polymorphic forms (3 A and 3 B) and a solvate (3Solv ). The bromo and iodo derivatives, 2 and 3 B, are isomorphous and form isomorphous co-crystals with I2F4, but behave differently when exposed to UV light because only crystalline 2 is photochromic. Interestingly, the replacement of bromine with iodine seems to turn off the photochromism because crystalline 3 A and 3Solv , and even the 20.7 30.3 solid solution, do not manifest photochromic behaviour.
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Affiliation(s)
- Andrea Carletta
- Department of Chemistry, University of Namur (UNamur), Rue de Bruxelles 61, Namur, 5000, Belgium
| | - Floriana Spinelli
- Università di Bologna, Dipartimento di Chimica G. Ciamician, Via Selmi 2, 40126, Bologna, Italy
| | - Simone d'Agostino
- Università di Bologna, Dipartimento di Chimica G. Ciamician, Via Selmi 2, 40126, Bologna, Italy
| | - Barbara Ventura
- Istituto per la Sintesi Organica e la Fotoreattività (ISOF)-CNR, Via P. Gobetti 101, 40129, Bologna, Italy
| | - Michele R Chierotti
- Dipartimento di Chimica and NIS Centre, Università di Torino, via Giuria 7, 10125, Turin, Italy
| | - Roberto Gobetto
- Dipartimento di Chimica and NIS Centre, Università di Torino, via Giuria 7, 10125, Turin, Italy
| | - Johan Wouters
- Department of Chemistry, University of Namur (UNamur), Rue de Bruxelles 61, Namur, 5000, Belgium
| | - Fabrizia Grepioni
- Università di Bologna, Dipartimento di Chimica G. Ciamician, Via Selmi 2, 40126, Bologna, Italy
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33
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Golovnev NN, Molokeev MS, Sterkhova IV, Golovneva II. Structure of ionic cocrystals piperidinium 2-thiobarbiturate–2-thiobarbituric acid. J STRUCT CHEM+ 2017. [DOI: 10.1134/s0022476616060287] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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34
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Mandal A, Patel BK. Metal Ion Directed Tautomeric Polymorphism in a Hydrazonamide/Hydrozonate System. ChemistrySelect 2017. [DOI: 10.1002/slct.201601432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Arkalekha Mandal
- Department of Chemistry; Indian Institute of Technology Guwahati; Guwahati-781039 Assam India, Phone: +91-9954090963
| | - Bhisma K. Patel
- Department of Chemistry; Indian Institute of Technology Guwahati; Guwahati-781039 Assam India, Phone: +91-9954090963
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35
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2-Methylthio-imidazolins: a rare case of different tautomeric forms in solid state and in solution. Struct Chem 2016. [DOI: 10.1007/s11224-016-0860-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Golovnev NN, Molokeev MS, Sterkhova IV, Atuchin VV, Sidorenko MY. Hydrates [Na2(H2O)x](2-thiobarbiturate)2 (x = 3, 4, 5): crystal structure, spectroscopic and thermal properties. J COORD CHEM 2016. [DOI: 10.1080/00958972.2016.1228914] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
| | - Maxim S. Molokeev
- Laboratory of Crystal Physics, Kirensky Institute of Physics, Krasnoyarsk, Russia
- Department of Physics, Far Eastern State Transport University, Khabarovsk, Russia
| | - Irina V. Sterkhova
- Laboratory of Physical Chemistry, Irkutsk Favorsky Institute of Chemistry, Irkutsk, Russia
| | - Victor V. Atuchin
- Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, Novosibirsk, Russia
- Functional Electronics Laboratory, Tomsk State University, Tomsk, Russia
- Laboratory of Semiconductor and Dielectric Materials, Novosibirsk State University, Novosibirsk, Russia
| | - Maxim Y. Sidorenko
- Department of Chemistry, Siberian Federal University, Krasnoyarsk, Russia
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Maini L, Braga D, Grepioni F, Lampronti GI, Gaglioti K, Gobetto R, Chierotti MR. From isomorphous to “anisomorphous” ionic co-crystals of barbituric acid upon dehydration and return. CrystEngComm 2016. [DOI: 10.1039/c6ce00566g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Vioglio PC, Chierotti MR, Gobetto R. Solid-state nuclear magnetic resonance as a tool for investigating the halogen bond. CrystEngComm 2016. [DOI: 10.1039/c6ce02219g] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Marshall MG, Lopez‐Diaz V, Hudson BS. Single‐Crystal X‐ray Diffraction Structure of the Stable Enol Tautomer Polymorph of Barbituric Acid at 224 and 95 K. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201508078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Madalynn G. Marshall
- Department of Chemistry, 1-014 Center for Science & Technology Syracuse University Syracuse NY 13244-4100 USA
- Syracuse University & Department of Chemistry Iowa State University 1605 Gilman Hall Ames IA 50011-3111 USA
| | - Valerie Lopez‐Diaz
- Department of Chemistry, 1-014 Center for Science & Technology Syracuse University Syracuse NY 13244-4100 USA
| | - Bruce S. Hudson
- Department of Chemistry, 1-014 Center for Science & Technology Syracuse University Syracuse NY 13244-4100 USA
- Syracuse University & Department of Chemistry Iowa State University 1605 Gilman Hall Ames IA 50011-3111 USA
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Marshall MG, Lopez‐Diaz V, Hudson BS. Single‐Crystal X‐ray Diffraction Structure of the Stable Enol Tautomer Polymorph of Barbituric Acid at 224 and 95 K. Angew Chem Int Ed Engl 2015; 55:1309-12. [DOI: 10.1002/anie.201508078] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Madalynn G. Marshall
- Department of Chemistry, 1-014 Center for Science & Technology Syracuse University Syracuse NY 13244-4100 USA
- Syracuse University & Department of Chemistry Iowa State University 1605 Gilman Hall Ames IA 50011-3111 USA
| | - Valerie Lopez‐Diaz
- Department of Chemistry, 1-014 Center for Science & Technology Syracuse University Syracuse NY 13244-4100 USA
| | - Bruce S. Hudson
- Department of Chemistry, 1-014 Center for Science & Technology Syracuse University Syracuse NY 13244-4100 USA
- Syracuse University & Department of Chemistry Iowa State University 1605 Gilman Hall Ames IA 50011-3111 USA
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Chan PF, Srikannathasan V, Huang J, Cui H, Fosberry AP, Gu M, Hann MM, Hibbs M, Homes P, Ingraham K, Pizzollo J, Shen C, Shillings AJ, Spitzfaden CE, Tanner R, Theobald AJ, Stavenger RA, Bax BD, Gwynn MN. Structural basis of DNA gyrase inhibition by antibacterial QPT-1, anticancer drug etoposide and moxifloxacin. Nat Commun 2015; 6:10048. [PMID: 26640131 PMCID: PMC4686662 DOI: 10.1038/ncomms10048] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/29/2015] [Indexed: 12/02/2022] Open
Abstract
New antibacterials are needed to tackle antibiotic-resistant bacteria. Type IIA topoisomerases (topo2As), the targets of fluoroquinolones, regulate DNA topology by creating transient double-strand DNA breaks. Here we report the first co-crystal structures of the antibacterial QPT-1 and the anticancer drug etoposide with Staphylococcus aureus DNA gyrase, showing binding at the same sites in the cleaved DNA as the fluoroquinolone moxifloxacin. Unlike moxifloxacin, QPT-1 and etoposide interact with conserved GyrB TOPRIM residues rationalizing why QPT-1 can overcome fluoroquinolone resistance. Our data show etoposide's antibacterial activity is due to DNA gyrase inhibition and suggests other anticancer agents act similarly. Analysis of multiple DNA gyrase co-crystal structures, including asymmetric cleavage complexes, led to a ‘pair of swing-doors' hypothesis in which the movement of one DNA segment regulates cleavage and religation of the second DNA duplex. This mechanism can explain QPT-1's bacterial specificity. Structure-based strategies for developing topo2A antibacterials are suggested. Type IIA topoisomerases (topo2As) create transient double-strand DNA breaks. Here, the authors report structures showing how QPT-1 binds in the DNA/topo2A complex at the same site as the fluoroquinolone moxifloxacin, and discuss the potential for developing new classes of antibiotics.
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Affiliation(s)
- Pan F Chan
- Antibacterial Discovery Performance Unit, Infectious Diseases, Therapy Area Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426-0989, USA
| | - Velupillai Srikannathasan
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Jianzhong Huang
- Antibacterial Discovery Performance Unit, Infectious Diseases, Therapy Area Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426-0989, USA
| | - Haifeng Cui
- Antibacterial Discovery Performance Unit, Infectious Diseases, Therapy Area Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426-0989, USA
| | - Andrew P Fosberry
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Minghua Gu
- Antibacterial Discovery Performance Unit, Infectious Diseases, Therapy Area Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426-0989, USA
| | - Michael M Hann
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Martin Hibbs
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Paul Homes
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Karen Ingraham
- Antibacterial Discovery Performance Unit, Infectious Diseases, Therapy Area Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426-0989, USA
| | - Jason Pizzollo
- Antibacterial Discovery Performance Unit, Infectious Diseases, Therapy Area Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426-0989, USA
| | - Carol Shen
- Antibacterial Discovery Performance Unit, Infectious Diseases, Therapy Area Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426-0989, USA
| | - Anthony J Shillings
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Claus E Spitzfaden
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Robert Tanner
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Andrew J Theobald
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Robert A Stavenger
- Antibacterial Discovery Performance Unit, Infectious Diseases, Therapy Area Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426-0989, USA
| | - Benjamin D Bax
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Michael N Gwynn
- Antibacterial Discovery Performance Unit, Infectious Diseases, Therapy Area Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426-0989, USA
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Crystal structure, spectroscopic and thermal properties of the coordination compounds M(1,3-diethyl-2-thiobarbiturate) M = Rb+, Cs+, Tl+ and NH4+. Polyhedron 2015. [DOI: 10.1016/j.poly.2015.05.048] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gomathi S, Nirmalram JS, Muthiah PT. Hydrogen bonding patterns in salts of derivatives of aminopyrimidine and thiobarbituric acid. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2015; 71:144-152. [PMID: 25827367 DOI: 10.1107/s2052520615001729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Accepted: 01/27/2015] [Indexed: 06/04/2023]
Abstract
Three salts, namely 2-amino-4,6-dimethylpyrimidin-1-ium thiobarbiturate trihydrate (I), 2-amino-4,6-dimethoxypyrimidin-1-ium thiobarbiturate dihydrate (II) and 2,4-diamino-5-(3',4',5'-trimethoxybenzyl)pyrimidin-1-ium thiobarbiturate (III), were synthesized and characterized by IR and X-ray diffraction techniques. The primary interaction between the acid and base happens via N-H...O hydrogen bonds in (II) and (III), and via water-mediated N-H...OW and OW-HW...S in (I). The water molecules present in compound (I) form a (H2O)12 water cluster via water-water interactions. In all three compounds (I)-(III), thiobarbiturate anions form self-complementary pairs with a robust R2(2)(8) motif via a pair of N-H...O/N-H...S hydrogen bonds. They mimic the nucleobase base pairs by utilizing the same groups (thymine/uracil uses N3-H and C4=O8 groups during the formation of Watson-Crick and Hoogsteen base pairs with adenine). Compound (I) forms a water-mediated base pair through N-H...OW hydrogen bonds and forms an R4(2)(12) motif. The formation of N-H...S hydrogen bonds, water-mediated base pairs and water-water interactions in these crystal systems offers scope for these systems to be considered as a model in the study of hydration of nucleobases and water-mediated nucleobase base pairs in macromolecules.
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Affiliation(s)
- Sundaramoorthy Gomathi
- Department of Chemistry, Periyar Maniammai University, Thanjavur 613 403, Tamil Nadu, India
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Cigáň M, Jakusová K, Donovalová J, Filo J, Horváth M, Gáplovský A. Fluorescence of isatinN-phenylsemicarbazones: aggregation and hydrazide-hydrazonol tautomerism. J PHYS ORG CHEM 2015. [DOI: 10.1002/poc.3415] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Marek Cigáň
- Institute of Chemistry, Faculty of Natural Sciences; Comenius University; Mlynská dolina CH-2 SK-842 15 Bratislava Slovakia
| | - Klaudia Jakusová
- Institute of Chemistry, Faculty of Natural Sciences; Comenius University; Mlynská dolina CH-2 SK-842 15 Bratislava Slovakia
| | - Jana Donovalová
- Institute of Chemistry, Faculty of Natural Sciences; Comenius University; Mlynská dolina CH-2 SK-842 15 Bratislava Slovakia
| | - Juraj Filo
- Institute of Chemistry, Faculty of Natural Sciences; Comenius University; Mlynská dolina CH-2 SK-842 15 Bratislava Slovakia
| | - Miroslav Horváth
- Institute of Chemistry, Faculty of Natural Sciences; Comenius University; Mlynská dolina CH-2 SK-842 15 Bratislava Slovakia
| | - Anton Gáplovský
- Institute of Chemistry, Faculty of Natural Sciences; Comenius University; Mlynská dolina CH-2 SK-842 15 Bratislava Slovakia
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Golovnev NN, Molokeev MS, Vereshchagin SN, Sterkhova IV, Atuchin VV. The cis–trans isomer transformation, spectroscopic and thermal properties of Li, Na, K 1,3-diethyl-2-thiobarbiturate complexes. Polyhedron 2015. [DOI: 10.1016/j.poly.2014.09.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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48
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Abstract
Recent applications of solid-state NMR spectroscopy to studies of nucleic acids and their components.
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Affiliation(s)
- Martin Dračínský
- Institute of Organic Chemistry and Biochemistry
- Prague
- Czech Republic
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49
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Zbačnik M, Nogalo I, Cinčić D, Kaitner B. Polymorphism control in the mechanochemical and solution-based synthesis of a thermochromic Schiff base. CrystEngComm 2015. [DOI: 10.1039/c5ce01445j] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three crystal forms of a thermochromic Schiff base derived fromo-vanillin and 3-aminoacetophenone were obtained by conventional solution-based methods. Two polymorphs out of three were synthesized by mechanochemical syntheses, under solvent-free conditions.
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Affiliation(s)
- Marija Zbačnik
- Department of Chemistry
- Faculty of Science
- University of Zagreb
- HR-10002 Zagreb, Croatia
| | - Ivana Nogalo
- Department of Chemistry
- Faculty of Science
- University of Zagreb
- HR-10002 Zagreb, Croatia
| | - Dominik Cinčić
- Department of Chemistry
- Faculty of Science
- University of Zagreb
- HR-10002 Zagreb, Croatia
| | - Branko Kaitner
- Department of Chemistry
- Faculty of Science
- University of Zagreb
- HR-10002 Zagreb, Croatia
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Juribašić M, Bregović N, Stilinović V, Tomišić V, Cindrić M, Šket P, Plavec J, Rubčić M, Užarević K. Supramolecular Stabilization of Metastable Tautomers in Solution and the Solid State. Chemistry 2014; 20:17333-45. [DOI: 10.1002/chem.201403543] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Indexed: 11/11/2022]
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