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Mycroft C, Smith MJ, Nilsson M, Morris GA, Castañar L. Pure shift FESTA: An ultra-high resolution NMR tool for the analysis of complex fluorine-containing spin systems. Magn Reson Chem 2023; 61:606-614. [PMID: 37688573 DOI: 10.1002/mrc.5393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 09/11/2023]
Abstract
NMR measurements of molecules containing sparse fluorine atoms are becoming increasingly common due to their prevalence in medicinal chemistry. However, the presence of both homonuclear and heteronuclear scalar couplings severely complicates their analysis by NMR. In complex systems, FESTA, a heteronuclear spectral editing method, allows simplified 1 H NMR spectra to be obtained containing only 1 H signals from the same spin system as a chosen 19 F. Despite spectral simplification, signal overlap due to the presence of scalar couplings is often a problem in FESTA spectra. Here, we report a new experiment that combines FESTA and pure shift methods to provide fully decoupled ultra-high resolution FESTA spectra showing a single signal for each 1 H chemical environment. The utility of the method is demonstrated for the analysis of two complex fluorine-containing mixtures of pharmaceutical and biochemical interest.
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Affiliation(s)
- Coral Mycroft
- Department of Chemistry, University of Manchester, Manchester, UK
| | - Marshall J Smith
- Department of Chemistry, University of Manchester, Manchester, UK
| | - Mathias Nilsson
- Department of Chemistry, University of Manchester, Manchester, UK
| | - Gareth A Morris
- Department of Chemistry, University of Manchester, Manchester, UK
| | - Laura Castañar
- Department of Chemistry, University of Manchester, Manchester, UK
- Department of Organic Chemistry, Faculty of Chemical Science, Complutense University of Madrid, Madrid, Spain
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Mycroft C, Dal Poggetto G, Barbosa TM, Tormena C, Nilsson M, Morris GA, Castañar L. Rapid Measurement of Heteronuclear Coupling Constants in Complex NMR Spectra. J Am Chem Soc 2023; 145:19824-19831. [PMID: 37650656 PMCID: PMC10510310 DOI: 10.1021/jacs.3c05515] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Indexed: 09/01/2023]
Abstract
The NMR analysis of fluorine-containing molecules, increasingly widespread due to their importance in pharmaceuticals and biochemistry, poses significant challenges. Severe peak overlap in the proton spectrum often hinders the extraction of critical structural information in the form of heteronuclear scalar coupling constants, which are crucial for determining pharmaceutical properties and biological activity. Here, a new method, IPAP-FESTA, is reported that drastically simplifies measurements of the signs and magnitudes of proton-fluorine couplings. Its usefulness is demonstrated for the structural study of the steroidal drug fluticasone propionate extracted from a commercial formulation and for assessing solvent effects on the conformational equilibrium in a physically inseparable fluorohydrin mixture.
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Affiliation(s)
- Coral Mycroft
- Department
of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United
Kingdom
| | - Guilherme Dal Poggetto
- Chemistry
Institute, University of Campinas −
UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP, Brazil
- Analytical
Research & Development, Merck &
Co., Inc., 126 Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Thaís M. Barbosa
- Chemistry
Institute, University of Campinas −
UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP, Brazil
- Nanalysis
Corp., 1-4600 5 Street NE, Calgary, Alberta, Canada T2E 7C3
| | - Cláudio
F. Tormena
- Chemistry
Institute, University of Campinas −
UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP, Brazil
| | - Mathias Nilsson
- Department
of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Gareth A. Morris
- Department
of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Laura Castañar
- Department
of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
- Department
of Organic Chemistry, Faculty of Chemical Science, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
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Mycroft C, Nilsson M, Morris GA, Castañar L. Simultaneous Broadband Suppression of Homonuclear and Heteronuclear Couplings in 1 H NMR Spectroscopy. Chemphyschem 2022; 23:e202200495. [PMID: 35994208 PMCID: PMC10099583 DOI: 10.1002/cphc.202200495] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/16/2022] [Indexed: 01/05/2023]
Abstract
The 1 H NMR analysis of species containing NMR-active heteronuclei can be difficult due to signal overlap caused by the combined effects of homonuclear and heteronuclear scalar (J) couplings. Here, a general pure shift method is presented for obtaining ultra-high resolution 1 H NMR spectra where spectral overlap is drastically reduced by suppressing both homonuclear and heteronuclear J-couplings, giving one single signal per 1 H chemical environment. Its usefulness is demonstrated in the analysis of fluorine- and phosphorus-containing compounds of pharmaceutical and biochemical interest.
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Affiliation(s)
- Coral Mycroft
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Mathias Nilsson
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Gareth A Morris
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Laura Castañar
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
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