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Aiello F, Uccello Barretta G, Balzano F, Spiaggia F. The Phenomenon of Self-Induced Diastereomeric Anisochrony and Its Implications in NMR Spectroscopy. Molecules 2023; 28:6854. [PMID: 37836697 PMCID: PMC10574224 DOI: 10.3390/molecules28196854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 09/21/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is an analytical technique largely applied in the analysis of discrimination processes involving enantiomeric substrates and chiral agents, which can interact with the analyte either via covalent bonding or via formation of diastereomeric solvates. However, enantiodiscrimination has been observed, in some cases, even in the absence of any additional chiral selector. The reasons behind this phenomenon must be found in the capability of some chiral substrates to interact with themselves by forming diastereomeric solvates in solution that can generate nonequivalences in the NMR spectra of enantiomerically enriched mixtures. As a result, differentiation of enantiomers is observed, thus allowing the quantification of the enantiomeric composition of the mixture under investigation. The tendency of certain substrates to self-aggregate and to generate diastereomeric adducts in solution can be defined as Self-Induced Diastereomeric Anisochrony (SIDA), but other acronyms have been used to refer to this phenomenon. In the present work, an overview of SIDA processes investigated via NMR spectroscopy will be provided, with a particular emphasis on the nature of the substrates involved, on the interaction mechanisms at the basis of the phenomenon, and on theoretical treatments proposed in the literature to explain them.
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Affiliation(s)
- Federica Aiello
- National Research Council, Institute for Chemical and Physical Processes (CNR-IPCF), Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Gloria Uccello Barretta
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy; (F.B.); (F.S.)
| | - Federica Balzano
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy; (F.B.); (F.S.)
| | - Fabio Spiaggia
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy; (F.B.); (F.S.)
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Dašková V, Padín D, Feringa BL. Turning Enantiomeric Relationships into Diastereomeric Ones: Self-Resolving α-Ureidophosphonates and Their Organocatalytic Enantioselective Synthesis. J Am Chem Soc 2022; 144:23603-23613. [PMID: 36516975 PMCID: PMC9801384 DOI: 10.1021/jacs.2c10911] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Controlling chiral recognition and chiral information transfer has major implications in areas ranging from drug design and asymmetric catalysis to supra- and macromolecular chemistry. Especially intriguing are phenomena associated with chiral self-recognition. The design of systems that show self-induced recognition of enantiomers, i.e., involving homochiral versus heterochiral dimers, is particularly challenging. Here, we report the chiral self-recognition of α-ureidophosphonates and its application as both a powerful analytical tool for enantiomeric ratio determination by NMR and as a convenient way to increase their enantiomeric purity by simple achiral column chromatography or fractional precipitation. A combination of NMR, X-ray, and DFT studies indicates that the formation of homo- and heterochiral dimers involving self-complementary intermolecular hydrogen bonds is responsible for their self-resolving properties. It is also shown that these often unnoticed chiral recognition phenomena can facilitate the stereochemical analysis during the development of new asymmetric transformations. As a proof of concept, the enantioselective organocatalytic hydrophosphonylation of alkylidene ureas toward self-resolving α-ureidophosphonates is presented, which also led us to the discovery of the largest family of self-resolving compounds reported to date.
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Stanovnik B. Enaminone, Enaminoesters, and Related Compounds in the Metal-Free Synthesis of Pyridines and Fused Pyridines. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900797] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Branko Stanovnik
- Faculty of Chemistry and Chemical Technology; University of Ljubljana; Večna pot113 1000 Ljubljana Slovenia
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Self-induced recognition of enantiomers (SIRE) and its application in chiral NMR analysis. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2018.07.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Prek B, Bezenšek J, Stanovnik B. Synthesis of pyridines with an amino acid residue by [2+2] cycloadditions of electron-poor acetylenes on enaminone systems derived from N -Boc protected amino acids. Tetrahedron 2017. [DOI: 10.1016/j.tet.2017.07.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Šinkovec R, Grošelj U, Prek B, Počkaj M, Ričko S, Svete J, Stanovnik B. A simple synthesis of dimethyl 2-[(Z)-3-amino-1-oxo-1-(substituted)but-2-en-2-yl]fumarates: potential intermediates in the synthesis of polysubstituted five- and six-membered heterocycles. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2016. [DOI: 10.1515/znb-2016-0017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In this communication, a simple synthesis of dimethyl 2-[(Z)-3-amino-1-oxo-1-(substituted)but-2-en-2-yl]fumarates is described. Methyl ketones were transformed by treatment with N,N-dimethylacetamide dimethyl acetal (DMADMA) into 3-dimethylamino-1-(substituted)but-2-en-1-ones, followed by treatment with ammonium acetate into (Z)-3-amino-1-(substituted)but-2-en-1-ones and addition to dimethyl acetylenedicarboxylate. These novel polysubstituted butadienes are potential intermediates for the metal-free preparation of polysubstituted five- and six-membered heterocycles.
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Affiliation(s)
- Rok Šinkovec
- Faculty of Chemistry and Chemical Technology, University of Ljubljana , P.O. Box 537, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Uroš Grošelj
- Faculty of Chemistry and Chemical Technology, University of Ljubljana , P.O. Box 537, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Benjamin Prek
- Faculty of Chemistry and Chemical Technology, University of Ljubljana , P.O. Box 537, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Marta Počkaj
- Faculty of Chemistry and Chemical Technology, University of Ljubljana , P.O. Box 537, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Sebastijan Ričko
- Faculty of Chemistry and Chemical Technology, University of Ljubljana , P.O. Box 537, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Jurij Svete
- Faculty of Chemistry and Chemical Technology, University of Ljubljana , P.O. Box 537, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Branko Stanovnik
- Faculty of Chemistry and Chemical Technology, University of Ljubljana , P.O. Box 537, Večna pot 113, 1000 Ljubljana, Slovenia
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Bezenšek J, Prek B, Grošelj U, Počkaj M, Svete J, Stanovnik B. [2+2] Cycloadditions of electron-poor acetylenes to endocyclic enaminones: ring-expansion reactions. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Jain N, Patel RB, Bedekar AV. Modified Kagan's amide: synthesis and application as a chiral solvating agent for hydrogen-bonding based chiral discrimination in NMR. RSC Adv 2015. [DOI: 10.1039/c5ra06959a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A modified Kagan's amide, N-((S)-1-(3,5-bis(trifluoromethyl)phenyl)ethyl)-3,5-dinitrobenzamide has been designed, synthesized and screened as a Chiral Solvating Agent for discrimination of optically active substrates.
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Affiliation(s)
- Nilesh Jain
- Department of Chemistry
- Faculty of Science
- M. S. University of Baroda
- Vadodara 390 002
- India
| | - Ravi B. Patel
- Department of Chemistry
- Faculty of Science
- M. S. University of Baroda
- Vadodara 390 002
- India
| | - Ashutosh V. Bedekar
- Department of Chemistry
- Faculty of Science
- M. S. University of Baroda
- Vadodara 390 002
- India
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Stanovnik B. [2+2] Cycloaddition of Electron-poor Acetylenes to Enaminones, Enamino Esters and Related Systems. Rearrangements and Ring-expansion Reactions. ORG PREP PROCED INT 2014. [DOI: 10.1080/00304948.2014.866468] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Uccello-Barretta G, Balzano F. Chiral NMR Solvating Additives for Differentiation of Enantiomers. Top Curr Chem (Cham) 2013; 341:69-131. [DOI: 10.1007/128_2013_445] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Del Bene JE, Sanchez-Sanz G, Alkorta I, Elguero J. Homo- and heterochiral dimers (PHFX)2, X=Cl, CN, CH3, NC: To what extent do they differ? Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.04.039] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Wenzel TJ, Chisholm CD. Using NMR spectroscopic methods to determine enantiomeric purity and assign absolute stereochemistry. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2011; 59:1-63. [PMID: 21600355 DOI: 10.1016/j.pnmrs.2010.07.003] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 07/28/2010] [Indexed: 05/30/2023]
Affiliation(s)
- Thomas J Wenzel
- Department of Chemistry, Bates College, Lewiston, Maine 04240, USA.
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Synthesis and structure of novel (S)-1,6-dialkylpiperazine-2,5-diones and (3S,6S)-1,3,6-trialkylpiperazine-2,5-diones. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.tetasy.2011.03.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Del Bene JE, Alkorta I, Elguero J. Do corresponding coupling constants in hydrogen-bonded homo- and hetero-chiral dimers differ? CAN J CHEM 2010. [DOI: 10.1139/v09-177] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ab initio equation-of-motion coupled cluster singles and doubles (EOM–CCSD) calculations have been carried out to evaluate spin–spin coupling constants in six pairs of homo- and hetero-chiral dimers: (HOOH)2, (H2NNH2)2, (FOOH)2, (FHNNH2)2, (HOOOH)2, and (FOOOH)2. Corresponding spin–spin coupling constants in these isomeric pairs of C2 and Ci symmetry may differ, but these differences are small and may not be detectable experimentally. For the complexes with O1–H···O and O1–H···F hydrogen bonds, 1J(O1–H) has a larger absolute value in the C2 isomer. For the same set of complexes, 1J(O1–O2) has a larger absolute value in the Ci isomer. No distinguishable patterns could be discerned in the remaining spin–spin coupling constants in the C2 and Ci isomers of these complexes, nor in complexes with N–H···N hydrogen bonds.
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Affiliation(s)
- Janet E. Del Bene
- Department of Chemistry, Youngstown State University, Youngstown, Ohio 44555, USA
- Instituto de Química Médica, CSIC (Consejo Superior de Investigaciones Científicas), Juan de la Cierva, 3, E-28006 Madrid, Spain
| | - Ibon Alkorta
- Department of Chemistry, Youngstown State University, Youngstown, Ohio 44555, USA
- Instituto de Química Médica, CSIC (Consejo Superior de Investigaciones Científicas), Juan de la Cierva, 3, E-28006 Madrid, Spain
| | - José Elguero
- Department of Chemistry, Youngstown State University, Youngstown, Ohio 44555, USA
- Instituto de Química Médica, CSIC (Consejo Superior de Investigaciones Científicas), Juan de la Cierva, 3, E-28006 Madrid, Spain
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Uršič U, Svete J, Stanovnik B. Synthesis of 4-(2-hydroxy-1-methyl-5-oxo-1H-imidazol-4(5H)-ylidene)-5-oxo-1-aryl-4,5-dihydro-1H-pyrrole-3-carboxylates, a new triazafulvalene system. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.04.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Bezenšek J, Koleša T, Grošelj U, Wagger J, Stare K, Meden A, Svete J, Stanovnik B. [2+2] Cycloaddition of electron-poor acetylenes to (E)-3-dimethylamino-1-heteroaryl-prop-2-en-1-ones: synthesis of highly functionalized 1-heteroaroyl-1,3-butadienes. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2010.04.106] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Matsuzawa A, Nojiri A, Kumagai N, Shibasaki M. Solvent-Dependent Self-Discrimination of Bis(2-hydroxyphenyl)diamides. Chemistry 2010; 16:5036-42. [DOI: 10.1002/chem.201000321] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Blanco F, Alkorta I, Rozas I, Elguero J. Chiral recognition in self-complexes of diketopiperazine derivatives. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1686] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Stanovnik B, Uršič U, Svete J. Transformations of Dimethyl (2E,3E)-2-[(Dimethylamino)methylene]-3-(1-methyl-2,5-dioxoimidazolidin-4-ylidene)succinate with C-Nucleophiles. HETEROCYCLES 2010. [DOI: 10.3987/com-10-s(e)97] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Kralj D, Friedrich M, Grošelj U, Kiraly-Potpara S, Meden A, Wagger J, Dahmann G, Stanovnik B, Svete J. A synthesis of 1-substituted 5-[2-(acylamino)ethyl]-1H-pyrazole-4-carboxamides. Tetrahedron 2009. [DOI: 10.1016/j.tet.2009.06.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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21
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Błażewska KM, Gajda T. Assignment of the absolute configuration of hydroxy- and aminophosphonates by NMR spectroscopy. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.tetasy.2009.05.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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22
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Uršič U, Grošelj U, Meden A, Svete J, Stanovnik B. [2+2] Cycloadditions of Electron-Poor Acetylenes to (5Z)-5-[(Dimethylamino)methylene]imidazolidine-2,4-diones. Helv Chim Acta 2009. [DOI: 10.1002/hlca.200800297] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Stanovnik B, Albreht A, Uršič U, Svete J. Transformations of Ethyl 2-Amino-4-(2-ethoxy-2-oxoethyl)thioazole-5-carboxylate into 5-Substituted 2-Amino-4-oxo-4,5-dihydrothiazolo[5,4-c]pyridine-7-carboxylates. HETEROCYCLES 2009. [DOI: 10.3987/com-09-11711] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Stanovnik B, Zupančič S, Svete J. Transformations of Diethyl 2-[(Dimethylamino)methylene]-3-oxopentanedioate. A Simple Synthesis of Substituted 2-Amino-5-oxo-5,6-dihydropyrido[4,3-d]pyrimidine-8-carboxylates. HETEROCYCLES 2009. [DOI: 10.3987/com-08-s(f)90] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Uršič U, Svete J, Stanovnik B. Transformations of (1E,3E)-1-(benzoylamino)-4-(dimethylamino)buta-1,3-diene-1,2,3-tricarboxylates into pyridine and pyrrole derivatives. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.07.109] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Kralj D, Novak A, Dahmann G, Grošelj U, Meden A, Svete J. One-Pot Parallel Solution-Phase Synthesis of 1-Substituted 4-(2-Aminoethyl)-1H-pyrazol-5-ols. ACTA ACUST UNITED AC 2008; 10:664-70. [DOI: 10.1021/cc8000794] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- David Kralj
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, P.O. Box 537, 1000 Ljubljana, Slovenia, and Department of Chemical Research, Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach, Germany
| | - Ana Novak
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, P.O. Box 537, 1000 Ljubljana, Slovenia, and Department of Chemical Research, Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach, Germany
| | - Georg Dahmann
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, P.O. Box 537, 1000 Ljubljana, Slovenia, and Department of Chemical Research, Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach, Germany
| | - Uroš Grošelj
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, P.O. Box 537, 1000 Ljubljana, Slovenia, and Department of Chemical Research, Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach, Germany
| | - Anton Meden
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, P.O. Box 537, 1000 Ljubljana, Slovenia, and Department of Chemical Research, Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach, Germany
| | - Jurij Svete
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, P.O. Box 537, 1000 Ljubljana, Slovenia, and Department of Chemical Research, Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach, Germany
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Malavašič Č, Wagger J, Stanovnik B, Svete J. (S)-N-Benzyl-3(6)-methylpiperazine-2,5-diones as chiral solvating agents for N-acylamino acid esters. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.tetasy.2008.06.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Uršič U, Grošelj U, Meden A, Svete J, Stanovnik B. Regiospecific [2+2] cycloadditions of electron-poor acetylenes to (Z)-2-acylamino-3-dimethylaminopropenoates: synthesis of highly functionalised buta-1,3-dienes. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.04.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Synthesis of (S,Z)-3-[(1H-indol-3-yl)methylidene]hexahydropyrrolo[1,2-a]pyrazin-4(1H)-one: an alternative, enaminone based, route to unsaturated cyclodipeptides. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.01.045] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Grošelj U, Meden A, Stanovnik B, Svete J. Synthesis of novel C2-symmetric 1,3-bis{(1S,2R,3S,4R)-1,7,7-trimethyl-3′H-spiro[bicyclo[2.2.1]heptane-2,2′-furan]-3-yl}benzoimidazolium tetrafluoroborates. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.tetasy.2008.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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31
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Stanovnik B, Zupancic S, Svete J. Transformation of 1,5-Diphenylpentane-1,3,5-trione. The Synthesis of Substituted (4H)-Pyranones, Pyridin-4(1H)-ones and 4H-Pyrano[3,2-c]pyridin-4-ones. HETEROCYCLES 2008. [DOI: 10.3987/com-07-11252] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Rečnik S, Meden A, Stanovnik B, Svete J. Ring Contractions of 3-Azido-4H-quinolizin-4-ones and 3-Azido-4H-azino[1,2 - x]pyrimidin-4-ones: a Novel Approach to 3-Aminoindolizines and their Aza Analogues. Aust J Chem 2008. [DOI: 10.1071/ch07318] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Thermal transformations of 3-azido-4H-quinolizin-4-ones 4a,b and 3-azido-4H-azino[1,2–x]pyrimidin-4-ones 4c,d, available from the corresponding heteroarylamines 2a–d, were studied. The reaction products were mostly dependent on the solvent. Thus, heating of 3-azido-1-cyano-4H-quinolizin-4-one (4a) in toluene afforded 2-(pyridin-2-yl)fumaronitrile 5a, whereas 3-amino-1-cyano-4H-quinolizin-4-one (8) was obtained on treatment of 4a in a mixture of toluene and trifluoroacetic anhydride. However, heating of 4a in acetic anhydride and in acetic acid resulted in a ring contraction to produce 3-(diacetylamino)indolizine-1-carbonitrile 6a and 3-(acetylamino)indolizine-1-carbonitrile 7a, respectively. Similarly, ring contractions took place on heating ethyl 3-azido-4-oxo-4H-quinolizin-1-carboxylate 4b and 3-azido-4H-azino[1,2–x]pyrimidin-4-ones 4c,d in acetic anhydride or acetic acid to produce the N-acetylated 3-aminoindolizine derivatives 6b, 7b and 3-aminoimidazo[1,2–x]azine derivatives 6c,d in 30–89% yields. The structures of compounds 5–8 were determined by NMR spectroscopy and X-ray diffraction.
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Stereoselective [4+2] cycloadditions of tetrazines to 3-oxo- and 3-arylimino-4′-methylenedihydro-3′H-spiro[bicyclo[2.2.1]heptane-2,2′-furans]. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.tetasy.2007.11.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Bevk D, Grošelj U, Meden A, Svete J, Stanovnik B. Synthesis and Transformation of Methyl 2-(6-Hydroxy-2-phenylpyrimidin-4-yl)acetate: Simple Preparation of Pyrimidines with Heterocyclic Substituents. Helv Chim Acta 2007. [DOI: 10.1002/hlca.200790182] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Grošelj U, Meden A, Stanovnik B, Svete J. Synthesis of spiro[bicyclo[2.2.1]heptane-2,2′-furan]-3-amines via stereoselective cycloadditions of trimethylenemethane to (1S,3EZ,4R)-3-arylimino-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ones. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.tetasy.2007.09.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Stanovnik B, Jakše R, Golič L, Meden A, Grošelj U, Svete J. Synthesis and Transformation of N,N-Dimethylaminomethylidene Derivatives of Indolylglycines and Some Other Dipeptides. HETEROCYCLES 2007. [DOI: 10.3987/com-07-s(w)6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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