Polyhalogenonitrobenzenes and derived compounds Part 5. Improved preparations of 1,2,3,4-tetrafluoro-5,6-dinitrobenzene and 3,4,5,6-tetrafluoro-1,2-phenylenediamine, and the use of the latter for the synthesis of tetrafluorobenzheterocycles

Heaton, Alan; Hill, Mark G.; Drakesmith, F. G.

doi:10.1016/s0022-1139(96)03517-8

Cited by 35 publications

(15 citation statements)

References 4 publications

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“…A Diels–Alder reaction of cyclohexadiene ( 5 ) with ketal 7a furnished exclusively the syn -bis-adduct 8a [20] which was then converted to the canary-yellow tetraketone 10 by Khan’s original RuCl 3 -catalyzed oxidation protocol [21–23] since Chou’s “optimized” procedure was somewhat capricious in our hands. The twofold condensation with di- or tetrafluoro- o -phenylenediamine ( 12b , c ) [24–25] provided access to the novel fluorinated species 15b – c in acceptable yields (60–70%). This last reaction required harsh conditions and delivered a dark crude product with unspecified tarry material after heating the substrates for several days to 115 °C ( 1 H and 19 F NMR control).…”

Section: Resultsmentioning

confidence: 99%

Preparation, structures and preliminary host–guest studies of fluorinated syn-bis-quinoxaline molecular tweezers

Etzkorn¹,

Timmerman²,

Brooker³

et al. 2010

Beilstein J. Org. Chem.

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SummaryA series of polycyclic frameworks with fluorinated syn-facial quinoxaline sidewalls has been prepared as potential molecular tweezers for electron-rich guest compounds. Our synthetic route to the cyclooctadiene-derived scaffolds 16a–d takes advantage of the facile isolation of a novel spirocyclic precursor 9b with the crucial syn-orientation of its two alkene moieties. The crystal structure of 16c displays two features typical of a molecular tweezer: inclusion of a solvent molecule in the molecular cleft and self-association of the self-complementary scaffolds. Furthermore, host–guest NMR studies of compound 16c in solution show chemical exchange between the unbound and bound electron-rich guest, N,N,N′,N′-tetramethyl-p-phenylenediamine.

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Section: Resultsmentioning

confidence: 99%

Preparation, structures and preliminary host–guest studies of fluorinated syn-bis-quinoxaline molecular tweezers

Etzkorn¹,

Timmerman²,

Brooker³

et al. 2010

Beilstein J. Org. Chem.

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“…All the reagents and solvents were purchased from Aldrich and used without further purification. The ligand 3,4,5,6-tetrafluoro-1,2-phenylenediamine (C 6 F 4 (NH 2 ) 2 ) was prepared as previously reported in ref (50). The reagent 2-propynal (2-propiolaldehyde) was synthesized in accordance with the procedure reported by Sauer et al 51…”

Section: Methodsmentioning

confidence: 99%

Structural and Electronic Effects Due to Fluorine Atoms on Dibenzotetraaza-Annulenes Complexes

et al. 2018

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The preparation and characterization of Ni(II) ( 1F ) and Cu(II) ( 2F ) complexes of the ligand 15,16,17,18,19,20,21,22-octafluoro-dibenzotetraaza[14]annulene (L F ) are here reported. These compounds have been characterized by elemental analysis, mass and UV–vis spectroscopies, single-crystal X-ray diffraction, and computational studies. The effects due to the presence of fluorine atoms have been highlighted by comparison with the analogous complexes of the ligand L H (Ni: 1H ; Cu: 2H ), which bears hydrogen atoms at the benzenoid rings instead of fluorine. 1F and 2F are isostructural, with the metal ions bound to the four nitrogen atoms in a square-planar geometry and where the planar molecules are arranged in a herringbone motif in the crystal lattice. Remarkable differences in the intermolecular interactions between 1F and 2F and the corresponding H-complexes are shown by Hirshfeld surface calculations. Moreover, the effects of fluorination on the electronic structures have been investigated by density functional theory (DFT) and time-dependent DFT calculations. The compounds with L F and L H ligands present corresponding molecular orbitals (MOs) with similar shapes. Furthermore, while the presence of F-atoms lowers the energy of the MOs in comparison with those of the L H complexes, it does not remarkably affect the highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) and HOMO–LUMO + 1 gaps, in agreement with the UV–vis results.

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“…Therefore, their mass spectrometric analysis is of crucial importance 1. Among these classes of compounds, the fluoronitroanilines are of special interest since they are used for synthesis of important biologically active compounds,2–8 and 2,3,5,6‐tetrafluoro‐4‐nitroaniline shows fungicidal activities 9. In this study, the tetra‐ and trifluoronitroanilines ( 1 – 7 , Scheme ) were analyzed by electron ionization (EI) and electrospray ionization (ESI) mass spectrometry (MS) to check the possibility of isomer differentiation.…”

Section: Methodsmentioning

confidence: 99%

Differentiation of fluoronitroaniline isomers by negative‐ion electrospray mass spectrometry

Gierczyk

Grajewski

Zalas

2005

Rapid Comm Mass Spectrometry

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Tetra- and trifluoronitroanilines were studied by electrospray ionization mass spectrometry. These compounds gave signals only in the negative-ion mode. It was found that the so-called 'in-source' fragmentation, induced by cone voltage increase, enables differentiation of isomers. For para-nitroanilines, in contrast to ortho derivatives, the loss of NO(2) was the most favored process and other fragment ions were characterized by low abundances. For trifluoro conjugates the substitution pattern of aromatic ring by fluorine atoms also affected their fragmentation patterns. For example, in 2,3,6-trifluoro-4-nitroaniline, in contrast to 2,3,5-trifluoro-4-nitroaniline, efficient NO loss, followed by HF loss, took place.

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Polyhalogenonitrobenzenes and derived compounds Part 5. Improved preparations of 1,2,3,4-tetrafluoro-5,6-dinitrobenzene and 3,4,5,6-tetrafluoro-1,2-phenylenediamine, and the use of the latter for the synthesis of tetrafluorobenzheterocycles

Cited by 35 publications

References 4 publications

Preparation, structures and preliminary host–guest studies of fluorinated syn-bis-quinoxaline molecular tweezers

Preparation, structures and preliminary host–guest studies of fluorinated syn-bis-quinoxaline molecular tweezers

Structural and Electronic Effects Due to Fluorine Atoms on Dibenzotetraaza-Annulenes Complexes

Differentiation of fluoronitroaniline isomers by negative‐ion electrospray mass spectrometry

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