Transition metal-free oxidative and deoxygenative C–H/C–Li cross-couplings of 2H-imidazole 1-oxides with carboranyl lithium as an efficient synthetic approach to azaheterocyclic carboranes

Lidia A. Smyshliaeva,
Mikhail V. Varaksin,
Pavel A. Slepukhin,
Oleg N. Chupakhin and
Valery N. Charushin

Letter
Published 12 Oct 2018

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1. Graphical Abstract
2. Scheme 1: C–H/C–Li cross-coupling reactions of 2H-imidazole 1-oxides 1a–d and carboranyl lithium 2. The react...
  
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3. Figure 1: The ¹H NMR spectra of 1-(5-(4-bromophenyl)-2-ethyl-2-methyl-2H-imidazol-4-yl)-1,2-dicarba-closo-dod...
  
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4. Figure 2: Fragment of the 2D ¹H–¹³C{¹H} HSQC (a) and HMBC (b) spectra of imidazolyl carborane 5d in CDCl₃ at ...
  
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5. Figure 3: Molecular structure of 5d. Selected bond distances (Å) and angles (deg) for molecule 1: C(3)–C(14),...
  
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Beilstein J. Org. Chem. 2018, 14, 2618–2626, doi:10.3762/bjoc.14.240

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¹⁵N-Labelling and structure determination of adamantylated azolo-azines in solution

Sergey L. Deev,
Alexander S. Paramonov,
Tatyana S. Shestakova,
Igor A. Khalymbadzha,
Oleg N. Chupakhin,
Julia O. Subbotina,
Oleg S. Eltsov,
Pavel A. Slepukhin,
Vladimir L. Rusinov,
Alexander S. Arseniev and
Zakhar O. Shenkarev

Full Research Paper
Published 29 Nov 2017

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1. Graphical Abstract
2. Figure 1: (A) Adamantylated azoles and derivatives of 1,2,4-triazolo[5,1-c][1,2,4]triazine with antiviral act...
  
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3. Scheme 1: Synthesis and adamantylation of ¹⁵N-labelled 13-¹⁵N₂ and J_HN and J_CN data confirming the structures...
  
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4. Scheme 2: Synthesis and adamantylation of ¹⁵N-labelled 20-¹⁵N₂ and J_HN and J_CN data confirming the structures...
  
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5. Scheme 3: Synthesis and adamantylation of ¹⁵N-labelled 23-¹⁵N₂ and J_HN and J_CN data confirming the structure ...
  
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6. Scheme 4: Isomerization of 15a in the presence of tetrazolo[1,5-b][1,2,4]triazin-7-one 13-¹⁵N₂ and isotopic e...
  
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7. Figure 2: 1D ¹⁵N NMR spectra of 30–70 mM 13-¹⁵N₂, 15a,b-¹⁵N₂, 20-¹⁵N₂, 21a,b-¹⁵N₂, 23-¹⁵N₂ and 24-¹⁵N₂ in DMS...
  
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8. Figure 3: Signals of the C1' and C6 atoms in the proton-decoupled 1D ¹³C NMR spectra of 30–42 mM 15a,b-¹⁵N₂, ...
  
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9. Figure 4: Detection and quantification of the ¹H-¹⁵N spin–spin interactions in compound 15a-¹⁵N₂ (DMSO-d₆, 45...
  
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10. Figure 5: ORTEP diagrams of the X-ray structures of compounds 15a-¹⁵N₂ (a) and 15b-¹⁵N₂ (b). For clarity, the...
  
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11. Scheme 5: Mechanism of the isomerization of compounds 15a and 15b.
  
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Beilstein J. Org. Chem. 2017, 13, 2535–2548, doi:10.3762/bjoc.13.250

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Combined experimental and theoretical studies of regio- and stereoselectivity in reactions of β-isoxazolyl- and β-imidazolyl enamines with nitrile oxides

Ilya V. Efimov,
Marsel Z. Shafikov,
Nikolai A. Beliaev,
Natalia N. Volkova,
Tetyana V. Beryozkina,
Wim Dehaen,
Zhijin Fan,
Viktoria V. Grishko,
Gert Lubec,
Pavel A. Slepukhin and
Vasiliy A. Bakulev

Full Research Paper
Published 15 Nov 2016

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1. Graphical Abstract
2. Figure 1: Biologically active isoxazoles conjugated to other azole rings.
  
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3. Scheme 1: Reactions of azolyl enamines with nitrile oxides.
  
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4. Figure 2: Structures of starting enamines 1 and hydroxamoyl chlorides 2.
  
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5. Scheme 2: Synthesis of 4-azolylisoxazoles 4a–p from enamines 1a–e and hydroxamoyl chlorides 2a–h. Reaction co...
  
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6. Figure 3: Imidazolylisoxazole 4a according to XRD data in the thermal ellipsoids of the 50% probability level....
  
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7. Figure 4: Isoxazolylisoxazole 4p according to XRD data with thermal ellipsoids of 50% probability level.
  
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8. Scheme 3: Plausible mechanisms for reaction of hydroxamoyl chlorides 2 with imidazolyl enamines 1a,b.
  
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9. Figure 5: Geometries of enamine 1a appropriate to the calculated minima on the PES, and their relative free e...
  
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10. Scheme 4: Calculated pathways for the formation of experimentally observed 3a, regioisomer 7 and isoxazoline 8...
  
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11. Figure 6: Structures of the localized transition states. Lengths of the forming bonds are given in Å.
  
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12. Figure 7: Summary of the calculated pathways of the cycloaddition reaction between enamine 1a and benzonitril...
  
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13. Figure 8: Isosurface plots of the HOMO of enamine 1a_1 (bottom) and the LUMO of nitrile oxide 6 (top) in the ...
  
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