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Synlett 2015; 26(11): 1486-1489
DOI: 10.1055/s-0034-1380716
letter
© Georg Thieme Verlag Stuttgart · New York

C3-Symmetric Pyridine and Bipyridine Derivatives: Simple Preparation by Cyclocondensation and 2D Self-Assembly at a Solution–Graphite Interface

Jyotirmayee Dash
a   Freie Universität Berlin, Institut für Chemie und Biochemie, Takustr. 3, 14195 Berlin, Germany
b   Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
,
Daniel Trawny
a   Freie Universität Berlin, Institut für Chemie und Biochemie, Takustr. 3, 14195 Berlin, Germany
,
Jürgen P. Rabe
c   Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany   Email: hans.reissig@chemie.fu-berlin.de
,
Hans-Ulrich Reissig*
a   Freie Universität Berlin, Institut für Chemie und Biochemie, Takustr. 3, 14195 Berlin, Germany
› Author Affiliations
Further Information

Publication History

Received: 06 March 2015

Accepted after revision: 14 April 2015

Publication Date:
29 April 2015 (online)

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Dedicated to Prof. K. Peter C. Vollhardt

Abstract

The efficient preparation of four C3-symmetric (star-shaped) pyridine and bipyridine derivatives is reported. The key steps are Suzuki couplings of 4-pyridyl nonaflates with 4-acetyl-phenylboronic acid followed by an acid-promoted cyclocondensation reaction converting the methyl ketone moiety into the central benzene ring of the target compounds. Based on STM studies at a graphite–solution interface the two-dimensional arrangements of the compounds are discussed, showing the influence of the pyridine substitution pattern.

Key words

allenes - heterocycles - cyclization - coupling - self-assembly - scanning tunneling microscopy - highly oriented pyrolytic graphite

Supporting Information

    Supporting information for this article is available online at http://dx.doi.org/10.1055/s-0034-1380716.
  • Supporting Information
 

  • References and Notes

  • 1 Current address: University of Oxford, Department of Chemistry, South Parks Road, Oxford, OX1 3TA, UK.
    • 5a Trawny D, Vandromme L, Rabe JP, Reissig H.-U. Eur. J. Org. Chem. 2014; 4985
    • 5b Trawny D, Schlexer P, Steenbergen K, Rabe JP, Paulus B, Reissig H.-U. ChemPhysChem 2015; 16: 949
      CrossrefSearch in Google Scholar
    • 5c Ciesielski A, Szabelski PJ, Rżysko W, Cadeddu A, Cook TR, Stang PJ, Samorì P. J. Am. Chem. Soc. 2013; 135: 6942
      CrossrefSearch in Google Scholar

      Recent reviews summarizing the versatile chemistry of alkoxyallenes:
    • 6a Brasholz M, Reissig H.-U, Zimmer R. Acc. Chem. Res. 2009; 42: 45
      CrossrefSearch in Google Scholar
    • 6b Nedolya NA, Tarasova O, Volostnykh OG, Albanov AL, Klyba LV, Trofimov BA. Synthesis 2011; 2192
      Thieme Connect
    • 6c Zimmer R, Reissig H.-U. Chem. Soc. Rev. 2014; 43: 2888
      Search in Google Scholar
  • 9 For a review about the advantages of alkenyl and aryl nonaflates in transition-metal-catalyzed reactions, see: Högermeier J, Reissig H.-U. Adv. Synth. Catal. 2009; 351: 2747
    CrossrefSearch in Google Scholar
    • 11a Kotha S, Kashinath D, Lahiri K, Sunoj RB. Eur. J. Org. Chem. 2004; 4003
    • 11b Cao X.-Y, Liu XH, Zhou XH, Zhang Y, Jiang Y, Cao Y, Cui Y.-X, Pei J. J. Org. Chem. 2004; 69: 6050
      CrossrefSearch in Google Scholar
  • 13 Due to the branched scaffold and low solubility of compounds 7a–d only 7b could be rigorously purified by chromatography. Thus signals of minor impurities (e.g., tetraethyl orthosilicate) were observed in the NMR spectra of the other products.
  • 15 Lazzaroni R, Calderone A, Bredas JL, Rabe JP. J. Chem. Phys. 1997; 107: 99
    CrossrefSearch in Google Scholar
  • 16 One may have expected to observe mirror-image domains, however, that was not the case. In the clean images, which we recorded at an overview scan area of 100 × 100 nm2, we typically observed only one domain. This may be due to a preferred 2D crystallization of one configuration, since the two half spaces – the graphite substrate below and the solution above the molecular monolayer – are very different. Since we did not focus on this issue, our statistics cannot rule out completely some finite probability for mirror-image domains.
  • 17 We expect order-disorder transitions to occur at elevated temperatures, but their study goes beyond the scope of the present work.Typical and Representative Experimental Procedures Typical Procedure A for Suzuki Coupling Reactions To a degassed solution of the corresponding nonaflate 5 (1 equiv), 4-acetylphenyl boronic acid (1.2 equiv), and K2CO3 (1.0 equiv) in DMF (5 mL/mmol) were added Pd(OAc)2 (5 mol%) and Ph3P (20 mol%). The resulting mixture was heated to 70 °C for 8 h. After cooling to room temperature and addition of water, the mixture was extracted with diethyl ether. The combined organic layers were washed with water and brine, dried with Na2SO4, filtered, and concentrated to dryness. The residue was purified by chromatography on silica gel (hexanes–ethyl acetate) to give the desired Suzuki coupling product 6. Typical Procedure B for Cyclocondensation Reactions To a stirred solution of the aryl methyl ketone derivative 6 in ethanol–toluene mixture (5:1, 6 mL) was added SiCl4 (1.5 or 15 equiv) at 0 °C. After complete addition, the mixture was allowed to warm to room temperature and was then heated to 55 °C for 16 h. After cooling to room temperature sat. aq NH4Cl solution and CH2Cl2 were added, the phases were separated, and the aqueous phase was extracted with CH2Cl2 and washed with brine. The combined organic layers were dried with Na2SO4 and concentrated to dryness to give product 7. Preparation of 1-{4-[3-Methoxy-2-octyl-6-(trifluoromethyl)pyridin-4-yl]phenyl}ethanone (6b) According to general procedure A, nonaflate 5b (587 mg, 1.00 mmol), 4-acetylphenyl boronic acid (197 mg, 1.20 mmol), K2CO3 (135 mg, 1.00 mmol), Pd(OAc)2 (11 mg, 0.05 mmol), and Ph3P (52 mg, 0.20 mmol) in DMF (5 mL) gave compound 6b (330 mg, 81%) as viscous oil after purification on silica gel (hexanes–ethyl acetate = 5:1). 1H NMR (500 MHz, CDCl3): δ = 0.86 (t, J = 7.1 Hz, 3 H, Me), 1.24–1.36 (m, 8 H, CH2), 1.72–1.77 (m, 2 H, CH2), 2.64 (s, 3 H, Me), 2.91 (mc, 2 H, CH2), 3.42 (s, 3 H, OMe), 7.48 (s, 1 H, Py), 7.71 (d*, J = 8.4 Hz, 2 H, Ar), 8.05 (d*, J = 8.4 Hz, 2 H, Ar) ppm; * only the largest coupling constant of the AA′XX′ system is given. 13C NMR (125.8 MHz, CDCl3): δ = 14.1, 22.7, 26.7, 29.0, 29.3, 29.5, 29.7, 31.9, 32.7 (Me, CH2), 61.0 (OMe), 119.9 (Ar), 121.6 (q, 1 J CF = 273.5 Hz, CF3), 128.8, 129.0, 137.3, 140.1, 140.9 (Ar), 142.9 (q, 2 J CF = 34.6 Hz, C-6), 153.7, 159.1 (Ar), 197.5 (C=O) ppm. IR (neat): ν = 3000 (=C–H), 2950–2860 (C–H), 1690, 1600 (C=C), 1460, 1370 cm–1. HRMS (80 eV): m/z calcd for C23H28F3NO2: 407.2067; found: 407.2063. Preparation of Compound 7b According to general procedure B, aryl methyl ketone 6b (106 mg, 0.26 mmol) and SiCl4 (0.45 mL, 3.90 mmol) gave compound 7b (72 mg, 71%) as yellow wax after purification on silica gel (hexanes–ethyl acetate = 3:1). 1H NMR (500 MHz, CDCl3): δ = 0.89 (t, J = 6.9 Hz, 9 H, Me), 1.22–1.50 (m, 30 H, CH2), 1.77–1.83 (m, 6 H, CH2), 2.91 (mc, 6 H, CH2), 3.53 (s, 9 H, OMe), 7.57 (s, 3 H, Ar), 7.78 (d*, J = 8.4 Hz, 6 H, Ar), 7.87 (d*, J = 8.4 Hz, 6 H, Ar), 7.94 (s, 3 H, Ar) ppm; * only the largest coupling constant of the AA′XX′ system is given. 13C NMR (125.8 MHz, CDCl3): δ = 14.2, 22.7, 29.2, 29.3, 29.5, 29.8, 32.0, 32.8 (Me, CH2), 60.9 (OMe), 120.1 (Ar), 121.8 (q, 1 J CF = 273.0 Hz, CF3), 125.6, 127.8, 129.3, 135.0, 141.48, 141.50, 141.8 (Ar), 142.9 (q, 2 J CF = 34.2 Hz, C-6), 153.8, 158.9 (Ar) ppm. IR (neat): ν = 3030 (=C–H), 2950–2855 (C–H), 1600 (C=C), 1540, 1520, 1460 cm–1. HRMS (80 eV): m/z calcd for C69H78F9N3O3: 1167.5894; found: 1167.5894.