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Synlett 2008(15): 2287-2290  
DOI: 10.1055/s-2008-1078269
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis of Phthalonitriles Using a Palladium Catalyst

Zafar Iqbala, Alexey Lyubimtseva,b, Michael Hanack*a
a Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
Fax: +49(7071)295244; e-Mail: hanack@uni-tuebingen.de;
b Ivanovo State University of Chemistry and Technology, Organic Chemistry Department, F. Engels Str. 7, 153460 Ivanovo, Russian ­Federation
Further Information

Publication History

Received 29 May 2008
Publication Date:
22 August 2008 (online)

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Abstract

An easy synthetic method to obtain phthalonitriles from o-dibromobenzenes under mild conditions in high yields using Zn(CN)2 and a catalytic amount of tris(dibenzylideneacetone)dipalladium and 1,1′-bis(diphenylphosphino)ferrocene is described.

Key words

cyanation - o-dibromobenzenes - palladium - phthalo­nitriles

    References and Notes

  • 1a De la Torre G. Claessens CG. Torres T. Chem. Commun.  2007,  2000 
  • 1b Hanack M. Heckmann H. Polley R. Methods of Organic Chemistry (Houben-Weyl)   Thieme; Stuttgart: 1997.  p.717 
  • 1c Leznoff CC. Phthalocyanines: Properties and Applications   VCH Publishers, Inc.; New York: 1989.  p.1 
  • 1d Hanack M. Lang M. Adv. Mater.  1994,  6:  819 
    Search in Google Scholar
  • 2 Sharman WM. Van Lier JE. In Porphyrin Handbook   Vol. 15:  Kadish E. Smith KM. Guilard R. Academic Press; New York: 2003.  p.1 
    Search in Google Scholar
  • 3 Friedman L. Shechter H. J. Org. Chem.  1961,  26:  2522 
    CrossrefSearch in Google Scholar
  • 4 Hanack M. Drechsler U. Synlett  1998,  1207 
    Thieme Connect
  • 5a Zhu Y.-Z. Cai C. Eur. J. Org. Chem.  2007,  2401 
  • 5b Weissman SA. Zewge D. Chen C. J. Org. Chem.  2005,  70:  1508 
    Search in Google Scholar
  • 5c Sundermeier M. Zapf A. Beller M. Eur. J. Inorg. Chem.  2003,  3513 
  • 6a Tsuji J. Transition Metal Reagents and Catalysts - Innovations in Organic Synthesis   John Wiley and Sons; Chichester: 2000. 
  • 6b Brandsma L. Vasilevsky SF. Verkruijsse HD. Application of Transition Metal Catalysts in Organic Synthesis   Springer; Berlin, Heidelberg: 1999.  p.149 
  • 6c Heck RF. Palladium Reagents in Organic Syntheses   Academic Press; London: 1985. 
  • 8 Martin MT. Liu B. Cooley BE. Eaddy JF. Tetrahedron Lett.  2007,  48:  2555 
    CrossrefSearch in Google Scholar
  • 9a Takagi K. Sasaki K. Sakakibara Y. Bull. Chem. Soc. Jpn.  1991,  64:  1118 
    Search in Google Scholar
  • 9b Maligres PE. Waters MS. Fleitz F. Askin D. Tetrahedron Lett.  1999,  40:  8193 
    Search in Google Scholar
  • 9c Jin F. Confalone PN. Tetrahedron Lett.  2000,  41:  3271 
    Search in Google Scholar
  • 10a

    Synthesis of 1,2-Dibromo-4- tert -butylbenzene ( 2a) To a solution of 1-bromo-4-tert-butylbenzene (8 g, 0.04 mol) in CCl4 (5 mL) in the presence of a small amount of iron powder was added a solution of bromine (9.5 g, 0.12 mol) in CCl4 (4 mL) at 5 ˚C over 10 min. The mixture was stirred at 15 ˚C for 2 h. Solvent was evaporated and product was purified by column chromatography using CH2Cl2-hexane (1:1) as eluent; yield 11 g (92%). ¹H NMR (400 MHz, CDCl3): δ = 7.59 (d, 4 J = 2.3 Hz, 1 H), 7.50 (d, ³ J = 8.4 Hz, 1 H), 7.16 (dd, ³ J = 8.4 Hz, 4 J = 2.3 Hz, 1 H), 1.27 (s, 9 H) ppm. MS (EI): m/z (%) = 291.8 (45) [M]+, 276.8 (100).

  • 10b Ashton P. Girreser U. Giuffrida D. Kohnke FH. Mathias JP. Raymo FM. Slawin AMZ. Stoddart JF. Williams DJ. J. Am. Chem. Soc.  1993,  115:  5422 
    Search in Google Scholar
  • 10c Andersh B. Murphy DL. Olson RJ. Synth. Commun.  2000,  30:  2091 
    Search in Google Scholar
  • 10d Wenderski T. Light KM. Ogrin D. Bott SG. Harlan CJ. Tetrahedron Lett.  2004,  45:  6851 
    Search in Google Scholar
  • 10e Ivanov AV. Svinareva PA. Tomilova LG. Zefirov NS. Russ. Chem. Bull. Int. Ed.  2001,  50:  919 
    Search in Google Scholar
  • 12a

    Synthesis of tert -Butyl-(3,4-dibromophenoxy)dimethylsilane ( 9a) and 3,4-Dibromophenol ( 10a)
    The hydroxy group in 3-bromophenol was protected with tert-butyldimethylsilyl chloride in the presence of imidazole to give tert-butyl(3-bromophenoxy)dimethylsilane quantitatively. [¹²b] ¹H NMR (400 MHz, CDCl3): δ = 7.09-7.04 (m, 2 H), 7.01-6.96 (m, 1 H), 6.79-6.70 (m, 1 H), 0.96 (s, 9 H), 0.18 (s, 6 H) ppm. MS (EI): m/z (%) = 286.0 (20) [M]+, 231.0 (100), which was brominated with NBS. [¹0c] After purification by column chromatography tert-butyl(3,4-dibromophenoxy)dimethylsilane (9a) was obtained in 78% yield. ¹H NMR (400 MHz, CDCl3): δ = 7.41 (d, ³ J = 7.5 Hz, 1 H), 7.10 (d, 4 J = 2.5 Hz, 1 H), 6.64 (dd, ³ J = 7.5 Hz, 4 J = 2.5 Hz, 1 H), 0.95 (s, 9 H), 0.18 (s, 6 H) ppm. MS (EI): m/z (%) = 365.9 (40) [M]+, 308.9 (100). tert-Butyldimeth-ylsilyl group in 9a was deprotected with tetrabutyl-ammonium fluoride [¹²b] to give 3,4-dibromophenol (10a) in 92% yield. ¹H NMR (400 MHz, CDCl3): δ = 7.28 (d, ³ J = 8.6 Hz, 1 H), 7.02 (s, 1 H), 6.55 (d, ³ J = 8.6 Hz, 1 H) ppm. MS (EI): m/z (%) = 252.0 (100) [M]+.

  • 12b Tew GN. Pralle MU. Stupp SI. J. Am. Chem. Soc.  1999,  121:  9852 
    Search in Google Scholar
  • 13 Rusanova J. Pilkington M. Decurtins S. Chem. Commun.  2002,  19:  2236 
    Search in Google Scholar
  • 14 Moerkved EH. Neset SM. Bjoerlo O. Kjoesen H. Hvistendahl G. Mo F. Acta Chem. Scand.  1995,  49:  658 
    CrossrefSearch in Google Scholar
  • 15 Vagin S. Hanack M. Eur. J. Org. Chem.  2004,  600 
    Crossref
  • 16a

    Synthesis of 6,7-Dibromo-2,2-dimethylnaphtho[2,3- d ][1,3]dioxole ( 19a)
    To 5.6 g (17.6 mmol) of 2,3-dibromo-6,7-dihydroxy-naphthalene [¹6b] dissolved in toluene (40 mL) toluene and anhydrous acetone (5 mL) was added P2O5 in three portions during 48 h while the reaction mixture was heated at 50 ˚C. The solution was diluted with toluene (50 mL), washed with H2O, 10% NaOH soln, H2O and brine. Combined organic phase was concentrated with a rotary evaporator. Purification of the crude product was carried out by column chromatography using dichloromethane as eluent; yield 3.42 g (57%). ¹H NMR (400 MHz, CDCl3): δ = 7.88 (s, 2 H), 6.87 (s, 2 H), 1.71 (s, 6 H) ppm. MS (EI): m/z (%) = 357.9 (60) [M]+, 342.8 (100).

  • 16b Youssev TE. Hanack M. J. Porphyrins Phthalocyanines  2002,  6:  571 
    Search in Google Scholar
7

Synthesis of Substituted Phthalonitriles - General Procedure A 25 mL two-neck round-bottom flask was charged with 1 mmol of o-dibromobenzene in DMAC (2 mL) and PMHS (20 mg) was added at r.t. The reaction mixture was heated to the required temperature (Table  [¹] ) and Pd2 (dba)3 (20 mg, 2 mol%) and DPPF (15 mg, 2.7 mol%) were added. Afterwards, Zn(CN)2 (117 mg, 1 mmol) was added in 4-5 portions during the time mentioned in Table  [¹] till TLC indicated completion of the reaction. The reaction mixture was cooled, diluted with EtOAc and filtered. Filtrate was washed with H2O, dried with MgSO4, and concentrated in vacuo. The crude product was purified by column chromatography using CH2Cl2 as eluent.

11

Synthesis of 1,2-Dibromo-4-acetanilide ( 8a)
3-Bromoacetanilide was brominated with NBS in acetone with catalytic amounts of HCl [¹0c] to give after purification by column chromatography 1,2-dibromo-4-acetanilide (8a) in 90% yield. ¹H NMR (400 MHz, CDCl3): δ = 7.84 (s, 1 H), 7.50 (d, ³ J = 8.8 Hz, 1 H), 7.38 (br s , 1 H), 7.30 (d, ³ J = 8.8 Hz, 1 H), 2.15 (s, 3 H) ppm. MS (EI): m/z (%) = 293.0 (100) [M]+.

17

Compound 19b: ¹H NMR (400 MHz, CDCl3): δ = 8.05 (s, 2 H), 7.10 (s, 2 H), 1.77 (s, 6 H) ppm. MS (EI): m/z (%) = 250.0 (40) [M]+, 235.0 (100), 210.0 (50).