Download PDF
Synlett 2009(18): 2943-2944  
DOI: 10.1055/s-0029-1218269
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

2-Azido-1,3-dimethylimidazolinium Chloride: An Efficient Diazo Transfer Reagent for 1,3-Dicarbonyl Compounds

Mitsuru Kitamura*, Norifumi Tashiro, Tatsuo Okauchi
Department of Applied Chemistry, Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata-ku, Kitakyushu-shi, Fukuoka, 804-8550, Japan
Fax: +81(93)8843304; e-Mail: kita@che.kyutech.ac.jp;
Further Information

Publication History

Received 22 July 2009
Publication Date:
08 October 2009 (online)

   Permissions and Reprints All articles of this category
Preview

Abstract

Diazo transfer from 2-azido-1,3-dimethylimidazolinium chloride to 1,3-dicarbonyl compounds has been developed. The ­reaction proceeds under mild conditions to give 2-diazo-1,3-dicarbonyl compounds in high yields, which are easily isolated because the by-products are highly soluble in water.

Key words

azides - diazo compounds - diazonium salt - diazo-transfer - heterocycles

    References and Notes

  • For reviews, see:
  • 1a Zhang Z. Wang J. Tetrahedron  2008,  64:  6577 
    Search in Google Scholar
  • 1b Doyle MP. Ye T. McKervey MA. Modern Catalytic Methods for Organic Synthesis with Diazo Compounds   John Wiley & Sons; New York: 1998. 
  • 1c Ye T. McKervey MA. Chem. Rev.  1994,  94:  1091 
    Search in Google Scholar
  • 1d Padwa A. Austin DJ. Angew. Chem. Int. Ed. Engl.  1994,  33:  1797 
    Search in Google Scholar
  • 1e Doyle MP. Chem. Rev.  1986,  86:  919 
    Search in Google Scholar
  • For reviews on the synthesis of α-diazo compounds by diazo transfer using tosyl azide, see:
  • 2a Regitz M. Synthesis  1972,  351 
  • 2b Regitz M. Angew. Chem. Int. Ed. Engl.  1967,  6:  733 
    Search in Google Scholar
  • For the use of alternative diazo transfer reagents and conditions, see:
  • 3a For imidazole-1-sulfonyl azide, see: Goddard-Borger ED. Stick RV. Org. Lett.  2007,  9:  3797 
    Search in Google Scholar
  • For trifluorometanesulfonyl azide, see:
  • 3b Wurz RP. Lin W. Charette AB. Tetrahedron Lett.  2003,  44:  8845 
    Search in Google Scholar
  • 3c Cavender CJ. Shiner VJ. J. Org. Chem.  1972,  37:  3567 
    Search in Google Scholar
  • 3d For mesyl azide, see: Taber DF. Ruckle RE. Hennessy MJ. J. Org. Chem.  1986,  51:  4077 
    Search in Google Scholar
  • 3e For p-carboxybenzenesulfonyl azide, see: Hendrickson JB. Wolf WA. J. Org. Chem.  1968,  33:  3610 
    Search in Google Scholar
  • 3f For 2-azido-3-ethylbenzothiazolium tetrafluoroborate, see: Balli H. Löw R. Müller V. Rempfler H. Sezen-Gezgin A. Helv. Chim. Acta  1978,  61:  97 
    Search in Google Scholar
  • 3g For(azidochloromethylene)dimethylammonium chloride, see: Kohel B. Viehe HG. Angew. Chem. Int. Ed. Engl.  1980,  19:  716 
    Search in Google Scholar
  • 3h For naphthalene-2-sulfonyl azide and p-(n-dodecyl)benzenesulfonyl azide, see: Hazen GG. Weinstock LM. Connell R. Bollinger FW. Synth. Commun.  1981,  11:  947 
    Search in Google Scholar
  • 3i For 2,4,6-triisopropylphenyl-sulfonyl azide, see: Lombardo L. Mander LN. Synthesis  1980,  368 
  • 3j For p-nitrophenyl azide, see: Herbranson DE. Hawley MD. J. Electroanal. Chem.  1983,  144:  423 
    Search in Google Scholar
  • 3k For azidotris(diethylamino)-phosphonium bromide, see: McGuiness M. Shechter H. Tetrahedron Lett.  1990,  31:  4987 
    Search in Google Scholar
  • For polymer-bound sulfonyl azide, see:
  • 3l Harned AM. Sherrill WM. Flynn DL. Hanson PR. Tetrahedron  2005,  61:  12093 
    Search in Google Scholar
  • 3m Green GM. Peet NP. Metz WA. J. Org. Chem.  2001,  66:  2509 
    Search in Google Scholar
  • 3n Roush WR. Feitler D. Rebek J. Tetrahedron Lett.  1974,  15:  1391 
    Search in Google Scholar
  • 3o For reaction in ionic liquid, see: Ramachary DB. Narayana VV. Ramakumar K. Tetrahedron Lett.  2008,  49:  2704 
    Search in Google Scholar
  • 4a Hudlicky T. Govindan SV. Frazier JO. J. Org. Chem.  1985,  50:  4166 
    Search in Google Scholar
  • 4b Doyle MP. Dorow RL. Terpstra JW. Rodenhouse RA. J. Org. Chem.  1985,  50:  1663 
    Search in Google Scholar
  • 4c Ledon H. Synthesis  1974,  347 
  • 5 Kitamura M. Chiba S. Narasaka K. Bull. Chem. Soc. Jpn.  2003,  76:  1063 
    CrossrefSearch in Google Scholar
  • 8a Ohira S. Synth. Commun.  1989,  19:  561 
    Search in Google Scholar
  • 8b Müller S. Liepold B. Roth GJ. Bestmann HJ. Synlett  1996,  521 
6

The formation of salt 2 was confirmed by mass spectral analysis. The FAB(positive) mass spectrum of the mixture of the chloroimidazorium salt 3 and sodium azide showed a peak at m/z = 140, which corresponds to the calculated mass of [2 - Cl-]+.

7

Typical procedure: [Caution: Although we have never had any trouble with azidoimidazolinium salt 2 , it is potentially explosive.] To a solution of 2-chloro-1,3-dimethyl-imidazolinium chloride (3; 1.2 mmol) in acetonitrile (2 mL), sodium azide (1.2 mmol) was added at 0 ˚C and the mixture was stirred for 30 min. 1,3-Dicarbonyl compound (1.0 mmol) and triethylamine (2.0 mmol) in THF (4 mL) was added to the mixture, which was stirred until the 1,3-dicarbonyl compound was consumed (reaction monitored by TLC). The reaction was quenched with water, and organic materials were extracted three times with CH2Cl2. The combined extracts were washed with water and brine, and then dried over anhydrous sodium sulfate. The solvent was removed in vacuo to afford the crude compound, which was almost pure. The crude materials were purified by flash column chromatography (silica gel: hexane-ethyl acetate) to give pure 2-diazo-1,3-dicarbonyl compound.