Chinese Journal of Catalysis ›› 2014, Vol. 35 ›› Issue (3): 319-323.DOI: 10.1016/S1872-2067(12)60743-8

• Articles • Previous Articles     Next Articles

Highly efficient and clean synthesis of 1-amino-2-acetylanthraquinone by copper-catalyzed reductive cleavage of isoxazole motif

Zhongkui Zhao, Renzhi Li, Yu Li   

  1. State Key Laboratory of Fine Chemicals, Department of Catalysis Chemistry and Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
  • Received:2013-10-10 Revised:2013-11-04 Online:2014-02-26 Published:2014-02-26
  • Supported by:

    This work was supported by the Chinese Ministry of Education via the Program for New Century Excellent Talents in University (NCET-12-0079) and the Fundamental Research Funds for the Central Universities (DUT12LK51).

Abstract:

A clean and highly efficient synthesis of 1-amino-2-acetylanthraquinone via reductive isoxazole ring cleavage of 3-methylanthra[1,2-c]isoxazole-6,11-dione catalyzed by trace copper using hydrazine hydrate as a clean reducing agent and water as a green reaction medium under mild reaction conditions was investigated. Various transition-metal catalysts were screened for the reductive ring-opening reaction, and Cu(NO3)2 was shown to be an excellent catalyst. A conversion of 97.2% and 1-amino-2-acetylanthraquinone selectivity greater than 95% were obtained in the presence of 2.6 mol% Cu(NO3)2 (turnover number 38) with 1.3 equiv. of hydrazine hydrate for 2 h in water. The structure of the product was confirmed by 1H nuclear magnetic resonance spectroscopy and mass spectrometry; the main byproduct was hydroxyl-substituted 1-amino-2-acetylanthraquinone. A possible reaction mechanism for the copper-catalyzed ring cleavage of 3-methylanthra[1,2-c]isoxazole-6,11-dione with hydrazine hydrate was proposed.

Key words: Copper catalyst, Reductive ring-cleavage, 1-Amino-2-acetyl anthraquinone, 3-Methylanthra[1,2-c]isoxazol-6,11-dione, Clean synthesis