Acta Chim. Sinica ›› 2014, Vol. 72 ›› Issue (11): 1139-1143.DOI: 10.6023/A14080584 Previous Articles     Next Articles



张茜, 吕允贺, 李燕, 熊涛, 张前   

  1. 东北师范大学化学学院 长春市 130024
  • 投稿日期:2014-08-14 发布日期:2014-10-10
  • 通讯作者: 张前
  • 基金资助:

    项目受国家自然科学基金(Nos. 21172033, 21372041)及高等学校博士点基金(No. 20110043110002)资助.

Copper-Catalyzed Benzylic sp3 C-H Amination Reaction of Amidines: Synthesis of Quinazoline Derivatives

Zhang Qian, Lü Yunhe, Li Yan, Xiong Tao, Zhang Qian   

  1. Department of Chemistry, Northeast Normal University, Changchun 130024
  • Received:2014-08-14 Published:2014-10-10
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21172033, 21372041) and the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20110043110002).

Quinazoline motif is an important heterocyclic framework, which widely exists in many biologically active molecules and natural products. Although numerous synthetic efforts have been made for the preparation of quinazoline derivatives in recent years, it is still highly desirable to search for a more convenient and efficient approach. As part of our ongoing interest in transition-metal-catalyzed C—H functionalization, herein, we report a novel copper-catalyzed synthesis of quinazoline derivatives from amidines. During these transformations, the selectivity of benzylic sp3 C—H over aryl sp2 C—H bond was efficiently realized. Various 2-arylquinazoline derivatives were obtained in moderate to good yields. A representative procedure for the copper-catalyzed construction of quinazolines from amidines is as following: N-(o-tolyl)benzimidamide (1a, 0.4 mmol, 89.7 mg), Cu(OTf)2 (0.04 mmol, 13.8 mg) and Ag2CO3 (0.8 mmol, 219 mg) were added to a 25 mL sealed tube, followed by addition of DMF (2 mL). The mixture was stirred at 140 ℃ for 10 h. After cooling to room temperature, the mixture was poured into ice-water and extracted with CH2Cl2 (15 mL×3). The combined organic layers were dried (Na2SO4), filtered over Celite, evaporated in vacuo. The residue was purified by a shot flash silica gel column chromatography (petroleum ether/ethyl acetate, V:V=15:1) to afford the product 2a (71%, 62.4 mg).

Key words: copper, N-arylamidines, C—N bond formation, quinazoline derivatives