Highly Efficient and Green Synthesis of Flavanones and Tetrahydroquinolones

Abstract

Highly efficient and green catalytic conversion of 2′-hydroxy and 2′-amino chalcones to flavanones and tetrahydroquinolones is reported herein. 2′-Hydroxy and 2′-amino chalcones can be almost completely converted to flavanones and tetrahydroquinolones in just 2 min in the presence of piperidine and KOH under room temperature. Liquiritigenin is also efficiently synthesized under similar conditions.

GRAPHICAL ABSTRACT

Keywords:

• Chalcone
• flavanone
• green chemistry
• liquiritigenin
• tetrahydroquinolone

ACKNOWLEDGMENTS

This work was supported by grants from the Ministry of Education of the People's Republic of China (No. 208119), Natural Science Foundation Project of CQ (No. CSTC, 2011BA5025), Innovative Research Team Development Program in University of Chongqing (No. KJTD201020), 100 leading scientists promotion project of Chongqing, and Chongqing Technology and Business University (No. yjscxx2009-07).

Notes

^a Unless indicated otherwise, the reaction of 1a (4.5 mmol) and base (2.7 mol%, 0.12 mmol) was carried out in water at room temperature for 1 h.

^a Unless indicated otherwise, the reaction of 1a (4.5 mmol), base (2.7 mol%, 0.12 mmol), and alkali hydroxide (18 mol%, 0.8 mmol) was carried out in water at room temperature for a predetermined time.

^a All other conditions are the same as in Table 2..