Diammonium Hydrogen Phosphate as a Recyclable Catalyst for the Rapid and Green Synthesis of 2-amino-1,4,5,6-tetrahydropyrano[3,2-c]-quinolin-5-one Derivatives

ABSTRACT

An efficient three-component synthesis of 2-amino-1,4,5,6-tetrahydro-pyrano[3, 2-c]quinolin-5-one derivatives via a reaction between 4-hydroxyquinolin-2(1H)-one, aromatic aldehydes, and malononitrile/ethyl cyanoacetate using diammonium hydrogen phosphate as catalyst was described. Mild conditions, short reaction time, good to excellent yields, cheap and easily available catalyst, reusability of catalyst and reaction media, and easy work-up are the key features of this method.

KEYWORDS:

• 4-Hydroxyquinolin-2(1H)-one
• catalysis
• diammonium hydrogen phosphate
• multi-component reaction
• pyranoquinoline

Funding

The authors are grateful to the Natural Science Foundation of Hubei Province (grant No. 2007ABA291) for financial support.