Molecular Diversity from the L-Proline-Catalyzed, Three-Component Reactions of 4-Hydroxycoumarin, Aldehyde, and 3-Aminopyrazole or 1,3-Dimethyl-6-aminouracil

Abstract

The three-component reaction of 4-hydroxycoumarin, aldehyde, and aminopyrazole in the presence of a catalytic amount of L-proline in ethanol under reflux conditions provided the cyclized product (dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridine-6(7H)-one), whereas under similar reaction conditions, replacing aminopyrazole by 1,3-dimethyl-6-aminouracil provided the acyclic three-component product (6-amino-5-((4-hydroxy-2-oxo-2H-chromen-3-yl)methyl)-1,3-dimethylpyrimidine-2,4(1H,3H)-dione). This method is metal free and atom economical, and avoids column chromatographic purification as all the products can be purified by recrystallization.

GRAPHICAL ABSTRACT

Keywords:

• Coumarin-fused polycyclic heterocycles
• 1,3-dimethyl-6-aminouracil
• L-proline
• multicomponent reaction

ACKNOWLEDGMENTS

The authors are grateful to IIT Patna and SAIF Panjab University for providing analytical facilities for characterization of compounds, and to SAIF-IIT Madras for providing single-crystal x-ray crystallographic data.

SUPPLEMENTAL INFORMATION

Supplemental materials for this article can be accessed on the publisher’s website.