Three-Component Synthesis and 1,3-Dipolar Cycloaddition of Highly Functionalized Pyrans with Nitrile Oxides: Easy Access to 1,2,4-Oxadiazoles

Abstract

Three-component reaction of 1-[(4-chlorophenyl)sulfanyl]acetone, malononitrile, and substituted aromatic aldehydes in the presence of sodium ethoxide under simple mixing at ambient temperature for 5–8 min afforded highly functionalized 4H-pyrans in good to excellent yields. 1,3-Dipolar cycloaddition of nitrile oxides over the nitrile functionality of the 4H-pyrans furnished 1,2,4-oxadiazoles in moderate yields.

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GRAPHICAL ABSTRACT

Keywords:

• 1,3-Dipolar cycloaddition
• nitrile oxide
• 1,2,4-oxadiazoles
• pyran

ACKNOWLEDGMENT

The authors acknowledge the Deanship of Scientific Research at King Saud University for the Research Grant RGP-VPP-026.