SOCl₂/β-Cyclodextrin: A New and Efficient Catalytic System for Beckmann Rearrangement and Dehydration of Aldoximes Under Aqueous Condition

Abstract

A rapid and efficient synthesis of amides via Beckmann rearrangement of ketoximes and dehydration of aldoximes to corresponding nitriles with good to excellent yields has been carried out in the presence of SOCl₂/β-cyclodextrin under aqueous conditions. The β-cyclodextrin has been recovered and reused.

GRAPHICAL ABSTRACT

Keywords:

• Beckmann rearrangement
• β-cyclodextrin (β-CD)
• thionyl chloride (SOCl₂)

ACKNOWLEDGMENT

We are thankful to the Department of Science and Technology, New Delhi, India, for financial support.

Notes

^a Reaction conditions: To a solution of 4-bromoacetophenone oxime in acetone, SOCl₂ was added dropwise at 0–10 °C. Then a clear solution of β-CD dissolved in distilled water (10 ml) was added at room temperature and stirred at the given temperature. Molar ratio of oxime–SOCl₂–β-CD = 5:6:0.5.

^b Isolated yield.

^a A molar ratio of oxime–SOCl₂ = 5:6 was used.

^b Isolated yield.

^a A molar ratio of ketoximes–SOCl₂–β-CD = 5:6:0.5.

^b Isolated yield after column chromatography.

^a Molar ratio of aldoximes–SOCl₂–β-CD = 5:6:0.5.

^b Isolated yield after column chromatography.