Highly Stereoselective Synthesis of β-Amino Ketones via a Mannich Reaction Catalyzed by Cellulose Sulfuric Acid as a Biodegradable, Efficient, and Recyclable Heterogeneous Catalyst

Abstract

The efficient use of cellulose sulfuric acid as a heterogeneous catalyst promotes three-component, one-pot Mannich reaction of various ketones, aromatic aldehydes, and aromatic amines in ethanol to make the corresponding β-amino ketones with high stereoselectivity in favor of the anti-isomer. This protocol has several advantages such as good yield, mild reaction conditions, no environmental hazards, and simple workup procedure.

Keywords:

• β-Amino ketones
• cellulose sulfuric acid
• Mannich reaction
• stereoselective

ACKNOWLEDGMENT

We thank the Department of Chemistry and Center of Gifted Students of Semnan University for supporting this work.

Notes

^a Reaction conditions: Aromatic aldehyde (2 mmol), aniline (2 mmol), cyclohexanone (3 mmol), CSA (0.3 g).

^b Isolated yields, products were confirmed by ¹H NMR.

^c Anti/syn ratio was determined by ¹H NMR.

^a Reaction conditions: Aldehyde (2 mmol), aromatic aniline (2 mmol), acetophenone (2 mmol) or 1,3-diphenylpropan-2-one (2 mmol) and CSA (0.5 g).

^b Isolated yield, products were confirmed by ¹H NMR.

^c No reaction.