ZrOCl₂·8H₂O: An Efficient Catalyst for One-Pot Synthesis of α-Amino Phosphonates Under Solvent-Free Conditions

Abstract

A highly efficient protocol has been developed for the three-component reaction of an amine, an aldehyde, and diethyl phopshite catalyzed by ZrOCl₂·8H₂O, an environmentally friendly catalyst, at ambient temperature. The catalyst exhibited remarkable activity and tolerated a wide variety of functional groups, providing the desired amino phosphonates in excellent yields under solvent-free conditions. Alternatively, the reaction rate can be significantly enhanced by carrying out the reaction in a monomode microwave reactor as a promoter.

Keywords:

• Aldehydes
• amines
• α-amino phosphonate
• diethyl phosphite
• solvent free
• zirconium oxychloride

ACKNOWLEDGMENTS

The financial assistance from the University Grants Commission, India, for a major research project (Project No. 32–273/2006 (SR)) is acknowledged.

Notes

^a Reaction conditions: aniline (1 mmol), benzaldehyde (1 mmol), diethyl phosphite (1.1 mmol), solvent (1 ml), time (8 h).

^b Yields determined by GC.

^a Reaction conditions: amine (1 mmol), aldehyde (1 mmol), diethyl phosphite (1.1 mmol), ZrOCl₂·8H₂O (0.1 mmol).

^b Yields determined by GC. Yields in parantheses are of isolated compounds.