Efficient Synthesis of Phosphono‐ and Phosphinoxidomethylated N‐Heterocycles under Solvent‐Free Microwave Conditions

Abstract

Simple N‐heterocycles were converted to N‐phosphono‐ and phosphinoxidomethyl derivatives by a solvent‐free microwave‐assisted condensation of the heterocycle, paraformaldehyde, and diethylphosphite or diphenylphosphine oxide in a convenient and, in most cases, efficient way. In contrast to an earlier report, imidazole proved to be unreactive in this type of phospha‐Mannich reaction.

Keywords:

• α‐aminomethylphosphine oxides
• α‐aminomethylphosphonates
• green chemistry
• N‐heterocycles
• microwave synthesis
• solvent‐free method

Acknowledgment

This work was supported by the joint funds from the European Union and the Hungarian State (GVOP‐3.2.2‐2004‐07‐0006/3.0). The financial support from Gedeon Richter Ltd is also acknowledged. I. P. is grateful to the Hungarian Scientific Research Funds (OTKA PD 050010) for the support.