Highly efficient one-pot synthesis of α-aminophosphonates using nanoporous AlSBA-15 catalyst in a three-component system

Abstract

Nanoporous AlSBA-15 catalysts with different nSi/nAl ratios (41, 129, and 210) were synthesized using a hydrothermal method. These catalysts were characterized by XRD, N2 sorption, TPD-NH3, FT-IR, SEM and TEM. XRD analyses of AlSBA-15 catalysts confirmed the presence of well-ordered crystalline structure with p6mm symmetry. The specific surface area and specific pore volume of the AlSBA-15 catalysts are in the range of 480 to 757 m2/g and 0.65 to 0.95 cm3/g, respectively. The catalytic performance of nanoporous AlSBA-15 catalysts are used as an outstanding catalytic system for one-pot synthesis of α-aminophosphonates via Kabachnik-Fields reaction in a three-component system using amines (primary/secondary), carbonyl compounds (aldehydes/ketones) and diethyl phosphite. The major advantages of the present contributions are excellent yields, short reaction time, simple experimental technique, high chemo-selectivity, catalyst recyclability, easy work-up procedure and green approach. Three-component synthesis of α-aminophosphonates follows first imine formation from amine and aldehyde/ketone followed by phosphate addition. The experimental findings suggest that the nanoporous AlSBA-15 catalysts can be recycled and reused up to six cycles without any loss in the catalytic performance.