Heterogeneous catalyst SiO2-LaCl3·7H2O: characterization and microwave-assisted green synthesis of α-aminophosphonates and their antimicrobial activity.

Silica-supported lanthanum (III) chloride (SiO2-LaCl3·7H2O) was prepared and characterized by infrared spectroscopy, X-ray diffraction analysis, scanning electron microscope, energy-dispersive X-ray spectroscopy, thermogravimetric analysis and differential thermal analysis techniques. The catalytic activity of this silica-supported lanthanum (III) chloride was investigated in a one-pot three-component Kabachnik-Fields reaction. A library of new α-aminophosphonates was prepared employing various benzothiazole and thiadiazole amines, different substituted aldehydes and diethylphosphite under solvent-free conditions using conventional/microwave methods with good to excellent yields (85-97%). The advantages of this catalyst are that it is environmentally benign, economically inexpensive, and easy to prepare, gives high yields and high purity is less time-consuming, offers easy purification is reusable and enables products to be obtained by simple recrystallization without column chromatography.

Synthesis of Bis(indolyl)methanes Using Hyper-Cross-Linked Polyaromatic Spheres Decorated with Bromomethyl Groups as Efficient and Recyclable Catalysts.

Highly uniform and hyper-cross-linked polyphenanthrene and polypyrene microspheres were synthesized by Friedel-Crafts bromomethylation of phenanthrene (Phn) and pyrene (Py) in the presence of zinc bromide as a catalyst, followed by self-polymerization of bromomethylated Phn and Py. The resultant 3-D carbon microspheres consisting of micro-, meso-, and macropores bear peripheral unreacted bromomethyl groups, which are directly utilized as catalysts to efficiently promote the electrophilic substitution reaction of indoles with aldehydes to yield a variety of bis(indolyl)methanes. The important features of this catalysis are easy catalyst synthesis, high product yields, environmental benignity, short reaction time, broad substrate scope, use of nontoxic solvents, and recyclability.

Efficient, Solvent-Free, Multicomponent Method for Organic-Base-Catalyzed Synthesis of ß-Phosphonomalonates.

An efficient, one-pot, di-n-butylamine-catalyzed, three-component synthesis of ß-phosphonomalonates has been developed. A wide range of substrates, including aromatic and fused aromatic aldehydes, were condensed with enolizable C-H activated compounds and dialkylphosphites to give the desired products in excellent yields. This method provides an eco-friendly alternative approach to rapid construction of a diversity-oriented library of ß-phosphonomalonates.

Synthesis of 2-amino-3-cyano-4H-chromen-4-ylphosphonates and their anticancer properties.

A series of 2-amino-3-cyano-4H-chromen-4-ylphosphonates have been synthesized by reacting substituted salicylaldehydes, malononitrile, and dialkylphosphites using a catalytic amount of dibutylamine as an organocatalyst employing Knoevenagel, Pinner, and phospha-Michael reactions simultaneously in ethanol. This protocol is an environmentally friendly procedure and gives high yields of the desired compounds (85-96%). In addition, no extraction or chromatography steps are needed to obtain the desired products. The compounds are tested against the viability of adenocarcinomic human alveolar basal epithelial (A549) and human epidermoid cancer (KB) cell lines using an MTT assay. Among these, diethyl 2-amino-3-cyano-4H-chromen-4-ylphosphonate and diethyl 2-amino-6-bromo-3-cyano-4H-chromen-4-ylphosphonate showed promising anticancer activity against the two tested cell lines.