Practical Synthesis of Low-Density Lipoprotein Receptor Upregulator, N-[1-(3-Phenylpropane-1-yl)piperidin-4-yl]-5-thia-1,8b-diazaacenaphthylene-4- carboxamide

Experimental and theoretical investigations of Cs+ adsorption on crown ethers modified magnetic adsorbent

Carboxyl Fe₃O₄ nanoparticles (Fe₃O₄@R-COOH) modified with 18-Crown-6 ether functional groups have been prepared via an amidation reaction and used as bifunctional adsorbent for Cs⁺. The adsorbent has a superparamagnetic property, allowing an easy recycling, and a high capacity of Cs⁺ adsorption on the crown ether. The adsorption isotherms and kinetic behaviors agree well with the Langmuir and the pseudo-second-order models. The material exhibits a high selectivity for Cs⁺ in the solution with co-existing cations (NH₄⁺, Rb⁺, K⁺, Na⁺ and Li⁺). A theoretical calculation according to density functional theory (DFT) is used to estimate the structure of Cs⁺ adsorption on crown ether, demonstrating an exothermic process and showing a good agreement with the experimental observations. The adsorption behavior is affected not only by the size of macrocyclic crown ethers, but also by the chelating symmetry and the binding energy. The newly developed adsorbent has a potential application for removing cesium out of wastewater and salt lakes.

Efficient electrochemical N-alkylation of N-boc-protected 4-aminopyridines: towards new biologically active compounds

The use of electrogenerated acetonitrile anion allows the alkylation of N-Boc-4-aminopyridine in very high yields, under mild conditions and without by-products. The high reactivity of this base is due to its large tetraethylammonium counterion, which leaves the acetonitrile anion “naked.” The deprotection of the obtained compounds led to high yields in N-alkylated 4-aminopyridines. Nonsymmetrically dialkylated 4-aminopyridines were obtained by subsequent reaction of monoalkylated ones with t-BuOK and alkyl halides, while symmetrically dialkylated 4-aminopyridines were obtained by direct reaction of 4-aminopyridine with an excess of t-BuOK and alkyl halides. Some mono- and dialkyl-4-aminopyridines were selected to evaluate antifungal and antiprotozoal activity; the dialkylated 4-aminopyridines 3ac, 3ae and 3ff showed antifungal towards Cryptococcus neoformans; whereas 3cc, 3ee and 3ff showed antiprotozoal activity towards Leishmania infantum and Plasmodium falciparum.