Liyan Dai

Knoevenagel condensations of 1,3-dicarbonyl compounds with aldehydes catalyzed by heterogeneous Ps-AlCl3 without solvents

A simple, efficient procedure is proposed for Knoevenagel condensations of 1,3-dicarbonyl compounds with aldehydes catalyzed by heterogeneous polystyrene-supported aluminum chloride (Ps-AlCl3) under solvent-free conditions. The condensations are carried out smoothly with high yields (87–98%) at 60 °C for 2–4 h in the presence of the Ps-AlCl3 catalyst. The catalyst is characterized by Fourier transfer-infrared spectroscopy (FT-IR). The catalyst is applicable to a wide range of aldehydes, and has excellent recyclability and can be reused several times without loss of activity.

The direct assembly of Mg–Al LDH nanosheets and Mn(II)–salen complex into sandwich-structured materials and their enhanced catalytic properties

The direct assembly of LDH nanosheets and organic molecules, such as Mn(II)–salen complex, into a sandwich-structured nanocomposite has been achieved via a modified flocculation method. When used as a catalyst, the obtained material has superior thermal stability and catalytic properties over a material prepared using a traditional ion exchange method in the oxidation of 4-picoline.

Improved Synthetic Approach to Tenatoprazole

Abstract An improved synthetic approach to tenatoprazole 1 is described. It started from 2,3,5‐trimethyl‐4‐nitropyridine‐N‐oxide 2 with acetic anhydride via rearrangement and hydrolysis to give 3, Chlorination with SOCl2 yielded 2‐chloromethyl‐3,5‐dimethyl‐4‐nitropyridine hydrochloride 4, then 4 condensed with 2‐mercapto‐5‐methoxy imidazole [4,5‐b]pyridine 5 to give 5‐methoxy‐2‐[(4‐nitro‐3,5‐dimethyl‐2‐pyridinyl)methylthio]imidazole[4,5‐b]pyridine 6. At last the title compound 1 was produced by two methods: 6 was oxidized with MCPBA and then methoxylated with CH3ONa to give 1 and 6 was first methoxylated with CH3ONa and then oxidized with MCPBA to give 1. The overall yield is around 26% for both five‐step syntheses.