Hong Gong

Inorganic Zinc Salts Catalyzed Knoevenagel Condensation at Room Temperature without Solvent

Abstract The Knoevenagel condensation of aromatic aldehydes with active methylene compounds (malononitrile or ethyl cyanoacetate), catalyzed by inexpensive and readily available Zn(OAc)2·2H2O, ZnCl2, and ZnBr2 to prepare arylidene compounds in excellent yields under solvent-free conditions at room temperature has been described.

Acetic Acid-Assisted Copper Methanesulfonate Catalyst for Chemoselective Conversion of Aldehydes to Acylals

Abstract A new catalytic system has been discovered by combining copper methanesulfonate with acetic acid for chemoselective conversion of aldehydes to acylals in high yields at ambient temperature under solvent‐free conditions. The efficiency of this system might result from the “double activation” of Brønsted–Lewis acid catalysis on aldehydes.

Praseodymium Methanesulfonate Catalyzed One‐Pot Synthesis of 3,4‐Dihydropyrimidin‐2‐(1H)‐ones

Abstract A series of 3,4‐dihydropyrimidin‐2‐(1H)‐ones compounds was synthesized efficiently by a one‐pot cyclocondensation of an aldehyde, 1,3‐dicarbonyl compound, and urea in absolute ethanol under refluxing temperature using praseodymium methanesulfonate as catalyst. After the reaction, the catalyst can be easily recovered and reused several times without distinct decrease in reaction yields.

Synthesis of 1,1‐Diacetates using a New Combined Catalytic System: Copper p‐Toluenesulfonate/HOAc

Abstract Copper p‐toluenesulfonate acetic acid has been established as an efficient combined catalytic system for chemoselective conversion of aldehydes to diacetates in high yields at ambient temperature in short reaction times. For the catalytic system, the amount of copper p‐toluenesulfonate reduced to 0.3 mol%. After the reaction, copper p‐toluenesulfonate can be easily recovered and reused for at least 10 runs.

WATER-TOLERANT AND REUSABLE LEWIS ACID CATALYST FOR THE ONE-POT SYNTHESIS OF 3,4-DIHYDROPYRIMIDIN-2-(1H)-ONES UNDER SOLVENT-FREE CONDITIONS

3,4-Dihydropyrimidin-2-(1H)-ones were synthesized in high yields by a one-pot cyclocondensation of an aldehyde, a 1,3-dicarbonyl compound, and urea using copper methanesulfonate (2 mol%) as a recyclable catalyst under solvent-free conditions in short reaction time (1–2 h).

Copper nitrate catalyzed three-component one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones.

Abstract An efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones from aldehydes, 1,3-dicarbonyl compounds, and urea using copper nitrate under refluxing temperature in ethanol was described. Compared with other Lewis copper salts, copper nitrate proved to be the most efficient. The advantages of the new method were good yields (61–93%), short reaction time (0.4–3 h), and inexpensive catalyst.