Hui Zheng

Lipase-catalysed tandem Knoevenagel condensation and esterification with alcohol cosolvents

Six lipases were screened for their ability to catalyse the Knoevenagel condensation between benzaldehyde and methyl cyanoacetate. Lipase from porcine pancreas tolerated a variety of functional groups on the aromatic ring, produced the highest yields, and also catalysed transesterification of the product in the presence of an alcoholic cosolvent. We show that, in organic solvents, lipase from porcine pancreas has higher activity for this “promiscuous” reaction than for naturally occurring esterification catalysis.

A highly efficient way to capture CX2 (O, S) mildly in reusable ReILs at atmospheric pressure

The highly efficient transformation of CX2 (O, S) into valuable chemicals at atmospheric pressure is an attractive topic. A novel method of preparing quinazoline derivatives by capturing CX2 (O, S) in reusable, room-temperature, reversible ionic liquids (ReILs) with high yields (up to 98%) at 40 °C and atmospheric pressure was developed in this paper. The different reaction conditions were optimized and the products were easily separated from the ReILs which could be reused at least six times without considerable loss in yield. The plausible mechanism of capturing CX2 (O, S) in the ReILs was proposed and it provides a green, efficient protocol to capture CX2 (O, S) in ReILs to synthesize quinazoline derivatives.

Synthesis, characterization, and cytotoxicity of some novel glycosyl thiazol-2-imines as antitumoral agents

A series of novel glycosyl thiazol-2-imines (3a-g) have been synthesized regioselectively in good yields from the hydrolysis of thiazol-2(3H)-imine-linked glycoconjugates. The glycosyl thiazol-2-imines were evaluated for their antitumor activity against Hela (cervical carcinoma), HCT-8 (colon carcinoma) and Bel-7402 (liver carcinoma). Among the compounds screened, 1-benzoyl-4-(4-nitrophenyl)-3-beta-D-glucopyranosyl-thiazol-2(3H)-imine (3c) was found to be the most active compound against HCT-8.

Synthesis of Some Novel Glucosyl Triazoles from 2,3,4,6-Tetra-O-pivaloyl-D-glucopyranosyl Azide

In the present study, we have synthesized a series of novel glucosyl triazoles for the first time. The glucosyl triazoles 4a–e were synthesized by reaction of some azidoglycosides with various terminal alkynes via a copper-catalyzed [3+2] cycloaddition (“click chemistry”) and were deprotected to afford the corresponding glucosyl triazoles 5a–e in good yields. The structures of the new compounds were determined by IR, NMR spectroscopy, and mass spectrometry. The antitumor (human cervical cancer cell) activity was evaluated for the target compounds.

Metal-free catalytic synthesis of diaryl thioethers under mild conditions

A novel method to synthesize diaryl thioethers from aryl halides and carbon disulfide catalyzed by the 1,8-diazabicyclo[5,4,0]undec-7-enium acetate [DBUH][OAc] ionic liquid (IL) under solvent-free conditions has been developed. This metal-free catalytic system displayed high efficiency for coupling aryl halides with CS2 to deliver thioethers. Compared to the conventional methods, no metal catalyst was needed, instead of which the DBU-based ILs played the catalyst and solvent roles simultaneously. Some reactions were carried out under mild conditions (55 °C, 0.5 h), giving moderate to high yields. Moreover, compared with the rare reports, the reaction of the aryl chlorides and fluorides with CS2 could smoothly react in this catalytic system. The products were easily separated from the ILs which could be reused at least three times. The present method provides an efficient and environment-friendly catalytic approach to synthesize diaryl thioethers.

A efficient protocol for the synthesis of thioamides in [DBUH][OAc] at room temperature

A novel, simple and eco-friendly method to synthesize thioamides from aryl nitriles and sodium sulfide (Na2S·9H2O) catalyzed by 1,8-diazabicyclo[5,4,0]undec-7-enium acetate ([DBUH][OAc]) ionic liquid (IL) at room temperature was developed in this paper. In this reaction, readily available inorganic salt (Na2S·9H2O) serves as the sulfur source, and various functional groups of aryl nitriles were well tolerated at room temperature. In addition, the products were easily separated from the IL which could be reused at least five times without considerable loss of its activity and applied in the green, concise synthesis of ethionamide.

Synthesis of novel Schiff bases from the reaction of 3-O-methyl-4, 6-o-benzylidene-β-D-glucopyranosylamine with substituted aldehydes

The synthesis of novel sugar derived Schiff base derivatives from reaction of 3-O-methyl-4, 6-O-benzylidene-β-D-glucopyranosylamine with several substituted aldehydes is described.