Pu Mao

nBu4NI-catalyzed direct synthesis of α-ketoamides from aryl methyl ketones with dialkylformamides in water using TBHP as oxidant.

A novel and easy practical direct synthesis of α-ketoamides has been developed without metals in water. This procedure was catalyzed by nBu(4)NI using TBHP as oxidant from simple substrates, aryl methyl ketones and dialkylformamides.

Cu/Ag-catalyzed double decarboxylative cross-coupling reaction between cinnamic acids and aliphatic acids in aqueous solution

A novel double decarboxylative cross-coupling catalyzed by copper and silver has been developed. This method provides a practical approach for the flexible synthesis of alkenes and alkynes from the readily affordable substrates.

Ultrasound-promoted enzymatic synthesis of troxerutin esters in nonaqueous solvents

Comparative studies of enzymatic acylation of troxerutin by the alkaline protease from Bacillus subtilis under ultrasound and shaking were carried out in nonaqueous media. Using divinyl dicarboxylates (CH(2)CH-OOC-(CH(2))(n)-COO-CHCH(2), n=2, 3, 4, 7, 8, 11) featuring different chain length as acyl donors, troxerutin was regioselectively acylated at B ethoxyl group, whether under ultrasound or shaking. Ultrasonic treatment increased the reaction rate and led to high conversion. Several factors, such as pre-irradiation on the enzyme, the power and frequency of the ultrasound, operation manner, as well as the length of the acyl donors were investigated. Using enzyme pre-irradiated for 8 h, the conversion of troxerutin was increased to 87.3% compared with 56.3% obtained from the untreated enzyme. Experimental results also showed that continual ultrasound caused greater rate acceleration than interval ultrasound. Powers of 100, 150 and 200 W, frequencies of 40, 80 and 100 kHz all showed significant improvement on the transesterification, with the greatest effect observed at 150 W, 80 kHz. The acceleration effect increased as the chain length of the acyl donors decreased from C(13) to C(4).

Iron-catalyzed regioselective direct coupling of aromatic aldehydes with coumarins leading to 3-aroyl coumarins

An efficient protocol for iron-catalyzed cross-coupling of coumarins with aromatic aldehydes has been developed. The various 3-aroyl coumarins were selectively afforded in moderate yields. Some notable features of this protocol are high efficiency, wide functional group tolerance, and commercially available and cheap aromatic aldehydes and coumarins as starting materials. Furthermore, these reaction conditions were also applicable to N-methyl quinolinones, affording the corresponding 3-aroyl quinolinone derivatives in good yields.

NCN pincer palladium complexes based on 1,3-dipicolyl-3,4,5,6-tetrahydropyrimidin-2-ylidenes: synthesis, characterization and catalytic activities

The synthesis of novel pincer palladium complexes containing ring expanded six-membered N-heterocyclic carbenes (NHCs) via direct metallation of the precursors tetrahydropyrimidin-1-ium hexafluorophosphates in the presence of NaN(SiMe3)2 is presented. The structure has been characterized unambiguously by X-ray single crystal analysis. Catalytic activity investigation showed that the complexes catalyzed the Heck reaction of aryl bromides with acrylate/styrene efficiently when using Et3N as base and DMA as solvent.

Chelating palladium complexes containing pyridine/pyrimidine hydroxyalkyl di-functionalized N-heterocyclic carbenes: synthesis, structure, and catalytic activity towards C–H activation

The synthesis of novel chelating palladium complexes containing pyridine/pyrimidine hydroxyalkyl di-functionalized N-heterocyclic carbenes (NHCs) via direct metallation of the precursor imidazolium salts is presented. The structure has been characterized unambiguously by X-ray single crystal analysis. Catalytic activity investigation showed that the complexes catalyse the direct C–H bond arylation of (benzo)oxazoles efficiently when using tBuOLi as base and DMF as solvent.

Synthesis of Novel Chiral Thioether Ligands Containing Imidazole Rings Based on Natural Amino Acids

Using commercially available natural amino acids (L-Val, L-Leu, L-Phe) as chiral precursors, a series of N-substituted imidazole derivatives containing chiral groups was synthesized from the condensation reaction of amino acids, formaldehyde, glyoxal, and ammonia. Through esterification, reduction, chlorination, and subsequent substitution by thiols, chiral thioethers containing imidazole rings were synthesized, and the synthetic conditions were optimized. All the intermediates and the final products were characterized by NMR, ESI MS, HR MS, and IR.

AgNO3-catalyzed direct C–H arylation of quinolines by oxidative decarboxylation of aromatic carboxylic acids

An efficient silver-catalyzed intermolecular decarboxylative arylation of quinolines has been developed using cheap aromatic carboxylic acids as arylating reagents under microwave irradiation. The reaction demonstrates a broad substrate scope and excellent functional group tolerance. This method provided an effective and easy way to synthesize arylated quinoline derivatives. The radical trapping experiments showed that this process involved the radical mechanism.

Inclusion complexes of phosphorylated daidzein derivatives with β-cyclodextrin: Preparation and inclusion behavior study.

In the present work the feasibility of β-cyclodextrin in complexation was explored, as a tool for improving the solubility and biological ability of daidzein derivatives. A series of phosphorylated daidzein derivatives featuring different chain lengths were synthesized through a modified Atherton-Todd reaction and their inclusion complexes with βCD were prepared by coprecipitation method. The inclusion complexation behavior was studied by fluorescence, UV, FT-IR, MS and (1)H NMR. The results showed that only phosphorylated daidzein derivative carrying small substituent group ((C(2)H(5)O)(2)PO) entered the cavity of βCD and formed 1:1 inclusion complex. The formation constant was 175(mol/L)(-1).

Silver-catalyzed synthesis of 2-arylvinylphosphonates by cross-coupling of β-nitrostyrenes with H-phosphites

An efficient protocol for stereoselective synthesis of 2-arylvinylphosphonates has been developed via AgNO3-catalyzed cross-coupling of β-nitrostyrenes with dialkyl H-phosphites under mild conditions. By losing the nitro group of β-nitrostyrenes, the reaction proceeds smoothly and could provide the desired products with moderate to good yield.