NOVEL BIS—(N—ALKYL—N,N—DIMETHYL AMMONIUM)POLYETHYLENEGLYCOL ETHER SALIS AS PHASE TRANSFER CATALYSTS IN THE CONDENSATION OF 1,4—DIACETYL—2,5—PIPERAZINEDIONE AND ALDEHYDES

Five novel bis—(N—alkyl—N,N—dimethyl ammoni(?)n)polyethyleneglyool ether salts prepared by our previously reported proced(?)e show high catalytic efficiency in the condensation of 1,4—diacetyl— 2,5—piperazinedione and aldehydes at both higher and lower temperature even in lower concentration.They al so show catalytic selectivity at lower temperature.

Synthesis of α-Aminoarylacetic Acids in the Presence of Phase Transfer Catalysts

Synthesis of aminoarylacetic acids with good yield in the presence of phase transfercatalyst (PTC) under sonication has been studied. Results obtained are superior to those by othersimilar methods. The data show that cyclodextrin (5 -CD) is a more efficient catalyst thanother PTC. Optimum reaction conditions and a preliminary mechanism are also discussed.

THE ASYMMETRIC SYNTHESIS OF AMINO ACIDS UNDER POLYMER-SUPPORTED PHASE TRANSFER CATALYTIC CONDITION

The optical alpha-amino acids were synthesized under room temperature by alkylation of N-(diphenyl methylene) glycine t-butyl ester under polymer-supported phase transfer conditions using polymer-supported cinchonine (or quinine) alkaloids as chiral phase transfer catalysts and dichloromethane as solvent, followed by hydrolysis of the above intermediates introduced to the final products-optical alpha-amino acids. This is a new method for the asymmetric synthesis of alpha-amino acids. The influences of catalyst, temperature, substrates, and organic solvents on the chemical yield and optical purities of products were studied.

The Reactions Between Halides and Alcohols in the Presence of Phase Transfer

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SYNTHESIS AND APPLICATIONS OF CROSS-LINKED POLY(DIALLYLDIMETHYL AMMONIUM CHLORIDE) AND ITS DERIVATIVE COPOLYMERS AS EFFICIENT PHASE TRANSFER CATALYST FOR NUCLEOPHILIC SUBSTITUTION REACTIONS

Cross-linked poly（diallyldimethylammonium chloride） and its derivative copolymers were synthesized and used as phase transfer catalyst in the nucleophilic substitution reaction especially halogen exchange reactions.In addition,the effect of hydrophilic-hydrophobic character of the polymers in the nucleophilic reactions was investigated.

Mild,convenient and efficient synthesis of novel 2,2-dichloro-1,3-diarylaziridines from Schiff bases by phase transfer CTAB catalysis under low concentration alkaline conditions

A mild and efficient method for preparation of novel 2,2-dichloro-1,3-diarylaziridines from Schiff base compounds in the presence of Ar-cetyl-N,N,N-trimethyl ammonium bromide（CTAB） as phase transfer catalyst has been described.The reaction is dramatically enhanced in the presence of quaternary ammonium salt.The corresponding products have been obtained in excellent yields,high purity and short reaction times.

Dehalogenation of Aryl Halides Catalyzed by MontK10 Immobilized PVP-Pd-Sn Catalyst in Aqueous System

A series of PVP-Pd-Sn/MontK10 catalysts were prepared by immobilization of PVP[poly(N-vinyl-2-pyrrolidone)] supported bimetallic catalyst using MontK10 as carrier. This catalyst has good catalytic activity for hydrogen transfer dehalogenation of aryl halides. The catalytic reaction was carried out in aqueous system in the presence of phase transfer catalyst and sodium formate as hydrogen source. The catalyst with loading Pd 0.19wt% and molar ratio of Pd/Dn 8:1 gives the highest activity and good stability. This catalyst is more reducible with NaBH4. It is also found that the catalyst is easily separated from the reaction system.

Syntheses of

The syntheses of α-hydroxyarylacetic acids with a good yield in the presence of different phase transfer catalysts (PTC) under sonication were studied. The results obtained are superior to those by other similar methods. The data show that β-cyclodextrin (β-CD) is more efficient than other PTC. The preliminary reaction conditions are also discussed.

Efficient Synthesis of a-Amino Acid Derivatives via Phase-transfer-catalyzed Directed Reductive Amination

An efficient phase-transfer-catalyzed directed reductive amination of α-keto esters was described using simple substituted benzyl amines as nitrogen source and K2CO3 as base at room temperature, giving a series of aliphatic a-amino acid derivatives in moderate to high yields（up to 99%）. Preliminary study on this asymmetric process showed that cinchona-derived phase transfer catalyst was elTective, aflbrding the corresponding product in 13% e.e. and 40% yield.

Chemoselective Benzylation and Allylation of 4-Nitrobenzaldehyde Promoted by Phase Transfer Catalyst and Metal in Aqueous Media

The benzylation and allylation of 4-nitrobenzaldehyde (1) could be controlled chemoselectively by using different phase transfer catalyst (FTC) and different metal catalysts. And then, benzylation and allylation of 1 with various organic halides has been realized in high yields in aqueous media.

Palladium-phosphinous acid complexes catalyzed Suzuki cross-coupling reaction of heteroaryl bromides with phenylboronic acid in water/alcoholic solvents

Highly active, air-stable and water-soluble palladium-phosphinous acid complexes have been applied to Suzuki cross-coupling reaction of heteroaryl bromides under mild conditions in water/alcoholic solvents. Suzuki cross-coupling reaction of heteroaryl bromides with phenylboronic acid occurred efficiently using palladium phosphinous acid complexes （POPd） and phase transfer catalyst （tetrabutylammonium bromide and polyethylene glycol） in water/ethanol mixture, water/propanol mixture and neat water respectively, the corresponding yields of cross-coupling heteroaryl-aryls were satisfied. The tert-butyl substituted ligand di-tert-butylphosphino in combination with POPd was found to be more active than the same family derived catalysts dipalladium complexes POPdl and POPd2, and other two kinds of Pd-catalysts Pd（PPh3）4 and Pd2（dba）3. The mechanism of Suzuki cross-coupling reaction between heteroaryl bromides and phenylboronic acid in water was proposed with respect to the key role of phase transfer catalyst on the transmetallation step. Compared with other solid phase transfer catalysts, TBAB was tested as the ideal one. The alkalinity of base and the molar proportion between POPd and TBAB were investigated in water and alcoholic solvents. Notably, in the presence of TBAB adding alcoholic solvents into water enhanced the yields of target products. However in terms of the liquid phase transfer catalyst of PEGs, mixing water into PEGs could slightly decrease the yields with respect to the water free PEGs bulk phase, which was probably due to the homogenous liquid conditions in pure PEGs and weak interactions between PEGs and heteroaryl bromide molecules in water depending on their molecular chain lengths.

Salen-Mn(III)-Complex-Catalyzed Oxidations of Secondary Alcohols

Secondary alcohols were catalytically oxidized with diacetoxyiodobenzene as oxidant in the presence of salen- Mn(III) complex to afford the corresponding ketones, in up to 99% yield, using CH 2Cl 2 or water as reaction media.