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Ali Reza Kiasat - One of the best experts on this subject based on the ideXlab platform.
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an effective green procedure for the synthesis of phenacyl derivatives catalyzed by silica bound 3 2 poly ethylene glycol ethyl substituted 1 methyl 1h imidazol 3 ium bromide as a recyclable Phase Transfer Catalyst under aqueous media
Organic Chemistry Research, 2017Co-Authors: Neda Ayashi, Mehdi Fallahmehrjardi, Ali Reza KiasatAbstract:The use of a recyclable Phase Transfer Catalyst, SiO2-PEG-ImBr, is demonstrated in a simple and highly efficient synthesis of phenacyl derivatives by nucleophilic substitution reaction of phenacyl halides with different anions in water. Advantages of this system are easy work-up, moderate to good yields, and recyclable Catalyst. The Catalyst can be recycled and reused several times with no loss of its efficiency.
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nanomagnetic double charged diazoniabicyclo 2 2 2 octane dichloride silica as a novel nanomagnetic Phase Transfer Catalyst for the aqueous synthesis of benzyl acetates and thiocyanates
Catalysis Communications, 2013Co-Authors: Jamal Davarpanah, Ali Reza KiasatAbstract:Abstract Nanomagnetic double-charged diazoniabicyclo[2.2.2]octane dichloride silica hybrid (Fe3O4@SiO2/DABCO) was used as an efficient and magnetically recoverable Phase-Transfer Catalyst (PTC) for nucleophilic substitution reactions of benzyl halides for the synthesis of benzyl acetates and thiocyanates in good to excellent yields at 100 °C in water. No evidence for the formation of by-products, for example, isothiocyanate or benzyl alcohol was observed and the products were obtained in pure form without further purification. The Catalyst was easily separated with the assistance of an external magnetic field from the reaction mixture and reused for several consecutive runs without significant loss of its catalytic efficiency.
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silica bound 3 2 poly ethylene glycol ethyl substituted 1 methyl 1h imidazol 3 ium bromide a recoverable Phase Transfer Catalyst for smooth and regioselective conversion of oxiranes to β hydroxynitriles in water
Helvetica Chimica Acta, 2013Co-Authors: Ali Reza Kiasat, Neda Ayashi, Mehdi FallahmehrjardiAbstract:A series of β-hydroxynitriles were efficiently synthesized from the regioselective ring opening of oxiranes by cyanide anion in the presence of silica-bound 3-{2-[poly(ethylene glycol)]ethyl}-substituted 1-methyl-1H-imidazol-3-ium bromide (SiO2PEGImBr) as a novel recoverable Phase-Transfer Catalyst in H2O (Scheme 1 and Table 2). The workup procedure was straightforward, and the Catalyst could be reused over four times with almost no loss of catalytic activity and selectivity.
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a facile and convenient method for synthesis of alkyl thiocyanates under homogeneous Phase Transfer Catalyst conditions
Chinese Chemical Letters, 2008Co-Authors: Ali Reza Kiasat, Rashid Badri, Soheil SayyahiAbstract:Abstract A simple and environmentally friendly method is described for the efficient conversion of alkyl halide to alkyl thiocyanate using tetrabutylammonium bromide (TBAB) as a Phase Transfer Catalyst. The reactions occur in water and furnish the corresponding alkyl thiocyanate in high yields. No evidence for the formation of isothiocyanates as by-product of the reaction was observed and the products were obtained in pure form without further purification .
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poly ethylene glycol grafted onto dowex resin an efficient recyclable and mild polymer supported Phase Transfer Catalyst for the regioselective azidolysis of epoxides in water
Journal of Organic Chemistry, 2008Co-Authors: Ali Reza Kiasat, Rashid Badri, Behrouz Zargar, Soheil SayyahiAbstract:In this study, an efficient method was designed to graft poly(ethylene glycol) effectively onto commercial Dowex resin. The catalytic efficiency of the copolymer obtained as a new solid-liquid Phase Transfer Catalyst was studied. It was proved that this organoCatalyst is an efficient heterogeneous Catalyst for regioselective azidolysis of epoxide in water and gave azidohydrin in excellent yield under mild reaction conditions. The polymeric Catalyst was easily recovered by simple filtration and showed no appreciable loss of activity when recycled several times.
Ayyanar Siva - One of the best experts on this subject based on the ideXlab platform.
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Effective Darzen's condensation of 4-nonanolide with 1,6-dibromohexan-2-one using new bead-shaped insoluble multi-site (six-site) Phase Transfer Catalyst and low concentration of aqueous NaOH
Journal of Molecular Catalysis A-chemical, 2007Co-Authors: Eagambaram Murugan, Ayyanar SivaAbstract:Abstract New bead-shaped insoluble polymer-supported multi-site (six-site) Phase Transfer Catalyst (BSIMPTC) was synthesized from mesitylene as a starting material and its catalytic efficiency was studied with the kinetics of Darzen's condensation of 4-nonanolide with 1,6-dibromohexan-2-one. The presence of six active-sites in the newly synthesized BSIMPTC, viz., 2,4,6-tris[(4-(2,2′-bis(N-triethylammoniummethylene chloride) eth-1-ene) phenoxy)benzene was characterized through FT-IR, solid 1H NMR, 13C NMR, SEM and [chloride ion] analyses and found that the BSIMPTC contains ≈6 active-site centers. The Darzen's condensation reaction of 4-nonanolide was performed at lower temperature (40 °C) under pseudo-first order rate conditions by taking lower concentration of aqueous NaOH (15%, w/v, 3.75 M) and excess of 1,6-dibromohexan-2-one. The disappearance of 4-nonanolide was quantitatively monitored by a gas chromatograph for the calculation of the pseudo-first order rate constant. The presence of more number of active-sites in BSIMPTC was further confirmed from the comparative study of pseudo-first order rate constant with the rate constants of single-site polymer-supported Phase Transfer Catalyst. The comparative rate constant results reveal that the BSIMPTC is highly active-than the corresponding soluble six-active-site and almost ≈4 times higher active-than with insoluble/soluble single-site PTCs. The effect of various experimental parameters such as [substrate], [Catalyst], [NaOH], stirring speed, and temperature on the rate of the reaction have also been studied and found that each variables are influenced the rate of reaction. Based on the obtained kinetic results, a suitable mechanism is proposed.
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synthesis and characterization of novel soluble multi site Phase Transfer Catalyst its efficiency compared with single site Phase Transfer Catalyst in the alkylation of phenylacetonitrile as a model reaction
Applied Catalysis A-general, 2004Co-Authors: T. Balakrishnan, Eagambaram Murugan, Ayyanar SivaAbstract:Abstract The kinetics of C-alkylation of phenylacetonitrile with 1-bromobutane has been studied using a novel α , α ′, α ″- N -hexakis(triethylammoniummethylene chloride)-melamine as a multi-site Phase Transfer Catalyst (MPTC) using a low concentration of aqueous sodium hydroxide as a base. The reaction was carried out at 50 °C under pseudo-first-order conditions by keeping aqueous base and 1-bromobutane in excess. The formation of the product was monitored by GLC. The effects of various experimental parameters such as [substrate], [NaOH], [Catalyst] and temperature on the rate of the reaction have been studied. The results obtained and also the thermodynamic parameters are discussed. The catalytic efficiency of the multi-site Catalyst was compared with efficiencies of the commercially available single-site Catalysts.
Soheil Sayyahi - One of the best experts on this subject based on the ideXlab platform.
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a facile and convenient method for synthesis of alkyl thiocyanates under homogeneous Phase Transfer Catalyst conditions
Chinese Chemical Letters, 2008Co-Authors: Ali Reza Kiasat, Rashid Badri, Soheil SayyahiAbstract:Abstract A simple and environmentally friendly method is described for the efficient conversion of alkyl halide to alkyl thiocyanate using tetrabutylammonium bromide (TBAB) as a Phase Transfer Catalyst. The reactions occur in water and furnish the corresponding alkyl thiocyanate in high yields. No evidence for the formation of isothiocyanates as by-product of the reaction was observed and the products were obtained in pure form without further purification .
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poly ethylene glycol grafted onto dowex resin an efficient recyclable and mild polymer supported Phase Transfer Catalyst for the regioselective azidolysis of epoxides in water
Journal of Organic Chemistry, 2008Co-Authors: Ali Reza Kiasat, Rashid Badri, Behrouz Zargar, Soheil SayyahiAbstract:In this study, an efficient method was designed to graft poly(ethylene glycol) effectively onto commercial Dowex resin. The catalytic efficiency of the copolymer obtained as a new solid-liquid Phase Transfer Catalyst was studied. It was proved that this organoCatalyst is an efficient heterogeneous Catalyst for regioselective azidolysis of epoxide in water and gave azidohydrin in excellent yield under mild reaction conditions. The polymeric Catalyst was easily recovered by simple filtration and showed no appreciable loss of activity when recycled several times.
T. Balakrishnan - One of the best experts on this subject based on the ideXlab platform.
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Kinetics of dichlorocyclopropanation of vinylcyclohexane catalyzed by a new multi-site Phase Transfer Catalyst
Catalysis Communications, 2009Co-Authors: P.a. Vivekanand, T. BalakrishnanAbstract:Abstract In this work, a novel soluble multi-site Phase Transfer Catalyst viz., 1,4-bis-(ethylmethyleneammounium chloride)-2,5-dimethoxybenzene (BEMACDB) was synthesized and its catalytic efficiency was assessed by observing the kinetics of dichlorocarbene addition to vinylcyclohexane. The formation of the product was monitored by GLC. Dichlorocyclopropanation of vinylcyclohexane catalyzed by the new Phase Transfer Catalyst was carried out in two-Phase medium under pseudo-first-order conditions by keeping aqueous sodium hydroxide and chloroform in excess. This newly synthesized Phase Transfer Catalyst possesses higher activity than the commercially available single-site Phase Transfer Catalysts. The effect of various experimental parameters on the rate of the reaction has been studied. From the Arrhenius plot, the activation energy was found to be 16.07 kcal mol−1. Also thermodynamic parameters such as ΔS#, ΔG# and ΔH# were evaluated; based on the experimental results, a suitable mechanism is proposed.
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synthesis and characterization of novel soluble multi site Phase Transfer Catalyst its efficiency compared with single site Phase Transfer Catalyst in the alkylation of phenylacetonitrile as a model reaction
Applied Catalysis A-general, 2004Co-Authors: T. Balakrishnan, Eagambaram Murugan, Ayyanar SivaAbstract:Abstract The kinetics of C-alkylation of phenylacetonitrile with 1-bromobutane has been studied using a novel α , α ′, α ″- N -hexakis(triethylammoniummethylene chloride)-melamine as a multi-site Phase Transfer Catalyst (MPTC) using a low concentration of aqueous sodium hydroxide as a base. The reaction was carried out at 50 °C under pseudo-first-order conditions by keeping aqueous base and 1-bromobutane in excess. The formation of the product was monitored by GLC. The effects of various experimental parameters such as [substrate], [NaOH], [Catalyst] and temperature on the rate of the reaction have been studied. The results obtained and also the thermodynamic parameters are discussed. The catalytic efficiency of the multi-site Catalyst was compared with efficiencies of the commercially available single-site Catalysts.
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Phase-Transfer-catalyzed Darzen's condensation of chloroacetonitrile with cyclohexanone using aqueous sodium hydroxide and a new Phase Transfer Catalyst
Journal of Molecular Catalysis A-chemical, 2000Co-Authors: Joseph Paul Jayachandran, T. Balakrishnan, Maw-ling WangAbstract:Abstract The kinetics of Darzen's condensation of chloroacetonitrile with cyclohexanone has been studied under Phase Transfer catalytic conditions using aqueous sodium hydroxide as the base and 2-benzylidine- N , N , N , N ′, N ′, N ′-hexaethylpropane-1,3-diammonium dichloride as a new “multi-site” Phase Transfer Catalyst (MPTC). The reactions were carried out at room temperature (29°C) under pseudo-first order conditions by keeping aqueous sodium hydroxide and cyclohexanone in excess and was monitored by GC. The effect of various experimental parameters on the rate of the reaction has been studied, and based on the results obtained, a suitable mechanism is proposed.
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synthesis and utility of α α bis triethyl ammonium methylene chloride β phenyl ethene in hydroxide ion initiated reactions a new multi site Phase Transfer Catalyst
Synthetic Communications, 1995Co-Authors: T. Balakrishnan, Paul J JayachandranAbstract:Abstract A three step synthesis of novel ‘multi-site’ water soluble Phase Transfer Catalyst viz., α,α′-bis(triethyl ammonium methylene chloride) β-phenyl ethene and its utility in various organic biPhase reactions are described.
Maryam Zayadi - One of the best experts on this subject based on the ideXlab platform.
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polyethylene glycol immobilized on silica gel as a new solid liquid Phase Transfer Catalyst for regioselective azidolysis of epoxides in water an efficient route to 1 2 azido alcohols
Catalysis Communications, 2008Co-Authors: Ali Reza Kiasat, Maryam ZayadiAbstract:Abstract Polyethylene glycol, a polymer widely used for biomedical applications and in supported synthesis, was easily immobilized on silica gel and used as a new solid–liquid Phase-Transfer Catalyst. It is proved to be an efficient heterogeneous Catalyst for regioselective ring opening of epoxide by azide ion in water to give azidohydrine in excellent yield under mild reaction conditions. The polymeric Catalyst easily recovered by simple filtration, shows no appreciable loss of activity when recycled several times.