A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multi- site phase-transfer catalyst, α,α＇,α＂-N-hexakis（triethylammoniummethylene chloride）-...A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multi- site phase-transfer catalyst, α,α＇,α＂-N-hexakis（triethylammoniummethylene chloride）-melamine, is developed. A variety of ^-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times. 2009 Ali Reza Kiasat. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
The monomer-activated anionic ring-opening copolymerization (AROP) of ethylene oxide (EO) and epichlorohydrin (ECH) using tetraoctylammonium bromide as an initiator and triisobutylaluminum (i-Bu3Al) as an activator wa...The monomer-activated anionic ring-opening copolymerization (AROP) of ethylene oxide (EO) and epichlorohydrin (ECH) using tetraoctylammonium bromide as an initiator and triisobutylaluminum (i-Bu3Al) as an activator was studied. The properties of the copolymers as well as the microstructure have been analyzed in detail via an in situ NMR kinetics study. The statistical copolymers exhibited molecular weights ranging from 2350 g·mol^-1 to 38000 g·mol^-1 (measured by SEC, PEG-standards) and moderate dispersities of 1.27-1.44. The thermal property tests revealed both a glass transition and melting for all copolymers, supporting a block-like nature. Applying in situ NMR kinetic measurements, the reactivity ratios of EO and ECH were determined to be strongly disparate, i.e., rEo = 9.2 and rECH = 0.10. This shows that the simple one-pot statistical anionic copolymerization of EO and ECH via the monomer-activated AROP resulted in the formation of strongly tapered, block-like structures. Furthermore, post-polymerization functionalization of the reactive chloromethyl groups by nucleophilic displacement was investigated for the copolymers. Copolymerization of EO and ECH offers a broad platform for further functionalization and therefore the possibility to prepare a variety of multifunctional PEGs.展开更多
The use of in situ generated N-thiocyanatosuccinimide with NH4SCN offers an efficient reagent system for the conversion of epoxides into their corresponding thiocyanohydrines in good to high yields. The major advantag...The use of in situ generated N-thiocyanatosuccinimide with NH4SCN offers an efficient reagent system for the conversion of epoxides into their corresponding thiocyanohydrines in good to high yields. The major advantages of this method are as follows： use of cheap reagent, high regioselectivity, simple availability of reagent, ease of workup of the reaction.展开更多
The large irreversible capacities of graphene oxide-based anodes hinder commercial applications of GO materials although the high specific capacity of it has been universally accepted. In this paper, GO was treated un...The large irreversible capacities of graphene oxide-based anodes hinder commercial applications of GO materials although the high specific capacity of it has been universally accepted. In this paper, GO was treated under alkaline condition and the composite consisting of the modified GO and graphite was used as anode for lithium ion batteries (LIBs), resulting in an improved initial coulombic efficiency. Electrochemical tests also showed that the modified GO/graphite electrode possessed 86.0% of initial coulombic efficiency, which was 15% higher than that of pristine GO/graphite electrode. The species and the content of functional groups were investigated via XPS, FTIR characterizations in detail, which certified that the ring-opening reaction of epoxides under alkaline condition could greatly reduce the irreversible capacity of GO/graphite anode, in addition, the reversible capacity was guaranteed at the same time. This modified GO/graphite electrodes in the LIBs exhibit superior rate capability and long cycle life. The uniqueness of this electrode lied in its chemical stability, which benefits from the transition of epoxide group and unstable functional groups removal.展开更多
Aziridines and epoxides were reacted with diphenyl diselenide in the presence of a stoichiometric amount of （n-Bu）3P, respectively, giving β-amino- or β-hydroxy selenides in moderate to excellent yields under mild...Aziridines and epoxides were reacted with diphenyl diselenide in the presence of a stoichiometric amount of （n-Bu）3P, respectively, giving β-amino- or β-hydroxy selenides in moderate to excellent yields under mild conditions. In the reactions the （n-Bu）3P might act as a reductant though it was a nucleophilic catalyst in other similar ring-opening reactions.展开更多
The asymmetric ring-opening of epoxides with dithiophosphorus acids catalyzed by a （salen）Ti（Ⅳ） complex formed in situ from the reaction of Ti（OPr-i）4 and the chiral Schiff base derived from （1R,2R）-（＋）-di...The asymmetric ring-opening of epoxides with dithiophosphorus acids catalyzed by a （salen）Ti（Ⅳ） complex formed in situ from the reaction of Ti（OPr-i）4 and the chiral Schiff base derived from （1R,2R）-（＋）-diaminocyclohexane was realized. The resulting products were obtained with low to good enantioselectivity （up to 73% ee）.展开更多
The title compound was synthesized from dihydroqinghao acid via a sequential facial selective oxidative lac- tonization and epoxidation, a molybdenum-catalyzed perhydrolysis of the epoxy ring and dimethyl sulfide redu...The title compound was synthesized from dihydroqinghao acid via a sequential facial selective oxidative lac- tonization and epoxidation, a molybdenum-catalyzed perhydrolysis of the epoxy ring and dimethyl sulfide reduction of the hydroperhydroxyl functionality. Some explorations on the lactonization and ring-opening of the epoxide along with data discrepancy found with the epoxy intermediate are also presented.展开更多
Efficient synthesis of polyester polyols with tunable molecular weight and microstructures from cyclic anhydride/epoxide mixtures by taking advantage of chain transfer reaction remains a great challenge,because most o...Efficient synthesis of polyester polyols with tunable molecular weight and microstructures from cyclic anhydride/epoxide mixtures by taking advantage of chain transfer reaction remains a great challenge,because most of the catalysts exhibit poor tolerance to chain transfer agent(CTA).In this contribution,we demonstrated that potassium acetate(KOAc)and 18-crown-6(18-C-6)combination has great potential in the synthesis of diverse polyester polyols with controllable molecular weight and high-end group fidelity.Com-pared with KOAc,KOAc/18-C-6 pair could induce a much faster chain transfer between the active and dormant chains,and thus produce polyester polyols with narrow and monomodal distribution.In addition,polyester polyols could be efficiently prepared in laboratory by using commercially available cyclic anhydride without further purification(containing about 2%diacid residual as CTA)with an extremely low catalyst loading([catalyst pair]:[anhydride]:[epoxide]=1:50000:250000,[catalyst pair]=0.0004 mol%).KOAc/18-C-6 could also promote the self-switchable copolymerization of cyclic anhydride/epoxide/cyclic ester mixtures.Ring-opening copolymerization of cyclic ester was initiated automatically after the full conversion of cyclic anhydride,finally producing polyester polyols with ABA-type block structure.展开更多
Intramolecular cyclization of A catalyzed by IDA in benzene or THF yields two γ-lactams through C-alkylation and one δ-and one 7-membered lactam by O-alkylation.
When the title compound was treated in protic solvent with alkali catalyses,γ-lacatam was almost the sole product.The ratio of ketone 1 to ketone 2 depended upon the reaction condition.
A new 2D coordination polymer, [Cd（tpim）（1,5-nds）]n （1）, was constructed from 1,5-naphthalenedi- sulfonate （1,5-nds）. 2.4,5-tri（4-pyridyl）-imidazole （tpim） and Cd（CH3COO）2.2H2O, which can be subsequently...A new 2D coordination polymer, [Cd（tpim）（1,5-nds）]n （1）, was constructed from 1,5-naphthalenedi- sulfonate （1,5-nds）. 2.4,5-tri（4-pyridyl）-imidazole （tpim） and Cd（CH3COO）2.2H2O, which can be subsequently used to promote the epoxide ring-opening reaction of epoxides and amines with remarkable catalytic activity. In addition, the thermal and luminescent properties of I in the solid state were also investigated.展开更多
采用简单、易重现的两步后合成法成功制备了Ce-Beta分子筛.制备过程中,H-Beta分子筛首先经过脱铝处理得到Si-Beta分子筛,然后再以异丙醇铈为前驱体,通过干法浸渍的途径向Si-Beta分子筛引入Ce(IV).利用XRD,FT-IR,UV-Vis和1H MAS NMR等对...采用简单、易重现的两步后合成法成功制备了Ce-Beta分子筛.制备过程中,H-Beta分子筛首先经过脱铝处理得到Si-Beta分子筛,然后再以异丙醇铈为前驱体,通过干法浸渍的途径向Si-Beta分子筛引入Ce(IV).利用XRD,FT-IR,UV-Vis和1H MAS NMR等对其结构进行了表征,结果表明,Ce(IV)物种以四配位的形式成功引入Beta分子筛的骨架,Ce原子进入分子筛骨架的机理通过DRIFT光谱得以证实.通过环氧化合物水合制备1,2-二醇反应对所制的Ce-Beta催化剂进行了催化性能评价.展开更多
A new polymeric reagent, cross-linked poly（4-vinylpyridine） supported azide ion, [P4-VP]N3, was introduced as polymeric reagents for efficient and regioselective conversion of epoxides to azidohydrins in the presenc...A new polymeric reagent, cross-linked poly（4-vinylpyridine） supported azide ion, [P4-VP]N3, was introduced as polymeric reagents for efficient and regioselective conversion of epoxides to azidohydrins in the presence of cross-linked poly（4-vinylpyridine） supported sulfuric acid, [P4-VP]H2SO4, as a solid proton source and as catalyst under solvent-free conditions. The advantages of this polymeric reagent over some of those reported in the literature are easy work-up procedure and regeneration of the reagent.展开更多
Allylalumination of alkynes （i.e. forming Negishi＇s （Z）-alkenyl dialkylalane） followed by alkenylation of epoxides provides 1,4-disubstituted （Z）-3,6-alkadienols. The alkenylation can be facilitated by the pres...Allylalumination of alkynes （i.e. forming Negishi＇s （Z）-alkenyl dialkylalane） followed by alkenylation of epoxides provides 1,4-disubstituted （Z）-3,6-alkadienols. The alkenylation can be facilitated by the presence of a neighbouring coordinating group in the epoxides. This ＂one-pot＂ approach has been successfully applied in the large-scale production of C 10--C 15 fragment of 9,10-didehydroepothilone D （a synthetic epothilone analog as an anti-cancer agent in phase 2 clinical trials）.展开更多
The nucleophilic ring opening of epoxy fatty esters was carried out using the amino-1,2,4-triazole to yield substituted derivatives of β-amino alcohol. The synthesis of the substituted beta amino alcohols has been ac...The nucleophilic ring opening of epoxy fatty esters was carried out using the amino-1,2,4-triazole to yield substituted derivatives of β-amino alcohol. The synthesis of the substituted beta amino alcohols has been achieved by refluxing equimolar quantities of long chain epoxy esters (epoxy fatty esters) and 4-amino-1,2,4-triazole in dichloromethane to yield following compounds, methyl 10-(4'-amino-1',2',4'-triazole)-11-hydroxy undecanoate (V), methyl 9-(4'-amino-1', 2',4'-triazole)-10-hydroxy octadecanoate (VI), methyl 9-(4'-amino-1',2',4'-triazole)-10,12-dihydroxy octadecanoate (VII), methyl 12-(4'-amino-1',2',4'-triazole)-9,13-dihydroxy octadecanoate (VIII). Epoxides of esters of fatty acids were obtained by reaction of esters of fatty acids with mchloroperbenzoic acid. All the newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and mass spectrometry.展开更多
基金the partial support of this work by Shahid Chamran Research Council
文摘A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multi- site phase-transfer catalyst, α,α＇,α＂-N-hexakis（triethylammoniummethylene chloride）-melamine, is developed. A variety of ^-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times. 2009 Ali Reza Kiasat. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘The monomer-activated anionic ring-opening copolymerization (AROP) of ethylene oxide (EO) and epichlorohydrin (ECH) using tetraoctylammonium bromide as an initiator and triisobutylaluminum (i-Bu3Al) as an activator was studied. The properties of the copolymers as well as the microstructure have been analyzed in detail via an in situ NMR kinetics study. The statistical copolymers exhibited molecular weights ranging from 2350 g·mol^-1 to 38000 g·mol^-1 (measured by SEC, PEG-standards) and moderate dispersities of 1.27-1.44. The thermal property tests revealed both a glass transition and melting for all copolymers, supporting a block-like nature. Applying in situ NMR kinetic measurements, the reactivity ratios of EO and ECH were determined to be strongly disparate, i.e., rEo = 9.2 and rECH = 0.10. This shows that the simple one-pot statistical anionic copolymerization of EO and ECH via the monomer-activated AROP resulted in the formation of strongly tapered, block-like structures. Furthermore, post-polymerization functionalization of the reactive chloromethyl groups by nucleophilic displacement was investigated for the copolymers. Copolymerization of EO and ECH offers a broad platform for further functionalization and therefore the possibility to prepare a variety of multifunctional PEGs.
基金Shahid Chamran University of Ahvaz for financial support of this investigation
文摘The use of in situ generated N-thiocyanatosuccinimide with NH4SCN offers an efficient reagent system for the conversion of epoxides into their corresponding thiocyanohydrines in good to high yields. The major advantages of this method are as follows： use of cheap reagent, high regioselectivity, simple availability of reagent, ease of workup of the reaction.
基金the National Natural Science Foundation of China (grant no. 51474196)The project of Sciece and Technology department in Sichuan Province (grant no. 2017GZ0114)
文摘The large irreversible capacities of graphene oxide-based anodes hinder commercial applications of GO materials although the high specific capacity of it has been universally accepted. In this paper, GO was treated under alkaline condition and the composite consisting of the modified GO and graphite was used as anode for lithium ion batteries (LIBs), resulting in an improved initial coulombic efficiency. Electrochemical tests also showed that the modified GO/graphite electrode possessed 86.0% of initial coulombic efficiency, which was 15% higher than that of pristine GO/graphite electrode. The species and the content of functional groups were investigated via XPS, FTIR characterizations in detail, which certified that the ring-opening reaction of epoxides under alkaline condition could greatly reduce the irreversible capacity of GO/graphite anode, in addition, the reversible capacity was guaranteed at the same time. This modified GO/graphite electrodes in the LIBs exhibit superior rate capability and long cycle life. The uniqueness of this electrode lied in its chemical stability, which benefits from the transition of epoxide group and unstable functional groups removal.
文摘Aziridines and epoxides were reacted with diphenyl diselenide in the presence of a stoichiometric amount of （n-Bu）3P, respectively, giving β-amino- or β-hydroxy selenides in moderate to excellent yields under mild conditions. In the reactions the （n-Bu）3P might act as a reductant though it was a nucleophilic catalyst in other similar ring-opening reactions.
基金the National Natural Science Foundation of China(No.20472033)the Ph.D Programs of Ministry of Education of China for generous financial support for our programs.
文摘The asymmetric ring-opening of epoxides with dithiophosphorus acids catalyzed by a （salen）Ti（Ⅳ） complex formed in situ from the reaction of Ti（OPr-i）4 and the chiral Schiff base derived from （1R,2R）-（＋）-diaminocyclohexane was realized. The resulting products were obtained with low to good enantioselectivity （up to 73% ee）.
基金Acknowledgement This work was supported by the National Basic Research Program of China （the 973 Program, 2010CB833200）, and the National Natural Science Foundation of China （Nos. 21172247, 21032002, 20921091, 20621062）.
文摘The title compound was synthesized from dihydroqinghao acid via a sequential facial selective oxidative lac- tonization and epoxidation, a molybdenum-catalyzed perhydrolysis of the epoxy ring and dimethyl sulfide reduction of the hydroperhydroxyl functionality. Some explorations on the lactonization and ring-opening of the epoxide along with data discrepancy found with the epoxy intermediate are also presented.
基金financial support from the National Natural Science Foundation of China(Nos.52222302 and 51973156).
文摘Efficient synthesis of polyester polyols with tunable molecular weight and microstructures from cyclic anhydride/epoxide mixtures by taking advantage of chain transfer reaction remains a great challenge,because most of the catalysts exhibit poor tolerance to chain transfer agent(CTA).In this contribution,we demonstrated that potassium acetate(KOAc)and 18-crown-6(18-C-6)combination has great potential in the synthesis of diverse polyester polyols with controllable molecular weight and high-end group fidelity.Com-pared with KOAc,KOAc/18-C-6 pair could induce a much faster chain transfer between the active and dormant chains,and thus produce polyester polyols with narrow and monomodal distribution.In addition,polyester polyols could be efficiently prepared in laboratory by using commercially available cyclic anhydride without further purification(containing about 2%diacid residual as CTA)with an extremely low catalyst loading([catalyst pair]:[anhydride]:[epoxide]=1:50000:250000,[catalyst pair]=0.0004 mol%).KOAc/18-C-6 could also promote the self-switchable copolymerization of cyclic anhydride/epoxide/cyclic ester mixtures.Ring-opening copolymerization of cyclic ester was initiated automatically after the full conversion of cyclic anhydride,finally producing polyester polyols with ABA-type block structure.
文摘Intramolecular cyclization of A catalyzed by IDA in benzene or THF yields two γ-lactams through C-alkylation and one δ-and one 7-membered lactam by O-alkylation.
文摘When the title compound was treated in protic solvent with alkali catalyses,γ-lacatam was almost the sole product.The ratio of ketone 1 to ketone 2 depended upon the reaction condition.
基金financial support from the National Natural Science Foundation of China(No.21272109)the Natural Science Foundation of Henan Province (No.112300410138)+1 种基金the Foundation of the Education Department of Henan Province(No.2011B150021)Luoyang Science and Technology Fund
文摘A new 2D coordination polymer, [Cd（tpim）（1,5-nds）]n （1）, was constructed from 1,5-naphthalenedi- sulfonate （1,5-nds）. 2.4,5-tri（4-pyridyl）-imidazole （tpim） and Cd（CH3COO）2.2H2O, which can be subsequently used to promote the epoxide ring-opening reaction of epoxides and amines with remarkable catalytic activity. In addition, the thermal and luminescent properties of I in the solid state were also investigated.
基金supported by the National Natural Science Foundation of China(21373119)the Ministry of Education of China(IRT13022,IRT13R30)+1 种基金111 Project(B12015)Deutsche Forschungsgemeinschaft~~
文摘采用简单、易重现的两步后合成法成功制备了Ce-Beta分子筛.制备过程中,H-Beta分子筛首先经过脱铝处理得到Si-Beta分子筛,然后再以异丙醇铈为前驱体,通过干法浸渍的途径向Si-Beta分子筛引入Ce(IV).利用XRD,FT-IR,UV-Vis和1H MAS NMR等对其结构进行了表征,结果表明,Ce(IV)物种以四配位的形式成功引入Beta分子筛的骨架,Ce原子进入分子筛骨架的机理通过DRIFT光谱得以证实.通过环氧化合物水合制备1,2-二醇反应对所制的Ce-Beta催化剂进行了催化性能评价.
文摘A new polymeric reagent, cross-linked poly（4-vinylpyridine） supported azide ion, [P4-VP]N3, was introduced as polymeric reagents for efficient and regioselective conversion of epoxides to azidohydrins in the presence of cross-linked poly（4-vinylpyridine） supported sulfuric acid, [P4-VP]H2SO4, as a solid proton source and as catalyst under solvent-free conditions. The advantages of this polymeric reagent over some of those reported in the literature are easy work-up procedure and regeneration of the reagent.
基金the National Natural Science Foundation of China (NSFC)，Fok Ying Tong Education Foundation
文摘Allylalumination of alkynes （i.e. forming Negishi＇s （Z）-alkenyl dialkylalane） followed by alkenylation of epoxides provides 1,4-disubstituted （Z）-3,6-alkadienols. The alkenylation can be facilitated by the presence of a neighbouring coordinating group in the epoxides. This ＂one-pot＂ approach has been successfully applied in the large-scale production of C 10--C 15 fragment of 9,10-didehydroepothilone D （a synthetic epothilone analog as an anti-cancer agent in phase 2 clinical trials）.
文摘The nucleophilic ring opening of epoxy fatty esters was carried out using the amino-1,2,4-triazole to yield substituted derivatives of β-amino alcohol. The synthesis of the substituted beta amino alcohols has been achieved by refluxing equimolar quantities of long chain epoxy esters (epoxy fatty esters) and 4-amino-1,2,4-triazole in dichloromethane to yield following compounds, methyl 10-(4'-amino-1',2',4'-triazole)-11-hydroxy undecanoate (V), methyl 9-(4'-amino-1', 2',4'-triazole)-10-hydroxy octadecanoate (VI), methyl 9-(4'-amino-1',2',4'-triazole)-10,12-dihydroxy octadecanoate (VII), methyl 12-(4'-amino-1',2',4'-triazole)-9,13-dihydroxy octadecanoate (VIII). Epoxides of esters of fatty acids were obtained by reaction of esters of fatty acids with mchloroperbenzoic acid. All the newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and mass spectrometry.
