Phase-transfer catalytic activity of soluble polystyrenes containing crown ether moieties and hydroxyl groups adjacent to the macrorings

Soluble polystyrenes with crown ether structures and hydroxyl groups adjacent to the macrorings were prepared by the reaction of epoxide-containing polystyrenes with monoaza-15-crown-5 or monoaza-18-crown-6. Rate of formation of the polymer-bound alkali cation-crown alkoxide ion pair from the soluble polystyrenes and aqueous NaOH or KOH depended on the loading of crown ether and hydroxyl units and on the size of the macroring. The elimination of HCl from less reactive 2-chloroethylbenzene with aqueous NaOH or KOH in the presence of the soluble polystyrene catalysts under two-phase conditions was limited mainly by the intrinsic reaction rate. The elimination of HBr from more reactive 2-bromoethylbenzene in the presence of the less (11%) ring-substituted polymer catalyst with 18-crown unit was limited by the alkoxide formation rate. © 1994 John Wiley & Sons, Inc.     

相转移催化法合成糖苷化合物

糖苷化合物广泛存在于生物体内，中草药和天然药物中的许多抗病活性化合物也是糖苷化合物。根据糖苷化合物分子结构中的配糖体与糖环碳原子相连的原子类型可把糖苷化合物分为氧苷、氮苷、硫苷和碳苷等。未作特殊说明的糖苷化合物均指氧苷，且配糖体为羧酸的糖苷化合物亦称为糖酯。有关糖苷（酯）化合物和其合成方法的研究很多，其中应用相转移催化法较为常见。我们曾用相转移催化法合成过许多糖酯化合物并对其生理活性进行研究报道。本文在原合成糖酯的基础上通过相转移催化法，选用不同于文献报道催化剂及溶剂体系，     

Synthesis of N-substituted imides via solid-liquid phase-transfer catalytic reaction

Summary N-substituted imides (RSIs) were synthesized from the reactions of alkylbromides (RX) and potassium salts of imides (KSIs) under solid-liquid phase-transfer catalytic conditions (SL-PTC). No water is required in the reaction system. In this work, serious hydration of KSIs is avoided using SL-PTC to synthesize RSIs. The reaction catalyzed by quaternary ammonium salts is greatly enhanced in the solid-liquid solution     

Synthesis of chiral crown ethers derived from d-galactose and their application in enantioselective reactions

A few new α- and β-d-galactopyranoside-based chiral lariat ethers of monoaza-15-crown-5 type were synthesized. These macrocycles proved to be efficient catalysts in a few asymmetric reactions under mild phase transfer conditions. The catalytic effect of the lariat ethers with methoxy, ethoxy, isopropoxy and aryloxy substituents on the C-1 of the sugar unit in both α and β positions was compared. In the presence of β-d-galactopyranoside-based crown ethers, the asymmetric Darzens condensation of α-chloroacetophenone and benzaldehyde, the epoxidation of trans-chalcone, the cyclopropanation (MIRC reaction) of benzylidenemalononitrile and 2-benzylidene-1,3-indandione with diethyl bromomalonate were performed with enantioselectivities of 61%, 64%, 86% and 96%, respectively. In all reactions, the β-anomers were more efficient in terms of enantioselectivity than the α forms.     

Synthesis of novel crown ethers. Part 1. Coumestan and coumestan analog derivatives of crown ethers

The presented ethylenedioxy compounds5a,5d,6a and6c are examples of novel cyclic ethers, while macrocyclic polyethers represent new crown ether analogues. New coumestan-crowns5a-f, derivatives of 6,7-dihydroxy-3,4-dihydro-2H-dibenzofuran-1-one and 6,7-dihydroxy-3,3-dimethyl-3,4-dihydro-2H-dibenzofuran-1-one6a-e were synthesized from the correspondingo-dihydroxy compounds3a-b,4a-b and ditosylates or dichlorides of di- or triethylene glycol in the presence of K₂CO₃, in DMF/H₂O (15/1) solutions at 65–75 °C for 35 hours. The structure of the macrocyclic ethers obtained were confirmed by¹H-NMR,¹³C-NMR, IR spectra and elemental analyses.Presented at the Sixth International Seminar on Inclusion Compounds, Istanbul, Turkey, 27–31 August, 1995.     

Synthesis of novel C2-symmetric chiral crown ethers and their application to enantioselective trifluoromethylation of aldehydes and ketones

Synthesis of novel C2-symmetric chiral crown ethers and their application to enantioselective trifluoromethylation of aldehydes and ketones are discussed. The use of a series of C2-symmetric chiral crown ethers 2 or 3 derived from commercially available (R)-1,1′-bi-2-naphthol for the enantioselective trifluoromethylation of 2-naphthyl aldehyde 1a with (trifluoromethyl)trimethylsilane in the presence of a base was attempted. Iodo-substituted crown ether 2b was found to be the most effective in the model reaction. Moderate enantioselectivities were observed for the trifluoromethylation of both aryl or alkyl aldehydes and alkyl aryl ketones in 21-44% ees. Although the ees are still improvable, this is the first example of a chiral crown ether-catalyzed enantioselective trifluoromethylation reaction.     

Retention behaviour of crown ethers and actinomycin D in reversed-phase HPLC

Summary Retention of crown ethers in reverse-phase HPLC has been determined by their bonding ability with cations present in the eluent. The dependence of retention of crown ethers on cation concentration exhibits an inflection and makes it possible to calculate stability constant for the crown ether-cation complex. It is shown that in 75% MeOH retention of antitumor antibiotic, actinomycin D, depends on [Na⁺] and not on [K⁺] at concentrations of K⁺ from 5×10^–7 to 10^–1 mol l^–1. Hence, actinomycin D may be classified as an ionophore-antibiotic.     

The complexation of alkali metal ions by crown ethers,aza crown ethers,and cryptands in propylene carbonate

The reactions between alkali metal ions and crown ethers, aza crown ethers, and cryptands in propylene carbonate were studied by potentiometric and calorimetric titrations. The most stable complexes formed by macrocyclic and macrobicyclic ligands are when the ligand and cation dimensions are comparable. On comparing the complex stabilities of crown ethers and aza crown ethers of the same size, crown ethers were, on the whole, found to form the most stable complexes, with the exception of the lithium cation. Enthalpic factors are responsible. Substitution of the amino group protons of the aza crown ethers by benzyl groups leads to a high increase in values of the reaction enthalpy. This effect is partly compensated by entropic contributions. The bulky benzyl groups reduce the ligand solvent interactions and induce a ligand conformation with the lone pair of electrons from the nitrogen donor atoms which are more or less directed inside the cavity. The thermodynamic data for the transfer from methanol to propylene carbonate indicate that the ligands containing nitrogen show specific interactions with methanol.This paper is dedicated to Professor H. Strehlow on the occasion of his 70th birthday.     

Synthesis and complex-forming properties of crown ethers incorporating glucuronic acid moieties

Crown ethers1 and4 of the 18-crown-6 type containing two glucose units have been oxidised by KMnO₄ into mono- and dicarboxylic acid derivatives (5 and11), and derivatives with different lipophilicities of the above crown ethers, namely the acetyl, benzyl and butyl derivatives (8–10, 13, 14) and methyl esters (6 and12) have been synthesizedThe association constants (K _a) with Li, Na, K and NH₄ cations measured in CHCl₃ indicate that complexing ability increases on introduction of carboxy groups, and selectivity changes in favour of the Na cation. These compounds were able to transport alkyl-ammonium salts through a CHCl₃ liquid membrane, displaying, however, no chiral recognition ability.     

Transfer activity coefficients of crown ethers and their complexes with univalent metal ions between pairs of polar organic solvents

From a comparison of transfer activity coefficients, [(LM⁺)]_PC,2 between propylene carbonate and solvent S₂ of alkali or silver ions complexed with dibenzo-substituted crown ethers (L=DB-18-cr-6, DB-21-cr-7, DB-24-cr-8, DB-30-cr-10) it can be concluded that in the complex LM⁺ both L and M⁺ are solvated, particularly in solvents of high donicity, e.g., N,N-dimethylformamide. From the abnormally low ionic mobility of DB-30-cr-10K⁺ in acetonitrile and the high value of the association constant of the ion pair DB-30-cr-10KBr it is concluded that the outer solvent shell is stripped upon formation of the ligand separated ion pair. A linear relation is found between [log (LM⁺)]_PC,2 and [log(M⁺)]_PC,2 only when L is 18-cr-6, B-18-cr-6, or DB-18-cr-6. Deviation from the linearity of complexes of the larger dibenzo crown ethers is attributed to the flexibility of L. It is shown that solution of 18-cr-6, DB-18-cr-6 and DB-30-cr-10 is enthalpy assisted to a greater extent in acetonitrile than in methanol, while the entropy of solution is more favorable in the latter.     

Preparation and X-ray structures of complexes of 18-membered crown ethers with polyfunctional guests: Urea and (O-alkyliso)uronium salts

The preparation and X-ray structure determinations of six complexes of urea and (O-n-butyliso)uronium salts with crown ethers are presented. Urea forms isostructural 5:1 adducts with 18-crown-6 (1) and aza-18-crown-6 (2), in which two urea molecules are each hydrogen bonded to two neighbouring hetero atoms of the macroring. The remaining urea molecules form two-dimensional layers alternating with crown ether layers. In both complexes the macroring has theg ⁺ g ⁺ a ag ^– a ag ^– a g ^– g ^– a ag ⁺ a ag ⁺ a conformation withC _i symmetry. In the solid 1:1 complex of O-n-butylisouronium picrate with 18-crown-6 (3) two types of conformations of the macroring were observed: theg ⁺ g ⁺ a ag ^– a ag ⁺ a ag ^– g ^– ag ^– a ag ⁺ a conformation with approximateC _m symmetry and to a lesser extent theg ⁺ g ⁺ a ag ^– a ag ⁺ a g ⁺ g ⁺ a ag ^– a ag ⁺ a conformation with approximateC ₂ symmetry. Both conformations allow the guest to form three hydrogen bonds to the macrocyclic host. Three complexes of 18-crown-6 and uronium salts have been prepared and characterized by X-ray crystallography. The 1:1 complexes with uronium nitrate (4) and uronium picrate (5) both exhibit the sameC ₂ conformation and the same hydrogen bonding scheme as in the least occupied form of the previous complex. A 1:2 complex with uroniump-toluenesulphonate (6) has a different hydrogen bonding scheme (two hydrogen bonds per cation to neighbouring oxygen atoms of the macroring) and a different conformation of the host molecule (theag ⁺ a ag ^– a ag ⁺ a ag ^– a ag ⁺ a ag ^– a conformation with almostD _3d symmetry). An attempt to prepare a solid uronium nitrate complex with diaza-18-crown-6 in the same way as the 18-crown-6·uronium nitrate (1:1) complex did not yield the expected result. Instead X-ray analysis revealed that the uronium ion is dissociated, resulting in the nitrate salt of the diprotonated diaza crown ether (7). Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82058 (26 pages).     

Complex formation of hydronium ion with several crown ethers in 1,2-dichloroethane,acetonitrile, and nitrobenzene solutions

A conductance study concerning the interaction between hydronium ion and several crown ethers in acetonitrile, nitrobenzene and 1,2-dichloroethane solutions has been carried out at 25°C. The stability constants of the resulting 1:1 complexes in acetonitrile and nitrobenzene solutions were determined from the molar conductance-mole ratio data and found to vary in the order 18C6>DB30C10>DC18C6>DB18C6>DB21C7>DB24C8>B15C5. In 1,2-dichloroethane solution, the complexation process results in the dissociation of ion pairs. There is an inverse relationship between the stabilities of the complexes and the Gutmann donicity of the solvents. In nitrobenzene solution, some evidence for the formation of a 2:1 sandwich adduct between the smaller crowns (i.e., B15C5 and 18-crowns) are observed from the molar conductance-mole ratio data which is supported by the¹H NMR data.     

Synthesis of C2-symmetric chiral crown ethers by lipase-catalyzed reactions

Kinetic resolution of a racemic mixture of C₂-symmetric 18-crown-6 diols (rac-1a) and 15-crown-5 diol (rac-1c) was achieved by lipase-catalyzed acetylation. The enantiomeric excess of the chiral crown diols (95% ee and 82% ee) was determined by ¹H NMR spectroscopy, using (R)-(+)-1-(1-naphthyl)ethylammonium hydrochloride as a shift reagent. The C₂-symmetric chiral 15-crown-5 diol (>95% ee) was also obtained by kinetic resolution of the racemic diacetate (rac-2c) using lipase-catalyzed solvolysis.     

氯代苯二酚双苯醚的合成与抑菌活性研究

为了寻求优良的苯醚类新化合物抑菌剂,本文设计合成了邻(对)苯二酚二-(2-氯-4-羟基苯基)醚,其结构均经1HNMR、IR、MS和元素分析证实,并且测试了化合物对大肠杆菌,金黄色葡萄球菌,白色念珠菌,白色葡萄球菌,变形杆菌,卡他双球菌,青枯假单胞菌的抑菌活性,初步研究结果表明:羟基的位置对活性存在较大影响,羟基的个数对试剂的抑菌活性没有明显的影响。     

手性奎宁-卟啉锰催化剂的合成及其催化性能

为了寻找催化活性、相转移活性和手性诱导为一体的卟啉配体[1-4],我们把卟啉和手性相转移源连结起来,用奎宁-卟啉化合物作配体[5],考察其锰 配合物为催化剂对烯烃环氧化反应的催化性能。奎宁-卟啉锰 配合物结构式如下:1　实验部分1.1　试剂和仪器苯乙烯和α-甲基苯乙烯在氮气保护下减压蒸馏处理。氧源ＮａＯＣｌ的浓度由碘量法测定。其余试剂均为化学纯,色谱标样环氧苯乙烯和α-甲基环氧苯乙烯按文献[6]方法合成。奎宁-卟啉配体按文献[5]合成。260-50型红外光谱仪,ＫＢｒ压片;ＵＶ-3000型紫外可见光谱仪,溶剂ＤＭＦ;ＭＴ-3型ＣＨＮ元素…     

Influence of ligand structure and solvent effects on complexation of neutral guests by several crown ethers

The formation of complexes between crown ethers and acetonitrile, chloroform, and nitromethane were investigated in carbon tetrachloride at 25°C. A significant influence of the ring size on the selectivity of the host is evident. The host 18-crown-6 forms complexes for which the reaction enthalpy and entropy are quite high. Host molecules with benzene side groups form complexes of lower reaction enthalpy and entropy and therefore the complexes formed are less stable than that of the analogous crown ethers without aromatic groups. Solvent effects on the stability constant K, the reaction enthalpy H, and the reaction entropy S were studied for the complexation of malonitrile by 18-crown-6. The reaction enthalpy and entropy values change in accordance with the dielectric constant of the solvent used, but no overall effect on complex stability with change in solvent dielectric constant was observed.     

Synthesis and structure of 13- and 26-membered crown ethers,derivatives of resorcinol

13- and 26-Membered crown ethers have been synthesized based on resorcinol and 1,8-dichloro-3,6-dioxaoctane. The products with substituents in the benzene ring have been prepared by alkylation of 13-membered crown ether. Complexing properties of the macrocycles have been studied with the use of ion-selective membrane electrodes. The structures of 13- and 26-membered crown ethers have been established by X-ray structural analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2458–2464, December, 1995.The work was supported by Technical University of Gdansk (Project DS No. 946197/003).     

新的偶氮酚型和酚兰型生色开链冠醚的合成和配位性质

用酚型开链冠醚1a和1b为原料, 在碱溶液中合成了两类生色开链冠醚: 一类是与对硝基苯重氮氟硼酸盐反应生成的偶氮酚型(2b和2b); 另一类是与N, N-二甲基对苯二胺和K~3[Fe(CN)~6]反应生成的酚兰型(3a和3b)。用紫外-可见光谱法研究了这些生色开链冠醚与碱金属和碱土金属离子的配位性质。发现在THF-H~2O中, 2a对LiClO~4和Ca(ClO~4)~2, 2b对LiClO~4、NaClO~4和Ca(ClO~4)~2, 有较显著的选择性变色作用; 而3a和3b在CH~3CN中, 则对LiClO~4、NaClO~4和各种碱土金属盐,均有不同程度的变色作用, 尤其以对Ca^2^+和Sr^2^+作用时的△λ~m~a~x为最大。这些结果表明, 2a和2b的配位性质分别与由邻苯二酚衍生的2'a和2'b相似, 而3a和3b的配位性质则分别与由邻苯二酚衍生的3'b相似。