Electrochemical fluorination of chlorine-containing ethers

The electrochemical fluorination of chlorine-containing ethers has been studied. In general, it was found that a chlorine bonded to an a-carbon atom in the ethers was readily removed during electrochemical reaction in anhydrous hydrogen fluoride, whilst a chlorine bonded to the β-carbon atom was retained to yield β-chlorinated polyfluoroethers.Through the use of this method, several new chloropolyfluoroethers, e.g. 2-chloro-1,1,2,2-tetrafluoroethyl difluoromethyl ether, 2,2-dichloro-1,1,2-trifluoroethyl trifluoromethyl ether 2,2-dichloro-1,1,2-trifluoroethyl difluoromethyl ether, 2,2-dichloro-1,1,2-trifluoroethyl chlorodifluoromethyl ether, 2-chloro-1,1,2,2-tetrafluoroethyl chlorodifluoromethyl ether and 2,2-trichloro-1,1-difluoroethyl trifluoromethyl ether, have isolated and characterized.     

镍催化转移缩聚合成全氟环丁基芳基醚聚合物

研究了通过镍催化转移缩聚的方法来合成全氟环丁基芳基醚聚合物.首先,我们以对溴苯酚和1,2-二溴四氟乙烷为起始原料,通过两步反应得到对溴三氟乙烯基芳基醚,进一步加热环化二聚得到单体1,2-二(4-溴苯氧基)六氟环丁烷.该二聚物再与异丙基格氏试剂发生镁交换反应,生成格氏试剂中间体,在催化剂Ni(dppe)Cl2的存在下发生镍催化转移缩聚生成聚合物.研究了反应时间、温度和单体投料比对催化缩聚反应的影响.     

Synthesis and Properties of New-type Troponoid Dithio-Crown Ethers

Troponoiddithio-crownethersareakindofnovelcomPounds.Takeshitaetall-'havereportedthesynthesisandmercurophilicpropertiesofthiskindofcompounds.lnthereportedcomPounds,thetWosulfuratomsareattached,partorall,tothetroponeringdirectly.Whetherthedithio-crownethersstillhaveselectiveandreversiblemercurysaltcaptUringabi1itywhenthetWosulfuratomslinktothebenZylic-mpepositionoftroponeringarousedourinterest.Herein,wewishtoreportthatfromthereactionof3,7-dichloromethyl-5-isopropyl-2-methoxytropone4withbis(mer…     

Chemical properties of <Emphasis Type="Italic">N</Emphasis>-polyfluoroethylimidazole and -pyrrole derivatives

Bromination, acylation, nitration, and metallation of imidazole and pyrrole derivatives containing the difluoromethylene fragment at the N atom were studied. 1-(1,1,2,2-Tetrafluoroethyl)pyrrole, 1-(1,1,2,2-tetrafluoroethyl)imidazole, and 1-(2-chloro-1,1,2-trifluoroethyl)imidazole were used as substrates. 1-Alkyl-3-(1,1,2,2-tetrafluoroethyl)- and 1-alkyl-3-(2-chloro-1,1,2-trifluoroethyl)imidazolium iodides were obtained. These can be used as intermediates for preparation of new ionic liquids of the imidazole series and 1-alkyl-3-polyfluoroethylimidazole-2-thiones.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 781–787, March, 2005.     

Polyetherimides. I. Preparation of dianhydrides containing aromatic ether groups

A general synthetic method and characterization of bis(ether anhydride)s, the ether containing aromatic dianhydrides of the following structure, are presented. The method involves aromatic nitro-displacement of N-substituted 3- or 4-nitrophthalimide with bisphenoxides to form N-substituted arylene-bis(phthalimido)ethers or bis(ether imide)s. Sixteen structurally different bis(ether imide)s have been prepared and subsequently converted to the corresponding bis(ether anhydride)s. Bis(ether anhydride)s are stable crystalline compounds of a moderate reactivity. Unlike highly reactive dianydrides such as pyromellitic and benzophenonetetracarboxylic dianhydrides bis(ether anhydride)s are semipermanently stable against hydrolysis in the presence of atmospheric moisture.     

Reaction of alkyl 2-chloro-1,1,2-irifluoroethyl ethers with lewis acids

Ethyl 2-chloro-1,1,2-trifluoroethyl ether heated with boron trifluoride etherate gave ethyl fluoride and chlorofluoroacetyl fluoride. When heated with aluminum chloride, it afforded a mixture of ethyl fluoride, ethyl chloride, chlorofluoroacetyl fluoride, and chlorofluoroacetyl chloride. Treatment of the acyl halides with ethanol yielded ethyl chloro- fluoroacetate. Butyl and octyl 2-chloro-1,1,2-trifluoroethyl ethers gave directly butyl and octyl chlorofluoroacetates, respectively, under similar conditions.     

Synthesis of 15‐, 16‐, and 17‐Membered Bis‐C‐Pivot Macrocycles Consisting of N2O2 Donor‐Type Crown Ethers and Dialkyl Phosphonates

Bis‐C‐pivot macrocycles containing aminophosphonate functions ( 5–10 ) have been synthesized and characterized by elemental analysis, FTIR, MS, 1D ¹H, ¹³C and ³¹P NMR, and 2D HETCOR techniques. The phosphorylation reaction of dibenzo‐bis‐imino crown ethers ( 1–4 ) with dimethyl and diethyl phosphite used here has the potential to provide bis‐C‐pivot macrocycles ( 5–10 ), which possess two stereogenic C‐centers giving rise to diastereoisomers (meso and racemic). Detailed spectral assignments for the meso and racemic forms of the compounds are reported on the basis of chemical shifts, signal intensities, spin–spin coupling constants, and splitting patterns. The bis‐C‐pivot macrocycles ( 5–10 ) may serve as a potential new class of supramolecular host molecules.     

冠醚的分子设计及其识别性质研究进展

综述了冠醚化学研究的最新进展：包括低对称冠醚、臂式冠醚、双冠醚等的分 子设计和离子键合、离子识别的热力学起源和分子组装的研究进展。     

几类新型中性载体的合成

本文为 满足研制钠离子选择电极的需要, 根据主客体化学, 配位化学和离子选择电极等理论,设计并合成了三类新型冠醚化合物, 它们的结构经元素分析, 红外, 核磁共振和质谱数据确证.     

Synthesis and Pharmacological Evaluation of Some Novel Imidazo[2,1-b][1,3,4]thiadiazole Derivatives

Synthesis of bis‐1,3‐{6′‐arylimidazo[2,1‐b][1,3,4]thiadiazol‐2‐yl}‐1,2,2‐trimethylcyclopentane ( 3 ), bis‐1,3‐{thiadiazolo[2′,3′:2,1]imidazo[4,5‐b]quinoxalinyl}‐1,2,2‐trimethylcyclopentane ( 5 ) has been achieved by the reaction of bis‐(5′‐amino‐1′,3′,4′‐thiadiazolyl)‐1,2,2‐trimethylcyclopentane with α‐haloketones, 2,3‐dichloroquinoxaline respectively. Bromination of compound 3 furnished bis‐1,3‐{5′‐bromo‐6′‐arylimidazo[2,1‐b][1,3,4]thiadiazol‐2‐yl}‐1,2,2‐trimethylcyclopentane ( 4 ). The structural assignment of these compounds was supported by IR, ¹H NMR and elemental analysis data. The antimicrobial, anti‐inflammatory and antifungal activities of some of the compounds have also been evaluated.     

A new bis(2,2,2-trifluoroethyl)phosphonate for the synthesis of Z-unsaturated N-methoxy-N-methylamides

The N-methoxy-N-methyl bis(2,2,2-trifluoroethyl)phosphonamide was easily obtained via the Arbuzov reaction with use of commercially available tris(2,2,2-trifluoroethyl)phosphite, 2-bromo-N-methoxy-N-methylacetamide, and KF/alumina. The reaction of bis(2,2,2-trifluoroethyl)phosphonate with several aldehydes demonstrates the versatility of the method, which gives Z-unsaturated amides in good yields.     

Defluorinations of fluoroformal and fluoroether to fluorocarbonate and fluoroester

Defluorinations of fluoroformal and fluoroether were carried out with SbF₃ and a catalytic amount of Br₂ in SO₂Cl₂ at room temperature. Bis(2-chloro-2,2-difluoroethyl) difluoroformal and 2-chloro-1,1,2-trifluoroethyl methyl ether were converted to bis(2-chloro-2,2-difluoroethyl) carbonate and methyl chlorofluoroacetate, respectively.     

Synthesis of trifluoroethyl ethers from 2,2,2-trifluoroethyl chloride (HCFC-133a) in high temperature aqueous medium

Treatment of 2,2,2-trifluoroethyl chloride (HCFC-133a) with alcohols (phenols) and aqueous KOH in autoclave at 240-280 °C gives the corresponding 2,2,2-trifluoroethyl (2-chloro-1,1-difluoroethyl) ethers in good yields.     

Extraction of alkali metal picrates with poly- and bis(crown ether)s

Extraction of alkali metal picrates by new poly- and bis(crown ether)s containing benzo-15-crown-5 and benzo-18-crown-6 moieties was carried out with chloroform as water-immiscible solvent. The poly- and bis(crown ether)s were found to extract the picrates more effectively than the corresponding monocyclic crown ethers. In particular, poly- and bis(benzo-15-crown-5), and bis(benzo-18-crown-6) are remarkably effective extracting reagents for potassium and rubidium, and for caesium, respectively. Extraction equilibrium constants and the complexation constants in the chloroform phase were also evaluated and the contribution of the complexation constants to the extractability is discussed.     

Facile preparation of fluorovinylene aryl ether telechelic polymers with dual functionality for thermal chain extension and tandem crosslinking

New fluorovinylene aromatic ether polymers, possessing dual reactivity, have been successfully prepared via the step-growth polymerization of commercial bis(trifluorovinyl) aromatic ethers and bisphenols.     

Acid/base controllable self-complexes that mimic flapping butterfly

A new type of self-complexed bis-crown ether containing two bis(p-phenylene)-34-crown-10 (BPP34C10) ether rings and two secondary ammoniums has been synthesized and characterized. The formation of these bis-self-complexes has been identified by NMR spectroscopy, mass spectrometry and X-ray analysis. The acid/base controlled movement of these bis–crown ethers can mimic a flapping butterfly.     

Dynamics of bichromophoric compounds in the excited and ionic states: Conformational and configurational aspects

Absorption spectra of N-ethylcarbazole, 1,2-trans-di-N-carbazolylcyclobutane, 1,3-di-N-carbazolylpropane, rac(dd, 11)-2,4-di-N-carbazolylpentane and meso(dl)2,4-di-N-carbazolylpentane in the excited singlet, triplet, cationic and anionic states were measured with nanosecond and picosecond laser photolysis methods. The main conformations in the excited and ionic states were determined, which made it possible to establish a relation among adsorption spectrum, intersystem crossing, and relative geometrical structure of two carbazolyl groups. Fast conformational changes of these compounds were directly measured and compared with slow ones of bis[1-(1-pyrenyl)ethyl]ethers.     

Reaction of 4-Oxocyclohexane-1,1,2,2-tetracarbonitriles and 5-Hydroxy-7-oxo-6-azabicyclo[3.2.1]octane-1,2,2-tricarbonitriles with Amines

New methods have been developed for the synthesis of fused amino-substituted pyrrolidinones and dihydropyrrolones. 4-Oxocyclohexane-1,1,2,2-tetracarbonitriles react with ammonia, hydrazine, and hydroxylamine to give, respectively, 5-amino-, 5-hydrazino-, and 5-hydroxylamino-7-oxo-6-azabicyclo[3.2.1]octane-1,2,2-tricarbonitriles, while with phenylhydrazine, semicarbazide, and thiosemicarbazide, 6-hydrazono-, 6-semicarbazono-, and 6-thiosemicarbazono-3-amino-1-oxo-3a,4,5,6,7,7a-hexahydro-1H-isoindole-3a,7a-dicarbonitriles are formed. The latter can also be obtained under analogous conditions from 5-hydroxy-7-oxo-6-azabicyclo[3.2.1]octane-1,2,2-tricarbonitriles. Reactions of 5-hydroxy-7-oxo-6-azabicyclo[3.2.1]octane-1,2,2-tricarbonitriles with diethylamine or triethylamine give 3-amino-1,6-dioxo-3a,4,5,6,7,7a-hexahydro-1H-isoindole-3a,7a-dicarbonitriles.     

Polymerization of novel trifluorovinyl ethers: Insight into the mechanisms of termination and chain transfer

New trifluorovinyl ether polymers were synthesized with the view toward overcoming the high chemical and thermal stabilities commonly associated with fluoropolymers. Trifluorovinyl ether copolymers, with fluorinated pendant groups, have previously been prepared to overcome limitations in processibility. To further enhance solubility in common organic solvents and to improve processibility, we prepared three new trifluorovinyl ether monomers, having hydrocarbon ether pendant groups, for polymerization: 1-[2-(2-ethoxy ethoxy)ethoxy]-1,2,2-trifluoroethene (Et-TFVE), 1-[2-(2-t-butoxy ethoxy)ethoxy]-1,2,2-trifluoroethene (t-Bu-TFVE), and 1-(2-phenoxy ethoxy)-1,2,2-trifluoroethene (Ph-TFVE). Homopolymers of these three monomers were prepared by aqueous emulsion polymerization with the use of a redox initiator. Poly(Et-TFVE) and poly(Ph-TFVE) were prepared with a range of molar masses, the highest of which had weight average molar masses of 33,800 g mol⁻¹ and 59,000 g mol⁻¹, respectively. As a result of monomer reactivity and structure, the polymerization mechanism was complicated, resulting in β-scission termination/chain transfer for all three polymers and hydrogen abstraction chain transfer for poly(Et-TFVE) and poly(t-Bu-TFVE). To the best of our knowledge, this is the first example of hydrogen abstraction from the pendant group of the trifluorovinyl ether itself. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3301–3308, 1999     

Cationic cyclopolymerization of new divinyl ethers: The effect of ether and ester neighboring functional groups on their cyclopolymerization tendency

The cationic polymerization of two new divinyl ethers, 1‐(2‐vinyloxyethoxy)‐2‐[(2‐vinyloxyethoxy)carbonyl]benzene ( 2 ) and 1,2‐bis[(2‐vinyloxyethoxy)carbonyl]benzene ( 3 ), as well as 1,2‐bis(2‐vinyloxyethoxy)benzene ( 1 ), with BF₃OEt₂ in CH₂Cl₂ at 0 °C at low initial monomer concentrations ([M]₀ = 0.15 and 0.075 M) gave soluble polymers with relatively high molecular weights and broad molecular weight distributions (MWDs), whereas reactions with the HCl/ZnCl₂ initiating system yielded soluble polymers with relatively narrow MWDs (weight‐average molecular weight/number‐average molecular weight ? 1.6) under similar reaction conditions. An NMR structural analysis of the HCl/ZnCl₂‐mediated polymers from the divinyl ethers showed that poly( 1 ) had virtually no unreacted vinyl ether groups throughout the polymerization (monomer conversion = 28–98%), whereas poly( 2 ) and poly( 3 ) possessed some amount of unreacted vinyl ether groups in the initial stage of the polymerization; the content of the vinyl groups of poly( 2 ) was 18 mol % at a 15% monomer conversion, and the content of the vinyl groups of poly( 3 ) was 31 mol % at an 18% monomer conversion. Therefore, divinyl ether 1 underwent cyclopolymerization exclusively to give almost completely cyclized polymers [degree of cyclization (DC) ～ 100%], whereas divinyl ethers 2 and 3 exhibited a lower cyclopolymerization tendency [DC for poly( 2 ) = 82%; DC for poly( 3 ) = 69%]. The differences in the cyclopolymerization tendencies among the divinyl ethers can be explained by the differences in the solvation powers of the neighboring functional groups adjacent to the vinyl ether moiety with the active center: the ether oxygen of the ether neighboring group solvates intramolecularly with the active center to accelerate the intramolecular propagation, but such an interaction is less effective with the more electron‐deficient oxygen attached to the carbonyl group of the ester neighboring group. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 281–292, 2003