β-氟烷基烯基碘与硫酚负离子的反应

在CH~3CN中,β-氟烷基烯基碘与硫酚负离子能发生消除-加成反应生成碘被取代的产物;硫醇负离子及氧负离子对β-氟烷基烯基碘进攻则生成消除产物氟烷基炔烃。     

五氟溴苯的合成工艺研究

五氟溴苯是一种非常重要的化工中间体.五氟苯甲酸通过脱羧、溴化两步反应可以得到五氟溴苯.本文通过采用加压脱羧的方法制备五氟苯,反应时间短,产品产率和纯度高,且操作简单方便,工艺绿色环保,适合工业化.同时分别研究了脱羧和溴化反应中反应条件对目的产物收率的影响.     

有机氟化学的新进展

本文综述氟有机化学的最新进展。论及:1.气溶胶直接氟化法,新的温和的氟化试剂——CH_3CO_2F,N-氟代二氢吡咯酮,R_F(?)(C_6H_5)CF_3SO_3(?)和喷雾干燥的KF。2.合成全氟烷基磺酸的新方法,如全氟烷基碘在金属活化下与SO_2在DMF中的反应,又如I(CF_2)_2O(CF_2)_2SO_2F与C_2F_4调聚和全氟卤代烷的亚磺化脱碘反应。3.惰性—CF_2—及—CF_3的新反应,如五氟一氯丙酮与KF的反应,多氯氟乙烷与硫酚钠的反应。4.具有生理活性的氟化物,如抗癌物fluorosesqisiloxane,杀虫剂29-fluorositosterol。     

全氟及α,α-二氯多氟烷基亚磺酸盐的反应

全氟烷基亚磺酸钠与溴水反应,得到全氟烷基磺酰溴(RfSO2Br),(但在乙腈,乙酸等有机溶剂中与溴反应,则生成溴代全氟烷.在碘化钾水溶液中,全氟烷基亚磺酸钠与碘反应,生成碘代全氟烷.α,α-二氯多币烷基亚磺酸钠在类似条件下与溴水反应,生成1-溴-1,1-二氯多氟烷,与碘在磺化钾水溶液中反应,生成1-碘-1,1-二氯多氟烷.1-溴-1,1-二氯多烷及1-碘-1,1-二氯多氟烷易对烯键加成,也可与连二亚硫酸钠在温和条件下发生亚磺化脱溴及脱碘反应.α,α-二氯二氟乙基亚磺酸钠在强酸中比较稳定,与强碱,氧化剂或还原剂发生反应,得到相应的产物.     

氟班色林的合成新方法

本文通过醋酸碘苯促进的苯甲醛、N-苯基羟胺和三甲基氰硅烷的一锅法反应首先构建氟班色林的重要骨架苯并咪唑酮结构,随后,与1,2-二溴乙烷反应得到中间体8,接着在浓盐酸中水解,得到中间体9,最后与哌嗪盐酸盐10反应,以29%的总收率得到氟班色林11。所有化合物的结构经过1H NMR、13C NMR、HRMS表征。该方法具有原料价廉易得、副产物少、收率较高等特点。     

烯烃类衍生物的碘三氟甲基化反应

在ZnI2为催化剂,Togni试剂为三氟甲基化试剂,CHCl3为溶剂的条件下,以中等收率(30%~65%)实现烯烃的碘三氟甲基化反应,合成了一系列既含碘又含三氟甲基的酯类、酮类、酰胺类、腈类等化合物,其结构经1H NMR,13C NMR,19F NMR,IR,MS和HR-MS表征。其中4,4,4-三氟-2-碘丁酰胺,4,4,4-三氟-2-碘-N,N-二甲基丁酰胺和6,6,6-三氟-4-碘-3-己酮为新化合物。     

氟烷基化与氟烷氧基化的研究——25.甲酸/三乙胺引发氟烷基碘对烯烃的加成

氟烷基碘对烯烃的催化加成,是将氟烷基引入碳氢化合物的有效途径。通常利用光照和自由基引发来实现。最近我们发现许多金属     

碘、氟、硅与人体健康的关系

碘、氟、硅是人体必需微量元素,它们的摄入量对人体健康起着重要作用。对碘、氟、硅的缺乏与疾病之间的关系进行了讨论,并对其治疗和防治方法作了介绍。     

一种由多氟碘代烷合成多氟羧酸的新方法

本文报道了一种新的合成多氟羧酸的方法:即在银(I)离子存在下,甲酸钠与多氟烷基碘代烷反应的结果。     

氟烷基化和氟烷氧基化的研究17:2-氟烷基吡咯的合成新法

芳杂环体系的氟烷基化方法报道甚少。wakselman 等曾报道 N-甲基吡咯与全氟烷基碘的反应,但在同样高温条件下,吡咯则难以氟烷基化。Kobayashi 等发现长时间光照     

A variable temperature study of the 19-F N.M.R. spectra of some fluoroalkylhydroxylamines: Conformational changes at the nitrogen atom [1]

The fluoroalkylhydroxylamines (I) - (VII) have been examined by variable temperature 19-F n.m.r. spectroscopy, and free energies of activation obtained for the process which renders equivalent the fluorines of the CF₂N group in (I), and the trifluoromethyl groups of the (CF₃)₂CFN group in (IV), and of the trifluoromethyl groups of the (CF₃)₂N group nearest to the asymmetric carbon atom in (V) - (VII). The possible conformational processes at the nitrogen atom are discussed. Δ$\text{G}$^≠/kJ mol^-1 (I) (CF₃CF₂CF₂)₂NOCF₂CF₂CF₃ 72 ± 6 (II) CF₃CF₂CF₂N(CF₃)OCF₂CF₂CF₃ (III) CF₃CF₂CF₂N(CF₃)OCF₃ (IV) (CF₃)₂CFN(CF₃)OCF(CF₃)₂ 71 ± 4 (V) (CF₃)₂NOCH₂CHClON(CF₃)₂ 60 ± 4 (VI) (CF₃)₂NOCH₂CHFON(CF₃)₂ 59 ± 4 (VII) (CF₃)₂NOCF₂CHFON(CF₃)2 59 ± 4 The perfluorotrialkylhydroxylamines (II) - (IV) were prepared by photochemical reaction of a perfluoroalkyl iodide with a perfluoroalkyl nitroso compound.Since it was observed that some alkyl hydroxylamines show magnetic non-equivalence in their low temperature n.m.r. spectra [2,3] there has been a number of studies of conformational changes in such compounds. For cyclic derivations [4,5] it is generally agreed that the changes are associated with hindered inversion at the nitrogen atom, but for acyclic compounds these have been variously ascribed to hindered inversion at the nitrogen atom [6,7] and to restricted rotation about the N-O bond [8,9]. The former explanation has received theoretical justification [10].     

The addition of fluorine to perhalogenated compounds containing carbon-nitrogen double bonds

The reaction of elementary fluorine with ten perhalogenated compounds containing carbon-nitrogen double bonds is reported. The reactions were carried out without added catalysts in a static system. With CF₃N=CF₂, (CF₃)₂NCF=NCF₃, SF₅N=CF₂, CF₂=NCl, CF₃CF=NCl and CF₂=NF a simple addition of fluorine to the carbon-nitrogen double bond was observed forming the respective N-fluoroamines in high yield. Two imines, CF₃CF=NF and (CF=NF)₂, were unreactive under the same conditions and reactions of CF₃CF₂CF=NF and (CF₃)₂C=NF were explosive.     

Some aspects of the chemistry of chlorofluoro-olefins which contain allylic chlorine atoms

Routes to perflouroallyl chloride, CF₂:CF.CF₂Cl, and to $\text{cis}$-and $\text{trans}$-1-chloro-hexafluoro-2-trifluoromethyl(but-2-ene), (CF₂Cl)(CF₃)C:CF.CF₃ are reported, and their susceptibility to attack by nucleophiles discussed; the allylic chlorine atoms in these olefins are the controlling factor in determining the products obtained.The conversion of 3-chloropentafluoropropene into a series of perfluoroallyl derivatives of general formula R.CF₂.CF:CF₂ [R = (CF₃)₃C-, CF₃O-, C₆F₅-, l-, MeO-, etc.] is described, and the further chemistry of 3-chloropentafluoropropene and its derivatives outlined.Water reacts rapidly with (CF₂Cl)(CF₃)C:CF.CF₃ to give CF₂:C(CF₃).CFCl.CF₃ or CF₃.CO.CH₂.CF₃. Methanol affords CF₂:C(CF₃).CFOMe.CF₃ and (MeOCF₂)(CF₃)C:CF.CF₃ as initial products, with subsequent secondary products such as CF₃.CFOMe.CH(CF₃).CF₂OMe, (CF₃)(MeO)C:C(CF₃).CF₃OMe, MeO.CF:C(CF₃).CFOMe.CF₃, (CF₃)(MeO)CF.CH(CF₃).CO₂Me, and (CF₃)(MeO)C:C(CF₃).CO₂Me. The influence of allylic chlorine and of reaction time on the formation of these products, and mechanistic pathways for their formation are considered.     

Methyl hypofluorite (MeOF) reactions with various fluoroolefins

The reaction of methyl hypofluorite (MeOF) with certain fluoroolefins, such as CF₂CF₂, CF₂CFCF₃, CF₂CFOCF₃, CF₂CFOMe, CF₂CClF, CF₂CHF, CF₂CH₂, CHFCH₂, CF₂CFCFCF₂, occurred in CD₃CN or in the presence of NaF. Using neat MeOF in the presence of NaF was a novel method and gave good results. We observed that when more than three fluorine atoms are bonded to the CC double bond, the addition products were obtained in mostly good yields.     

The reaction of photochemically generated CF3O radicals with CO

CF₃O₂CF₃ was photolyzed at 254 nm in the presence of CO in 760 torr N₂ or air at 296 K in a static reactor. In N₂, the products CF₃OC(O)C(O)OCF₃ and CF₃OC(O)O₂C(O)OCF₃ were detected by FTIR spectroscopy. In air, the only observed products were CF₂O and CO₂ and a chain process, initiated by CF₃O, was invoked for the conversion of CO to CO₂. From both product studies, a mechanism for the CF₃O initiated oxidation of CO was derived, involving the addition reaction CF₃O₂ + CO → CF₃OC(O). The rate constant for the reaction CF₃O + CO at 296 K at a total pressure of 760 torr air was determined to be k(CF₃O + CO) = (5.0 ± 0.9) × 10⁻¹⁴ cm³ molecule⁻¹ s⁻¹. © 1997 John Wiley & Sons, Inc.     

Reactions of bis(trifluoromethyl)nitroxyl with (CF3)2AsX (where X = F,Cl and Br)

(CF₃)₂AsX (X = F, Cl) give at elevated temperatures substitution reactions with (CF₃)₂NO to afford (CF₃)₂NOAs(CF₃)X and (CF₃)₂NOCF₃. The formation of addition products at low temperatures to give [(CF₃)₂NO]₂As(CF₃)₂X, followed by elimination reactions at elevated temperatures to give the final products provide for the first time direct evidence for the mechanisms of the substitution reactions. With (CF₃)₂AsBr, bromine was initially displaced to afford (CF₃)₂NOAs(CF₃)₂, followed by addition reactions to give [(CF₃)₂NO]₃As(CF₃)₂.     

UV absorption spectrum,and kinetics and mechanism of the self reaction of CF3CF2O2 radicals in the gas phase at 295 K

The ultraviolet absorption spectrum, kinetics, and mechanism of the self reaction of CF₃CF₂O₂ radicals have been studied in the gas phase at 295 K. Two techniques were used; pulse radiolysis UV absorption to measure the spectrum and kinetics, and long-path length FTIR spectroscopy to identify and quantify the reaction products. Absorption cross sections were quantified over the wavelength range 220–270 nm. At 230 nm, σ = (2.74 ± 0.46) ×10^?18 cm² molecule^?1. This absorption cross section was used to derive the observed self reaction rate constant for reaction (1), defined as, ?d[CF₃CF₂O₂]/dt = 2k_1obs[CF₃CF₂O₂]²: k_1obs = (2.10 ± 0.38) ×10^?12 cm³ molecule^?1 s^?1 (2σ). The observed products following the self reaction of CF₃CF₂O₂ radicals were COF₂, CF₃O₃CF₃, CF₃O₃C₂F₅, and CF₃OH. CF₃O₂CF₃ was tentatively identified as a product. The carbon balance was 90–100%. The self reaction of CF₃CF₂O₂ radicals was found to proceed via one channel to produce CF₃CF₂O radicals which then decompose to give CF₃ radicals and COF₂. In the presence of O₂, CF₃ radicals are converted into CF₃O radicals. CF₃O radicals have several fates; self reaction to give CF₃O₂CF₃; reaction with CF₃O₂ radicals to give CF₃O₃CF₃; reaction with C₂F₅O₂ radicals to give CF₃O₃C₂F₅; or reaction with CF₃CF₂H to give CF₃OH. As part of this work a rate constant of (2.5 ± 0.6) ×10^?16 cm³ molecule^?s^?1 was measured for the reaction of Cl atoms with CF₃CHF₂ using a relative rate technique. Results are discussed with respect to the atmospheric chemistry of CF₃CF₂H (HFC-125). © 1993 John Wiley & Sons, Inc.     

(CF3)2Cd·D und (CF3)2Zn·D: neue reagenzien für difluorcarben-reaktionen [1]

During the thermal decomposition of (CF₃)₂Cd and (CF₃)₂Zn complexes primarily difluorocarbene is eliminated. The formation of CF₂ is unambiguously proved by matrix i.r. spectroscopy. Both (CF₃)₂Cd·D and (CF₃)₂Zn·D are excellent CF₂ sources, which can easily be prepared and handled, and which undergo CF₂ reactions even at low temperature. CF₂ insertion was found during the reaction of (CF₃)₂Te with (CH₃)₂Cd via the intermediate formation of a CF₃Cd compound to form CH₃TeCF₂CH₃. (CF₃)₂Cd·glyme reacts with (CH₃)₃Si(OCOCF₃) to CF₃Cd(OCOCF₃)·glyme; during this reaction CF₂ is also eliminated.     

Preparation and Reactivity Study of a Versatile Trifluoromethylthiolating Agent: S-Trifluoromethyl Trifluoromethanesulfonothioate (TTST)

A novel, air and thermally stable, yet highly reactive trifluoromethylthiolating reagent, CF₃SO₂SCF₃ ( 1 ), was prepared easily in one step from commercially inexpensive CF₃SO₂Na and Tf₂O. 1 is a highly versatile and atom-efficient reagent that can generate one equivalent of CF₃S ⁺ , two equivalents of CF₃S⁻, or a combination of CF₃S⋅/CF₃⋅ species. Many high-yielding CF₃S reactions of C, O, S, and N-nucleophiles were achieved, including the simple-step preparations of many reported CF₃S reagents. 1 delivered a hitherto hard-to-synthesize ArOSCF₃ that was followed by a novel CF₃S^II-rearrangement. Through Cu or TDAE/Ph₃P combinations, 1 generated two equivalents of CF₃S anion species, and the photo-catalyzed reactions of alkenes with 1 provided CF₃/CF₃S-containing products in high atom-efficiency.