Reactions of highly electrophilic polyfluoro unsaturated compounds with pyrazole derivatives

Pyrazole derivatives were hydroxyalkylated at the C⁴ atom by hexafluoroacetate and methyl trifluoropyruvate. The products of the hydroxyalkylation were dehydrated to the corresponding alkylidene derivatives which were reacted with nucleophiles. Dicyanoethylenes, obtained from polyfluorocarbonyl compounds, alkylated pyrazol-5-ones with the formation of pyrazolopyran derivatives.A. N. Nesmeyanov Institute for Organometallic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2617–2623, November, 1992.     

Epoxidation of unsaturated carbonyl compounds

Russian Journal of Organic Chemistry - Epoxidation of unsaturated carbonyl compounds by reaction with chloromethyl propargyl(allyl) ether in the presence of an alcoholate occurs exclusively at the...     

Epoxidation of syndiotactic 1,2-polybutadiene with peracids

The epoxidation of syndiotactic 1,2-polybutadiene (84 and 16% 1,2 and 1,4 units, respectively) with carboxylic peracids prepared in situ and m-chloroperbenzoic acid was studied. In the course of epoxidation in the presence of carboxylic peracids, oxirane groups are formed only through epoxidation of double bonds in the macromolecular backbone, whereas m-chloroperbenzoic acid is responsible for the chemical modification of 1,2 and 1,4 units of polybutadiene. The basic kinetic parameters of 1,2-polybutadiene epoxidation with peracids of various chemical structures were determined.     

Salt effects and the mechanism of electrophilic mercuration of unsaturated compounds

The kinetics of the addition of Hg(OAc)₂ to strained and unstrained alkenes was studied in MeOH solution in the presence of NaOAc. Based on salt effects, the HgOAc ion was shown to be the actual reagent in the reaction of the unstrained alkenes, whereas Hg(OAc)₂ was the reagent in the case of the strained alkenes. The mechanisms of the solvomercuration of alkenes of various structures were proposed.For the previous report seeIzv. Akad. Nauk, Ser. Khim., 1994, 819 [Russ. Chem. Bull., 1994,43, 760 (Engl. Transl.)].Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 344–352, February, 1995.     

Salt effects and the mechanism of electrophilic mercuration of unsaturated compounds

The reaction of Hg(OAc)₂ with bornylene in THF-H₂O and CH₃CN-H₂O mixed solvents (75 25, v/v) was studied. The effects of the addition of NaOAc on the reaction rate and the composition of products were investigated. In the CH₃CN-H₂O mixture, the addition of NaOAc decreases the amount of the rearranged product, fundamentally changes the ratio between the regioisomeric solvoadducts, and promotes the formation of products of Hg(OAc)₂ addition. The reaction proceedsvia an ion pair and free mercurinium ion; the cation of the ion pair and the free mercurinium ion have dissimilar structures.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 544–548, March, 1995.     

Reactions of highly electrophilic polyfluorocarbonyl compounds with primary arylamines

C-Hydroxyalkylation of primary arylamines by highly electrophilic polyfluorocarbonyl compounds results from the direct reaction of the initial reagents and is competitively inhibited by equilibrium N-hydroxyalkylation. The presence of steric hindrances to the formation of N-hydroxyalkylation products and an increase in the ring C-nucleophilicity facilitate the C-hydroxyalkylation reaction.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 383–389, February, 1990.     

First example of the electrophilic addition of perfluoroalkyl iodides to unsaturated compounds

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. I, pp. 226–227, January, 1990.     

Epoxidation of unsaturated alcohols of the decahydroquinoline series

The epoxy derivatives of stereoisomeric 1-alkyl-, 1,2-dimethyl-, and 1,2,2-trimethyl-4-vinyl-trans-decahydroquinolols were synthesized by oxidation with performic acid in formic acid solution. The compounds were characterized by their PMR and mass spectra. An analysis of the spectral data made it possible to conclude that the synthesized compounds and the starting vinyl alcohols have the same configurations.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1. pp. 78–82, January, 1982.     

Gas-chromatographic identification of fluorine-containing organic compounds

The gas-chromatographic retention of a series of fluoroalkylarenes on the standard nonpolar polydimethylsiloxane stationary phase OV-101 was characterized, and the retention indices of these compounds were determined. It was found that large negative values of the homological increments of these constants can serve as a sign of fluorine derivatives that contain no less than three fluorine atoms per molecule. The retention indices on polar inorganic sorbents, the silica gels Silipor 75 and Silipor 600, were chosen as the second chromatographic parameter. On these sorbents (unlike partition separation), the nonadditivity effect of the retention indices of polyfunctional organic compounds with respect to their simpler structural analogs was found for the first time. It was found that a mutual correlation between indices for this combination of a phase and a sorbent was lower than that for the combinations of phases with different polarities; this fact is responsible for the higher information content of this combination for the identification of compounds from this class.     

The microanalysis of fluorine-containing organic compounds

Summary The method previously described for the micro-determination of fluorine in organic compounds by fusion with alkali metal in a nickel bomb followed by a thorium nitrate titration using a back-titration procedure, has been modified to meet the interferences caused by the presence of phosphorus and arsenic in the organic compound. The method ofOverman andGarrett for the removal of phosphate and arsenate ions by the addition of solid zinc carbonate was adapted for the quantitative removal of those ions. Difficulties in the determinations of carbon and hydrogen in fluoro-phosphorus compounds were overcome by mixing the samples with tungstic oxide.

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Zusammenfassung Die früher beschriebene Methode zur Mikrobestimmung von Fluor in organischen Verbindungen durch Schmelzen mit Alkalimetall in einer Nickelbombe und nachfolgende Titration mit Thoriumnitrat unter Verwendung eines Rücktitrationsverfahrens wurde weiter ausgearbeitet, um Störungen durch allenfalls anwesenden Phosphor oder Arsen zu vermeiden. Die vonOverman undGarrett angegebene Bindung von Phosphat und Arsenat durch Zusatz von festem Zinkcarbonat wurde zu einer quantitativen Entfernung dieser Ionen entwickelt. Schwierigkeiten bei der C-H-Bestimmung in fluor- und phosphorhältigen Verbindungen können durch Mischen der Probe mit Wolframoxyd umgangen werden.

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Résumé Les perturbations apportées par la présence du phosphore et de l'arsenic ont conduit à modifier la méthode antérieurement décrite pour le microdosage du fluor dans les composés organiques et qui comportait une fusion en présence d'un métal alcalin dans une bombe de nickel suivie par un titrage par le nitrate de thorium d'après une technique de dosage en retour. La méthode deOverman etGarrett pour l'élimination des ions phosphate et arseniate par addition de carbonate de zinc solide a été adaptée à l'élimination quantitative de ces ions. Les difficultés rencontrées lors du dosage du carbone et de l'hydrogène dans les composés simultanément fluorés et phosphorés ont été surmontées par le mélange des prises d'essais avec de l'oxyde tungstique.

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We wish to express our thanks to Dr.K. Sellars for the provision of samples and to Dr.J. C. Tatlow for his interest in this project.     

The microanalysis of fluorine-containing organic compounds

Summary Methods are described for the micro determination of chlorine, bromine, and iodine in organic compounds containing fluorine. The sample is heated with sodium in a nickel bomb, and the chloride ion produced is determined titrimetrically by a modified procedure involving the use of mercuric oxycyanide. Bromide is determined titrimetrically after oxidation to bromate with sodium hypochlorite; iodide is also determined by an amplified procedure after oxidation to iodate with bromine.The method has been extended to the simultaneous determination of chlorine, bromine, and iodine when present in organic compounds containing fluorine. All four halogens, and all possible combinations of halogens, can be determined in one compound after a single fusion.

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Zusammenfassung Es werden Methoden zur Mikrobestimmung von Chlor, Brom und Jod in fluorhaltigen organischen Substanzen beschrieben. Die Probe wird in einer Nickelbombe mit Natrium erhitzt. Das hierbei entstehende Chlorid wird mit Quecksilberoxycyanid nach einem modifizierten Verfahren titriert. Das Bromid wird nach Oxydation zu Bromat mit Natriumhypochlorit titriert. Das Jodid wird mit Brom zu Jodat oxydiert. Nach Zugabe von Jodid wird die sechsfache Jodmenge mit Thiosulfat bestimmt.Das Verfahren wurde für die gleichzeitige Bestimmung von Chlor, Brom und Jod in fluorhaltigen organischen Substanzen erweitert. Alle vier Halogene können somit unabhängig von ihrem gegenseitigen Verhältnis in einer Verbindung nebeneinander ineiner Einwaage bestimmt werden.

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Résumé Des méthodes sont décrites pour le microdosage du chlore, du brome, de l'iode dans les composés organiques contenant du fluor. L'échantillon est chauffé avec du sodium dans une bombe de nickel et l'ion chlorhydrique produit est déterminé titrimétriquement par une méthode modifiée mettant en jeu l'emploi d'oxycyanure mercurique. Le brome est dosé volumétriquement après oxydation en bromate a ec l'hypochlorite de sodium. L'iode est déterminé également par une methode amplifiée après oxydation en iodate par le brome.La méthode a été étendue au dosage simultané du chlore, du brome, de l'iode quand ils sont présents dans des composés organiques contenant du fluor. Les 4 halogènes et toutes les combinaisons possibles d'halogènes peuvent être déterminées sur un seul composé après une simple fusion.

     

The microanalysis of fluorine-containing organic compounds

Summary Kirsten's method for the determination of nitrogen has been applied to the analysis of fluorine-containing organic compounds. Some slight modifications to the original method have been introduced.

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Zusammenfassung Die vonKirsten angegebene Methode zur Bestimmung von Stickstoff wurde für die Analyse fluorhältiger organischer Verbindungen angewendet. Einige geringfügige Modifikationen des ursprünglichen Verfahrens werden angegeben.

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Résumé On a employé la méthode deKirsten pour la détermination de l'azote de composés organiques contenant du fluor. On a introduit quelques légères modifications à la méthode originale.

     

The electrophilic substitution of ferrocene by protonated carbonyl compounds

The α-ferrocenylalkyl caebenium ions are formed from ferrocene and carbonyl compounds in strongly acidic media, in particular mixtures of fluorosulfuric acid and trichloroacetic acid. The α-ferrocenylalkyl carbenium ions are scavenged by nucleophiles or bases. The addition of nucleophiles produces the corresponding α-substituted ferrocenyl alkanes. Proton abstraction by base from the β-position leads to the ferrocenylethene derivatives.Such electrophilic substitutions of ferrocene by carbonyl compounds, followed by suitable scavengeing of the α-ferrocenylalkyl carbenium ion, form the basis of one-pot syntheses of various ferrocene derivatives.     

Aromatic compounds with new fluorine-containing substituents

The introduction of strong electron-accepting fluorine-containing substituents into the aromatic moiety gives compounds with unique properties. Determination of the electronic nature of the grouping (R_f)₂PO in arylbis(perfluoroalkyl)-phosphine oxides has shown that this substituent is comparable with R_fSO₂, one of the most electron-accepting groups.A general principle is proposed for the construction of the new superstrong electron-accepting substituents by the replacement of oxygen atoms for trifluoromethylsulfonylimino groups. For example, when the oxygen atoms in CF₃SO and CF₃SO₂ groups are replaced by CF₃SO₂N=, new stable and even more electron-accepting substituents are formed. The grouping CF₃S(O)=NSO₂CF₃ corresponds to two nitro groups. A similar increase in electron-accepting ability is observed in groupings derived from other elements by replacement of oxygen atoms by the CF₃SO₂N= group.