Alexander M. Maksimov

Reactions of polyfluoroaromatic imidoyl chloride derivatives with S-nucleophilic reagents

Abstract The interactions of N -pentafluorophenylcarbonimidoyl dichloride, N -pentafluorophenylbenzimidoyl chloride and N -pentafluorophenyl (C-pentafluorophenyl) imidoyl chloride with the S-nucleophilic reagents thiourea, sodium N,N -diethyldithiocarbamate, thiocarbonyl difluoride and bis(trifluoromethyl)trithiocarbonate in the presence of CsF or AgSCF 3 , or thiophenol and polyfluorinated thiophenols in the presence of anhydrous K 2 CO 3 , were studied. Reactions with charged S-nucleophiles and with S-nucleophiles in the presence of a base proceeded with preservation of the N-C multiple bond in the reaction products. By varying the reaction conditions in the case of N -pentafluorophenylcar-bonimidoyl dichloride it was possible to substitute one or two chlorines and obtain mono- or di-thioimidates. When C 6 F 5 or SC 6 F 5 groups were present at the C atom of the N-C multiple bond, preferential substitution of the para -fluorine atom occurred. Semiempirical PM3 calculation data were used to explain the direction of these reactions. N -Pentafluorophenylcarbonimidoyl dichloride reacted with sodium N , N -diethyldithiocarbamate or thiourea to give pentafluorophenylisothiocyanate. Depending on the conditions of the reactions of polyfluorinated benzimidoyl chlorides with thiourea, N -pentafluorophenylthioamides and 2-aryl-4,5,6,7-tetrafluorobenzothiazoles were formed. An attempt to produce SCF 3 derivatives from AgSCF 3 was unsuccessful.

Reactivity of 12π-electron arenothiazines : synthesis and molecular structure of triphenyl[(4,5,6,7-tetrafluoro-1,2λ4δ2,3-benzodithiazol-2-yl)imino]-λ5-phosphane

5,6,7,8-Tetrafluoro-1,3λ4δ2,2,4-benzodithiadiazine 1 adds Ph3P to form triphenyl [(4,5,6,7-tetrafluoro-1,2λ4δ2,3-benzodithiazol-2-yl)imino]-λ5-phosphane 2 whose structure has been identified by X-ray structure analysis.

Fluoro-organic sulphur-containing compounds. IV. Haloalkylation reactions of polyfluorinated thiophenols with CHal3R compounds in the presence of AlCl3: Synthesis and some reactions of polyfluorophenylthio derivatives of halomethanes

Abstract The haloalkylation of polyfluorothiophenols with CHal 3 R compounds (Hal=Cl, F; R=Cl, H, C 6 H 5 , C 6 F 5 ) in the presence of AlCl 3 has been investigated. The reactions of polyfluorothiophenols 4-XC 6 F 4 SH (X=F, H, CH 3 ) with CCl 4 and AlCl 3 lead to dichloromethane derivatives (4-XC 6 F 4 S) 2 CCl 2 . The reaction of pentafluorothiophenol with CHCl 3 in the presence of AlCl 3 gave (C 6 F 5 S) 2 CHCl and (C 6 F 5 S) 3 CH (ratio by GLC 8:1). In the reaction of pentafluorothiophenol with ArCX 3 (Ar=C 6 H 5 , C 6 F 5 ; X=Cl, F) compounds (C 6 F 5 S) 2 CClAr (Ar=C 6 H 5 , C 6 F 5 ) together with C 6 F 5 SCCl 2 Ar (Ar=C 6 H 5 , C 6 F 5 ) are formed. Peculiarities of these processes are considered. The hydrolysis of (C 6 F 5 S) 2 CCl 2 and C 6 F 5 SCCl 2 C 6 H 5 leads to bis(pentafluorophenyl)dithiocarbonate and the S -(pentafluorophenyl) ester of thiobenzoic acid, respectively. Compounds (C 6 F 5 S) 2 CF 2 and (C 6 F 5 S) 2 CClF were obtained from (C 6 F 5 S) 2 CCl 2 by the action of caesium fluoride. An attempt to produce these compounds through the action of antimony fluorides was unsuccessful. The compounds (C 6 F 5 S) 2 CCl 2 , (C 6 F 5 S) 2 CClF and (C 6 F 5 S) 2 CF 2 are stable to oxidation. The reactions of (C 6 F 5 S) 2 CF 2 and (C 6 F 5 S) 2 CClF with CrO 3 in acetic acid proceeded only with the formation of mono-sulphoxide. The conversion is low in the former case.

Reactions of polyfluorobenzenethiols with polyhalomethanes and their derivatives in an alkaline medium

New process direction was found in the reaction of polyfluoroarenethiols with fluorodichloromethane, chloroform, and bromoform in an alkaline medium consisting in the replacement of the thiol group by a hydrogen atom. This process competes with the formation of expected products, dihalomethyl polyfluoro-aryl sulfides and tris(arylsulfanyl)methanes. In reaction of 2,3,5,6-tetrafluorobenzenethiol with dichloro-methane bis(2,3,5,6-tetrafluorophenylsulfanyl)methane was obtained. Reactions of polyfluoroarenethiols with pentafluorobenzyl chloride occur mainly with the substitution of the chlorine atom, with pentafluorobenzal chloride and with pentafluorobenzotrichloride a substitution of a fluorine atom in the para-position takes place.

Synthesis of 1,2-dichlorotetrafluoro- and 1,2,4-trichlorotrifluorobenzenes

Abstract1,2-Dichlorotetrafluorobenzene was obtained by reactions of chlorine with 5,6,7,8-tetrafluoro-1,4-benzodioxane and with a mixture of 3,4,5,6-tetrafluorophthaloyl chloride and 3,3-dichloro-4,5,6,7-tetrafluorophthalide at 500–550°C. Pyrolysis of pure 3,4- and 2,5-dichlorotrifluorobenzenethiols, as well as of a mixture of 3,4-, 2,4-, and 2,5-dichlorotrifluorobenzenethiols, in the presence of chlorine at 400–415°C in a flow system gave difficultly accessible 1,2,4-trichlorotrifluorobenzene.

Synthesis of 1,3,4-trifluoroisoquinoline by copyrolysis of 2,3,5,6-tetrafluoropyridine-4-sulfonyl chloride with butadiene

The reaction of 2,3,5,6-tetrafluoropyridine-4-sulfonyl chloride with butadiene in a flow system at 510--520 °C afforded 1,3,4-trifluoroisoquinoline. A scheme of this process is proposed.

The formation of 1,2,3,4-tetrafluoronaphthalene in the co-pyrolysis of pentafluorobenzenesulphonyl chloride or pentafluoronitrobenzene with butadiene

Abstract Co-pyrolysis of pentafluorobenzenesulphonyl chloride or pentafluoronitrobenzene with butadiene in a flow system at 500–635°C gave 1,2,3,4-tetrafluoronaphthalene.

Organofluorine sulfur-containing compounds

Polyfluorinated aryldifluoromethyl sulfides have been obtained by treatment of polyfluorinated 4-X-substituted thiophenols with chlorodifluoromethane in an alkaline medium. Reactions of difluoromethylpentafluorophenyl sulfide with H2O2, KMnO4, and HNO3, giving the corresponding sulfoxide and sulfone, were studied.

Fluoroorganic sulphur-containing compounds. II. The synthesis of perfluoro-2,3-dihydrobenzo[b]thiophene and an investigation of some of its chemical properties

Abstract Perfluoro-2,3-dihydrobenzo[b] thiophene (I), along with some quantities of perfluoroindane, has been obtained by copyrolysis of a number of 4-substituted tetrafluorothiophenols with tetrafluoroethylene in the presence of iodine. The interaction of sulphide I with some nucleophilic and oxidizing agents has been studied. The 5-and 6-substituted derivatives of polyfluoro-2,3-dihydrobenzothiophene have been synthesized.

Reaction of difluoromethyl pentafluorophenyl sulfoxide with nucleophiles

Reactions of 1-(difluoromethanesulfinyl)pentafluorobenzene with sodium methoxide, sodium phenoxide, potassium hydrosulfide, and methylamine resulted in substitution of fluorine atom in the 4-position (in the reaction with methylamine, also in the 2-position). Treatment of the title compound with sodium hydroxide afforded pentafluorobenzene due to cleavage of the Carom‒S bond.