Perfluoro

FLUORINECOMPOUNDS,ORGANIC - PERFLUOROEPOXIDES] (Vol 11) Perfluoro-3,4-epoxy-2,3,5-trimethylhexane [2355-27-3]... 

Pyridazine, perfluoro-3,5-diisopropyl-photolysis, 7, 283 Pyridazine, tetrachloro-nucleophilic substitution, 3, 26 Pyridazine, tetrafluoro-nucleophilic substitution, 3, 26 Pyridazine, tetrahydro-, 3, 39-Uo Pyridazine, 3,4,5,6-tetrahydro-... 

Fluonnation of isoquinoline gave a mixture of partly and fully fluorinated compounds of which perfluoro-3,4,5,6,7,8-hexahydroisoqumoline and perfluoromethylcyclohexane were fully identified [28] (equation 11)... 

Sodium amalgam converts perfluoro(3,4-dimethyI-3-hexene) to perfluoro-(3,4-dimetliyl-2,4-hexadiene at room temperature in 70% yield [62] (equation 31). 

The reactions of some fluorinated ethers may result in the elimination of alkyl fluorides In the case of 2-methoxyperfluoro-2-butene, treatment with antimony pentafluoride gives perfluoro-3-buten-2-one and methylfluoride [107] By reacting 2-chloro-l,l,2-trifluorodiethyl ether with boron trifluoride etherate or with aluminum chloride, chlorofluoroacetyl fluoride can be obtained with the elimination of ethyl fluonde [108] (equations 76 and 77)... 

At elevated temperatures perfluoro-3,4-dimethyl (or -diethyl) cyclobutenes equilibrate with isomeric perfluorobutadienes [138, 139] via nonstereoselective... 

The Reactions of Highly Fluorinated Organic Compounds., Part IX. 17/-Decafluoro-4-tri(luo-romethylcyc/ohexane, Nonafluoro-4-trifluoromethylcycfohex-l-ene, and Perfluoro-(3-methyladipic) Acid, C. B. Barlow, M. Stacey, and J. C. Tatlow,/. Chem. Soc., (1955) 1749-1752. 

Perfluoro(3-isothiocyanato-2-methyl-2-pentene) reacts with N-nucleophiles to produce a series of fluoroalkyl-substituted 6/f-l,3-thiazines <1997RJO720>. The acid-catalyzed cyclization of thioureas immobilized on Wang (X = O) or Rink resin (X = NH) provides a convenient route to a wide range of 2-amino-4/7-benzothiazine derivatives 212 (Scheme 23) <20000L3667>. The thioureas are obtained in four steps from 2-nitrocinnamic acids. A general synthesis of 2-alkylidene-4-imino-l,4-dihydrobenzo-l,3-thiazines 213-215 involves treatment of 2-isothiocyanato-benzonitrile with acidic methylene compounds under basic conditions <2003SL1503>. The ( )-isomers are the predominant isomers formed. 

Heinze, MacNeil and coworkers developed the first methodology for the preparation of isomerically pure E- and Z-perfluoro-l,3-pentadienes, as described in equations 56 and 5749,50. Similar methodology was employed for the preparation of related perfluoro-3,5-octadiene systems49. These dienes were key components for studying the kinetic and thermodynamic electrocyclic interconversions of perfluorinated dienes and cyclobutenes,... 

C6o fullerene surfaces were thermally functionalized with perfluoro-(3-oxo-penta-4-ene)sulfonyl fluoride and then converted into sulfonic acid derivatives by basic hydrolysis. The product mimiced the electroconductive properties of perfluorosulfonyl Nation 1100 resins. When the modified fullerence was blended with platinum nanoparticles imbedded in Nation 1100 the material was effective as electrodes in fuel cells. 

Preparation of Ceo fullerene-g-perfluoro(3-oxo-penta-4-ene)sulfonyl fluoride... 

A 70-ml stainless steel reactor was charged with C ) fullerene (50 mg), 20 ml of 1,2,4-trichlorobenzene, and perfluoro(3-oxo-penta-4-ene)sulfonyl fluoride (3 g) and cooled to 50°C and then evacuated and filled with nitrogen and the mixture heated to 200°C for 18 hours. The solvent was then removed and the product isolated as a brown solid. 

The effluent gases from the cell were passed over NaF pellets and then bubbled through two consecutive bottles containing H20 (for collection of the perfluorocarboxylic acids which were formed as a result of the hydrolysis of the pcrfluoroalkanoyl fluorides). The gaseous products which did not react with H20 were led into an alkaline solution of K2S03, and finally collected in traps immersed in liquid N2. Products pcrfluoro(2.4-dimethyltetrahydrofuran) (20%), perfluoi o(2-methyltetrahydropyran) (5.5%), perfluoro(3-methyltetrahydropyran) (10%) and perfiuoro(2-methylpentanoyl fluoride) (7%). 

Perfluoroacy fluorides are obtained by electrochemical perfluorination of alkoxycarboxylic acids (nickel electrodes electrolyte anhyd HF voltage 6.5 V current density 0.01 — 0.02Acm 2 temperature 10"C) with yields of ca. 5 to 15%.42 Hence the products of the perfluorination of 3-mcthoxypropanoic acid are perfluoro(3-methoxypropanoyl fluoride) (7 %), pentafluoropropanoyl fluoride (19%), and trifluoroacetyl fluoride (52%). 

Under flash vacuum thermolysis (FVT) the 1,2,3-triazine (32) was readily thermolyzed to an alkyne, a nitrile, and nitrogen in high yields. For unsymmetrically substituted 1,2,3-triazines as FVT substrates, fragmentation proceeded selectively a bulky substituent at C-4(6) made the adjacent C—N bond break more easily than the opposite C—N bond. The FVT method was applied to the synthesis of the fluorinated alkynes, perfluoro-3-methyl-l-butyne and difluoroethyne [(33), R = (CF3)2CF, F] (Equation (1)) (89CC1657, 91CC456). It has been claimed, however, that tris(dimethylamino)-1,2,3-triazine forms the monocyclic azete. 

When there is a hydrogen or perfluoroalkyl substituent on the alk-l-ene chain, Lewis acid catalyzed migration of the C = C bond to the 3-position can proceed to minimize the number of alkenic fluorine atoms,3 as illustrated by the isomerizations of 4//-perfluorobut-l-ene (3),8 4//-perfluoro(5-methylhex-l -enc) (5),18 perfluoro(4-methylpent-2-ene) (7),14 and perfluoro(3-methylcyclopentene) (9).2 3... 

The allene perfluoropenta-1,2-dicne isomerizes in 96% yield to pent-2-ync 16 on distillation, maintained al 100 C/O.lTorr for 1 hour, through a column packed with cesium fluoride.46 When run in perfluorohexanc solution, the reaction yields only 28% of 16 and 55% dimer. Either perfluoro(3-methylbuta-l,2-diene) or its isomer periluoroisoprene can be converted into a mixture of the two, favoring the allene by about 2 1, by passage over cesium fluoride at 100-205 C/0.01 Torr.47... 

Finally, a bis(azomethine)-azomethine isomerization has been reported for perfluorinated a,w-bis(azomethines)28 which resembles the isomerizations of perfluorinated a.ro-dienes discussed in Section 5.1.2.3. Perfluoro-2,4-diazapenta-l,4-diene (43) and perfluoro-2.5-diazahexa-l,5-diene (45) rearrange completely with cesium fluoride to the internal azomethine isomers 44 and 46. respectively. In the case of perfluoro(3.4-dimethyl-2.5-diazahexa-l.5-diene) (47). the expected double-bond-migration product 48 is accompanied by cyclic product 49, which suggests a reaction mechanism involving addition of a fluoride ion to form a nitrogen anion, as opposed to a concerted SN2 -mechanism. 

Studies of perfluoro(3,4-dichlorocyclobutene),2 perfluoro(l,2-dimethylcyclobutene),4 per-fluoro(3,4-dimethylcyclobutene) (l).5,6 perfluoro(3-methylcyclobutene) (3),6,7 and... 

A similar kinetic effect was found for the perfluoro(3,4-diethylcyclobutene)/perfluoroocta-3,5-diene system.6 For the perfluoro(3-methylcyclobutene) (3)/perfluoropenta-1,3-diene (4) system,6-7 the kinetic preference lor the outward rotation of fluorine at position 3 is reflected in a A Ea of 12.9 kcal mol 1 between the conrotatory processes resulting in the formation of the Z- and E-isomers of 4. The equilibrium lies far on the side of perfluoro(3-methylcyclobutene) (3). with only 0.5% of (Z)-4 and 0.3% of ( )-4 present at 200 C. As is the case for per-iluorohexa-2.4-diene (2), the Z-isomer of 4 is more stable than ( >4, in this case by 2.2 kcal mol ... 

Photolysis of octafluorohexa-1.3,5-triene in the gas phase gives bicyclic hexene 24 as the major product (53 % yield) along with perfluoro(3-vinylcyclobutene) (30 % yield).19 Bicyclic product 24 is presumed to be formed via cyclohexadiene 23. Mercury-vapor sensitization accelerates the reaction and leads to a higher percentage of bicyclic product. Photolysis of octafluorohexa-1,3,5-triene in solution gives only EjZ isomerization. Heating octafluorohexa-1,3,5-triene at 400 to 500 C provides perfluorocyclohexa-1,3-diene (23) as the sole product in 60 to 80% conversion.19... 

Benzocyclobutenes form a special class of cyclobutenes because the double bond is part of an aromatic ring. Perfluoro(3-alkyl-l,2-benzocyclobutenes) rearrange in the presence of anti-mony(V) fluoride to indanes via styrene intermediates.27-31 Thus, perfluorobenzocyclobutenes 34 give perfluoroindanes 35 in moderate yields.27... 

Perfluorostyrene analogs can be isolated from perfluoro(3-ethyl- and perfluoro(3-isopropyl-1,2-benzocyclobutene), as well as from perfluoro(3,3-dialkyl-l,2-benzocyclobutenes).29-31 For example, perfluoro(3-ethyl-3-methyl-l,2-benzocyclobutene) (36) can be converted into an EjZ mixture of the perfluorostyrene 37 at 50 CC in 91 % yield.30 Heating 37 at 130CC in the presence of antimony(V) fluoride gives the corresponding indane 38. The mechanism of these reactions has been discussed in a review article.32... 

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