Reactions of polyfluorocyclohexane- and polyfluorocyclohexene-carbonitriles

Abstract

The vapour phase reaction of undecafluorocyclohexanecarbonitrile (1) with cobalt(III) or silver(II) fluoride caused stepwise saturation of the CN triple bond to give C₆F₁₁CFNF and C₆F₁₁CF₂NF₂, whereas reaction in a sealed tube with silver(II) fluoride gave the azomethane C₆F₁₁CF₂NNCF₂C₆F₁₁ and with silver(I) fluoride gave tris(undecafluorocyclohexyl)-s-triazine. Methylamine, isopropylamine, and dimethylamine with the nitrile (1) gave the corresponding amidines. Vapour phase fluorination of pentafluorobenzonitrile by cobalt(II) fluoride or potassium tetrafluorocobaltate(III) afforded the nitrile (1), together with nonafluorocyclohex-3-enecarbonitrile (4). The latter was oxidised by potassium permanganate to 3-cyanoheptafluorohexane-1,6-dioic acid. Nonafluorocyclohex-1-enecarbonitrile (2) underwent classical nucleophilic addition–elimination sequences with methanol and with sodium methoxide to give progressively octafluoro-2-methoxy-, heptafluoro-6,6-dimethoxy-, and hexafluoro-2,6,6-trimethoxy-cyclohex-1 -enecarbonitrile, whilst with ammonia, 2-aminohexafluoro-6-iminocyclo-hex-1 -enecarbonitrile was formed, again by stepwise addition–elimination.