- Simons electrochemical fluorination of substituted homopiperazines(hexahydro-1,4-diazepines) and piperazines
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Simons electrochemical fluorination (ECF) of 1,4-dimethyl-1,4-homopiperazine, methyl 4-ethylhomopiperazin-1-ylacetate and 1,4-bis(methoxycarbonylmethyl)-1,4-homopiperazine was studied. For comparison, ECF of three piperazines with a N-(methoxycarbonylmethyl) group(s) was also studied. ECF of 1,4-dimethyl-1,4-homopiperazine gave a low yield of corresponding perfluoro(1,4-dimethyl-1,4-homopiperazine) together with perfluoro(2,6-diaza-2,6-dimethylheptane) as the major product. Corresponding perfluoro(homopiperazines) with mono- and/or di-(fluorocarbonyldifluoromethyl) groups [-CF2C(O)F] at the 1- and/or 4-position were formed in low yields from methyl 4-ethylhomopiperazin-1-ylacetate and 1,4-bis(methoxycarbonylmethyl)-1,4-homopiperazine, respectively. These new seven-membered perfluoro(1,4-dialkyl-1,4-homopiperazines) were accompanied by the formation of mono- and/or di-basic linear perfluoroacid fluorides resulting from the C-C bond scission at the 2- and 3-positions of the ring. From mono- and/or di-N-(methoxycarbonylmethyl)-substituted piperazines, corresponding perfluoropeperazines having the acid fluoride group(s) were formed in low yields.
- Abe, Takashi,Baba, Hajime,Fukaya, Haruhiko,Tamura, Masanori,Sekiya, Akira
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- Mechanistic studies on the electrochemical fluorination of trialkylamines and tetraalkylammonium salts
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The comparative electrochemical fluorination (ECF) of selected trialkylamines and tetraalkylammonium salts was studied in order to obtain experimental data allowing a precise valuation of the ECF mechanism. The results of the investigation favour the ECF mechanism already proposed by Simons, via oxidation of F- .(HF)n to F and nHF, as probably the only relevant electrochemical process at the anode. For the first time some experimental proof has been obtained that a direct electrochemical oxidation of the substrate can be ruled out as a decisive step in ECF.
- Dimitrov,Pfeifer,Jonethal,Ruediger,Seppelt
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p. 143 - 150
(2007/10/03)
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- The electrochemical fluorination of N-containing carboxylic acids (Part 4). Fluorination of methyl 3-dialkylamino-isobutyrates and methyl 3-dialkylamino-n-butyrates
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Several methyl esters of 3-dialkylamino-substituted n- and isobutyric acids have been subjected to electrochemical fluorination to give the corresponding perfluoroacid fluorides.Dimethyl, diethyl, pyrrolidino, morpholino, piperidino and N-methylpiperazino groups were investigated as dialkylamino substituents.The structure/yield relationship was evaluated both in terms of the structure of the acid and the kind of amino group, respectively.Better yields of perfluoroacid fluorides were obtained from methyl esters having isobutyric acid skeletons than those having n-butyric acid groups, and from the acids containing cyclic amino groups than those containing acyclic ones.
- Abe, Takashi,Fukaya, Haruhiko,Hayashi, Eiji,Hayakawa, Yoshio,Nishida, Masakazu,Baba, Hajime
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p. 193 - 202
(2007/10/02)
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