Shunji Nagase

The electrochemical fluorination of α-alkyl-substituted carboxylic acids

Abstract The electrochemical fluorination of acid chlorides and methyl esters of the α-alkyl-substituted carboxylic acids (2-methyl-n-valeryl chloride, 2-methyl-n-caproyl chloride, 2-methyl-n-enanthyl chloride, 2,3-dimethyl-n-buturyl chloride, methyl 2-ethyl-n-valerate, 2-n-propyl-n-valeryl chloride, 2-ethyl-n-caproyl chloride and methyl 2-n-butyl-n-caproate) was conducted to give a series of the substituted perfluorooxolanes and perfluorooxanes fluorides in good yields. The physical properties of the new compounds obtained are reported together with some of the 19 F nmr data.

The electrochemical fluorination of 2-methyloxane, oxepane, 2-chloromethyloxane and 2-choloromethyloxolane

The electrochemical fluorination of 2-methyloxane, oxepane, 2-chloromethyloxane and 2-chloromethyloxolane has been carried out. The corresponding perfluoro(2-methyloxane) and perrfluorooxepane were obtained in fair yields from the first two compounds, but from the later two, the corresponding chlorine-containing perfluorocyclic ethers, i.e. perfluoro(2-chloromethyloxane) and perfluoro(2-chloromethyloxolane), were obtained only in small yields, respectively. These new compounds have been characterized by elemental analysis, and infrared, mass and 19F nmr spectra.

Synthesis of perfluorobicyclic ethers [1]. The electrochemical fluorination of cycloalkyl-substituted carboxylic acids

Abstract A new synthetic method for making perfluorobicyclic and perfluoromonospiro ethers by fluorinating the cycloalkyl-substituted carboxylic acid electrochemically is presented. Novel perfluoro(2-oxabicyclo[3.3.0]octane) and perfluoro(7-oxabicyclo- [4.3.0]nonane) were obtained by the fluorination of methyl cyclopentylacetate and methyl cyclohexylacetate in yields of 10.5% and 11.8% respectively. The fluorination of methyl 3-cyclopentylpropionate and methyl 3-cyclohexylpropionate afforded the new perfluoro(1-oxaspiro[4.4]nonane) and perfluoro(1-oxaspiro[4.5]- decane) as the main cyclization products in yields of 12.4% and 16.6% respectively. Several kinds of perfluorinated cyclization products having a perfluoroalkyl group at the β-carbon to oxygen were also prepared by the fluorination of α-alkyl-α-cycloalkyl- substituted acetic acids. These new fluorination products, including some perfluorocycloalkanes and perfluoroalkanoyl fluorides, have been characterized by elemental analysis and infrared, mass and 19 F nmr spectra.

Fluorination of 2-alkyl-substituted oxanes. The synthesis and purification of perfluoro(2-alkyl-substituted oxane)s

Abstract Five kinds of 2-alkyl-substituted oxanes like 2-ethyloxane, 2-n-propyloxane, 2-iso-propyloxane, 2-n-butyloxane and 2-n-amyloxane were fluorinated electrochemically to give the corresponding perfluoro(2-alkyloxane)s. The perfluoro(2-alkyloxane)s were obtained in good yields from these starting materials together with isomeric perfluoro(2-alkyloxolane)s, perfluoro(2-alkyl-5-methyloxolane)s and perfluoro(dialkyl ether)s. The purification of the perfluoro(2-alkyloxane)s which contained small amounts of isomeric perfluoro(2-alkyloxolane)s was successfully achieved by recovering the former unreacted after treating these mixture with anhydrous aluminum chloride at 150 /sR 160 °C during /sR 48 hrs in order to convert the latter into the easy-separable perfluoro(2,5,5- trichloro-2-alkyloxolane)s. Small quantities of new perfluoro(5,5-dichloroalkanoyl chloride)s were also among the chlorination products. The spectroscopic data as well as the physical properties of these new fluorination products, and perfluoro(2,5,5-trichloro-2-alkyloxolane)s and perfluoro(5,5-dichloroalkanoyl chloride)s are presented.

Electrochemical fluorination of chlorine-containing amines

Abstract The electrochemical fluorination of chlorine-containing ethers has been studied. In general, it was found that a chlorine bonded to an a -carbon atom in the ethers was readily removed during electrochemical reaction in anhydrous hydrogen fluoride, whilst a chlorine bonded to the β-carbon atom was retained to yield β-chlorinated polyfluoroethers. Through the use of this method, several new chloropolyfluoroethers, e.g. 2-chloro-1,1,2,2-tetrafluoroethyl difluoromethyl ether, 2,2-dichloro-1,1,2-trifluoroethyl trifluoromethyl ether 2,2-dichloro-1,1,2-trifluoroethyl difluoromethyl ether, 2,2-dichloro-1,1,2-trifluoroethyl chlorodifluoromethyl ether, 2-chloro-1,1,2,2-tetrafluoroethyl chlorodifluoromethyl ether and 2,2-trichloro-1,1-difluoroethyl trifluoromethyl ether, have isolated and characterized.

The reaction of perfluoro-2,4-dialkyloxolanes with anhydrous aluminum chloride

Abstract Several kinds of perfluoro-2,4-dialkyloxolanes (A), having such alkyl groups as R f R′ f CF 3 (2a); R f C 2 F 5 , R′ f CF 3 (3a); R f CF 3 , R′ f C 2 F 5 (4a); R f R′ f C 2 F 5 (5a); R f CF 3 , R′ f nC 3 F 7 (6a) on the 2 and 4 positions of the oxolane ring, respectively, were treated with AlCl 3 in a heterogeneous reaction to give the corresponding perfluoro-2,5,5-trichloro-2,4-dialkyloxolanes (B). For purposes of comparison, the respective reactions of perfluoro-2-methyl-oxolane (la), perfluoro-2-n-butyloxolane (7a), and perfluoro-2, 5-dimethyloxolane (8a) with AlCl 3 were also conducted. An increasingly higher reaction temperature was needed for the reaction of A with AlCl 3 to give B as the carbon number of A increased. Cis- and trans-perfluoro-4-chloro-2,4-dimethyl-γ-butyrolactones (2c) were obtained from the hydrolytic reactions of cis- and trans-perfluoro-2,5,5-trichloro-2,4-dimethyloxolanes (2b), respectively, with fuming H 2 SO 4 . Physical properties and 19 F nmr data are given for these new compounds.

Synthesis of perfluorobicyclic ethers [2]. The electrochemical fluorination of α-cyclohexenyl-substituted carboxylic acid derivatives

Abstract The electrochemical fluorination of α-cyclohexenyl-substituted carboxylic esters [ ; R′CH3, C2H5, C3H7)] afforded both perfluoro(9-alkyl-7-oxa-bicyclo[4.3.0]nonane)s and perfluoro(8-alkoxy-9-alkyl-7-oxabicyclo[4.3.0]nonane)s in fairly good yields. As the driving force for the ring-closure in this fluorination, a mechanism which involves a resonance stabilized intermediate radical is proposed. Perfluoro(8-chloro-8-methoxy-9-ethyl-7-oxabicyclo[4.3.0]nonane) and perfluoro(8,8-dichloro-9-ethyl-7-oxabicyclo[4.3.0]nonane) were obtained by the controlled chlorination of perfluoro(8-methoxy-9-ethyl-7-oxabicyclo[4.3.0]nonane) with anhydrous aluminum chloride in low yields. Some new fused perfluorobicyclic ethers and a perfluoroacid fluoride obtained in this experiment have been characterized by infrared, mass and 19F nmr spectra and elemental analysis.

The electrochemical fluorination of N-(ω-chloroalkyl)pipecolines and N-(ω-chloroalkyl)hexamethyleneimines

Abstract Electrochemical fluorinations of six kinds of N-(ω-chloroalkyl)pipecolines [N-(2-chloroethyl)-2-, N-(3-chloropropyl)-2-, N-(2-chloroethyl)-3-, N-(3-chloropropyl)-3-, N-(2-chloroethyl)4- and N-(3-chloropropyl)-4-pipecolines] and two kinds of N-(ω- chloroalkyl)-substituted hexamethyleneimines [N-(2-chloroethyl)- and N-(3-chloropropyl)hexamethyleneimines] were conducted. From these starting materials, corresponding chlorine-retained fully fluorinated amines together with ring isomerized products were formed in yields of 7.6∼14.8% from the former and 5.4∼5.5% from the latter, respectively. New chloropolyfluoroamines obtained in the present investigation have been isolated and characterized by spectroscopic (infrared, 19 F nmr and mass) and elemental analysis.

Electrochemical fluorination of N-chloroalkyl-substituted cyclic amines

Abstract The electrochemical fluorination of such N-chloroalkyl substituted cyclic amines as N-chloromethylpyrrolidine ( 1 ), N-(3-chloropropyl)pyrrolidine ( 2 ), N-chloromethylpiperidine ( 3 ), N-(2-chloroethyl)piperidine ( 4 ), N-(3-chloropropyl)piperidine ( 5 ), N-chloromethylmorpholine ( 6 ), N-(3-chloropropyl)morpholine ( 7 ), N-(2-chloroallyl)morpholine ( 8 ) has been conducted. Except in the cases of the N-chloromethyl-substituted ones ( 1 , 3 and 6 ), the corresponding chlorine-retaining-perfluoroamines were obtained in a yield of 5 ∼ 20% together with perfluorinated ones (Yield = 20 ∼ 60%). Neither chlorine-retaining amines nor perfluorinated amines, both of which having the original skeleton, was produced from fluorinations of 1 , 3 and 6 in an appreciable yield. The spectroscopic data and physical properties of newly synthesized perfluoro-N-chloroalkyl-substituted cyclic amines are presented.

The reaction of perfluoro (N-alklyl-cyclic amines) with oleum. The formation and characterization of perfluorolactams

Abstract Treatment of several kinds of perfluoro (N-alkyl-cyclic amines) (-pyrrolidines, -morpholines, -piperidines and -hexahydroazepin) with oleum at 140 ∼ 170 °C afforded the corresponding perfluorolactams in fair yields. The reaction conditions and the properties of perfluorolactams are described.