Teruo Ueda

Generation and thermal polymerization of 1-fluoro-2-phenylacetylene

Abstract Some routes to the synthesis of 1-fluoro-2-phenylacetylene were attempted. Although the halogen exchange of chloro- and bromophenylacetylenes and dehydrobromination of dibromofluorophenylacetylene were unsuccessful, defluorosilylation of 1,1- difluoro-2-phenyl-2-trimethylsilylethene (which was prepared by lithiation of bromodifluorovinylbenzene followed by silylation with chlorotrimethylsilane) with CsF gave an oligomer of fluorophenylacetylene. The reaction of the phenyldifluorovinylsilane with CsF in DMF in the presence of phenylazide afforded a 1,3-dipolar cycloadduct, fluorodiphenyl-1,2,3-triazole. Vapor phase vacuum pyrolysis of the phenyldifluorovinylsilane yielded the acetylene, which spontaneously polymerized.

Synthesis and polymerization of some ethynyl trifluoromethyl napthhalenes

Abstract Some bromonaphthoic acids were fluorinated with SF4 to bromo(trifluoromethyl)naphthalenes. Although a reaction of Grignard reagent of one of the bromides with Cl2C=CF2 gave low yield of a (dichlorofluorovinyl) (trifluoromethyl) naphthalene, lithio derivatives gave the desired ethynyl(trifluoromethyl) naphthalenes in improved yields after subsequent eliminations of the vinylic halogens with n –butyllithium. Polymerization of the acetylenes was carried out with photo-activated W(CO)6 catalyst to yield high-molecular-weight polymers.

Synthesis of some ethynyltrifluoromethylfurans and their polymerization

Abstract Some trifluoromethyl group substituted ethynylfurans were prepared according to the method of Okuhara. However, dichlorofluorovinylation of lithiated 2,3-bis(trifluoromethyl)- furan did not undergo so smoothly because of the electron- withdrawing trifluoromethyl groups and the initially substituted dichlorofluorovinyl group. Thermal, γ-ray induced, or oxidation polymerizations were investigated, and 1,4-diethynyl- 2,3-bis(trifluoromethyl)furan thermally polymerized to give an insoluble polymer in a violent exothermal reaction.

Synthesis and polymerization of 2,5-disubstituted phenylacetylenes containing trifluoromethyl groups

Abstract Four phenylacetylenes (2-R 2 5-R 5 -C 6 H 3 C≡CH: 1a R 2 =R 5 =CF 3 ; 1b R 2 =CF 3 , R 5 =CH 3 1c R 2 =CH 3 , R 5 =CF 3 ; 1d R 2 =R 5 =CH 3 ) were synthesized via lithio compounds or Grignard reagent. Bromo-(methyl)benzotrifluorides, the precursors for the lithio compounds, were prepared by the fluorination of the corresponding benzoic with sulfur tetrafluoride. Polymerization using transition metal catalysts provided polyacetylenes in high yields for all the monomers, while the yields of γ-ray induced polymerization depended on the monomers. The molecular weights of polyacetylenes have a positive correlation with the yields for all the polymerizations. The substituent effects on the molecular weights and thermal stabilities of polymers obtained were discussed.

Syntheses of polyfluoro-α-amino acids

Abstract Some fluorine-containing amino acids have been known to inactivate certain enzymes selectively and irreversibly. We have synthesized β-(polyfluoro ethyl)alanines and β-(trifluorovinyl)alanine from polyfluoroiodoethanes and acrylate. The synthetic schemes of β-(polyfluoroethyl)- alanines are shown below. Using similar procedures, we have also prepared β-(polyfluoroethyl)-β-methylalanines, CF 2 XCFX′CH(CH 3 )- CH(NH 2 )CO 2 H from polyfluoroiodoethanes and ethyl crotonate. β-(Trifluorovinyl)alanine was synthesized in a good yield from the ester of β-(dichlorotrifluoro ethyl)alanine as follows: The reactive trifluorovinyl group in the amino acid allows us to synthesize various kinds of fluorine- containing amino acids with a functional group through radical and ionic addition reactions. Some reactions of the ester of N-acetylated β-(trifluorovinyl)alanine with alkoxides (nucleophilic addition) and alcohols (radical addition) will be mentioned.