The synthesis and reactins of ortho bromophenyllithium

Experimental conditions have now been developed whereby o-bromophenyllithium(II) may be prepared in excellent yields and used as an organometallic intermediate for the synthesis of a variety of ortho bromo substituted phenyl compounds (o-BrC₆H₄X). THe thermal stability, decomposition products and reactions of II wre studied. REactions between II and a variety of substrates, e.g., CO₂, dimethylformamide, fluorinated esters, hexafluorobenzene, and organosilicon chlorides were examined.     

Reactions of 1,2-bis(trifluoroacetyl)benzene with nucleophiles leading to heterocyclic compounds

The reaction of 1,2-bis(trifluoroacetyl)benzene (II) with ammonia, hydrazine, hydroxylamine and L-alanine has been investigated and the resulting heterocyclic compounds fully characterized on the basis of spectral data. The reaction of II with $\text{o}$-aminophenol and $\text{o}$-phenylenediamine led to the formation of tetracyclic compounds XI and XII respectively. The structure of compound XII has been further supported by single crystal X-ray crystallography. Our studies reveal the potential of the diketone II as a valuable synthon for the synthesis of a variety of heterocyclic systems with trifluoromethyl substituents.     

Fluoroalkylation of aromatic compounds

Perfluoroalkylation of benzene, halobenzenes, pyridine, furan and thiophene has been accomplished through thermolysis of perfluoroalkyl iodides (CF₃I, n-C₁₀F₂₁I and R_fOR_fI) in the presence of the appropriate aromatic compound. Yields of alkylated products vary depending on temperature, presence of an HI acceptor and reactants ratio. Isomeric mixtures are obtained with halobenzenes, pyridine and thiophene. Furan however yields only the alpha substituted product.     

Synthesis of some benzimidazoles containing 2-perfluoro substituents

A new method is described for the preparation of 2-perfluoroalkylether- benzimidazoles through the N-monoacyl derivatives of o-phenylenediamine. 2-pentafluorophenylbenzimidazole has been obtained by the reaction of o-phenylenediamine and pentafluorobenzoic acid in the presence of polyphosphoric acid. 2-Perfluoroalkylbenzimidazoles have been prepared in excellent yields by direct condensation of o-phenylenediamine with perfluoroalkane- carboxylic acids in the absence of any solvent or added reagent. Some derivatives of these compounds are also described.     

Liquid alkoxides of a perfluorotertiary alcohol and their derivatives

Sodium and lithium alkoxides of (CF₃)₂CFOCF₂CF₂C(CF₃)₂OH have been prepared in high yields by the addition of sodium hydride to the alcohol or in the case of the lithium salt through the addition of (CF₃)₂C=O to the organolithium compound (CF₃)₃CFOCF₂CF₂Li. These salts react with active halides e.g. PCl₃ or cyanuric chloride to yield completely substituted products.     

Fluoro-ketones. I reactions of hydrocarbon grignards with perfluoroalkylacid fluorides

The reaction between Grignard reagents and perfluoroacid fluorides provides a convenient synthesis procedure for ketones R_fOR_fC(O)R′, where R_fOR_f is perfluoroalkylether group and R' is either an aromatic or aliphatic group. Reaction temperature is an important factor in producing higher yields of ketones. Meta and para-bromophenyl Grignard reagents, which thus far have not been prepared as pure mono Grignards, present secondary competing reactions which detract from their synthetic utility.     

Addition-elimination reactions between phenyllithium and some perfluorovinylether compounds

Reactions between C₆H₅Li and C₃F₇OCFCF₂ (I) yield phenyl substituted perfluorovinylethers. Stoichiometry and reaction temperature dictate the degree of substitution. With each replacement of F^θ by C₆H₅^θ the subsequent substitutions require more forcing conditions. The F^θ is substituted easier than the C₃F₇O^θ during the addition-elimination reactions.     

Synthesis and reactions of perfluoro-n-octylmagnesium bromide

Perfluoro-n-octylmagnesium bromide has been conveniently synthesized through the metal-halogen exchange reaction between perfluoro-n-octyl iodide and ethyl- or phenyl-magnesium bromide. The thermal stability of the Grignard reagent and the products of the thermal decomposition have been estimated in diethyl ether and tetrahydrofuran. Reactions of the Grignard reagent with various substrates such as water, acetone, hexafluoroacetone, trimethylchlorosilane and carbon dioxide indicate the synthetic utility of n-octylmagnesium bromide.