Aromatic polyfluoro-compounds. Part XLI. Some reactions of pentafluorobenzaldehyde

Abstract

Pentafluorobenzaldehyde has been converted into a range of derivatives by reactions involving the carbonyl group, viz., a pentafluorostilbene, a pentafluorocinnamic acid, an azine, an oxime, and a range of acetals. Other derivatives were made by reactions involving replacement of fluorine using dimethylamine, sodium hydrogen sulphide, sodium thiophenoxide, and sodium methoxide.

Pentafluorobenzaldehyde and its utilizing in organic synthesis

“…The PFBA does not afford the Cannizzaro reaction, but so-called ''haloform reaction'' [185], which is typical of fluorocarbonyl compounds with pentafluorobenzene and formic acid forming, proceeds in the presence of water solution NaOH and KOH (Scheme 32).…”

“…There are many known cases, when the substitution of all fluorine atoms occurs by utilizing 5 equivalents of alkaline salts of sulphur nucleophiles. In the first case, the potassium salt of benzenethiol in dimethylformamide (DMF) is utilized [185] and in the second, the sodium salt of benzenethiol 1,3-dimethyl-2-imidazolidinone (DMI) is utilized [193][194][195]. When the temperature was raised to 60 8C, the benzene derivative 26 resulted (Scheme 14 [185]).…”

“…The first publications dealing with issue of nucleophilic substitution of flourine originated in the year 1968 [185], and focused on nucleophilic substitution of o-fluorine and pfluorine by dimethylamine (Scheme 11). Other works like that [186][187][188][189][190] were published later and dealt with nucleophilic substitution of p-fluorine by sulphur, oxygen and nitrogen nucleohpiles (Scheme 11).…”

Exploitation of aldoxime esters as radical precursors in preparative and EPR spectroscopic roles

“…The alternative method, which involved DCC coupling of an oxime with the corresponding carboxylic acid (catalysed by DMAP), was usually more convenient and often led directly to crystalline products without the need to resort to column chromatography (Method B). The oximes (1) chosen for investigation, which were prepared using standard methods from the corresponding aldehyde and hydroxylamine hydrochloride, were benzaldoxime, 9 4-nitrobenzaldoxime, 9 pentafluorobenzaldoxime, 10 2,4-dimethoxybenzaldoxime, 11 2,4,6trimethoxybenzaldoxime, 12 and benzophenone oxime. 9 Oxime esters 3-7a, b, e-g, i-l and 8 were prepared mainly for EPR investigations and to examine intermolecular addition, whilst 3-7c, d, and h were prepared primarily for examination of intramolecular reactions.…”

Synthesis, structure, electrostatic properties and spectroscopy of 3-methyl-4,5,6,7-tetrafluoro-1H-indazole. An experimental and ab initio computational study †

“…The azine of pentafluorobenzaldehyde had been previously prepared by stirring pentafluorobenzaldehyde with hydrazine in water at room temperature 21 and we intended to prepare the symmetrical azine 3 from 2,3,4,5,6-pentafluoroacetophenone 1 via the hydrazone 2 in a similar fashion (Scheme 1). However, due to the insolubility of 1 in water, no azine was formed when this procedure was attempted with the acetophenone 1.…”