Pentafluoropyridine synthesis

Dmowski, W. Haas, A. Trifluoromethanethiolate ion. Part 2. Nucleophilic substitution in pentafluoropyridine. Synthesis and characteristics of trifluoromethylthio and trifluoro-methylsulphonyl derivatives. J. Chem. Soa, Perkin Trans. 1 1987, 2119-2124. 

Dmowski W, Haas A (1985) Chimia 39 185 (b) Dmowski W, Haas A (1987) Trifluoro-methanethiolate ion. Part 2. Nucleophilic substitution in pentafluoropyridine. Synthesis and characteristics of trifluoromethylthio and trifluoromethylsulphonyl derivatives. J Chem Soc Perkin Trans 1 2119-2124. doi 10.1039/P19870002119 (c) Dmowski W, Haas A (1988) Tiifluoromethanethiolate ion. Part 3. Reactions with tetrafluoropyridazine and tetrafluoropy-limidine. J Chem Soc Perkin Trans 1 1179-1181. doi 10.1039/P19880001179... 

The reactivity profile established for pentafluoropyridine, where the 4, 2- and 6-positions are sequentially, regiospecifically substituted by a succession of oxygen-centred nucleophiles, has allowed medicinal chemists to use pentafluoropyridine as a core scaffold for the synthesis of small arrays of biologically active pyridine systems that fall within the Lipinski parameters (see Table 11.3). 

Figure 11.8 Strategy for the synthesis of ring-fused heterocycles from pentafluoropyridine.

Figure 11.13 Synthesis of 2-pyridone systems from pentafluoropyridine.

Chambers, R. D., Hoskin, P. R., Sandford, G., et al. (2001) Synthesis of multi-substituted pyridine derivatives from pentafluoropyridine. J. Chem. Soc., Perkin Trans 1, 2788-2795. 

Systematic exploitation of the different susceptibilities of the different positions of perfluoroaromatic compounds can be used as a tool for combinatorial synthesis of (fluoro)aromatic compounds. The feasibility of this concept was recently demonstrated by R. D. Chambers and coworkers who used the pentafluoropyridine system as an example [99] (Scheme 2.43). Further differentiation of the reactivity toward hard and soft nucleophiles was achieved by partial replacement of fluorine by bromine in this system. 

A comprehensive review of the synthesis and general chemistry of silylphos-phines has appeared. Routes to diorgano(trichlorosilyl)phosphines have been developed. A route to perfluoroarylphosphines, e.g., (172), is afforded by the reactions of fluoroarenes with either dimethyl(trimethylsilyl)- or dimethyl(trimethylstannyl)-phosphine. In a similar manner, primary, secondary, and tertiary phosphines, and their trimethylsilyl analogues, have been shown to react with pentafluoropyridine to give a range of tetrafluoropyridyl-phosphines The synthesis, coordination chemistry, and catalytic applications... 

Procedures involving the formation of saturated fluorocarbons followed by defluorination (e.g., over iron) have been very successful in the synthesis of benzenoid compounds.1 However, defluorination of perfluoropiperidine (9) is not a practical synthesis of pentafluoropyridine.61 An indirect process has been described recently for the preparation of pentafluoropyridine from... 

Since 10 and pentafluoropyridine are the principal products in the small-scale fluorination of pyridine over cesium tetrafluorocobaltate (Eq. 10), this constitutes an overall direct synthesis of pentafluoropyridine via a very interesting rearrangement. 

Fluorides are more reactive than the other hahdes, (cf. 3.3.2) for example 2-fluoropyridine can be converted into 2-dialkylamino-pyridines using hthium amides at room temperature. This could be compared with the 130 °C required to displace a-bromine using the potassium salt of pyrazole. Displacement of nitro can be made the means for the synthesis of a- and y-fluoro-pyridines. Of the five fluorines in pentafluoropyridine, the y-fluorine is displaced most rapidly. ... 

Perfluorinated systems are molecules in which all of the hydrogen atoms have been replaced by fluorine and so, in this chapter, we are concerned with the chemistry of perfluorinated heteroaromatic systems containing one or more nitrogen atoms such as pentafluoropyridine, tetrafluoropyrimidine, and trifluoro- -triazine. Since the first realistic synthesis of pentafluoropyridine was reported in the 1960s, the chemistry of perfluorinated heteroaromatic systems has developed extensively and been discussed in several detailed reviews and in more general monographs. 

Recently, the reactivity profile of pentafluoropyridine, where reaction at the 4-position is followed by substitution at the 2- and 6-positions selectively, has been used by medicinal chemists for the synthesis of small arrays of biologically active... 

FIGURE 8.11 General strategy for the synthesis of macrocyclic derivatives from pentafluoropyridine. 

Pentafluoropyridine (144) was applied for the synthesis 2,4-diamino-3,5,6-trifluoropyridine (244) [142], Thus double nucleophilic substitution of fluorine atoms in 2 and 4 positions of the pyridine 144 occurred to give 244. The same... 

Ranjbar-Karimi R, Mashak-Shoshtari M, Darehkordi A (2011) Ultrasound promoted facile synthesis of some pentafluoropyridine derivatives at ambient conditions. Ultrason Sonochem 18 258-263... 

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