Halogens Group fluoride

This topic has been reviewed [2, pp 94, 100-111, 130-134] All of the standard approaches to the synthesis of a compound like methyl 2-fluorostearate from methyl 2-bromostearate result mall yield of the 2-fluoro ester and the unsaturated esters. Although silver fluoride is not a new reagent, its use moist in wet acetonitrile to convert methyl 2-bromostearate to its fluoro ester is a departure from the traditional set of anhydrous conditions (Procedure 6, p 194) [71] In contrast, silver tetrafluoroborate converts a-chloroketones to their respective fluoroketones under anhydrous conditions. The displacement of less activated halogen groups by silver tetrafluoroborate to form their respective fluorides is novel Although silver tetrafluoroborate could not be used to convert an aliphatic terminal dichloromethyl or trichloromethyl group to its corresponding fluoro derivative, it is an effective fluorine source in other situations [72] (Table 8)... 

Metal halides can in some cases, be used to replace other atoms or groups besides fluorine with halogen Polyfluoroacyl fluorides and chlorides can be converted to fluoroalkyl iodides by simply heating the reactant in the presence of an alkali metal iodide [[Pg.382]

The displacement of less activated halogen groups by silver(I) tetrafluoroborate to the corresponding fluorides is not so widespread. Although silver(I) tetrafluoroborate cannot be used to transform an aliphatic terminal dichloromethyl or trichloromethyl group to the corresponding fluoro compound, it has been known to work in many other cases (Table 13).70... 

Synonyms Bifluoriden (Dutch) Fluor Fluor (Dutch, French, German, Polish) Fluorine-19 Fluoro (Italian) Fluorures acide (French) Fluor-uri acidi (Italian) Saeure fluoride (German) Chemical/Pharmaceutical/Other Class Halogen group... 

These reactions, involving nucleophilic displacement of other halogens by fluoride anion are important industrially and of some use in the laboratory for electron-deficient rings. The exchange/equilibrium of with is of use in PET (see 31.2.3). Nitro is also a good leaving group for this process in a number of systems purines (27.5), pyridines (8.3.2) and 1,2,4-triazoles (29.1.1.2). 

Ca " and F. The fluoride ion, F, is the first member of the halogen group of elements adjacent to the inert gas elements. 

Fluorine is at the top of the column (VII A) in the Periodic Table known as the halogens or salt formers. Chlorine, bromine, iodine, and astatine are also in the halogen group. Halogens easily accept electrons from other atoms and combine with metals to form salts. In nature, fluorine is found in ores of fluorspar (calcium fluoride) and cryolite (a combination of sodium, fluorine, and aluminum). In the body, fluorine is found in the blood, bones, and teeth. Many communities in the United States add small amounts of fluorine to drinking water, since the presence of fluorine has been found to prevent the formation of cavities in teeth. 

Groundwater containing dissolved salts beyond the permissible limits is harmful and unsuitable for human consumption. Excessive fluoride concentration in groundwater is a major problem in many parts of the world. Fluorineis, a natural constituent of the environment, belongs to the halogen group of... 

The lUPAC rules permit alkyl halides to be named m two different ways called func twnal class nomenclature and substitutive nomenclature In functional class nomencla ture the alkyl group and the halide (fluoride chloride bromide or iodide) are desig nated as separate words The alkyl group is named on the basis of its longest continuous chain beginning at the carbon to which the halogen is attached... 

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