Halides, inorganic, with carboxylic acid

Many organic compounds react with carboxylic acids, acyl halides, or anhydrides in the presence of certain metallic halides, metallic oxides, iodine, or inorganic acids to form carbonyl compounds. The reaction is generally applicable to aromatic hydrocarbons. Benzene, alkylbenzenes, biphenyl, fluorene, naphthalene, anthracene, acenaphthene, phenanthrene, higher aromatic ring systems, and many derivatives undergo the reaction. 

Inhibition of the Oxidase Activity. The oxidase activity of ceruloplasmin has been reported to be inhibited by a wide variety of different substances, and it would be well to briefly point out several ways in which an Inhibition of the activity may be manifested (a) A true inhibition of the activity resulting from a combination of enzyme or an enzyme-substrate complex with the effector, (b) Inhibition resulting from the sequestering of free iron, as has already been discussed, (c) Alteration of the chromophoric properties of the substrate or product by the effector, for example, the reduction of the colored radical cation of DPD. (d) Apparent inhibition will also result when the inhibitor causes aggregation or precipitation of the protein. Inhibition attributable to each of the above has been reported, [cf. Curzon and Speyer (175) for a lucid discussion of these points.] We will be concerned here primarily with three types of inhibitors, all of which act by a direct combination with some form of the enzyme halide and inorganic anions, carboxylic acids having a double bond a- to the carboxyl function, and certain divalent cations. 

The preferred reagent for Hunsdiecker-type reactions is lead(IV) acetate in the presence of an inorganic halide.18,19 The yields are usually good to excellent. Reaction of cyclobutanecar-boxylic acid with lead(IV) acetate in the presence of lithium chloride gave chlorocyclobutane (1) in good yield.18 Other carboxylic acids reacted under similar conditions.18 However, care should always be taken when lead(IV) acetate is used, as the use of this reagent in the absence of the halide results in decarboxylative elimination to give an alkene, which is found as a byproduct.19... 

Volume 10 is devoted to formation and solvolysis of esters and related reactions, with discussion of the effect of neighbouring groups and biological implications, e.g. enzyme action, where appropriate. The first chapter deals mainly with esters of the inorganic acids of phosphorus and sulphur, Chapter 2 with the formation and solvolysis of esters of organic acids and the final chapter with the solvolysis of related derivatives of carboxylic acids, e.g. halides, amides, anhydrides, cyanides, carbamic acid derivatives. 

Carboxylic acid amide functionalised imidazolium salts can be reacted with group 10 halides directly in the presence of an inorganic base (e.g. K COj) to form homoleptic complexes (see Figure 4.41) [122]. Interestingly, the carbene units are cis to each other and not trans as would be expected (see Figures 4.30 and 4.38). The cis complexation is not aided by hydrogen bonding as the carboxylic acid amide functionality loses its proton upon complexation to nickel. 

Silicon halides (especially the readily available chlorides) are probably the most synthetically useful and versatile monomeric inorganic silicon compounds. They may readily be reduced to hydrides, hydrolyzed to silanols (and subsequently to siloxanes), treated with other protic species such as alcohols, carboxylic acids, amines, and thiols to give SiA)R, Si-0C(0)R, Si NR2, and Si SR species respectively, used to make sUyl pseudohalogen derivatives by treatment with silver or alkali metal salts, for example, treated with sodium... 

Aryl halides can be carbonylated to give the corresponding carboxylic acids (Scheme 138) under very mild conditions in presence of inorganic bases (like alkaline metal hydroxides, carbonates, acetates etc.) and certain palladium catalysts (like Pd(OAc)2, K PdCl, Pd(NH3) Cl, PdCl2(PPh3)2 etc.). Best results are obtained with simple palladium salt using K2CO3 as base (Scheme 138). 

Salty tastes are exhibited almost exclusively by some inorganic salts (especially halides, sulfates, phosphates, nitrates and carbonates of alkali metals, alkaline earth metals and ammonium salts). Salty tastes combined with other tastes are also shown by some salts of carboxylic acids (salts of formic, acetic, succinic, adipic, fumaric, lactic, tartaric and citric acids), amino acids (such as salts of glutamic acid and chohne) and some oligopeptides. 

By phase transfer catalyzed reaction of alkyl or aryl halide with inorganic salts of carboxylic acid... 

These reactions are most important for the preparation of acyl fluorides. " Acyl chlorides and anhydrides can be converted to acyl fluorides by treatment with polyhydrogen fluoride-pyridine solution" or with liquid HF at — 10°C. Formyl fluoride, which is a stable compound, was prepared by the latter procedure from the mixed anhydride of formic and acetic acids. Acyl fluorides can also be obtained by reaction of acyl chlorides with KF in acetic acid or with DAST. Carboxylic esters and anhydrides can be converted to acyl halides other than fluorides by the inorganic acid halides mentioned in 10-77, as well as with PhsPXa (X = Cl or but this is seldom done. Halide exchange can be carried out in a... 

Generally, cement-forming liquids are aqueous solutions of inorganic or organic adds. These adds include phosphoric add, multifunctional carboxylic adds, phenolic bodies and certain metal halides and sulphates (Table 2.1). There are also non-aqueous cement-forming liqtiids which are multidentate acids with the ability to form complexes. 

---