Cupric carbonate, reaction with acids

Furthermore we found that kasugamycin forms a chelate compound with basic cupric carbonate (7), which is stable to acid and unstable to heat and base. This evidence together with the results obtained above strongly supports the amidine structure (13) for kasugamycin. Finally the amidine compound was successfully prepared by the reaction of kasuganobiosamine with the diethyl ester of oxalimidic acid (14) and... 

In real systems (hydrocarbon-02-catalyst), various oxidation products, such as alcohols, aldehydes, ketones, bifunctional compounds, are formed in the course of oxidation. Many of them readily react with ion-oxidants in oxidative reactions. Therefore, radicals are generated via several routes in the developed oxidative process, and the ratio of rates of these processes changes with the development of the process [5], The products of hydrocarbon oxidation interact with the catalyst and change the ligand sphere around the transition metal ion. This phenomenon was studied for the decomposition of sec-decyl hydroperoxide to free radicals catalyzed by cupric stearate in the presence of alcohol, ketone, and carbon acid [70-74], The addition of all these compounds was found to lower the effective rate constant of catalytic hydroperoxide decomposition. The experimental data are in agreement with the following scheme of the parallel equilibrium reactions with the formation of Cu-hydroperoxide complexes with a lower activity. 

In any reaction where the cleavage of a carbon-hydrogen bond is important, the introduction of a metal ion into the molecule in the proper position will facilitate reaction. For example, in the elimination of the elements of a phosphoric acid monoester from the molecule below, the electrostatic attraction of the cupric ion facilitates removal of the proton on the o -carbon atom with subsequent elimination of the phosphoryl residue (8). 

N-Acetylation of basic amino acids. The reagent reacts with an aqueous solution of the copper salt of a basic amino acid to give the N-acetyl derivative.1 The procedure is superior to the usual synthesis in which acetic anhydride is used because the reaction goes to completion. As applied to L-lysine, the method is simple and gives better yields of pure e-N-acetyl-L-lysine. Excess cupric carbonate is added to a boiling aqueous solution of L-lysine (0.1 mole) and the solution is filtered and cooled to 25° and treated with sodium bicarbonate, p-nitrophenylacetate, and a few milliliters of ethyl acetate to keep the acetate in solution. After stirring for 15 hrs the copper salt which separates is filtered, suspended in water, and freed of copper with H2S. The solution is evaporated to dryness and the N-acetyllysine crystallized from water-ethanol. 

The production of another important chemical and polymer intermediate, acetic acid, was revolutionized by the Wacker process that was introduced in 1960. It was a simple, high yield process for converting ethylene to acetaldehyde, which replaced the older process based on ethanol and acetylene. In the Wacker reaction, the palladium catalyst is reduced and then reoxidized. Ethylene reacts with water and palladium chloride to produce acetaldehyde and palladium metal. The palladium metal is reoxidized by reaction with cupric chloride, which is regenerated by reaction with o gen and hydrochloric acid. In 1968, BASF commercialized an acetic acid process based on the reaction of carbon monoxide and methanol, using carbonyl cobalt promoted with an iodide ion (74). Two years later, however, Monsanto scored a major success with its rhodium salt catalyst with methyl iodide promoter. Developed by James F. Roth, this new catalyst allowed operation at much milder conditions (180°C, 30-40 atm) and demonstrated high selectivity for acetic acid (75). 

Acid amides give a color reaction with fluorescein chloride which has already been described in the discussion on amines (p. 324). The biuret reaction is given by compounds which contain a group in which two carbonamide groups are bound to one carbon or nitrogen atom, as, for example, in malonamide (I), biuret (II), or oxamide (III) in an alkaUne medium these substances give a red-violet complex compound with cupric hydroxide. 

Cupric chloride or copper(II) chloride [7447-39 ], CUCI2, is usually prepared by dehydration of the dihydrate at 120°C. The anhydrous product is a dehquescent, monoclinic yellow crystal that forms the blue-green orthohombic, bipyramidal dihydrate in moist air. Both products are available commercially. The dihydrate can be prepared by reaction of copper carbonate, hydroxide, or oxide and hydrochloric acid followed by crystallization. The commercial preparation uses a tower packed with copper. An aqueous solution of copper(II) chloride is circulated through the tower and chlorine gas is sparged into the bottom of the tower to effect oxidation of the copper metal. Hydrochloric acid or hydrogen chloride is used to prevent hydrolysis of the copper(II) (11,12). Copper(II) chloride is very soluble in water and soluble in methanol, ethanol, and acetone. 

In terms of A -substitution, Hartwig reported improved conditions for the Pd(0) catalyzed N-arylation of indoles and pyrrole <99JOC5575>. It was found that when commercially available P(<-Bu)3 was employed as ligand and cesium carbonate as base, the reaction between indoles 95 and unhindered aryl bromides 96 or chlorides occurred under milder conditions than the Pd(OAc)2/DPPF system previously reported yielding the A/-arylated products 97. Alternatively, it has been found that pyrrole- and indole-2-carboxylic acid esters can be selectively 7V-arylated with phenylboronic acids in the presence of cupric acetate and either tiiethylamine or pyridine <99T12757>. 

In a number of nonenzymatic reactions catalyzed by pyridoxal, a metal ion complex is formed—a combination of a multivalent metal ion such as cupric oi aluminum ion with the Schiff base formed from the combination of an amino acid and pyridoxal (I). The electrostatic effect of the metal ion, as well as the electron sink of the pyridinium ion, facilitates the removal of an a -hydrogen atom to form the tautomeric Schiff base, II. Schiff base II is capable of a number of reactions characteristic of pyridoxal systems. Since the former asymmetric center of the amino acid has lost its asymmetry, donation of a proton to that center followed by hydrolytic cleavage of the system will result in racemic amino acid. On the other hand, donation of a proton to the benzylic carbon atom followed by hydrolytic cleavage of the system will result in a transamination reaction—that is, the amino acid will be converted to a keto acid and pyridoxal will be converted to pyridoxamine. Decarboxylation of the original amino acid can occur instead of the initial loss of a proton. In either case, a pair of electrons must be absorbed by the pyridoxal system, and in each case, the electrostatic effect of the metal ion facilitates this electron movement, as well as the subsequent hydrolytic cleavage (40, 43). 

Metalated ferrocenes have served as valuable intermediates for the synthesis of a number of other derivatives. Treatment of lithiated ferrocenes with tributyl borate followed by hydrolysis leads to ferroceneboronic acid (XXXIII) as well as the diboronic acid (73). Ferroceneboronic acid, like benzeneboronic acid, is readily cleaved by cupric bromide or cupric chloride to form the corresponding halo derivatives (XXXIV). Ferrocene-l,l -diboronic acid reacts in the same manner, and either one or two carbon-boron bonds can be cleaved. Further reactions of this type have led to a variety of mixed dihaloferrocenes (73, 75). 

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