Cooper acetate

In 1% aqueous acetic acid, the peptides of the sequence (Ala-Gly-Pro)n, bridged with Lys-Lys and beginning with n = 8 show a cooperative transition, which was interpreted as a triple helix-coil transition (see Figs. 35, 36). 

Cooper(I) carboxylates give esters with primary (including neopentyl without rearrangement), secondary, and tertiary alkyl, allylic, and vinylic halides. A simple Sn mechanism is obviously precluded in this case. Vinylic halides can be converted to vinylic acetates by treatment with sodium acetate if palladium(II) chloride is present. ... 

Cooper RA, MA Skinner (1980) Catabolism of 3- and 4-hydroxyphenylacetate by the 3,4-dihydroxyphenyl-acetate pathway in Escherichia coli. J Bacterial 143 302-306. 

The reaction is endothermic, and heat transfer to the reactor is required in order to accomplish the decomposition of the acetylated oil, to liberate acetic acid vapour. The example has been considered previously by Perona (1972), Smith (1972), Cooper and Jeffreys (1971) and Froment and Bischoff (1990), although their solution procedures differ from that here. Data values are based on those used by Froment and Bischoff. 

Fahey (16) suggests that intermediate 3 dissociates formaldehyde he finds supportive evidence in the rhodium-based system by observation of minor yields of 1,3-dioxolane, the ethylene glycol trapped acetal of formaldehyde. For reasons to be discussed later, we believe the formation of free formaldehyde is not on the principal reaction pathway. (c) We have also rejected two aspects of the reaction mechanism proposed by Keim, Berger, and Schlupp (15a) (i) the production of formates via alcoholysis of a formyl-cobalt bond, and (ii) the production of ethylene glycol via the cooperation of two cobalt centers. Neither of these proposals accords with the observed kinetic orders and the time invariant ratios of primary products. 

The first reports on asymmetric hydroformylation using diphosphite ligands revealed no asymmetric induction [71], In 1992, Takaya et al. published the results of the asymmetric hydroformylation of vinyl acetate (e.e.=50%) with chiral diphosphites [72], In 1992, an important breakthrough appeared in the patent literature when Babin and Whiteker at Union Carbide reported the asymmetric hydroformylation of various alkenes with e.e. s up to 90%, using bulky diphosphites derived from homochiral (2R,4R)-pentane-2, 4-diol (see Figure 8.20). Van Leeuwen et al. studied the influence of the bridge length, bulky substituents and cooperativity of chiral centres on the performance of the catalyst [73,74],... 

Buss KA, Cooper DR, Ingram-Smith C, et al. 2001. Urkinase structure of acetate kinase, a member of the ASKHA superfamily of phosphotransferases. J Bacte-riol 183 680-6. 

After anomerisation and before initiation of the ring-expansion process, the a-and p-glucofuranosides were found to be present in a -equilibrium in the ratio 1 1.7 which agrees with the value obtained by radiochemical methods and with that observed by Bishop and Cooper for the methyl xylofuranosides 4). However, the ratio for the xylosides was found in the isotope work to be 1 1.2 (1 1.3 for ethyl xylofuranosides) regardless of whether they were derived from xylose or either of its methyl furanosides. A further relevant observation made with these furanosides was that acetal was formed during their anomerisation indicating that pathways (C) and (E) (Scheme 3) are open. 

Cooper and Waters (13) first reported the oxidation of cyclohexane by cobalt(III) perchlorate in aqueous acetonitrile to give a mixture of cyclohexanol, cyclohexanone, and adipic acid. A more detailed study of this oxidation (74), using cobalt(III) acetate in acetic acid at 80°C, both with and without oxygen, gives products, such as cyclohexylacetate, that can only be explained if there is a direct interaction of cobalt(III) with the C—H [Pg.182]

Malcolm, A.R., Mills, L.J. McKenna, E.J. (1985) Effects of phorbol myristate acetate, phorbol dibutyrate, ethanol, dimethylsulfoxide, phenol, and seven metabolites on phenol on metabolic cooperation between Chinese hamster V79 lung fibroblasts. Cell biol. Toxicol., 1, 269-283... 

In the area of catalysis, the esterolysis reactions of imidazole-containing polymers have been investigated in detail as possible models for histidine-containing hydrolytic enzymes such as a-chymotrypsin (77MI11104). Accelerations are observed in the rate of hydrolysis of esters such as 4-nitrophenyl acetate catalyzed by poly(4(5)-vinylimidazole) when compared with that found in the presence of imidazole itself. These results have been explained in terms of a cooperative or bifunctional interaction between neighboring imidazole functions (Scheme 19), although hydrophobic and electrostatic interactions may also contribute to the rate enhancements. Recently these interpretations, particularly that depicted in Scheme 19, have been seriously questioned (see Section 1.11.4.2.2). 

Clarification by removal of casein with such agents as calcium chloride, acetic acid, cooper sulfate, or rennin has often been employed to obtain a serum more suitable for refractometric measurements. Obviously the composition, and hence the refractive index, of such sera will depend on the method of preparation. Furthermore, some of the serum proteins may be precipitated with the casein by some of the agents used, particularly if the milk has been heated. Refractive index measurements of such sera are not generally considered as satisfactory as freezing point measurements for detection of added water (David and MacDonald 1953 Munchberg and Narbutas 1937 Schuler 1938 Tell-mann 1933 Vleeschauwer and Waeyenberge 1941). Menefee and Overman (1939) reported a close relation between total solids in evaporated and condensed products and the refractive index of serum prepared therefrom by the copper sulfate method. Of course, a different proportionality constant would hold for each type of product. 

Cooper et al. (10) and Cox (11) were the first to report the gas chromatographic analysis of urinary pregnanediol. These methods normally involved hydrolysis, extraction, and the chromatographic analysis of the free pregnanediol, the acetate derivative, the trimethylsilyl ether derivative, or the bis-heptafluor-obutyrate derivative. 

During the same period in Germany Farbenfabriken Bayer, in cooperation with Farbwerke Hoechst, developed a vapor-phase process, which avoids many of the possible corrosion problems. This process has not yet been practiced by Bayer on a large scale but has been licensed widely, especially in Japan (4, 5), where, as a result, acetylene is no longer used to produce vinyl acetate. 

Catalysts used to convert ethylene to vinyl acetate are closely related to those used to produce acetaldehyde from ethylene. Acetaldehyde was first produced industrially by the hydration of acetylene, but novel catalytic systems developed cooperatively by Farbwerke Hoechst and Wacker-Chemie have been used successfully to oxidize ethylene to acetaldehyde, and this process is now well established (7). However, since the largest use for acetaldehyde is as an intermediate in the production of acetic acid, the recent announcement of new processes for producing acetic acid from methanol and carbon monoxide leads one to speculate as to whether ethylene will continue to be the preferred raw material for acetaldehyde (and acetic acid). 

A positive cooperative effect of formamidine and acetic acid is possible because we have found that acetic acid acts as a promotor in various types of hydrogenations. 

Citrate lyase catalyzes the cleavage of citrate to oxaloacetate and acetate in the presence of Mg2+ or Mn2+, but in the presence of EDTA it catalyzes its synthesis. The enzyme is a complex of three subunits. The y-subunit functions as an acyl carrier protein (ACP). The a-subunit is an acyl transferase involved in citryl-ACP formation and the release of acetate, and the /8-subunit catalyzes the cleavage of the citryl-ACP intermediate to oxaloacetate and acetyl-ACP. The enzyme from Klebsiella aerogenes has been purified, and binds 18 Mn2"1 in a cooperative manner. 

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