Copper® hydroxy acetate

In closely related studies, French workers reacted 1,4-benzoquinone with the N,N-dimethylhydrazone of propenal, using BF3.0Et2 as catalyst. Treatment of the initially formed product with copper(II) acetate in buffered aqueous THF gave 2-formyl-5-hydroxy-2,3-dihydrobenzofuran in excellent overall yield. 

Scheme 5.2 Synthesis of tetra (hydroxy propyl) cyclam (5.21) via Michael addition followed by reduction, and X-ray crystal structure of its 1 1 copper(II) acetate complex.19...

Mixtures of the examined solvents are frequently used to obtain ICC. Thus, an aqueous-ethanol mixture was used for the preparation of 678 from 5-(2-hydroxy-phenyl)-3-phenyl-l,2,4-oxadiazole and copper(II) acetate [249] ... 

The earliest synthesis of imidazole was achieved by Debus from glyoxal, formaldehyde and ammonia (Scheme 70), and many of the classical methods of Imidazole synthesis were based on this general type of reaction. Initially, most syntheses utilized a-diketones, but in the 1930s it was shown that a-hydroxy ketones could serve equally well provided that some oxidizing agent (e.g. ammoniacal copper(II) acetate, citrate or sulfate) was incorporated in the reaction mixture. Further improvement used ammonium acetate in acetic acid as the nitrogen source. 

Reduction of Unsaturated Steroids.—Reduction with di-imide [provided by hydrazine hydrate and copper(ii) acetate in methanol] provides a novel and stereospecific conversion of steroidal 4-en-3)5-ols into 5a-dihydro-compounds. By contrast, catalytic hydrogenation is non-stereospecific and is often accompanied by partial hydrogenolysis, so the new method offers considerable promise. Catalytic reduction of 3jS-hydroxyandrost-4-en-17-one with tritium and a Pt catalyst gave 3)5-hydroxy-5a-androstan-17-one with the tritium distribution 4a, 37% 5a, 43% and 6a, 20%. The 5jS-isomer was also formed, with tritium at 4, 29 % 5, 54 % 6, 4.7 %, and 6a, 13 %. Tritium analysis was achieved by a combination of equilibration with base, bromination-dehydrobromination, and dehydrogenation. The appearance of tritium at C-6 indicates olefinic bond migration in contact with the catalyst. ... 

Oxidation. The copper(ii) acetate-catalysed oxidation of 6-hydroxy-benzothiazoles by molecular oxygen in the presence of a secondary amine proceeds exothermally and is attended by simultaneous amination, yielding (54). The presence of a 2-aryl group inhibits the amination, possibly owing to steric factors. ... 

Cupferron (Baudisch s reagent for iron analysis). Dissolve 6 g of Cupferron, the ammonium salt of Af-hydroxy-Af-nitrosoaniline (NH fC HjNlOlNO)) in 100 mL of distilled water. The reagent is good only for one week and must be kept in the dark. Cupric acetate (Barfoed s reagent for reducing monosaccharides). Dissolve 66 g of copper (11) acetate and 10 mL of glacial acetic acid in water and dilute to 1.0 L. 

Scheme 15 Glaser reactions using arylethynes and copper(II) hydroxy acetate...

The first successful separation using ligand exchange, via the technique of impregnation, on TLC was reported for enantiomers of amino acids by Gunther et al. [2-4] the commercial RP-18 silica gel plates were first immersed in a 0.25% copper (II) acetate solution prepared in methanol/water (1 9), dried and then immersed for 1 min in a 0.8% methanolic solution of the chiral selector (25,4R,2 / 5)-4-hydroxy-l-(2 -hydroxydodecyl)-proline. The impregnated plate, thus prepared, provided resolution of a number of enantiomeric amino acids, including substituted ones, when developed in methanol/water/acetonitrile (1 1 4 or 5 5 3). 

Biacetyl is produced by the dehydrogenation of 2,3-butanediol with a copper catalyst (290,291). Prior to the availabiUty of 2,3-butanediol, biacetyl was prepared by the nitrosation of methyl ethyl ketone and the hydrolysis of the resultant oxime. Other commercial routes include passing vinylacetylene into a solution of mercuric sulfate in sulfuric acid and decomposing the insoluble product with dilute hydrochloric acid (292), by the reaction of acetal with formaldehyde (293), by the acid-cataly2ed condensation of 1-hydroxyacetone with formaldehyde (294), and by fermentation of lactic acid bacterium (295—297). Acetoin [513-86-0] (3-hydroxy-2-butanone) is also coproduced in lactic acid fermentation. 

A hydroxy and an arylthio group can be added to a double bond by treatment with an aryl disulfide and lead tetraacetate in the presence of trifluoroacetic acid." Manganese and copper acetates have been used instead of Pb(OAc)4. ° Addition of the groups OH and RSO has been achieved by treatment of alkenes with O2 and a thiol (RSH)." Two RS groups were added, to give vie- dithiols, by treatment of the alkene with a disulfide RSSR and Bp3-etherate."° This reaction has been carried... 

The most widely used approach for the separation of enantiomers by TLC is based on a ligand exchange mechanism using commercially available reversed-phase plates impregnated with a solution of copper acetate and (2S,4R,2 RS)-4-hydroxy-l-(2-hydroxydodecyl)proline in optimized amounts. Figure 7.9 (10,97,98,107-109). Enantiomers are separated based on the differences in the stability of the diastereomeric complexes formed between the sample, copper, and the proline selector. As a consequence, a prime requirement for separation is that the seumple must be able to form complexes with copper. Such compounds include... 

Although the resulting vinylallenes 48 were usually obtained as mixtures of the E and Z isomers, complete stereoselection with regard to the vinylic double bond was achieved in some cases. In addition to enyne acetates, the corresponding oxiranes (e.g. 49) also participate in the 1,5-substitution (Scheme 2.18) and are transformed into synthetically interesting hydroxy-substituted vinylallenes (e.g. 50) [42], Moreover, these transformations can also be conducted under copper catalysis by simultaneous addition of the organolithium compound and the substrate to catalytic amounts of the cuprate (see Section 3.2.3). 

FIGURE 11.16. A possible mechanism for the ortho-hydroxy aXion of phenol over copper acetate dimers. 

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