Mercuration Aluminum

Acetic acid, fp 16.635°C ((1), bp 117.87°C at 101.3 kPa (2), is a clear, colorless Hquid. Water is the chief impurity in acetic acid although other materials such as acetaldehyde, acetic anhydride, formic acid, biacetyl, methyl acetate, ethyl acetoacetate, iron, and mercury are also sometimes found. Water significantly lowers the freezing point of glacial acetic acid as do acetic anhydride and methyl acetate (3). The presence of acetaldehyde [75-07-0] or formic acid [64-18-6] is commonly revealed by permanganate tests biacetyl [431-03-8] and iron are indicated by color. Ethyl acetoacetate [141-97-9] may cause slight color in acetic acid and is often mistaken for formic acid because it reduces mercuric chloride to calomel. Traces of mercury provoke catastrophic corrosion of aluminum metal, often employed in shipping the acid. 

Catalytic amounts of mercuric chloride are usually employed in this preparation. Aluminum isopropoxide is a useful Meerwein-Potmdorf-Verley reducing agent in certain ester-exchange reactions and is a precursor for aluminum glycinate, a buffering agent (see Alkoxides, metal). 

WeU-cleaned aluminum filings react at room temperature in the presence of mercuric chloride (20,21). In an autoclave, metallic aluminum and ethyl alcohol react without a catalyst at 120°C (22). The reaction can also be promoted by the addition of sodium ethoxide (23). Aluminum should be avoided as a material of constmction for ethanol service. 

A rather special procedure for the preparation of 21-hydroxy-20-ketopreg-nanes starts with the 17a-ethoxyethynyl-17 -hydroxy steroids described earlier. Free radical addition of ethanethiol to the triple bond, followed by acid-catalyzed hydrolysis and dehydration gives the 20-thioenol ether 21-aldehyde. This can be reduced with lithium aluminum hydride to the C-21 alcohol and then hydrolyzed to the C-20 ketone in the presence of mercuric chloride. The overall yield, without isolation of intermediates, is in the order of 50% ... 

Reduction of the enamine system of an aminostilbene by sodium in liquid ammonia 189) and of a 17-enaminosteroid by aluminum and mercuric chloride in alcohol 560) have also been reported. 

The second method, published later that year, represents probably the best laboratory preparation of Cp2Ti(CO)2 (1) to date (27). It involved the reduction of Cp2TiCl2 by means of aluminum filings activated with mercuric chloride. This reaction occurs via the green (Cp2TiCl)2 complex... 

Corynantheidol (255) has been prepared by Hanaoka et al. (155), who started from piperideine derivative 268 and tryptophyl bromide (197). The key cyclization step, resulting in indolo[2,3-a]quinolizine 270 as the major product besides 271, was carried out by mercuric acetate oxidation in the presence of the disodium salt of ethylenediaminetetraacetic acid (EDTA), followed by sodium borohydride reduction. Finally, lithium aluminum hydride reduction of 270 provided ( )-corynantheidol in good yield (155). 

To obtain an N-substituted amine reflux 0.1M ketone, 17 g aluminum filings or foil, 50 ml ethanol, 40 ml 30% aqueous n-butylamine (or other amine), and 0.5 g of mercuric chloride for 3 hours. Cool and pour on 500 g crushed ice and 200 ml 10% KOH. Extract 3 times with ether and dry, evaporate in vacuum (or wash combined ether layers 2 times with 10% HCI, basify acid extract with 15% NaOH and extract 3 times with ether and dry, evaporate in vacuum) to get the n-butyl-amine (or other amine). 

Aluminum Amalgam. Immerse thin strips of aluminum foil in a two percent aqueous solution of mercuric chloride for 30-60 seconds. Use a big bowl and plenty of solution for a moderate amount of foil. Decant off the solution, rinse the foil strips with dry ethanol, ether, and cut them into pieces of about Icm. ... 

Reductions with aluminum are carried out almost exclusively with aluminum amalgam. This is prepared by immersing strips of a thin aluminum foil in a 2% aqueous solution of mercuric chloride for 15-60 seconds, decanting the solution, rinsing the strips with absolute ethanol, then with ether, and cutting them with scissors into pieces of approximately 1 cm [141,142]. In aqueous and non-polar solvents aluminum amalgam reduces cumulative double bonds [143], ketones to pinacols [144], halogen compounds [145], nitro compounds [146, 147], azo compounds [148], azides [149], oximes [150] and quinones [151], and cleaves sulfones [141, 152, 153] and phenylhydrazones [154] (Procedure 30, p. 212). 

In a one-liter flask fitted with a reflux condenser 31.8 g (0.265 mol) of acetophenone is dissolved in 130 ml of absolute ethanol and 130 ml of dry sulfur-free benzene, and 0.5 g of mercuric chloride and 8 g (0.296 g-atom) of aluminum foil are added. Heating of the mixture initiates a vigorous reaction which is allowed to proceed without external heating until it moderates. Then the flask is heated to maintain reflux until all of the aluminum has dissolved (2 hours). After cooling the reaction mixture is treated with dilute hydrochloric acid and the product is extracted with benzene. The combined organic layers are washed with dilute acid, with a solution of sodium carbonate, and with a saturated solution of sodium chloride they are then dried with sodium sulfate and the solvent is evaporated under reduced pressure. A rapid vacuum distillation affords a fraction at 160-170° at 0.5 mm which, after dissolving in petroleum ether (b.p. 65-110°), gives 18.0 g (56%) of 2,3-diphenyl-2,3-butanediol, m.p. 100-123°. 

This reaction was applied to the synthesis of quinonoid natural products [34]. Propargyl bromides 62 a and 62b, which were prepared from prenyl bromide and phytyl bromide by a standard procedure, were converted to the corresponding aluminum reagents by reaction with powdered aluminum and a catalytic amount of mercuric chloride [35]. Then the iodomagnesium salt of cyclopropanol hemiacetal was treated with these reagents [36] affording the prenyl derivative 63 a and the phytyl derivative 63 b in 49 and 50% yield, respectively (Scheme 26). 

In a 1-1. three-necked round-bottomed flask, wrapped with aluminum foil to exclude light, and equipped with a mechanical stirrer, a reflux condenser, and an addition funnel, is suspended 37 g. (0.17 mole) of red mercuric oxide (Note 1) in 330 ml. of carbon tetrachloride (Note 2). To the flask is added 30.0 g. (0.22 mole) of 3-chlorocyclobutaneearboxylic acid (Note 3), and the mixture is heated to reflux while stirring. To the mixture is added dropwise a solution of 40 g. (0.25 mole) of bromine in 180 ml. of carbon tetrachloride as fast as possible (4-7 minutes) without loss of bromine from the condenser (Note 4). After a short induction period, carbon dioxide is evolved at a rate of 150-200 bubbles per minute (Note 5). The solution is allowed to reflux until the rate of carbon dioxide evolution slows to about 5 bubbles per minute. This will usually take 25-30 minutes (Note 6). The mixture is then cooled in an ice bath, and the precipitate is removed by filtration. The residue on the funnel is washed with carbon tetrachloride, and the filtrates are combined. The solvent is removed by distillation using a modified Claisen distillation apparatus with a 6-cm. Vigreux column, and vacuum distillation of the residual oil gives 13-17 g. (35-46%) of... 

Diethyl ether, Dichloromethylphosphine, Ethyl alcohol, N,N-Diethylamine, 2-Dimethylaminomethanol, Rhombic sulfur Acetylene, Arsenic trichloride. Aluminum chloride Acetylene, Arsenic trichloride. Mercuric chloride, Hydrochloric acid Methylene chloride. Magnesium metal turnings, Tetrahydrofuran, Arsenic trichloride, Hexanes... 

A standard solution of B-5 fixative containing a concentration of mercuric chloride of 60 g/1 was plated for 8 hours and yielded 60% recovered mercury metal. Two liters of solution were plated, thus a total of 120 g of mercuric chloride were processed. The stoichiometric amount of mercury metal from the reduction of 120 g of mercuric chloride equals 88 g. The recovered mercury metal totaled 53 g, thus demonstrating a 60% recovery efficiency. During the eight hour process the aluminum cathodes were changed once. The solution pH was between 3.6-3.8. 10 g of calcium chloride were added in order to... 

The use of larger amounts of mercuric chloride increases the difficulty of getting the final product free from color. This difficulty may be avoided by previously amalgamating the aluminum.3, 4 The mixture is shaken to distribute the mercuric chloride and thus aid in an even amalgamation of the aluminum. 

Aluminum fer/.-butoxide can be prepared by refluxing dry tert. -butyl alcohol with amalgamated aluminum 5l 6 or aluminum plus mercuric chloride.6 The method described is that of Adkins and Cox.0 The preparation of amalgamated aluminum has been described.3, 4 Aluminum isopropoxide can be prepared from dry isopropyl alcohol and aluminum,1 2 the method being essentially that described for aluminum ethoxide (Org. Syn. is, 82). 

ELECTRODE. Either ul two substances having different electromotive activity that enables an electric current to flow in the presence of an electrolyte. See also Electrolyte. Electrodes are sometimes called plates or terminal. Commercial electrodes are made uf a number of materials that vary widely in electrical conductivity, i.e.. lead, lead dioxide, zinc, aluminum, copper, iron, manganese dioxide, nickel, cadmium, mercury, titanium, and graphite research electrodes may be calomel mercurous chloride), platinum, glass or hydrogen. 

SYNTHESIS A solution of 0.12 g mercuric chloride in 180 mL H20 was added to 5 g aluminum foil that had been cut into 1 inch squares, and amalgamation allowed to proceed for0.5 h. The gray cloudy aqueous phase was decanted, and the resulting... 

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