Copper sulfate-sodium borohydride

AMIDES Copper(II) sulfate-Sodium borohydride. Di-ji-carbonylhexacarbonyl-dicobalt. Diphenyl 2-keto-3-oxazolinylphosphonate. 4(R)-Methoxycarbonyl- l,3-thiazolidine-2-thione. Phenyl N-... 

Refluxing of 9-fluorenone-l-carboxylic acid with zinc dust and copper sulfate in aqueous potassium hydroxide for 2.5 hours afforded 9-fluorenol-1-carboxylic acid in 94% yield [1004]. Reduction with sodium borohydride in aqueous methanol at 0-25° converted 5-ketopiperidine-2-carboxylic acid to /ra j-5-hydroxypiperidine-2-carboxylic acid in 54-61% yield [1005], On the other hand, reduction of V-benzyloxycarbonyl-5-ketopiperidine-2-carboxylic acid gave 89% yield of V-benzyloxycarbonyl-cis-5-hydroxypiperidine-2-car-boxylic acid under the same conditions [1005],... 

Palladium(II) chloride-Copper(II) chloride, 235 Phenylthiocopper, 209 Phosphomolybdic acid-Potassium di-chromate-Copper(II) sulfate, 248 Sodium borohydride-Copper(II) acetate, 279... 

Nitrophenyl Phenyl Tellurium5 Under nitrogen, 0.29 g (0.70 mmol) of diphenyl ditellurium are reduced with 0.03 g (0.73 mmol) of sodium borohydride in 5 ml of hexamethylphosphoric triamide at 70-80° with stirring for 0.5 h. Then 0.14 g (0,73 mmol) of copper(l) iodide are added whereupon the mixture turns black. 0.18 g (0.73 minol) of l-iodo-2-nitrobenzene are added and the mixture is stirred well and heated at 80 90° for 1.5 h. The mixture is cooled, water is added, the whole is extracted with diethyl ether, the extract is washed with concentrated sodium chloride solution, and the organic layer is dried with anhydrous sodium sulfate. The solvent is evaporated under vacuum and the residue is chromatographed on a short column of alumina with hexane as eluent. Fractions containing the product are combined and evaporated to dryness and the residue is rccrystallized from ethanol yield 0.22 g (95%) m.p. 94°. 

Dean-Stark trap. During this period the yellow reaction mixture turned first crimson and then dark brown. Toluene was removed under reduced pressure and the residual enamine crystallized from acetone as discolored crystals (8 g). The enamine (10 g) was treated with concentrated HC1 (1 ml) in methanol (200 ml). The crimson solution was evaporated and the residual dark oil crystallized from acetone, yielding the intermediate ketopyran (8.4 g, yellow needles from acetone). The crystals were added to methanol and an excess of sodium borohydride was gradually added to the solution, yielding on standard workup 7.47 g of the hydroxypyran. The crystalline hydroxy intermediate was well mixed with 4.5 g of anhydrous copper sulfate and heated to 150-160°C in a carbon dioxide current for 10 min. Upon cooling, the product was extracted into methylene chloride. Removal of the solvent under reduced pressure gave 6.3 g of discolored solid that was decolorized with carbon and recrystallized from acetone (melting point not reported). 

Reducing agents Aluminum hydride. Bis-3-methyl-2-butylborane. n-Butyllithium-Pyridine. Calcium borohydride. Chloroiridic acid. Chromous acetate. Chromous chloride. Chromous sulfate. Copper chromite. Diborane. Diborane-Boron trifluoride. Diborane-Sodium borohydride. Diethyl phosphonate. Diimide. Diisobutylaluminum hydride. Dimethyl sulfide. Hexamethylphosphorous triamide. Iridium tetrachloride. Lead. Lithium alkyla-mines. Lithium aluminum hydride. Lithium aluminum hydride-Aluminum chloride. Lithium-Ammonia. Lithium diisobutylmethylaluminum hydride. Lithium-Diphenyl. Lithium ethylenediamine. Lithium-Hexamethylphosphoric triamide. Lithium hydride. Lithium triethoxyaluminum hydride. Lithium tri-/-butoxyaluminum hydride. Nickel-aluminum alloy. Pyridine-n-Butyllithium. Sodium amalgam. Sodium-Ammonia. Sodium borohydride. Sodium borohydride-BFs, see DDQ. Sodium dihydrobis-(2-methoxyethoxy) aluminate. Sodium hydrosulflte. Sodium telluride. Stannous chloride. Tin-HBr. Tri-n-butyltin hydride. Trimethyl phosphite, see Dinitrogen tetroxide. 

Reduction with sodium borohydride is sometimes carried out on samples without previous digestion. Margel and Hirsh (1984) reported a detection limit of 1-2 /phenylmercury compounds were also completely reduced at pH 9.5 and a temperature above 25°C. Copper sulfate had to be added to urine in order to get a satisfactory recovery of MeHg. However, in case of MeHg. Toffaletti and Savory (1975) reported the formation of an unidentified mercury compound, which was aerated from the sample, but was not detected by AAS unless the vapour was heated to about 700 °C. 

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