Sodium chloroiridate

The reduction of keto steroids by treatment with chloroiridic acid, or sodium chloroiridate, and trimethyl phosphite has been studied in some detail.Ketones at the 2- and 3-positions are reduced predominantly to the corresponding axial alcohols, while ketones at 4,6,7,11,12,17 and 20 are not affected. The rate of reaction is increased by addition of aqueous sodium hydroxide. Replacement of sodium chloroiridate by tris(triphenylphos-phine)rhodium chloride gives a system which reduces a 3-keto steroid to the... 

The first report (325) of iridium(IIl) dithiocarbamate complexes appeared in 1973. The procedure is straightforward, consisting in addition of an excess of NaR2dtc to sodium chloroiridate in aqueous methanol. On being kept for several days, an orange-yellow precipitate... 

The mineral osmiridium may alternatively be chlorinated at elevated temperatures on a bed of sodium chloride. Osmium is converted to water-soluble sodium chloroosmate. Iridium and ruthenium also are converted into water-soluble sodium chloroiridate and chlororuthenate. The insoluble residues are filtered out. Osmium is recovered from this solution in several steps as mentioned above. 

Available forms Iridium metal or potassium or sodium chloroiridate in hydrochloric acid solution. 

The complexes are usually made by refluxing sodium chloroiridate and phosphine in 2-methoxyethanol or diethylene glycol under an atmosphere of CO. 

Insoluble iridium dioxide from the sodium peroxide fusion is dissolved in aqua regia, oxidized with nitric acid, and precipitated with ammonium chloride as impure ammonium hexachloroiridate(IV), (NH4)2IrCl6. To purify this salt, it is necessary to redissolve the compound and precipitate out the impurities as sulfides. Nitric acid and ammonium chloride are again used to produce pure ammonium chloroiridate, which is ignited and reduced with hydrogen to give iridium metal. 

Available from Johnson, Matthey Company, Ltd., London, England. tSimilar results are obtained by using sodium or potassium chloroiridate(UI). Checkers found a yield of 74%. 

Henbest redmetkm. Reduction of the ketone (I) with chloroiridic acid and trimethyl phosphite resulted in a 73 % yield of the axial 3 -alcohol (2). Sodium borohydride... 

Derivation By heating the chloroiridate K,IrCI6with sodium carbonate. 

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. 

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