Gold chloride salts

Hydrobromide-gold chloride salt 164 Yellow scales (HjO-HCl) 197... 

Pilocarpine dissolves in dilute soda solution, and the rotation is thereby reduced, due to the formation of the sodium salt of pilocarpic acid, CiiHigOgNa, of which pilocarpine is the lactone. Amorphous barium and copper salts have been prepared. Pilocarpine in dilute sulphuric acid gives with hydrogen peroxide, followed by potassium dichromate, a bluish-violet colour soluble in benzene. For the identification of the alkaloid Wagenaar recommends precipitation with gold chloride solution. 

Carbene complexes have also been prepared by transmetallation reactions. Lithiated azoles react with gold chloride compounds and after protonation or alkylation the corresponding dihydro-azol-ylidene compounds, e.g., (381) or (382), are obtained.22 9-2264 Silver salts of benz-imidazol have also been used to obtain carbene derivatives.2265 Mononuclear gold(I) carbene complexes also form when trimeric gold(I) imidazolyl reacts with ethyl chlorocarbonate or ethyl idodate.2266,2267 The treatment of gold halide complexes with 2-lithiated pyridine followed by protonation or alkylation also yields carbene complexes such as (383).2268 Some of these carbene complexes show luminescent properties.2269-2271... 

Thiols like pyridine-2-thiol yield (carbene)gold thiolates, and onium salts give cationic (carbene)gold ylide complexes, isolated and characterized as the perchlorates.170 The reaction of dithiocatechol with (cyclohexylisocya-nide)gold chloride affords a carbene complex [(CyNC)AuC(NHCy)2]+Cl-, which co-crystallizes with a neutral tetranuclear complex [(CyNCAu)2Au2(S2C6H4)2].224... 

When an alkaline solution of tetrammino-auric salt is kept it becomes yellow in colour, and a yellow precipitate which is explosive is formed. This appears to have composition similar to that of explosive gold chloride. 

The halogen acids do not form salts with the tetrammino-auric ion in solution, for if an aqueous solution of potassium chloride be added to tetrammino-auric nitrate a yellow colour is produced, and a yellow precipitate formed which apparently is a derivative of explosive gold chloride. 

In this case, double addition products were obtained. More recently, Hashmi and Blanco described the twofold intermolecular hydroarylation of unactivated C-C triple bonds, using the chloride-bridged gold (I) salt [(p.-Cl)(AuPMes3)2]BF4 [129, 130]. 

E. P. Alvarez 2 found that the pemitrates react with soln. of lead acetate (white precipitate), silver nitrate (white precipitate), mercurous nitrate (white precipitate with rapid decomposition), mercuric chloride (red precipitate), copper sulphate (blue precipitate), zinc and cadmium sulphates (white precipitate), bismuth nitrate (white precipitate), gold chloride (slight effervescence and escape of oxygen), manganous chloride (pink precipitate), nickelous chloride or sulphate (greenish-white precipitate), cobaltous nitrate and chloride (pink precipitate), ferrous sulphate (green or bluish-green precipitate), ferric chloride (red ferric hydroxide), and alkaline earth chlorides (white precipitates). The precipitates are all per-salts of the bases in question. 

Action of ammonia or ammonium salts on gold chloride, oxide or other salts under a wide variety of conditions gives explosive or fulminating gold [1], Of uncertain composition but containing Au—N bonds, this is a heat-, friction- and impact-sensitive explosive when dry, similar to the related mercury and silver compounds [2]. In an attempt to precipitate finely divided gold from its solution in aqua regia... 

Recent developments in gold chloride catalyzed C C and C- 0 coupling reactions provide a fitting opportunity to highlight the current status [8] of homogeneous catalysis with gold salts and to show the potential for further developments. 

When cyanuric chloride reacts with DMF in t-butyl methyl ether it forms Gold s salt, [3-(dimethylamino)-2-azaprop-3-enylidene]dimethylammonium chloride, in almost quantitative yield. Methylate-promoted condensation of this salt with the methyl ester of sarcosine gives methyl 1-methylimidazole-5-carboxylate in up to 75% yield. The synthetic utility of this method is dependent on interception of the eliminated dimethylamine by addition of dimethyl oxalate and the bubbling of nitrogen through the solution [38]. 

Alkaloids are invariably found in combination with acids forming salts which dissolve in water or alcohol. They are composed of carbon, hydrogen and nitrogen. Some contain oxygen. They are precipitated from saline solutions by the addition of alkalies. They are mostly colorless and crystallizable. They can be precipitated by one or more of the following alkaloidal reagents tannic acid, gold chloride, phospho-molybdic acid, picric acid and potassio-mercuric iodide. 

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