Thallium salts

The relative toxicities of thallium compounds depend on their solubHities and valence states. Soluble univalent thallium compounds, eg, thaHous sulfate, acetate, and carbonate, are especiaHy toxic. They are rapidly and completely absorbed from the gastrointestinal tract, skin peritoneal cavity, and sites of subcutaneous and intramuscular injection. Tb allium is also rapidly absorbed from the mucous membranes of the respiratory tract, mouth, and lungs foHowing inhalation of soluble thallium salts. Insoluble compounds, eg, thaHous sulfide and iodide, are poorly absorbed by any route and are less toxic. 

A mild and effective method for obtaining N- acyl- and N- alkyl-pyrroles and -indoles is to carry out these reactions under phase-transfer conditions (80JOC3172). For example, A-benzenesulfonylpyrrole is best prepared from pyrrole under phase-transfer conditions rather than by intermediate generation of the potassium salt (81TL4901). In this case the softer nature of the tetraalkylammonium cation facilitates reaction on nitrogen. The thallium salts of indoles prepared by reaction with thallium(I) ethoxide, a benzene-soluble liquid. 

N-Unsubstituted 1,2,3-triazoles are methylated mainly in the 1-position with methyl iodide and silver or thallium salts, but mainly in the 2-position by diazomethane. There is also some steric control. For example, 4-phenyl-l,2,3-triazole with dimethyl sulfate gives the 2-methyl-4-phenyl (38%) and l-methyl-4-phenyl isomers (62%), but none of the more hindered 1-methyl-5-phenyltriazole (74AHC(16)33). JV-Unsubstituted 1,2,4-triazoles are generally alkylated at N-1. 

AuCN has a similar structure to AgCN and likewise dissolves in excess cyanide to form Au(CN)J this is important in the extraction of gold. It has been characterized as various salts (Tl, K, Bu4N, Cs) with Au-C 1.964A (Bu4N salt [91]). The thallium salt has short Au-Au (3.10A) and Au-Tl (3.50 A) interactions extended-Huckel calculations indicate the importance of relativistic effects in these covalent interactions. Isocyanides form stable complexes ... 

Thallium Salts. Although the same prepn had been carried out many times a violent expln occurred during the evapn of a soln. of ethylbenzene, T1 triacetate, and perchloric ac in acetic ac. No satisfactory explanation for the expln was found (Ref 40)... 

Caution Thallium salts are very toxic. This preparation should be carried out in a well-ventilated hood. The operator should ivear rubber gloves. For disposal of thallium wastes, see Note 1 on p. 74. 

The reaction between acyl halides and alcohols or phenols is the best general method for the preparation of carboxylic esters. It is believed to proceed by a 8 2 mechanism. As with 10-8, the mechanism can be S l or tetrahedral. Pyridine catalyzes the reaction by the nucleophilic catalysis route (see 10-9). The reaction is of wide scope, and many functional groups do not interfere. A base is frequently added to combine with the HX formed. When aqueous alkali is used, this is called the Schotten-Baumann procedure, but pyridine is also frequently used. Both R and R may be primary, secondary, or tertiary alkyl or aryl. Enolic esters can also be prepared by this method, though C-acylation competes in these cases. In difficult cases, especially with hindered acids or tertiary R, the alkoxide can be used instead of the alcohol. Activated alumina has also been used as a catalyst, for tertiary R. Thallium salts of phenols give very high yields of phenolic esters. Phase-transfer catalysis has been used for hindered phenols. Zinc has been used to couple... 

The present procedure offers a convenient alternative to the Prevost reaction and the Woodward modification of the Prevost reaction in which silver carboxylates are used instead of thal-lium(I) carboxylates. Thallium(I) salts have the advantages of being generally stable crystalline solids that can be readily prepared in high yield by neutralization of the appropriate carboxylic acid with thallium(I) ethoxide. Silver salts, on the other hand, are frequently unstable and difficult to dry. Thallium and its compounds are, however, extremely toxic, and great care must therefore be taken in the use and disposal of thallium salts. ... 

Thallium(I) acetate Acetic acid, thallium salt (8, 9) (15843-14-8) Acetic acid, thallium (H-) salt (8,9) (563-68-8)... 

The imidazolide of 2-methylthiobenzoic acid was transformed with the thallium salt of ethyl acetoacetate into ethyl acety 1(2 -methylthiobenzoyl)acetate.[71 ]... 

The electron rich aurate [Au(C6F5)2] also reacts with thallium salts in the presence of a ligand to give extended unsupported gold-thallium linear chain derivatives. The first example... 

Interaction is violent [1], and many of the products and derivatives are both shock- and heat-sensitive explosives [2], These include the ammonium, potassium, silver and thallium salts of the triselenimidate ion, systematically 2,4,6-tris(dioxoselena)perhydrotriazine-l,3-5-triide. 

The thallium salts 153 are stable to moisture and oxygen both in solution and in the solid state. X-ray crystallography of 153a (R = Ph) revealed a significant separation between the thallium ion and the anionic borate counteranion (B-Tl distance is equal to 425.3 pm) <2001CC2152>. 

In a similar way to the corresponding thallium salts 153, cobalt(n) complexes [PhB(CH2PPh2)3]CoI 156 <2001CC2152>, [PhBtCfTPTr lCoCl 157, and [PhB(CH2PiPr2)3]CoI 158 <2003IC5074> iron(n)... 

Treatment of ZnMe2 with the thallium salt of a bis(pyrazolyl)hydroborate gave the methylzinc complex [BpZnMe] 104 in which zinc is three coordinate.162 This complex reacted with paraformaldehyde, Scheme 73, with the direct insertion of the CH20 moiety into the B-H bond to produce the methylzinc complex 105 (Figure 51), in which zinc is tetrahedrally surrounded by the methyl group and the newly formed N,N,O-ligand.163... 

Silver and thallium salts of pyrazolylborates provide cleaner routes to metal complexes of these ligands than alkali metal derivatives. The silver complex [HB 3,5-Pz(CF3)2 3]Ag(THF), for example, reacted with diethylzinc to afford [HB 3,5-(CF3)2Pz 3]ZnEt 106, shown in Figure 52, as the sole product.164... 

The mucic acid test is now only of historical interest. It depends on the oxidation of galactose or saccharides containing a galactose residue, such as lactose, with nitric acid to yield mucic acid. Mucic acid is highly insoluble in water, while the isomeric dicarboxylic acids yielded by other sugars are soluble. Mucic acid may be identified by its characteristic thallium salt. 

Thallium(I) acetate, 24 630-632 Thallium compounds, in organic reactions, 24 635 Thallium formate, 24 630 Thallium halides, 24 632 Thallium ion, 24 629 Thallium nitrate, uses for, 24 636 Thallium salts, 24 630, 632 Thallium sulfate, uses for, 24 636 Thallium (III) compounds, in organic reactions, 24 635-636 Thallium(III) fluoride, 24 632 Thallium(III) ion, 24 630 Thallium(III) salts, 24 632 Thallium(III) trifluoroacetate, 24 635 Thallium (Tl), 24 627-641... 

The B oH o2 anion is best obtained by heating [Et3NH]2[BioHi2] to 160 °C. Its alkali metal salts are soluble in water, while the thallium salt is insoluble. The white alkali metal salts are stable up to 500 °C. Their aqueous solutions react neutral because the corresponding acid is a strong acid. It can be isolated as [H30]2[B1oH1o] (m.p. 202 °C) from its aqueous solutions obtained by ion exchange from the alkali metal salts. 

Displacement reactions at Pm have been carried out with the thallium salt of cyclopentadiene, and various phosphinocyclopentadienes (28) isolated.29 Triphenyl-... 

The ammonium, potassium, and thallium salts are all violently explosive. The entries are ... 

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