Thallium complexes carboxylates

Thallium complexes amidines, 205 phthalocyanines, 863 porphyrins, 821 triazines, 205 Thallium(I) complexes hexafluoroacetylacetone, 372 Thallium III) complexes carboxylic acids reactions, 443 1,3-diketones synthesis, 377... 

The higher acidity of pyrroles and indoles bearing electron-withdrawing substituents at the a- or /3-positions permits their alkylation under mildly basic conditions, but although the thallium salt of 2-formylpyrrole is Af-alkylated, the corresponding alkylation of the thallium salts of ethyl pyrrole-2-carboxylate yields a complex mixture of products resulting from iV-alkylation and transesterification (B-77MI30502). N-Alkylation of pyrrolyl and indolyl esters is most conveniently effected under phase-transfer conditions. 

Many 1,2,4-triazines form complexes with metal ions and can be used for their determination. Thus, 3- and/or 5-(2-pyridyl)-substituted 1,2,4-triazines (e.g. 820) can be used for the determination of iron (II), cobalt(II), nickel(II), zinc(II) and copper(I) ions, thallium and palladium ions can be analyzed by 6-phenyl- (821a) and 5,6-diphenyl-l,2,4-triazine-3-thione (821b), while osmium can be determined by 3-thioxo-l,2,4-triazin-5-one (822), 3-thioxo-dihydro-l,2,4-triazin-5-one (823), 6-mercapto-l,2,4-triazine-3,5-dione (824a), 6-mercapto-5-thioxo-l,2,4-triazin-3-one (824b) and 3,5-dithioxo-l,2,4-triazine-6-carboxyl-ates (825) <78HC(33)189, p. 1004). 

Adducts of triazoles with transition metal salts are usually prepared by direct reactions between the two components involved and frequently precipitate or crystallize spontaneously from the reaction mixture (55,172,194, 202). Complexes containing triazolate anions can usually be obtained from the corresponding transition metal halide, carboxylate, nitrate, or perchlorate complex and an alkali metal (146, 147, 172) or thallium(I) triazolate salt (33). Other routes to triazolate complexes include the direct reactions of metal halides with triazoles in the presence of a base (201) and the treatment of triazole/metal halide... 

Thallium(Il) complexes, 171 Thallium(III) complexes, 171 amines, 172 ammines, 172 aqua, 172 bipyridyl, 172 bromates, 173 bromides, 174 carboxylates, 173 chlorates, 173 chlorides, 174 cyanides, 171 dichlorophosphates, 173 ethers, 173... 

Oxidative rearrangements, via oxythallation, have been improved in yield and selectivity by the use of thallium(iii) nitrate supported on clay rather than in methanolic solution. Thus, cyclohexene gave an 85% yield of dimethoxymethyl-cyclopentane while 1-tetralone, which normally gives a complex mixture of products, gave a 1 1 mixture of methyl indane-l-carboxylate and 2-methoxytetralone. An efficient, large-scale procedure for the direct cis-dihydroxylation of olefins has been reported. The oxidant is t-butyl hydroperoxide and the catalyst osmium tetroxide, with the reaction conducted under alkaline conditions (E%N OH ), so facilitating a rapid turnover of catalyst via enhanced hydrolysis of the osmate esters. The method appears to be more advantageous for the more substituted olefins than the Hofmann and Miles procedure. 

Monensin (7), has been studied as its silver salt, which is isomorphous with the potassium and thallium salts, and as the free hydrated acid. Complex formation takes place through the six oxygen atoms marked with an asterisk. As shown in Figure 4, the carboxylate group is not co-ordinated... 

We reasoned that such a decarboxylation step could also be employed in a redox-neutral cross-coupling reaction with carbon electrophiles. On this basis, we drew up a catalytic cycle that starts with an oxidative addition of aryl halides or pseudohalides to a coordinatively unsaturated palladium(O) species f (Scheme 5). The more weakly coordinating the leaving group X, the easier should be its subsequent replacement by a carboxylate. At least for X = OTf, the palladium(ll) carboxylate h should form quantitatively, whereas for X = halide, it should be possible to enforce this step by employing silver or thallium salts as species g. The ensuing thermal decarboxylation of the palladium(ll) intermediate i represents the most critical step. Myers results indicated that certain palladium(ll) carboxylates liberate carbon dioxide on heating. However, it remained unclear whether arylpalladium (II) carboxylate complexes such as i would display a similar reactivity. If this were to be the case, they would form Ar-Pd-Ar intermediates k, which in turn are... 

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