Thallic nitrate

Nitrates. Thallous nitrate, a convenient source of other thallium(I) derivatives, eg, halides, is prepared from the reaction of the pure metal with dilute nitric acid (9). The solid is stable to 300°C and decomposes at 800°C to Tl O, NO, and N02. Thallic nitrate is obtained as a trihydrate upon dissolving T Oj in cold nitric acid. It decomposes to T C on heating to 100°C or upon hydrolysis. Thallic nitrate, soluble in alcohols and ethers of polyethylene glycols, is often used as an oxidizing agent in oiganic syntheses. 

The highly ionic thallic nitrate, which is soluble in alcohols, ethers, and carboxylic acids, is also a very useful synthetic reagent. Oxidation of olefins, a,p-unsaturated carbonyl compounds, p-carbonyl sulfides, and Ot-nitrato ketones can all be conveniently carried out in good yields (31,34—36). 

The action of ethanolic thallic nitrate on the diketone, 2-hydroxy-6>-(4-methoxybenzoyl)acetophenone, at ambient temperature during 20 mins, gave by oxidation the cyclic product, 2-ethoxy-2-(4-methoxybenzoyl)-3(2H)benzofuranone in 66% yieid (ref.79). 

In contrast to the usually expensive organo transition metal complexes, sodium tetracarbonylferrate(-II) is inexpensive and versatile. E.g. aldehydes and unsym. ketones can be synthesized from halides and tosylates in high yields with this reagent Thallic nitrate converts acetophenones directly into methyl phenylacetates. Where applicable this new method is more convenient than the rather tedious Willgerodt-Kindler reaction... 

Aq. titanium tridiloride added gradually with stirring under Ng to a mixture of acetophenone oxime, NH4-acetate, acetic acid, dioxane, and water, the product isolated after 1 hr. acetophenone. Y 81.5%. F. e. s. G. H. Timms and E. Wild-smith, Tetrah. Let. 1971, 195 0x0 compds. from oximes and other 0x0 compd. N-derivs. with thallic nitrate s. A. McKillop et al.. Am. Soc. 93, 4918 (1971). 

Thallic nitrate s. under HCIO4 Perchloric acid/thallic nitrate Arylacetic acid esters... 

M. Meyer-Dayan, B. Bodo, C. Deschamps-Vallet, and D. Molko. The oxythallation of flavylium salts by thallic nitrate, a new synthesis of flavones. Tetrahedron Letters, 1978,3359. 

A soln. of thallic nitrate in methanol added at room temp, to a stirred soln. of an equimolar amount of a-methylstyrene in methanol, after a few min. the inorganic salt removed by filtration, and the filtrate containing the intermediate ketal shaken 5 min. with 2 N H2SO4 phenylacetone. Y 81%. F. e., also aldehydes, s. A. McKillop, E. C. Taylor et al., Tetrah. Let. 1970, 5275 oxidation of acetylene derivs. s. Am. Soc. 93, 7331 (1971). 

Thallic nitrate perchloric acid Arylacetic acid esters from aryl methyl ketones... 

A methanolic soln. of 2.1 moles thallic nitrate added to 3-ethyl-5(4H)-pyrazolone in the same solvent, stirred 15 min. at room temp, and 15 min. with reflux on a water bath -> product. Y 95%. - This is part of a method for the prepn. of a,y -acetylene- from y -keto-carboxylic acid esters, of which the latter can be easily converted into 5-pyrazolones. F. e. s. E. C. Taylor, R. L. Robey, and A. McKillop, Ang. Ch. 84, 60 (1972) a-allene- from cx-alkyl- -keto-carhoxylic acid esters s. J. Org. Chem. 37, 2797 (1972). 

Startg. m. treated 24 hrs. at room temp, with thallic perchlorate in 3 1 water-tert-buXsLnol -> 7-keto-13-norprotoilludane. Y 57% (and 19% 8-keto isomer). Y. Ohfune, H. Shirahama, and T. Matsumoto, Tetrah. Let. 1975, 4377 with thallic nitrate s. E. C. Taylor, C.-S. Chiang, and A. McKillop, ibid. 1977, 1827. 

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