Preparation of Diversely Substituted Triarylmethyl Radicals by the Quenching of Tris(2,3,5,6-tetrathiaaryl)methyl Cations with C-, N-, P-, and S-Nucleophiles.

C-, N-, P-, and S-nucleophiles reacted with symmetrical tris(2,3,5,6-tetrathiaaryl)methyl cations, generated from the corresponding triarylmethanols by strong acids, to give a variety of asymmetrical monosubstituted persistent triaryl-methyl (TAM) radicals as the major products. The only byproducts were symmetrical TAMs.

Generation of Trityl Radicals by Nucleophilic Quenching of Tris(2,3,5,6-tetrathiaaryl)methyl Cations and Practical and Convenient Large-Scale Synthesis of Persistent Tris(4-carboxy-2,3,5,6-tetrathiaaryl)methyl Radical.

Tris(2,3,5,6-tetrathiaaryl)methyl cations, which were generated from the corresponding triarylmethanols in the presence of strong acids, underwent reaction with nucleophiles to give trityl radicals, as the product of a one-electron reduction of the carbocation. Depending on the nature of the nucleophile, the only byproducts were either diamagnetic quinone methides or asymmetrical monosubstituted trityl radicals. Herein, we report a protocol for the large-scale synthesis of the Finland trityl, which has the advantage of high overall yield and reproducibility.

Interaction of acetonitrile with trifluoromethanesulfonic acid: unexpected formation of a wide variety of structures.

Interaction of acetonitrile with trifluoromethanesulfonic acid has been studied by multinuclear NMR and ESI-MS. It has been found that the interaction results in formation of a great variety of different cations and neutral compounds which is controlled by the ratio of CH(3)CN to TfOH. In the presence of an excess of the acid (molar ratio 1 : 8-14) diprotonated N-acetylacetamidine 1 is formed as the major product, which eventually transforms into protonated acetamidine 3 and acetic acid 4. At molar ratio of (1 : 1-2) diprotonated 2,4-dimethyl-6-methylidene-3H-1,3,5-triazine 12, tautomer of the diprotonated trimethyl-s-triazine 11, becomes the main product at an early stage of the reaction and diprotonated 1-(dimethyl-1,3,5-triazin-2-yl)prop-1-en-2-ol 15 at a later stage. In the case of a large excess of acetonitrile (4-20 : 1) trication 17 is formed as a result of the interaction between 11 and 12 along with some oligomers [(CH(3)CN)(3)](n) (n = 4-12).

Facile and High-Yielding Synthesis of TAM Biradicals and Monofunctional TAM Radicals.

Facile and high-yielding procedures for synthesis of monocarboxylic acid derivatives of triarylmethyl radicals (TAMs) were developed. Reaction of methyl thioglycolate with tris(2,3,5,6-tetrathiaaryl)methyl cation smoothly afforded the monosubstituted TAM derivative, which was hydrolyzed to a monocarboxylic acid, with the TAM moiety attached to thioglycolic acid via the sulfur atom. Alternatively, the diamagnetic tricarboxylic acid precursor of Finland trityl was transformed to a trimethyl ester and partially hydrolyzed under controlled conditions. The diester product was isolated and the remaining fractions were converted back to the trimethyl ester for production of more diester. The first representatives of TAM biradicals with different TAM cores and interspin distances were obtained by reaction of these new TAM monocaboxylic acids with N,N'-dimethylethylenediamine.

Deaminated UV filter 3-hydroxykynurenine O-beta-D-glucoside is found in cataractous human lenses.

Analysis of UV filter levels in 48 cataractous human lenses was performed with the use of HPLC. A new chromophore with the absorption maximum at 410nm and molecular mass of 369Da was detected and assigned as deaminated 3-hydroxykynurenine O-beta-D-glucoside (3OHCKAG). Cataractous lenses are characterized by the wide range of the UV filter concentrations and remarkably lower levels of UV filters and glutathione than published for the normal lenses. No correlation between the lens age and the level of UV filters has been found in cataractous lenses.