Acetate, active oxidation-reduction couple with

A modified form of cellulose acetate containing some periodate-oxidized D-glucopyranosyl residues has been prepared. Fibres of cellulose acetate have been used to immobilize enzymes. Selectively oxidized cellulose (dialdehydo-cellulose) has been treated with hydroxylamine, bisulphite, and acetic acid. Dialdehydocellulose provides a matrix suitable for coupling with trypsin, giving an active immobilized enzyme. Reduction of the unchanged aldehydo-groups on the matrix stabilized the enzyme. 

The thiazine dyes used in the preparation of this type of leuco are obtained through oxidative coupling of phenothiazine with an active methylene compound or an aniline. The reduction of the dye 23 with zinc powder in acetic acid is straightforward.9 Treatment of the leuco 24 with acetic anhydride at 40°C yields a more air stable leuco 25.9 Addition of arylsulfinic acid to thiazine dyes such as 26 produces directly leuco dyes such as 27.Sb... 

The mechanism proposed was confirmed by the work of Cariati et al. [43]. In addition to their studies on rhodium WGSR catalysis in acid media, Cheng and Eisenberg have also reported [27] that mixtures of platinum chloride and tin chloride are active WGSR catalysts in an acetic acid/HCl solvent system. They proposed the following mechanism (Scheme 7.2). The catalytic cycle appears to involve the Sn(ll)/Sn(IV) redox couple. The formation of H2 coincides with the oxidation of Sn(ll) to Sn(IV) and CO is oxidized to CO2 concurrent with reduction of Sn(IV) to Sn(II). 

C-Labelled dotriacontane has been used to study the retention of tobacco smoke in the respiratory system of smoke-exposed laboratory animals. High-resolution autoradiography studies within the respiratory tract needed tritium-labelled dotriacontane (34) with a specific activity of 0.5 Cimmol" This compound has been prepared by synthesizing the diacetylene 35 and by its reduction to dotriacontane-15,15,16,16,17,17,18,18- H, 34 (equation 48). Sodium acetylide with myristyl bromide yielded hexadec-l-yne 36. Oxidative coupling of 36 using cupric acetate gave the diyne 35 which, upon reduction with tritium gas in the presence of Adams catalyst, yielded 34, with the specific activity of 0.50 Ci mmol as required. 

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