389. Homolytic aromatic substituion. Part II. Competitive experiments on the phenylation of benzene, nitrobenzene, chlorobenzene, and pyridine. Partial rate factors for nitrobenzene

Quantitative Investigation of Homolytic Arylation

“…The high-boiling residues have been shown (Augood, Hey and Williams, 1952;Augood, Cadogan, Hey and Williams, 1953) to consist largely of mixtures of polyaryls, and one obvious way in which they might be formed is by further phenylation of primary reaction products. It is not unreasonable that this process should be less important in the presence of fast solvents.…”

“…Nevertheless, although correction in this way is possible, experiments in which residues are formed and corrections applied are regarded as less reliable than those in which nitrobenzene was used as reference solvent. In most cases, where residues are formed (Augood, 1952;Augood, Hey and Williams, 1952), it was found that, to a first approximation, the X-and Y-diphenyls were removed by further phenylation in the same ratio as that in which they were formed by the phenylation of C 6 H 5 X and C 6 H 5 Y, that is:…”

Theoretical Treatments of Aromatic Substitution

“…Augood, Hey and Williams, 1952), it may be seen that, for both instances, all the nuclear positions available for substitution are equivalent, e.g. for C 6 H 4 X 2 , all the positions are ortho to one group X and meta to the other; hence, for any position, 6*-$K = 4*-g* 0 , w…”

Mechanisms of Oxygen Metabolism

“…These properties are consistent with the possibility that here is the first example of an iron-sulfhydryl ) I . 8. MASON enzyme, employing the aame principle as the early iron-aulfhydryl models of respiratory systema studied by Warburg" (433).…”

“…Its structure has been clarified by the preparation and characterization of a stable derivative (830). The substance appears to be acroleinaminofumaric acid, which is H. 8 The formation of acroleinaminofumaric acid from 3-hydroxyanthranilic acid requires splitting of an aromatic carboncarbon bond adjacent to a phenolic hydroxyl group (compare 171) and the incorporation of two atoms of oxygen, aa generalized in equation (22) . Hayaishi, Rothberg, and Mehler have conducted the enzymic oxidation of 3-hydroxyanthranilic acid in an atmosphere of 0% and in HzOIS solution (331). They report that, in the isolated picolinic acid, one atom of oxygen arises from molecular oxygen and none from water.…”