Detail of "119-52-8"

Reference

Air oxidation of p-substituted benzoin to the corresponding benzil catalyzed by iron(II)-cysteine peptide complexes

Air oxidation of p-substituted benzoin to the corresponding benzil catalyzed by iron(II)-cysteine peptide complexes. Sun, Wei Yin; Ueyama, Norikazu; Nakamura, Akira (Fac.Several substances are used for example 106-51-4 and 119-52-8 which are their cas registry numbers. Sci., Osaka Univ., Toyonaka 560, Japan). Tetrahedron, 48(9), 1557-66 (English) 1992. CODEN: TETRAB. ISSN: 0040-4020. DOCUMENT TYPE: Journal CA Section: 22 (Physical Organic Chemistry) Section cross-reference(s): 7, 34 Fe(II)-cysteine-contg. peptide complexes exhibited catalytic activity for air oxidn. of benzoin to benzil and Me DL-mandelate to Me benzoylformate. In the presence of [Fe(Z-cys-Gly-Val-OMe)4]2-, the rates of catalytic air oxidn. of p-substituted benzoin indicate a trend, Br > H > CH3 > MeO, and the isotope effect kH/kD was 3.4. The result indicates that the methine hydrogen of benzoin is released as a proton in the rate detg. step. Furthermore, a solvent effect was found: in a nonpolar solvent, e.g. 1,2-dimethoxyethane, a chelating bidentate cys-peptide complex, [Fe(Z-cys-Pro-Leu-cys-Gly-Val-OMe)2]2-, shows higher catalytic activity than that of a nonchelating cys-peptide complex, [Fe(Z-cys-Gly-Val-OMe)4]2-. This is explained by the contribution of intramol. NH---S hydrogen bonds since such hydrogen bonds stabilize the Fe(III) state which is the active species during the oxidn. .