The palladium and copper contrast: a twist to products of different chemotypes and altered mechanistic pathways
作者:Kapileswar Seth、Sudipta Raha Roy、Asim Kumar、Asit K. Chakraborti
DOI:10.1039/c6cy00415f
日期:——
Unprecedented Pd–Ag/Cu–Ag nanocluster-catalyst switch leads to a phenazine/azoarene twist for non-radical mode C–H activation vs. radical mode N–N self-coupling of anilines.
Substituted phenylazo and phenylazoxy compounds were systematically prepared and their anti-androgenic activity was measured in terms of (1) the growth-inhibiting effect on an androgen-dependent cell line, SC-3, and (2) the binding affinity of nuclear androgen receptor. Generally, azo/azoxy compounds showed cell toxicity, and the growth-inhibiting effects on SC-3 cells correlated with the toxicity. However, some compounds, including 4, 4'-dinitroazobenzene (25), 4, 4'-dimethoxyazobenzene (33), and 2, 2'-dichloroazoxybenzene (47), possessed potent anti-androgenic activity without apparent cell toxicity.
Phenyliodine(III) Diacetate (PIDA) Mediated Synthesis of Aromatic Azo Compounds through Oxidative Dehydrogenative Coupling of Anilines: Scope and Mechanism
An efficient and environmentally benign method has been developed for the synthesis of symmetrical and unsymmetrical aromatic azo compounds through phenyliodine(III) diacetate (PIDA) mediatedoxidative dehydrogenative coupling of anilines in high yields. The scope of the reaction is broad for both homo- and cross-dimerization. A plausible reaction mechanism has been proposed based on a structurally
for the direct oxidation of anilines to the corresponding azo and azoxy homocoupling products by using a planetary ballmill was developed. Various oxidants and grinding auxiliaries were tested and a variety of substituted anilines were investigated. It was possible to form chemoselectively either azo, azoxy, or the nitro compounds from reaction of aromatic anilines. The selectivity of the solvent‐free
another, the Pdatom is inserted directly into the N–Br bond of NBS, and in the last one, Br+ migrates spontaneously from the protonated NBS to Pd. In all three cases, the subsequent elimination step is remarkably lower in energy. In the fourth mechanism, Br+ migrates from free NBS directly to the activated carbon, simultaneously with the Pd–C bond breaking. Besides NBS, the hydrogen bond complex NBS···TsOH