Stilbazoles oxidation

Reactions using picoline 1-oxides have been less successful than those using picolines. 2- and 4-Picoline 1-oxides did not react with aromatic aldehydes under various acidic and basic conditions, 199 but poor yields of stilbazole oxides were obtained using piperidine acetate in boiling tolu-ene . Under these conditions, the picolines performed no better than their oxides. 3-Methyl-4-nitropyridine 1-oxide reacted with benzaldehyde in presence of piperidine, circumstances under which 3-methyl-4-nitropyridine did not reacti 3 More successful have been reactions of the oxides catalysed by metal alkoxides or hydroxides (p. 383). 

In the oxides of styrene, stilbene, and stilbazole, the chemical shifts of the cis protons of the oxirane ring are larger than those for the trans isomers. This can be explained by the polarization effect of the electric dipole moment of one of the CH protons on the other CH. The anisotropc shielding of the ring in the case of oxiranes substituted with an aromatic group can be utilized well in the determination of the configuration. ... 

He et al. [68] examined the effect of adding flexibility to the hydrogen bond acceptor bis-pyridyl units. They attached stilbazole derivatives to either end of differently sized oligo(ethylene oxide) spacers (4) (Fig. 7). Mixing... 

The second-order NLO response of various bipyridine and phenanthroUne ligands increases upon coordination to a metal center, as in the case of pyridines and stilbazoles (see Sect. 3.1.2), the EF of the quadratic hyperpolarizabUity stiU depending on the electronic configuration of the metal, its oxidation state, and its sphere of ancillary ligands [10, 16]. 

A comparison of the activity of [Pd(PPh3)4] and [Pd(dba)2] + PPhs in the oxidative addition of Phi concluded that for an equivalent Pd loading the former contained more of the active species [Pd(PPh3>2]. 5 An electrochemical and 31p NMR study of the mechanism of addition of PhX to reduced [PdCl2(PPh3)2] has also appeared. e New aryl complexes have been formed by addition of rrans-4 -bromo-4-stilbazoles and 2,4,6-tribromophosphorin to [PdLa] (L = various... 

The preparation of substituted diaryl-ethenes, stilbenes, and analogues (e.g., stilbazoles) has been achieved by Wittig [45] or Homer-Emmons reactions [46] of substituted benzaldehydes and benzyl-triphenylphosphonium halides or benzyl-diethoxyphosphonates (see Scheme 4). 4-Methylpicolinium salts [96a,b] or 4-meth-ylpicoline-A-oxides [96c], upon reaction with benzaldehydes under basic conditions lead directly to the corresponding stilbazo-lium salts or stilbazole-TZ-oxides, respectively. As of late, the metal-catalysed cross-... 

Gatalytic reduction of 2-stilbazole 1-oxide can be arranged to give 2-stilbazole, 2-phenethylpyridine 1-oxide or 2-phenethylpyridine " . 

The sodium derivative of methyl pyridine-3-acetate gave the corresponding stilbazole with benzaldehyde and 2- and 4-picoline 1-oxide behaved similarly in presence of potassium methoxidei i 126ft,... 

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