Pyridyls 2-pyridyl group

A quantitative correlation between rate and equilibrium constants for the different metal ions is absent. The observed rate enhancements are a result of catalysis by the metal ions and are clearly not a result of protonation of the pyridyl group, since the pH s of all solutions were within the region where the rate constant is independent of the pH (Figure 2.1). 

Some active 5-pyrazolone derivatives (707) and (708) in which the 1-phenyl substituent of antipyrine was replaced by 2 -, 3 - and 4 -pyridyl groups have been prepared (66HCA272). A series of aminoesters substituted at the nitrogen atom of the ester grouping with an antipyryl residue (709) were found to possess local anesthetic properties (69MI40400). 

A synthetic strategy which ensures retention of the monomeric form of SnR2 even in the crystalline state is to use functionalized R groups which contain a chelating substituent, e.g. by replacing the H atom in -CH(SiMe3)2 with a 2-pyridyl group. 

Methyl 2-substituted perhydropyrido[l,2-u]pyrazine-8-acetates were obtained by catalytic hydrogenation of 2-substituted 8-(methoxycarbonyl-methylene)perhydropyrido[l,2-a]pyrazines over 10% Pd/C catalysts (00JAP(K)00/86659). A side chain 4-pyridyl group was hydrogenated over Pt02 catalysts to yield a 4-piperidyl derivative. 

Compounds containing phenyl or pyridyl groups Nitrogen trifluoride... 

Molecular arrangements in the as-prepared dimer and 2 OPr-a-dimer-PrOH crystals are shown schematically in Figs 16(a) and (b), respectively. In the complex, propanol molecules are hydrogen-bonded to the pyridyl groups and, as expected from its high photoreactivity, the... 

Palladium metal catalysts supported on organic resins containing tertiary amino, cyano, carboxyl, and pyridyl groups have been recently investigated in some Heck reactions, such as the coupling of iodobenzene with methyl acrylate and methyl vinyl ether (Scheme 11) [31]. 

A strong interaction of the very small palladium particles (diameter 3.5 nm, as shown by HRTEM analysis) with the nitrogen atoms of the pyridyl groups in the polymeric support may account for this interesting result. 

More than 2,000 potential replacements for the bromophenyl or pyridyl groups were then screened using the NMR-screening technique. Several fragments were identified which caused chemical shift changes in the desired binding site of the protein, amongst them indole (7) and 2-phenylimidazole... 

If necessary for further applications, the 2-pyridyl group can be exchanged by alkyl in a two-step sequence that takes advantage of the enhanced leaving-group ability of the 2-pyridyl group. 

A polymeric structure can be generated by intermolecular coordination of a metalloporphyrin equipped with a suitable ligand. Fleischer (18,90) solved the crystal structure of a zinc porphyrin with one 4-pyridyl group attached at the meso position. In the solid state, a coordination polymer is formed (75, Fig. 30). The authors reported that the open polymer persists in solution, but the association constant of 3 x 104 M 1 is rather high, and it seems more likely, in the light of later work on closed macrocycles (see above), that this system forms a cyclic tetramer at 10-3 M concentrations in solution (71,73). 

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