Quinoline chelating group

The first catalytic insertion of a C=C bond into an acyl CO bond was attained with Rh catalysts. Thus, the ort/io-substituted olefinic phenol esters with the quinoline chelating group (70) were converted into the )3-alkoxy ketones (72). The stabilization of the intermediate Rh-alkoxide by chelation (71) is a prerequisite for the reaction to occur. 

Platinum-group metals (qv) form complexes with chelating polymers with various 8-mercaptoquinoline [491-33-8] derivatives (83) (see Chelating agents). Hydroxy-substituted quinolines have been incorporated in phenol—formaldehyde resins (84). Stannic chloride catalyzes the condensation of bis(chloromethyl)benzene with quinoline (85). 

Resins can also be prepared with chelating functional groups which show selective affinities for certain metals. Iminodiacetic acid, vinylacetylacetone, glyoxal-thiophenol and 8-hydroxy quinoline have all been used to produce these so-called chelating resins. Their selectivities are similar to those of the free reagent. 

This deactivation of the amino group in (J-hydroxyalkylamines has already been proposed by Alvey 70) and is supported by the results of the initiation of copolymerization by quinoline and its 8-hydroxy derivative. Whereas a high initiation efficiency was found for quinoline, 8-hydroxyquinoline, a very effective chelating agent, does not initiate copolymerization 69). 

Methoxyquinoline is regioselectively oxidized at the methyl group by a chelate-directed palladium-catalyzed C-H bond activation <2004JA2300>. 8-Methylquinoline is selectively oxidized at the methyl position on treatment with palladium(ll) acetate followed by the oxidant phenyliodinium diacetate in acetic acid. The reaction proceeds via formation of a palladacycle (Scheme 4). Performing the reaction in methanol leads to isolation of 8-(methoxy-methyl)quinoline in 77% yield. 

In the course of an investigation on axial chirality in metal chelates [60], 4- and 5-aryl-substituted quinolin-8-ols were required. If, in the case of aryl groups bearing bulky sub-... 

Thus, the Grignard reagent can add to the less accessible 4 -position of the quinoline moiety rather than the 2 -position, and single diastereomers were isolated from all reactions (e.g., 14 and 15). Both observations were explained by assuming a group transfer within a metal chelate (Scheme 12.7). The choice of toluene as solvent for not breaking up those metal clusters is a key factor for obtaining satisfactory... 

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