A convenient synthesis of bifunctional chelating agents based on diethylenetriaminepentaacetic acid and their coordination chemistry with yttrium(III).
The bifunctional chelating agents N,N,N',N'',N''-pentakis(carboxymethyl)-1- [(4-aminophenyl)methyl]-diethylenetriamine and N,N,N',N'',N''-pentakis(carboxymethyl)-1-[(4-aminophenyl)methyl]-4- methyldiethylenetriamine were prepared in six-step syntheses in overall yields of 38% and 31%, respectively. The use of bromoacetate esters in the synthesis allowed large-scale flash chromatographic purification of reaction products. The synthesis of N,N,N',N'',N''-pentakis(carboxymethyl)-1- [(4-aminophenyl)-methyl]-4-methyldiethylenetriamine resulted in a mixture of two diastereomers. Chelation of yttrium-(III) with these bifunctional chelating agents resulted in 1:1 chelates. In the case of N,N,N',N'',N''-pentakis(carboxymethyl)-1-[4- aminophenyl)methyl]diethylenetriamine, two diastereomers were observed upon chelation, as expected. In the case of N,N,N',N'',N''- pentakis(carboxymethyl)-1-[(4-aminophenyl)-methyl]-4- methyldiethylenetriamine, only three of the four anticipated diastereomers were observed.
Cummins
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Dow Chemical Company, Midland, Michigan 48674.
Rutter
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Fordyce
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D002614:Chelating Agents / Q000138:chemical synthesis*; D003432:Cross-Linking Reagents / Q000138:chemical synthesis*; D004369:Pentetic Acid / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D015019:Yttrium / Q000737:chemistry*
D002614:Chelating Agents; D003432:Cross-Linking Reagents; C071641:1-(4-aminobenzyl)-4-methyl-DTPA; C071640:1-(4-aminobenzyl)-DTPA; D015019:Yttrium; D004369:Pentetic Acid