Chelation amine groups

In an aminoglycoside a vicinal amino hydroxy group can be protected as a Cu(II) chelate. After acylation of other amine groups, the chelate is cleaved by aqueous ammonia. The copper chelate can also be cleaved with Bu2NC(S)NHBz (EtOH, reflux, 2 h). ... 

Figure 20.18 The bifunctional chelating reagent DTPA may be used to modify amine groups on antibody molecules, forming amide bond linkages. Indium-111 then may be complexed to the chelator group to create a radiolabeled-targeting reagent.

Ihnat and coworkers substituted the primary amine group with a series of gradually increasing alkyl amides 113-119, aromatic amides 120 and 121, succinamide 122 and methylsulfonamide 123 with a systematic increase in partition coefficient (octanoFwater), to increase permeability while retaining iron-chelating ability. The formamide derivative... 

Figure 4.12 Amine groups for the manufacture of chelating resins.

A statistical calculation was carried out and the calculated value of x at saturation (0.63) was nearly equal to the experimental value of x2 The profile for the BPEI-Co(III) complex was considered to be as in Fig. 2(b), with the Co(III) chelates coordinated preferentially to the end primary amine groups of the branched poly(ethyleneimme)4. ... 

Although the pK of the cy-amine group for Lys is within the titratable range and that for Arg would probably become so on coordination, the relatively long methylene chains render any tridentate chelation unlikely, and this appears to be the case.10- 4 The shorter methylene side chains in the synthetic diamine-monocarboxylates ornithine, 2,4-diaminobutanoic acid and 2,3-diamino-propionic acid lead to increased tridentate behaviour in that order. 

Dance and Guerney248 isolated a number of water-soluble complexes of (38) and X-ray analysis of a complex of Pb11 demonstrated its N—S coordination. The cyclic molecule 5-methyl-l-thia-5-azacyclooctane (39) forms complexes with Pd11 chloride and iodide in which it adopts a boat-chair configuration. These provide the first examples of bidentate chelates in which both thioether and tertiary amine groups are coordinated.132 H NMR analysis shows the inflexible chloride complex to remain bidentate in solution, whereas in the iodide chelate the ligand is S monodentate in dichloromethane. 

Scheme 6. Folate-targeted dendrimeric contrast agent (a 2nd generation species is presented) on a 4th generation dendrimer, 3 to 5 peripheral amine groups are randomly substituted by folic acid, the rest being conjugated to Gd-DTPA chelates...

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