Diglycolic acid, derivatives

Attachment of carbonyl groups to crowns makes these products more akin structurally to the natural ionophore antibiotics such as valinomycin. The dioxo-derivative (179) of 18-crown-6 was prepared in 35% yield by condensation of tetraethylene glycol and diglycolic acid chloride in benzene at 50 °C for 48 hours (Izatt et al., 1977a and 1977b). This product gives binding constants for Na+, K+ and Ba2+ in methanol which are 102—104 times less stable than for the parent crown - the lower constants are a reflection of less favourable AH values for complexation in these... 

Similar results were observed using the N-acyl thiazolidinethione derivative of a bis(diglycolic) acid (method M-6) (Cazaux et al., 1989). Again, as in the method M-5 process, 2 2 cyclization to form an 18-membered ring was the major process since 1 1 cyclization would form a 9-membered ring. 

Shimojo K, Naganawa H, Noro J, Kubota F, Goto M (2007) Extraction behavior and separation of lanthanides with a diglycol amic acid derivative and a nitrogen-donor ligand. Anal Sci 23 1427-1430... 

The glycosidic link is immune to attack by periodate and this reaction.can be used not only to establish the ring size of glycosides but also the configuration of the glycosidic link. a-D-Hexopyranosides reduce two moles of periodic acid, release a mole of formic acid and all yield the same diglycollic dialdehyde derivative (CXI). This has lost the asymmetric centres at C-2,... 

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