Cleavage of the carbon–nitrogen double bond

Release from polymeric prodrugs: Linkages and their degradation

“…Thus, in the case of imines, the pH‐rate profile is bell‐shaped. At pH 7.5, the rate of hydrolysis is determined by the attack of hydroxide ion on the protonated imine 88. As the pH decreases to about 5.0, the rate‐determining step changes from formation of the carbinolamine intermediate to its decomposition, with a concomitant increase in the rate of hydrolysis.…”

“…The functional groups attached to the carbonyl sp2 carbon are known not to have a significant influence on the rate of hydrolysis unless they are involved in resonance stabilization altering the electronic environment around the imine 89. A more thorough treatment of the hydrolytic cleavage of CN has been given by Bruylants and Feymants 88. PEG based polymeric prodrugs of doxorubicin containing the imine (PegCNR), have been tested for controlled release by Hoffman et al, but the reaction was incomplete, with only 50% of the drug being released 90…”

The Reactivity of Multidentate Schiff Base Ligands Derived from Bi‐ and Terphenyl Polyamines towards M(II) (M=Ni, Cu, Zn, Cd) and M(III) (M=Co, Y, Lu)

“…1 H NMR and 13 C NMR spectra have been referenced relative to the residual solvent signals, and the peaks are numbered according to Figure 27. Chemical shifts in 19 F NMR have been referenced to CFCl 3 by using C 6 F 6 (À 164.9 ppm with respect to CFCl 3 at 0 ppm) as an internal standard, and are proton decoupled. Chemical shifts in 15 N NMR have been calibrated against CH 3 NO 2 as an external standard (0.0 ppm).…”

“…As expected for compounds exhibiting rotamers in their 1 H NMR spectra, [18] the 1 H NMR resonances of the ligands were solvent-and temperature-dependent (see SI). Although Schiff bases derived from aromatic amines often are quite robust towards hydrolytic degradation in the absence of strong acids or bases, [19] it was found that ligand 1b would undergo partial hydrolysis in [D 6 ]DMSO, and the hydrolytic sensitivity of 1b is a key aspect of its reactivity towards Cu(II), Zn(II) and Cd(II) (vide infra). One of the ligands, 1d, was analyzed by single-crystal X-ray diffraction analysis (Figure 3).…”

A Kinetic Model for Non‐Oxidative Thermal Degradation of Nylon 66

“…The evolution of significant quantities of CPK, which was not included in the Steppan model, is accounted for by reaction (a.6). Hydrolysis of Schiff bases is a well‐known reaction that has been studied previously 31. Branching reactions (a.7) and (a.8), are included in the model to account for the appreciable concentrations of BHMT detected in the hydrolyzed polymer samples.…”