イミダゾリジノン系化合物の薬剤学的研究(第4報) : 分解機構に関する考察

抄録

The stability of various imidazolidinone derivatives was examined and it was found that the 2-substituted derivatives were comparatively unstable and that the substituent introduced into the phenyl attaching at the 3-position of the imidazolidinone ring affected the decomposition rate. Such unstability seemed to be due to steric hindrance and electron effect. In rapidly decomposed derivatives, the pH-profile of apparent decomposition rate constants was a bell-shaped curve. It was assumed that the bell shape of the pH-profile over the whole pH region was brought about by the main participation of OH ion in the decomposition of protonated molecules in acidic region and by the predominance of decomposition rate of the intermediate carbinolamines over the rate-determining step with a resultant decrease in the decompo-sition rate in neutral to alkaline region.