The present invention relates to N-alkylpiperidine derivatives represented by general formula (1) or (2);
1
wherein R
1
represents optionally fluorinated lower alkyl; R
2
represents lower alkyl; and R
3
represents alkenyl substituted at the 1-position with hydroxy, lower alkoxy, lower alkoxyalkyloxy, lower alkoxyalkyloxyalkyloxy, or lower alkanoyloxy and substituted at the end with radioactive iodine, or alkenyloxymethyl substituted at the end with a radioactive iodine reagent containing the same for assaying central local AchE activity; a method for assaying the central local AchE activity; and labeled precursors of the above compounds. After easily passing through the blood-brain barrier, these compounds are hydrolyzed specifically by AchE in the brain into alcohols, which are then captured by the brain. In contrast, alcohols formed outside the brain do not migrate into the brain. The compounds of the invention emit &ggr;-rays at an appropriate energy level. These characteristics make the compounds highly useful as tracers for SPECT in assaying the central AchE activity.
本发明涉及由通式(1)或(2)表示的N-烷基
哌啶衍
生物;其中R1表示可选的
氟化较低烷基;R2表示较低烷基;R3表示在1位被羟基,较低烷
氧基,较低烷
氧烷氧基,较低烷
氧烷氧烷氧烷基或较低烷酰
氧基取代的
烯基,并在末端用放射性
碘取代,或在末端用含有放射性
碘试剂的
烯氧甲基取代,用于测定中央局部AchE活性的方法;以及上述化合物的标记前体。这些化合物易于通过血脑屏障,特异性地被脑内AchE
水解成醇,然后被大脑捕获。相比之下,在大脑外形成的醇不会迁移到大脑中。本发明的化合物以适当的能量
水平发射γ射线,这些特性使得这些化合物在测定中央AchE活性的
SPECT示踪剂中非常有用。