This invention provides a serotonin 5-HT
3
receptor partial activator which has a serotonin 5-HT
3
receptor activating action, in addition to its serotonin 5-HT
3
receptor antagonism, and does not cause constipation as a side effect.
Particularly, based on the finding that newly synthesized benzoxazole derivatives typified by the compounds of the following formula (2) have strong serotonin 5-HT
3
receptor antagonism and serotonin 5-HT
3
receptor activating action, this invention provides these benzoxazole derivatives as serotonin 5-HT
3
receptor partial activators.
1
In the above formula, R
1
to R
4
may be the same or different from one another and each represents a hydrogen atom, a halogen atom, a substituted or unsubstituted lower alkyl group, a substituted or unsubstituted lower alkenyl group or a substituted or unsubstituted amino group, or two groups of R
1
and R
2
may be linked together to form a ring structure, namely benzene ring; R
5
represents a hydrogen atom, a substituted or unsubstituted lower alkyl group or a substituted or unsubstituted lower alkenyl group; and m is an integer of 1 to 4.
本发明提供了一种5-HT3受体部分激动剂,该激动剂具有5-HT3受体激活作用,除了其5-HT3受体拮抗作用外,不会引起便秘等副作用。特别是,基于新合成的
苯并咪唑衍
生物发现,该衍
生物以以下式子(2)的化合物为代表具有强烈的5-HT3受体拮抗作用和5-HT3受体激活作用,本发明提供这些
苯并咪唑衍
生物作为5-HT3受体部分激动剂。在上述公式中,R1到R4可以相同也可以不同,每个表示氢原子、卤素原子、取代或未取代的低级烷基、取代或未取代的低级烯基或取代或未取代的
氨基;或R1和R2的两个基团可以连接在一起形成环结构,即苯环;R5表示氢原子、取代或未取代的低级烷基或取代或未取代的低级烯基;m是1到4的整数。