The present invention features compounds useful in the treatment of neurological disorders. The compounds of the invention, alone or in combination with other pharmaceutically active agents, can be used for treating or preventing neurological disorders.

The present invention provides a novel compound having an antiviral activity, in particular, an HIV replication inhibiting activity, as well as a pharmaceutical composition, in particular, an anti-HIV agent.

##STR00001##

wherein ring A is substituted or unsubstituted carbocycle or substituted or unsubstituted heterocycle; R.sup.1 is substituted or unsubstituted alkyl etc.; R.sup.2 is substituted or unsubstituted alkyloxy etc.; n is 1 or 2; R.sup.3 is substituted or unsubstituted carbocyclyl or substituted or unsubstituted heterocyclyl; R.sup.4 is a hydrogen atom etc.; R.sup.6 is substituted or unsubstituted alkyl etc.

The present invention provides a novel compound having an antiviral activity, in particular, an HIV replication inhibiting activity, as well as a pharmaceutical composition, in particular, an anti-HIV agent.

##STR00001##

wherein ring A is substituted or unsubstituted carbocycle or substituted or unsubstituted heterocycle; R.sup.1 is substituted or unsubstituted alkyl etc.; R.sup.2 is substituted or unsubstituted alkyloxy etc.; n is 1 or 2; R.sup.3 is substituted or unsubstituted carbocyclyl or substituted or unsubstituted heterocyclyl; R.sup.4 is a hydrogen atom etc.; R.sup.6 is substituted or unsubstituted alkyl etc.

The invention concerns a paralytic shellfish poison for the treatment of itching in a human being or another mammal.