A radical polymerization method may use a compound having a polycyclic aromatic skeleton and an endoperoxide compound having a polycyclic aromatic skeleton. An endoperoxide compound may have a polycyclic aromatic skeleton of formula (1), and a compound may have a polycyclic aromatic skeleton, which is a raw material of the endoperoxide compound:

##STR00001##

wherein R is a C.sub.1-10 alkyl group, an alkoxymethyl group having a C.sub.1-5 alkoxy group, a C.sub.6-10 aryl group, an alkylcarbonyl group having a C.sub.1-10 alkyl group, an arylcarbonyl group having a C.sub.6-20 aryl group, an alkyloxycarbonyl group having a C.sub.1-10 alkyl group, an aryloxycarbonyl group having a C.sub.6-10 aryl group, an alkyloxycarbonylmethyl group having a C.sub.1-12 alkyl group or an aryloxycarbonylmethyl group having a C.sub.6-12 aryl group.

Provided herein is a compound of Formula (I-I), or a pharmaceutically acceptable salt thereof, wherein the variables are defined herein. Also provided herein are pharmaceutical compositions comprising a compound of Formula (I-I), and methods of using the compounds, e.g. in the treatment of CNS-related disorders. ##STR00001##

A radical polymerization method may use a compound having a polycyclic aromatic skeleton and an endoperoxide compound having a polycyclic aromatic skeleton. An endoperoxide compound may have a polycyclic aromatic skeleton of formula (1), and a compound may have a polycyclic aromatic skeleton, which is a raw material of the endoperoxide compound: ##STR00001##
wherein R is a C.sub.1-10 alkyl group, an alkoxymethyl group having a C.sub.1-5 alkoxy group, a C.sub.6-10 aryl group, an alkylcarbonyl group having a C.sub.1-10 alkyl group, an arylcarbonyl group having a C.sub.6-20 aryl group, an alkyloxycarbonyl group having a C.sub.1-10 alkyl group, an aryloxycarbonyl group having a C.sub.6-10 aryl group, an alkyloxycarbonylmethyl group having a C.sub.1-12 alkyl group or an aryloxycarbonylmethyl group having a C.sub.6-12 aryl group.