Compounds of formula (I) or pharmaceutically acceptable salts thereof are provided: wherein: A is alkylenyl of 1 to 4 carbon atoms, or alkenylenyl of 2 to 4 carbon atoms; R.sub.1 and R.sub.2 are, independently, hydrogen or a C.sub.5 to C.sub.7 aryl optionally substituted with 1 to 2 substituents, independently, selected from the group consisting of --C(O)R.sub.3, halogen, cyano, nitro, hydroxyl, C.sub.1-C.sub.6 alkyl, and C.sub.1-C.sub.6 alkoxy, with the proviso that at least one of R.sub.1 and R.sub.2 is not hydrogen; R.sub.3 is, independently, hydrogen, --OR.sub.4, alkyl, aryl, or heteroaryl; R.sub.4 is hydrogen, alkyl, aryl, or heteroaryl; R.sub.5 and R.sub.6 are, independently, hydrogen, alkyl, hydroxyl, alkoxy, or C.sub.5 to C.sub.7 aryl; wherein any R.sub.3 to R.sub.6 group having an aryl or heteroaryl moiety can optionally be substituted on the aryl or heteroaryl moiety with 1 to about 5 substituents, independently, selected from the group consisting of halogen, cyano, nitro, hydroxyl, C.sub.1-C.sub.6 alkyl, and C.sub.1-C.sub.6 alkoxy. Methods of making these compounds as well as methods using the compounds for treating a variety of conditions are also disclosed.