A compound having the following formula or a pharmaceutically acceptable salt thereof:where:R independently represents a hydrogen atom, a halogen atom, a (C1-C3)alkyl group, a —NR1R2 group, a (C1-C3)fluoroalkoxy group, a —NO2 group, a phenoxy group, or a (C1-C4)alkoxy group,R1 and R2 are independently a hydrogen atom or a (C1-C3)alkyl group,R′ is a hydrogen atom, a halogen atom, a (C1-C3)alkyl group, or a (C1-C4)alkoxy group,R″ is a hydrogen atom or a (C1-C4)alkyl group,n is 1, 2, or 3, andn′ is 1 or 2.
