N,N'-Dicyclohexylcarbamimidothioic Acid (5,6-Dihydro-6,6-dimethylimidazo[2,1-b]thiazol-3-yl)methyl Ester is a selective CXCR4 inhibitors that block CXCR4/CXCL12 interactions in vitro and in vivo as well as the infection of target cells by X4-tropic HIV.