Patent ID: 8476043

Claim:
A compound having a formula: and its pharmaceutically acceptable salts, wherein R 1 is selected from the group consisting of cyclohexyl, cycloheptyl, cyclooctyl, norbornyl, adamantyl, noradamantyl, and phenyl, wherein the phenyl group is either unsubstituted or substituted with from one to three substituents selected from the group consisting of halogen, lower alkyl, lower halo alkyl, lower alkoxy, lower haloalkoxy, C 3 -C 5 cycloalkyl and cyano; P 1 is —NHC(O)NH—; P 2 is selected from the group consisting of —C(O)—, —O(CH 2 CH 2 O) q —, and —C(O)O—; P 3 is —C(O)OR 2 , wherein R 2 is a member selected from the group consisting of hydrogen, methyl and ethyl; the subscripts n and m are each 1, and the subscript q is 0 to 6; L 1 is cyclohexylene; and L 2 is a phenylene.