Patent ID: 8809285

Claim:
A compound of formula I: (monophosphorylated lipid A)-L-X (I); wherein L is a linker having a first end Y and a second end Z; wherein the linker has formula Y—(CH 2 ) 2 —NHC(O)—(CH 2 ) a —C(O)NH—(CH 2 ) b —Z, wherein a and b are integers selected from 2 to 6; and wherein monophosphorylated lipid A is attached at the first end Y of the linker L, and X is attached at the second end Z of the linker L; and wherein R 9 and R 19 are independently selected from H or one to two substituents selected from the group consisting of C 1 -C 6 alkyl, —OC 1 -C 4 alkyl, —C(O)C 1 -C 4 alkyl, and halo; or a pharmaceutically acceptable salt thereof.