| 主权项 |
1. A compound of formula:wherein:
L1 and L2 are each independently selected from C1-4alkylene, C2-4alkenylene and C2-4alkynylene wherein each C1-4alkylene, C2-4alkenylene or C3-4alkynylene L1 and/or L2 is independently optionally substituted with one or more C1-4alkyl, C2-4alkenyl or C2-4alkynyl; L3 is selected from C1-7alkylene, C2-7alkynylene and C2-7alkynylene wherein each C1-4alkylene C2-4alkenylene or C3-4alkynylene L3 is optionally substituted with one or more groups selected from OH, C1-4alkyl, C2-4alkenyl or C2-4alkynyl; R1 is alkyl, aryl, heteroaryl, alkenyl, alkynyl, arylalkyl, heteroarylalkyl, NR72, halogen, OR7, H or NH2; R2 and R3 are independently selected from OH, OR7, SR7, NHR7, NR72, and Rp; R4 is NH2, NHOH, N3, NHR7, NR72, C(O)NHR7, C(O)NR72, SH, SR7, CHO, alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, heterocycloalkyl wherein R4 is optionally substituted with one or more OH, CH2OH, C(O)R7, OR7, COOR7, CN, COOH, OH, and/or P(O)R5R6 or R4 is —O—C1-2alkylene-P(O)R5R6; R5 and R6 are independently selected from OH, OR7, SR7, NHR7, NR72, and Rp; R8 is selected from H, alkyl, aryl, heteroaryl, NR72, halogen, OR7; wherein Rp is selected from an amino acid residue, an optionally substituted alkoxy group and RCOSCH2CH2O— (SATE), wherein R is C1-4alkyl and wherein the or each R7, where present, is independently selected from alkyl, alkenyl, alkynyl, aryl, acyl and arylalkyl, R7 optionally containing one or more heteroatoms; X1 is N; X2 is C; X3 is N; X4 is C; Y1 where present is selected from S and O, and Y2 where present is selected from halogen; wherein the combined number of carbon atoms in L1 and L2 excluding the number of carbon atoms in the optional substituent(s), where present, is between 3 and 5; and wherein the combined number of non-hydrogen atoms in L3 and R4 excluding the number of atoms in the optional substituent(s), where present, and excluding the number of atoms in R5 and R6 is less than or equal to 8, or a pharmaceutically acceptable salt thereof. |
