A compound of formula I or a pharmaceutically acceptable salt thereof, wherein X is absent or is an alkyl, alkylamino, cycloalkyl, aryl, or heterocycle; Q is H, (CH 2) q NR 1 R 2, NR 1 (CH 2)pNR b R c, OR 1, SR 1, or CHR 1 R 2, in which q is 0 or 1 and p is 2-4; R 1 and R 2 are each independently hydrogen, alkyl, alkenyl, cycloalkyl, alkylcycloalkyl, aryl, alkylaryl, heterocycle, alkylheterocycle, or R 1 and R 2 together with the nitrogen atom to which they are bonded form a heterocycle, which may be optionally substituted by from one to four groups which may be the same or different selected from (C 1 -C 4)alkyl, phenyl, benzyl, C(=O)R 12, (CH 2) p OR a, and (CH 2) p NR b R c, in which p is 2-4; R 7 is H, alkyl, heteroaryl or NR 3 R 4, wherein the heteroaryl is optionally substituted by (C 1 -C 4)alkyl; R 3 and R 4 are each independently hydrogen, alkyl, cycloalkyl, alkenyl, aryl or alkylaryl, or R 3 and R 4 together with the nitrogen atom to which they are bonded form a heterocycle; Y is oxygen, sulfur, or NR 11, where R 11 is hydrogen, alkyl, cycloalkyl, alkenyl, or aryl group; R 12 is alkyl, aryl, or heterocycle; L is alkyl or alkenyl containing from 2 to 10 carbon atoms; R 5 is hydrogen, halogen, cyano, nitro, CF 3, OCF 3, alkyl, cycloalkyl, alkenyl, aryl, heterocycle, OR a, SR a, S(=O)R a, S(=O) 2 R a, NR b R c, S(=O) 2 NR b R c, C(=O)OR a, C(=O)R a, C(=O)NR b R c, OC(=O)R a, OC(=O)NR b R c, NR b C(=O)OR a, or NR b C(=O)R a; R 6 is hydrogen, alkyl, alkenyl, (CH 2) r C(=O)O(C 1 -C 4)alkyl, aryl, aralkyl, benzyl, heterocycle, (CH 2) p NR b R c, or alkylheterocycle, wherein r is 0-4; each occurrence of R a is independently hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, heterocycle, or aryl; and each occurrence of R b, and R c is independently hydrogen, alkyl, cycloalkyl, heterocycle, aryl, or said R b and R c together with the nitrogen atom to which they are bonded optionally form a heterocycle; provided that when R 5 and R 6 are H or C 1 -C 3 alkyl, then Q is not H. X is absent or is an alkyl, alkylamino, cycloalkyl, aryl, or heterocycle; Q is H, (CH 2) q NR 1 R 2, NR 1 (CH 2)pNR b R c, OR 1, SR 1, or CHR 1 R 2, in which q is 0 or 1 and p is 2-4; R 1 and R 2 are each independently hydrogen, alkyl, alkenyl, cycloalkyl, alkylcycloalkyl, aryl, alkylaryl, heterocycle, alkylheterocycle, or R 1 and R 2 together with the nitrogen atom to which they are bonded form a heterocycle, which may be optionally substituted by from one to four groups which may be the same or different selected from (C 1 -C 4)alkyl, phenyl, benzyl, C(=O)R 12, (CH 2) p OR a, and (CH 2) p NR b R c, in which p is 2-4; R 7 is H, alkyl, heteroaryl or NR 3 R 4, wherein the heteroaryl is optionally substituted by (C 1 -C 4)alkyl; R 3 and R 4 are each independently hydrogen, alkyl, cycloalkyl, alkenyl, aryl or alkylaryl, or R 3 and R 4 together with the nitrogen atom to which they are bonded form a heterocycle; Y is oxygen, sulfur, or NR 11, where R 11 is hydrogen, alkyl, cycloalkyl, alkenyl, or aryl group; R 12 is alkyl, aryl, or heterocycle; L is alkyl or alkenyl containing from 2 to 10 carbon atoms; R 5 is hydrogen, halogen, cyano, nitro, CF 3, OCF 3, alkyl, cycloalkyl, alkenyl, aryl, heterocycle, OR a, SR a, S(=O)R a, S(=O) 2 R a, NR b R c, S(=O) 2 NR b R c, C(=O)OR a, C(=O)R a, C(=O)NR b R c, OC(=O)R a, OC(=O)NR b R c, NR b C(=O)OR a, or NR b C(=O)R a; R 6 is hydrogen, alkyl, alkenyl, (CH 2) r C(=O)O(C 1 -C 4)alkyl, aryl, aralkyl, benzyl, heterocycle, (CH 2) p NR b R c, or alkylheterocycle, wherein r is 0-4; each occurrence of R a is independently hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, heterocycle, or aryl; and each occurrence of R b, and R c is independently hydrogen, alkyl, cycloalkyl, heterocycle, aryl, or said R b and R c together with the nitrogen atom to which they are bonded optionally form a heterocycle; provided that when R 5 and R 6 are H or C 1 -C 3 alkyl, then Q is not H.