Patent ID: 8183384

Claim:
A compound represented by structural formula (IV): or a tautomer or a pharmaceutically acceptable salt thereof, wherein: X is a C1-C4 alkyl, NR 7 , C(O), C(S), C(NR 8 ), or S(O) p ; R 1 is —SH or —OH; R 3 and R 25 are —OH; R 5 is an optionally substituted aryl, or an optionally substituted heteroaryl; R 6 is a lower alkyl, C3-C6 cycloalkyl, lower alkoxy, a lower alkyl sulfanyl, or —NR 10 R 11 ; R 7 and R 8 , for each occurrence, are, independently, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heterocyclyl, aryl, heteroaryl, aralkyl, or heteraralkyl; R 10 and R 11 , for each occurrence, are independently —H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heterocyclyl, aryl, heteroaryl, aralkyl, or heteraralkyl; or R 10 and R 11 , taken together with the nitrogen to which the are attached, form an heterocyclyl or an heteroaryl; p, for each occurrence, is, independently, 1 or 2; provided that when X is —CH 2 —, —CH 2 CH 2 —, or —NH—, R 5 is not an unsubstituted phenyl, p-fluorophenyl, p-chlorophenyl, or trifluoromethyl-phenyl.