Patent ID: 7825142

Claim:
A compound of the formula: or a pharmaceutically acceptable salt thereof, wherein: X is N or NR 9 ; Y is CR 4 , N, NR 9 , O or S; Z is CR 4 , CHR 4 , N, NR 9 , O or S; R 1 is hydrogen or optionally substituted lower alkyl; each R 4 is independently OR 4A , OC(O)R 4A , hydrogen, halogen, or optionally substituted alkyl, aryl, alkylaryl, arylalkyl, heteroalkyl, heterocycle, alkylheterocycle, or heterocyclealkyl; R 5 is OR 5A or OC(O)R 5A ; R 6 is OR 6A or OC(O)R 6A ; R 7 is OR 7A or OC(O)R 7A ; R 8 is hydrogen, CH 2 OR 8A or CH 2 OC(O)R 8A ; each R 9 is independently hydrogen or optionally substituted alkyl, aryl, alkylaryl, arylalkyl, heteroalkyl, heterocycle, alkylheterocycle, or heterocyclealkyl; and each of R 4A , R 5A , R 6A , R 7A and R 8A is independently hydrogen or lower alkyl.