7,8 and 9-substituted tetracycline compounds

1. A substituted tetracycline compound of the formula(I) or a pharmaceutically acceptable salt thereof:

wherein:

R 4 and R 4′ are each methyl;

R 5 is hydrogen or hydroxyl;

R 6 and R 6′ are each independently hydrogen, methyl, or hydroxyl;

R 7 is substituted or unsubstituted phenyl, wherein said substituted phenyl is phenyl substituted with at least one substituent selected from the group consisting of halogen, hydroxyl, alkoxy, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, carboxylate, alkylcarbonyl, alkylaminocarbonyl, aralkylaminocarbonyl, alkenylaminocarbonyl, alkylcarbonyl, arylcarbonyl, aralkylcarbonyl, alkenylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylthiocarbonyl, phosphate, phosphonato, phosphinato, cyano, amino, alkylamino, dialkylamino, arylamino, diarylamino alkylarylamino, acylamino, alkylcarbonylamino, arylcarbonylamino, carbamoyl, ureido, amidino, imino, sulfhydryl, alkylthio, arylthio, thiocarboxylate, sulfate, alkylsulfinyl, sulfonato, sulfamoyl, sulfonamido, nitro, trifluoromethyl, cyano, azido, heterocyclyl, alkylaryl, an aromatic moiety and a heteroaromatic moiety;

R 8 is hydrogen, phenyl, nitrophenyl, halo, or lower alkynyl; and

R 9 is hydrogen, amino, acetamide, or lower alkynyl.

2. The compound of claim 1 , wherein R 5 is hydrogen, R 6 is methyl, R 6′ is hydroxyl, R 7 is unsubstituted phenyl, and R 8 and R 9 are each hydrogen.

3. The compound of claim 1 , wherein R 5 is hydroxyl, R 6 is methyl, and R 6′ is hydrogen.

4. The compound of claim 3 , wherein R 7 is unsubstituted phenyl, and R 8 and R 9 are each hydrogen.

5. The compound of claim 3 , wherein R 7 is substituted phenyl.

6. The compound of claim 3 , wherein said compound is 7-phenyl doxycycline or 7-(4-fluorophenyl) doxycycline.

7. The compound of claim 3 , wherein R 8 is phenyl or ethynyl, and R 9 is amino.

8. The compound of claim 1 , wherein R 5 is hydrogen, R 6 is hydroxyl, R 6′ is hydrogen, R 7 is unsubstituted phenyl.

9. A pharmaceutical composition comprising a therapeutically effective amount of a compound of claim 1 and a pharmaceutically acceptable carrier.

10. The pharmaceutical composition of claim 9 , wherein said compound is selected from the group consisting of 7-phenyl demeclocycline, 7-phenyl tetracycline, 7-phenyl doxycycline and 7-(4-fluorophenyl) doxycycline.

11. A method for treating a bacterial infection in a mammal, comprising administering to said mammal the compound of claim 1 .

12. The method of claim 11 wherein said compound is selected from the group consisting of 7-phenyl tetracycline, 7-phenyl doxycycline, 7-(4-fluorophenyl) doxycycline, 7-phenyl demeclocycline.

13. The method of claim 11 , wherein said bacterial infection is associated with E. coli.

14. The method of claim 11 , wherein said bacterial infection is associated with S. aureus.

15. The method of claim 11 , wherein said bacterial infection is associated with E. faecalis.

16. The method of claim 11 , wherein said compound is administered with a pharmaceutically acceptable carrier.