Antibacterial agents

1. A compound of formula (I)

wherein:

Z 1 and Z 4 are N;

Z 2 , Z 3 , Z 5 , and Z 6 are each CR 1a ;

A is CH 2 ;

W 1 , W 2 , and W 4 are each CH 2 ;

W 3 is a bond;

B is a bond;

R 1a is independently at each occurrence H or halo;

R 1 is unsubstituted C (1-6) -alkoxy;

R 6 , R 7 , R 8 , and R 11 are each H;

R 12 is UR 13 ; where R 13 is 4H-pyrido[3,2-b][1,4]thiazin-3-oxo-6-yl, 4H-pyrido[3.2-b][1,4]oxazin-3-oxo-6-yl, or 2,3-dihydro-[1,4]dioxino[2,3-c]-pyridin-6-yl;

U is CH 2 ; C(═O); or SO 2 ;

or a pharmaceutically acceptable salt thereof.

2. A compound according to claim 1 , wherein:

R 1 is OCH 3 .

3. A compound which is:

6-{[((1S,5R,6S)-3-{2-[3-fluoro-6-(methyloxy)-1,5-naphthyridin-4-yl]ethyl}-3-azabicyclo[3.2.0]hept-6-yl)amino]methyl}-2H-pyrido[3,2-b][1,4]thiazin-3 (4H)-one; or

6-{[((1S,5R,6S)-3-{2-[3-fluoro-6-(methyloxy)-1,5-naphthyridin-4-yl]ethyl}-3-azabicyclo[3.2.0]hept-6-yl)amino]methyl}-2H-pyrido[3,2-b][1,4]oxazin-3 (4H)-one;

or a pharmaceutically acceptable salt thereof.

4. A pharmaceutical composition comprising a compound according to claim 1 and a pharmaceutically acceptable carrier.

5. A method of treating a bacterial infections in mammals in need thereof which comprises administering to the mammal an effective amount of a compound according to claim 1 , which infection is caused by an organism selected from the group consisting of Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Enterococcus faecalis, Haemophilus influenza, E. Coli , and Moraxella catarrhalis.