Compounds

1. A compound of Formula (I) or pharmaceutically acceptable salt thereof:

wherein

R 1 is halogen; cyano; C 1-6 straight alkyl; C 3-4 branched alkyl; C 1-6 straight alkoxy; C 3-4 branched alkoxy; methyl substituted by one or more fluoro; ethyl substituted by one or more fluoro; methoxy substituted by one or more fluoro; or ethoxy substituted by one or more fluoro.

2. The compound or pharmaceutically acceptable salt thereof according to claim 1 , wherein R 1 is fluoro, chloro or bromo; cyano; C 1-6 straight alkyl; C 3-4 branched alkyl; C 1-6 straight alkoxy; C 3-4 branched alkoxy; methyl substituted by one or more fluoro; ethyl substituted by one or more fluoro; methoxy substituted by one or more fluoro; or ethoxy substituted by one or more fluoro.

3. The compound or pharmaceutically acceptable salt thereof according to claim 1 , wherein R 1 is fluoro, chloro or bromo; cyano; C 1-6 straight alkyl; C 3-4 branched alkyl; C 1-6 straight alkoxy; C 3-4 branched alkoxy; mono-, di- or trifluoromethyl; mono-, di- or trifluoromethoxy; 2-fluoroethyl; 2,2-difluoroethyl; 2,2,2-trifluoroethyl; 2-fluoroethoxy, 2,2-difluoroethoxy; or 2,2,2-trifluoroethoxy.

4. The compound or pharmaceutically acceptable salt thereof according to claim 1 , wherein R 1 is fluoro, chloro, bromo, cyano, C 1-6 straight alkyl, C 3-4 branched alkyl, C 1-6 straight alkoxy, C 3-4 branched alkoxy, trifluoromethyl, trifluoromethoxy, 2,2,2-trifluoroethyl or 2,2,2-trifluoroethoxy.

5. The compound or pharmaceutically acceptable salt thereof according to claim 1 , wherein R 1 is fluoro, chloro, bromo, cyano, C 1-6 straight alkyl, C 3-4 branched alkyl, C 1-6 straight alkoxy, C 3-4 branched alkoxy, trifluoromethyl, 2,2,2-trifluoroethyl or 2,2,2-trifluoroethoxy.

6. The compound or pharmaceutically acceptable salt thereof according to claim 1 , wherein R 1 is fluoro, bromo, cyano, C 1-4 straight alkyl, C 1-6 straight alkoxy, C 4 branched alkoxy, trifluoromethyl, 2,2,2-trifluoroethyl or 2,2,2-trifluoroethoxy.

7. The compound or pharmaceutically acceptable salt thereof according to claim 1 , wherein R 1 is fluoro, bromo, cyano, methyl, ethyl, trifluoromethyl, 2,2,2-trifluoroethoxy, methoxy, ethoxy, n-propoxy, iso-butoxy or hexyloxy.

8. The compound or pharmaceutically acceptable salt thereof according to claim 1 selected from:

4,4,4-trifluoro-1-[3-(2,2,2-trifluoroethoxy)-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl]butan-1-one;

4,4,4-trifluoro-1-(3-propoxy-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl)butan-1-one;

4,4,4-trifluoro-1-(3-isobutoxy-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl)butan-1-one;

4,4,4-trifluoro-1-(3-hexyloxy-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl)butan-1-one;

1-(3-bromo-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl)-4,4,4-trifluorobutan-1-one;

1-(3-ethoxy-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl)-4,4,4-trifluorobutan-1-one;

4,4,4-trifluoro-1-(3-methoxy-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl)butan-1-one;

4,4,4-trifluoro-1-(3-(trifluoromethyl)-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl)butan-1-one;

4,4,4-trifluoro-1-(3-methyl-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl)butan-1-one;

1-(3-ethyl-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl)-4,4,4-trifluorobutan-1-one;

8-(4,4,4-trifluorobutanoyl)-1-oxa-2,8-diazaspiro[4.5]dec-2-ene-3-carbonitrile; and

4,4,4-trifluoro-1-(3-fluoro-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl)butan-1-one.

9. The compound or pharmaceutically acceptable salt thereof according to claim 8 , wherein the compound is 4,4,4-trifluoro-1-(3-(trifluoromethyl)-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl)butan-1-one having the following structure:

10. A method for the treatment of a mycobacterial infection in a human in need thereof, comprising administering to said human a therapeutically effective amount of the compound or a pharmaceutically acceptable salt thereof, according to claim 1 .

11. A method for the treatment of a disease caused by infection with a mycobacterium in a human in need thereof, comprising administering to said human a therapeutically effective amount of the compound or a pharmaceutically acceptable salt thereof, according to claim 1 .

12. A pharmaceutical composition comprising (a) the compound or pharmaceutically acceptable salt thereof according to claim 1 ; and (b) a pharmaceutically acceptable excipient.

13. A combination of (a) the compound or pharmaceutically acceptable according to claim 1 and (b) a further anti-mycobacterial agent.

14. The combination according to claim 13 , wherein the further anti-mycobacterial agent is an anti-tuberculosis agent.

15. The combination according to claim 14 , wherein the anti-tuberculosis agent is selected from isoniazid, rifampin, pyrazinamide, ethambutol, moxifloxacin, rifapentine, clofazimine, ethionamide, prothionamide, isoxyl, thiacetazone, rifabutin, a diarylquinoline, nitroimidazo-oxazine PA-824, delamanid (OPC-67683), an oxazolidinone, EMB analogue SQ109, OPC-167832, GSK3036656, GSK2556286, GSK3211830, a benzothiazinone, an azaindole, a dinitrobenzamide, and a beta-lactam or beta-lactam combinations.

16. The combination according to claim 13 , further comprising an antiviral agent.

17. The combination according to claim 16 , wherein the antiviral agent is an antiretroviral agent selected from zidovudine, didanosine, lamivudine, zalcitabine, abacavir, stavudine, adefovir, adefovir dipivoxil, fozivudine, todoxil, emtricitabine, alovudine, amdoxovir, elvucitabine, nevirapine, delavirdine, efavirenz, loviride, immunocal, oltipraz, capravirine, lersivirine, GSK2248761, TMC-278, TMC-125, etravirine, saquinavir, ritonavir, indinavir, nelfinavir, amprenavir, fosamprenavir, brecanavir, darunavir, atazanavir, tipranavir, palinavir, lasinavir, enfuvirtide, T-20, T-1249, PRO-542, PRO-140, TNX-355, BMS-806, BMS-663068 and BMS-626529, 5-Helix, raltegravir, elvitegravir, GSK1349572, GSK1265744, vicriviroc (Sch-C), Sch-D, TAK779, maraviroc, TAK449, didanosine, tenofovir, lopinavir, and darunavir.

18. A method for the treatment of tuberculosis in a human in need thereof, comprising administering to said human a therapeutically effective amount of the compound, or pharmaceutically acceptable salt thereof, according to claim 1 .

19. The method according to claim 10 , wherein the mycobacterial infection is a Mycobacterium tuberculosis infection.

20. A method for the treatment of a mycobacterial infection in a human in need thereof, comprising administering to said human (a) the compound or pharmaceutically acceptable salt thereof according to claim 1 ; and (b) at least one other anti-mycobacterial agent.

21. The method according to claim 20 , wherein the at least one other anti-mycobacterial agent is an anti-tuberculosis agent.

22. The method according to claim 21 , wherein the anti-tuberculosis agent is selected from isoniazid, rifampin, pyrazinamide, ethambutol, moxifloxacin, rifapentine, clofazimine, ethionamide, prothionamide, isoxyl, thiacetazone, a diarylquinoline, nitroimidazo-oxazine PA-824 (pretomanid), delamanid (OPC-67683), an oxazolidinone, EMB analogue SQ109, OPC-167832, GSK3036656A, GSK2556286, GSK3211830, a benzothiazinone, an azaindole, a dinitrobenzamide, and a beta-lactam or beta-lactam combination.

23. The method according to claim 20 , further comprising administering to said human an antiviral agent.

24. The method according to claim 23 , wherein the antiviral agent is antiretroviral agent selected from zidovudine, didanosine, lamivudine, zalcitabine, abacavir, stavudine, adefovir, adefovir dipivoxil, fozivudine, todoxil, emtricitabine, alovudine, amdoxovir, elvucitabine, nevirapine, delavirdine, efavirenz, loviride, immunocal, oltipraz, capravirine, lersivirine, GSK2248761, TMC-278, TMC-125, etravirine, saquinavir, ritonavir, indinavir, nelfinavir, amprenavir, fosamprenavir, brecanavir, darunavir, atazanavir, tipranavir, palinavir, lasinavir, enfuvirtide, T-20, T-1249, PRO-542, PRO-140, TNX-355, BMS-806, BMS-663068 and BMS-626529, 5-Helix, raltegravir, elvitegravir, GSK1349572, GSK1265744, vicriviroc (Sch-C), Sch-D, TAK779, maraviroc, TAK449, didanosine, tenofovir, lopinavir, and darunavir.

25. The compound according to claim 8 , wherein the compound is 4,4,4-trifluoro-1-(3 -(trifluoromethyl)-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl)butan-1-one, having the following structure:

26. The combination according to claim 14 , wherein the anti-tuberculosis agent is ethionamide.

27. A method for the treatment of tuberculosis in a human in need thereof, comprising administering to said human a therapeutically effective amount of the compound, or a pharmaceutically acceptable salt thereof, according to claim 9 .

28. A method for the treatment of a mycobacterial infection in a human in need thereof, comprising administering to said human a therapeutically effective amount of the compound or a pharmaceutically acceptable salt thereof according to claim 9 , wherein the mycobacterial infection is a Mycobacterium tuberculosis infection.