Antibacterial compounds

1. A compound of formula (IA) for use in the treatment of tuberculosis

wherein

R 1 represents C 1-6 alkyl or hydrogen;

L 1 represents a linker group —C(R a )(R b )—;

X 1 represents an aromatic linker group that is phenylene (which linker group may itself be optionally substituted by one or more substituents selected from fluoro, —OH, —OC 1-6 alkyl and C 1-6 alkyl, wherein the latter two alkyl moieties are themselves optionally substituted by one or more fluoro atoms);

R a and R b independently represent hydrogen or C 1-6 alkyl (optionally substituted by one or more fluoro atoms);

X a represents CH or N;

X b represents CH, N, O (in which case L 2 is not present) or C═O (in which case L 2 is also not present);

q 1 represents —CH 2 —, —CH 2 —CH 2 —, —O—CH 2 —, or “—”;

q 2 represents —CH 2 —, or —CH 2 —CH 2 —;

q 3 represents —CH 2 —, or —CH 2 —CH 2 —;

q 4 represents —CH 2 —, or —CH 2 —CH 2 —;

when X b represents O or C═O, then L 2 is not present;

when X b represents C(R a ) or N, then L 2 may represent hydrogen, halo, —OR f , —C(O)—R g , C 1-6 alkyl (optionally substituted by one or more halo), or an aromatic group (optionally substituted by one or more substituents selected from halo, C 1-6 alkyl (itself optionally substituted by one or more substituents selected from fluoro, —CF 3 and/or —SF 5 ), —OC 1-6 alkyl (itself optionally substituted by one or more fluoro atoms), —O-phenyl (itself optionally substituted by halo, C 1-6 alkyl, C 1-6 fluoroalkyl and/or —OC 1-6 alkyl) or —SF 5 ); or, when X b is N, L 2 represents —S(O) 2 —C 1-6 alkyl optionally substituted by one or more fluoro atoms;

R f represents hydrogen, C 1-6 alkyl (optionally substituted by one or more fluoro) or an aromatic group (itself optionally substituted by one or more substituents selected from halo, C 1-6 alkyl and —OC 1-6 alkyl, where the latter two alkyl moieties may themselves be optionally substituted by one or more fluoro atoms);

R g represents hydrogen or C 1-6 alkyl (optionally substituted by one or more substituents selected from fluoro, or —OC 1-3 alkyl, which latter moiety is also optionally substituted by one or more fluoro atoms) or an aromatic group (optionally substituted by one or more substituents selected from halo, C 1-6 alkyl or —OC 1-6 alkyl);

wherein the combined ring systems, i.e. Ring A and Ring B may be represented as follows:

either ring A and/or ring B may be optionally substituted by one or more substituents selected from: halo, C 1-6 alkyl (optionally substituted by one or more halo) and/or —OC 1-6 alkyl (itself optionally substituted by one or more fluoro atoms),

or a pharmaceutically-acceptable salt thereof.

2. The compound of claim 1 in which such linker group X 1 is substituted by one or more substituents selected from fluoro, CH 3 , CF 3 , —OCH 3 and —OCF 3 .

3. The compound of claim 1 , wherein the spiro-cyclic moiety, i.e. the combined X a and X b -containing ring may be represented as follows:

4. The compound of claim 1 , wherein X b is N and wherein L 2 represents —S(O) 2 —C 1-6 alkyl group optionally substituted by one or more fluoro atoms.

5. The compound of claim 4 , wherein L 2 represents —S(O) 2 CF 3 .

6. The compound of formula (IA) as defined in claim 1 wherein:

L 1 represents —CH 2 —;

X 1 represents phenylene and at least one of X a and X b represents N and the other represents CH, N or (in the case of X b ) O;

optional substituents on ring A and ring B are halo, C 1-3 alkyl and —OC 1-3 alkyl,

or a pharmaceutically-acceptable salt thereof.

7. A compound of formula (IB) as depicted below:

wherein

the integers are as hereinbefore defined in claim 1 , and where:

n1, n2, n3 and n4 independently represent 1; and

at least one of X a and X b represents N and the other represents CH or N.

8. A pharmaceutical composition comprising a therapeutically effective amount of a compound as defined in claim 1 and a pharmaceutically acceptable carrier.

9. A method for inhibiting Mycobacterium tuberculosis , which method comprises administering a therapeutically effective amount of a compound according to claim 1 to a subject in need thereof.

10. A product containing (a) a compound according to claim 1 , and (b) one or more other antibacterial agents, as a combined preparation for simultaneous, separate or sequential use in the inhibition of Mycobacterum tuberculosis.

11. The method of claim 9 , further comprising administering one or more other antibacterial agents.

12. The method of claim 11 , wherein the one or more other antibacterial agents are selected from rifampicin, isoniazid, pyrazinamide, amikacin, ethionamide, ethambutol, streptomycin, para-aminosalicylic acid, cycloserine, capreomycin, kanamycin, thioacetazone, PA-824, delamanid, moxifloxacin, gatifloxacin, ofloxacin, ciprofloxacin, sparfloxacin, clarithromycin, amoxycillin with clavulanic acid, rifamycins, rifabutin, rifapentine, or a combination thereof.

13. The method of claim 11 , wherein the one or more other antibacterial agents and the compound of claim 1 are administered simultaneously.

14. The method of claim 11 , wherein the one or more other antibacterial agents and the compound of claim 1 are administered separately.

15. The method of claim 11 , wherein the one or more other antibacterial agents and the compound of claim 1 are administered sequentially.

16. The product of claim 10 , wherein the the one or more other antibacterial agents are selected from rifampicin, isoniazid, pyrazinamide, amikacin, ethionamide, ethambutol, streptomycin, para -aminosalicylic acid, cycloserine, capreomycin, kanamycin, thioacetazone, PA-824, delamanid, moxifloxacin, gatifloxacin, ofloxacin, ciprofloxacin, sparfloxacin, clarithromycin, amoxycillin with clavulanic acid, rifamycins, rifabutin, rifapentine, or a combination thereof.

17. The product of claim 10 , wherein the weight ratio of the compound of claim 1 to the one or more other antibacterial agents range from 1/10 to 10/1.

18. The compound intermediate FE: