Gold (I)-Phosphine Compounds as Anti-Bacterial Agents

Abstract

A compound of formula (I) for use in the prevention or treatment of a bacterial infection wherein R.sup.P1 is either methyl, ethyl, isopropyl, cyclohexyl or phenyl; R.sup.P2 is selected from methyl, ethyl, isopropyl, cyclohexyl and phenyl; R.sup.P3 is either ethyl, isopropyl, cyclohexyl, phenyl or pyridyl; A is either S or Se; R.sup.A is selected from wherein each of Y.sup.1, Y.sup.2, Y.sup.3, Y.sup.4 and Y.sup.9 is independently selected from CH or N, wherein at least three of Y.sup.1, Y.sup.2, Y.sup.3, Y.sup.4 and Y.sup.9 are CH; V is selected from O, CHOR.sup.O1, NCO.sub.2R.sup.C2 or NR.sup.N2; one of V, Y.sup.6, Y.sup.7 and Y.sup.8 is selected from CH and N, and the others are CH; X is selected from NH, S or O; R.sup.C1 is selected from OR.sup.O2 or NHR.sup.N1; R.sup.O1 is selected from H and C.sub.1-3 unbranched alkyl; R.sup.O2 is C.sub.1-3 unbranched alkyl; R.sup.N1 is selected from H and C.sub.1-3 unbranched alkyl; R.sup.N2 is C.sub.1-3 unbranched alkyl; R.sup.C2 is either C.sub.1-3 unbranched alkyl or C.sub.3-4 branched alkyl; R.sup.C3 is selected from C.sub.1-3 unbranched alkyl and C.sub.2H.sub.4CO.sub.2H; R.sup.C4 is either H or Me; R.sup.C5 is either H or Me; R.sup.C6 represents one or two optional methyl substituents; and n is an integer from 2 to 8.

##STR00001##

Claims

1. A compound of formula (I): ##STR00054## for use in the prevention or treatment of a bacterial infection wherein: R.sup.P1 is either methyl, ethyl, isopropyl, cyclohexyl or phenyl; R.sup.P2 is selected from methyl, ethyl, isopropyl, cyclohexyl and phenyl; R.sup.P3 is either ethyl, isopropyl, cyclohexyl, phenyl or pyridyl; A is S; R.sup.A is selected from: ##STR00055## wherein: each of Y.sup.1, Y.sup.2, Y.sup.3, Y.sup.4 and Y.sup.9 is independently selected from CH or N, wherein at least three of Y.sup.1, Y.sup.2, Y.sup.3, Y.sup.4 and Y.sup.9 are CH; V is selected from O, CHOR.sup.O1, NCO.sub.2R.sup.C2 or NR.sup.N2; one of Y.sup.5, Y.sup.6, Y.sup.7 and Y.sup.8 is selected from CH and N, and the others are CH; X is selected from NH, S or O; R.sup.C1 is selected from OR.sup.O2 or NHR.sup.N1; R.sup.O1 is selected from H and C.sub.1-3 unbranched alkyl; R.sup.O2 is C.sub.1-3 unbranched alkyl; R.sup.N1 is selected from H and C.sub.1-3 unbranched alkyl; R.sup.N2 is C.sub.1-3 unbranched alkyl; R.sup.C2 is either C.sub.1-3 unbranched alkyl or C.sub.3-4 branched alkyl; R.sup.C3 is selected from C.sub.1-3 unbranched alkyl and C.sub.2H.sub.4CO.sub.2H; R.sup.C4 is either H or Me; R.sup.C5 is either H or Me; R.sup.C6 represents one or two optional methyl substituents; and n is an integer from 2 to 8.

2. A compound according to claim 1, wherein (a) R.sup.P1 and R.sup.P3 are the same or (b) R.sup.P1 and R.sup.P2 are the same.

3. A compound according to claim 2, wherein: (a) R.sup.P1, R.sup.P2 and R.sup.P3 are ethyl; or (b) R.sup.P1, R.sup.P2 and R.sup.P3 are isopropyl; or (c) R.sup.P1 and R.sup.P3 are phenyl and R.sup.P2 is methyl; or (d) R.sup.P1 and R.sup.P2 are methyl and R.sup.P3 is phenyl.

4-6. (canceled)

7. A compound according to claim 1, wherein R.sup.A is A1: ##STR00056## and either: (a) one of Y.sup.1, Y.sup.2, Y.sup.3, Y.sup.4 and Y.sup.9 is N; or (b) two of Y.sup.1, Y.sup.2, Y.sup.3, Y.sup.4 and Y.sup.9 are N; or (c) R.sup.A is phenyl.

8-10. (canceled)

11. A compound according to claim 1, wherein R.sup.A is A2: ##STR00057## and either: (a) V is O, or (b) V is CHOR.sup.O1; or (c) V is NCO.sub.2R.sup.C2; or (d) V is NR.sup.N2.

12-18. (canceled)

19. A compound according to claim 11, wherein there are no optional methyl substituents.

20. A compound according to claim 11, wherein there is a single methyl substituent represented by R.sup.C6.

21. A compound according to claim 11, wherein there are two methyl substituents represented by R.sup.C6.

22. A compound according to claim 1, wherein R.sup.A is A3: ##STR00058## and either: (a) X is O and one of Y.sup.5, Y.sup.6, Y.sup.7 and Y.sup.8 is N; or (b) X is NH and Y.sup.5, Y.sup.6, Y.sup.7 and Y.sup.8 is are CH.

23-24. (canceled)

25. A compound according to claim 1, wherein R.sup.A is R.sup.A is A4: ##STR00059## and either: (a) R.sup.C1 is OR.sup.O2 where R.sup.O2 is methyl; or (b) R.sup.C1 is NHR.sup.N1, and R.sup.N1 is H.

26-27. (canceled)

28. A compound according to claim 25, wherein either: (a) R.sup.C4 and R.sup.C5 are both H; or (b) R.sup.C4 is H and R.sup.C5 is Me; or (c) R.sup.C4 and R.sup.C5 are both Me.

29-30. (canceled)

31. A compound according to claim 1, wherein R.sup.A is A5: ##STR00060## and either: (a) R.sup.C3 is methyl; or (b) R.sup.C3 is C.sub.2H.sub.4CO.sub.2H.

32-33. (canceled)

34. A compound according to claim 31, wherein n is an integer from 4 to 8.

35. A compound according to claim 1, wherein the bacterial infection prevented and/or treated is infection by one or more Gram-positive bacteria.

36. A compound according to claim 1, wherein the bacterial infection prevented and/or treated is infection by one or more Gram-negative bacteria.

37-44. (canceled)

45. A method of removing or eliminating an existing biofilm, inhibiting biofilmformation, reducing the biomass of a biofilm, promoting the dispersal of microorganisms from a biofilm, sensitizing a microorganism in a biofilm to an antimicrobial agent, killing a microorganism within a biofilm, treating or preventing an infection, disease or disorder caused by a biofilm, inhibiting the growth of a microbial persister cell, killing a microbial persister cell, or treating or preventing an infection, disease or disorder caused by or associated with a microbial persister cell; the method comprising exposing the biofilm to an effective amount of a compound as described in claim 1.

46-47. (canceled)

48. The method according to claim 45, wherein the biofilm comprises bacteria, or the microbial persister cells are bacteria.

49-52. (canceled)

53. The method according to claim 45, comprising further administering at least one additional antimicrobial agent.

54. A medical device coated or impregnated with a compound as described in claim 1.

55. A compound of formula (I): ##STR00061## wherein R.sup.P% R.sup.P2, R.sup.P3, A and R.sup.A are as defined in claim 1, with the proviso that when R.sup.A is (A1), then Y.sup.1, Y.sup.2 and Y.sup.9 are CH and Y.sup.3 and Y.sup.4 are N; and with the further proviso that when R.sup.A is A3, then one of Y.sup.5, Y.sup.6, Y.sup.7 and Y.sup.8 is N.

56. A pharmaceutical composition comprising a compound according to claim 55.

57. A pharmaceutical composition according to claim 56, which also comprises a pharmaceutical acceptable diluent or excipient.

58. (canceled)

Description

EXAMPLES

[0243] Analytical Methods

[0244] MeCN-FA Method:

[0245] Phenomenex Luna C18(2) 3 m, 4.650 mm; H.sub.2O+0.1% formic acid; B=MeCN+0.1% formic acid; 45 C.; 0 min 5%, 1 min 37.5%, 3 min 95%, 3.5 min 95%, 3.51 min 5%, 4.5 min 5%; 2.2-2.3 mL/min.

[0246] MeOH-Bicarbonate Method:

[0247] Phenomenex Luna C18(2) 3 m, 4.650 mm; H.sub.2O+10 mmol ammonium bicarbonate; B=MeOH; 45 C.; 0 min 5%, 1 min 37.5%, 3 min 95%, 3.5 min 95%, 3.51 min 5%, 4.5 min 5%; 2.2-2.3 mL/min.

[0248] Synthesis of Key Intermediates

4-Mercapto cyclohexanol (I1)(Used During Synthesis of 6)

[0249] ##STR00020##

[0250] 7-Oxabicyclo[2.2.1]heptane (1 mL, 10.2 mmol), p-TsOH (2.6 g, 15.3 mmol) and thiourea (1.2 g, 15.3 mmol) were combined and dissolved in EtOH (10 mL) at rt. The reaction was heated at reflux for 21 h whereupon it was cooled to rt and NaOH (1.3 g, 32.4 mmol) as a solution in H.sub.2O (3 mL) was added in one portion. The resultant suspension dissolved upon heating the reaction mixture at reflux for a further 2 h. The EtOH was removed in vacuo and the aqueous residue cooled to 0 C. before a solution of H.sub.2SO.sub.4 (0.8 mL, 14.5 mmol) in H.sub.2O (5 mL) was added dropwise over the course of 10 minutes. The reaction mixture was diluted with H.sub.2O (20 mL) and extracted with EtOAc (340 mL) before passing the organic extracts through a phase separator cartridge. Removal of the solvent under reduced pressure gave the crude product as a yellow oil which was purified by column chromatography (Biotage Isolera 4) eluting with neat EtOAc to provide the title compound as a colourless oil (740 mg, 5.6 mmol, 55%).

(R)-2-Acetylamino-3-((R)-2-acetylamino-2-methoxycarbonyl-ethyldiselanyl)-propionic acid methyl ester (I2)(Used During Synthesis of 12)

[0251] ##STR00021##

[0252] Anhydrous MeOH (15 mL) was cooled to 0 C. and acetyl chloride (1.6 mL, 22.5 mmol) added dropwise over the course of 5 minutes. The colourless solution was stirred at 0 C. for 10 minutes whereupon L-selenocysteine (500 mg, 1.5 mmol) was added in one portion. The resultant yellow reaction mixture was warmed to rt and stirred at this temperature for 24 h before concentrating in vacuo to give the crude di-selenide ester hydrochloride as a yellow solid. The crude material was re-suspended in DCM (15 mL) and cooled to 0 C. at which point Et.sub.3N (1 mL, 7.5 mmol) was added followed by acetyl chloride (0.3 mL, 4.5 mmol). The reaction was stirred at rt for 4 h, before DCM (30 mL) and H.sub.2O (30 mL) were added. The layers were separated and the aqueous phase extracted with DCM (220 mL). The combined organic extracts were passed through a phase separator cartridge and the solvent removed in vacuo to give the crude product as a yellow oil which was purified by column chromatography (Biotage Isolera 4) eluting with neat EtOAc to provide the title compound as a colourless oil (270 mg, 0.6 mmol, 41%).

Chloro(trialkyl phosphine) gold (I) complexes (I6, I7Used in the Synthesis of 26 & 27)

[0253] ##STR00022##

(a) Dimethylphosphine borane I3

[0254] CeCl.sub.3 (25 g, 101.4 mmol) was suspended in THF (100 mL) and stirred at rt for 1 hour. NaBH.sub.4 (3.8 g, 101.4 mmol) was then added and the suspension stirred at rt for a further 1 hour. The reaction was cooled to 0 C. at which point dimethylphosphine oxide (2.6 g, 33.8 mmol) was added drop wise followed by LiAIH.sub.4 (1M in THF, 40.7 mL, 40.7 mmol) also drop wise. The reaction was stirred at rt for 18 h before diluting with toluene (50 mL) then quenching with H.sub.2O (25 mL) and 6N HCl (aq., 25 mL). The suspension was filtered through celite and the layers separated. The aqueous phase was extracted with DCM (340 mL) and the combined organic extracts washed with brine (140 mL) and passed through a phase separator cartridge. Concentration in vacuo gave the crude product as a yellow oil which was purified by column chromatography (Biotage Isolera 4) eluting with neat iso-hexane to 20% EtOAc/iso-hexane to provide the title compound as a colourless oil (1.49 g, 19.6 mmol, 58%).

(b) Dimethyl-ethylphosphine borane I4

[0255] Dimethylphosphine borane I3 (100 mg, 1.3 mmol) was dissolved in THF (3 mL) and the colourless solution cooled to 0 C. NaH (60% in mineral oil, 53 mg, 1.3 mmol) was added in one portion, whereupon effervescence was observed. The opaque reaction was stirred at rt for 10 minutes then cooled back down to 0 C. whereupon iodoethane (0.12 mL, 1.4 mmol) was added in one portion. When TLC had indicated completion of the reaction, H.sub.2O (10 mL) and Et.sub.2O (10 mL) were added and the phases separated. The aqueous phase was extracted with Et.sub.2O (215 mL) and the combined organic extracts washed with brine (120 mL) before passing through a phase separator cartridge.

[0256] Concentreation in vacuo gave the crude material as a colourless gum. Purification by column chromatography (Biotage Isolera 4) eluting with neat iso-hexane to 20% EtOAc/iso-hexane provided the title compound as a white solid (122 mg, 1.1 mmol, 90%).

(c) Dimethyl-isopropylphosphine borane I4

[0257] Procedure as described for dimethyl-ethylphosphine borane I3, except 2-iodo-2-methyl propane was used instead of iodoethane. The method provided the title compound as a white solid (232 mg, 2.04 mmol, 76%).

(d) Gold (I) Chloride I6

[0258] Dimethyl-ethylphosphine borane I4 (55 mg, 0.53 mmol) was dissolved in THF (5 mL) and the colourless solution degassed with nitrogen for 5 minutes. DABCO (178 mg, 1.6 mmol) was added and the reaction sealed with a Teflon screw cap. The reaction was heated to 100 C. and stirred at this temperature for 4 h before cooling in an ice bath and adding chloro(tetrahydrothiophene)gold(I) (170 mg, 0.53 mmol) in one portion. After stirring at rt for 18 h the reaction was diluted with EtOAc (10 mL) and H.sub.2O (10 mL) and the phases separated. The aqueous phase was extracted with EtOAc (220 mL) and the combined organic extracts washed with brine (20 mL) before passing theough a phase separator cartridge. Concentration in vacuo gave the crude product as a brown oil which was purified by column chromatography (Biotage Isolera 4) eluting with neat iso-hexane to 50% EtOAc/iso-hexane to provide the title compound as a colourless oil (16.5 mg, 0.05 mmol, 10%).

(e) Gold (I) chloride I7

[0259] Procedure as described for gold (I) chloride I6, except dimethyl-isopropylphosphine borane I5 was used instead of dimethyl-ethylphosphine borane I4. The method provided the title compound as a white solid (98 mg, 0.29 mmol, 45%).

Example 1

[0260] ##STR00023##

[0261] Method A:

[0262] To a stirred suspension of the chlorophosphine gold (I) compound (0.32 mmol) in EtOH (1 mL) at 0 C., was slowly added the appropriate thiol (0.32 mmol) as a solution in 10% K.sub.2CO.sub.3 (aq., 1 mL) and EtOH (1 mL). The reaction was stirred at 0 C. for 1 hour before warming to rt and allowing to stir at this temperature for 3 h. Once the reaction had gone to completion (by TLC) the reaction was diluted with H.sub.2O (5 mL) and the solution extracted with DCM (315 mL). The combined organic extracts were passed through a phase separator cartridge and the solvent evaporated to provide the title compound.

[0263] Method B:

[0264] As Method A, except after stirring at 0 C. the reaction was heated at 50 C. for 16 h whereupon a thick white ppt had formed. The solid was collected by filtration, washed with EtOH (1 mL) and H.sub.2O (2 mL) before drying under high vacuum for 24 h to give the title compound.

[0265] Method C:

[0266] As Method A, except the reaction is stirred at 0 C. for 1 hour only

[0267] Method D:

[0268] As Method C, except MeOH is used instead of EtOH

[0269] The following compounds were made using these methods:

TABLE-US-00002 TABLE 2 Compound Analytical Data Structure Number Method Yield/Physical appearance [00024] 1 A .sup.1H-NMR (400 MHz, CDCl.sub.3): ppm 1.10 (dt, 9H J = 18.4, 7.8 Hz), 1.64 (m, 2H), 1.74 (dq, 6H, J = 9.6, 7.8 Hz), 1.94 (m, 2H), 3.24-3.36 (m, 3H), 3.85 (m, 2H). .sup.13C-NMR (100 MHz, CDCl.sub.3): ppm 8.96 (s), 18.06 (d, J = 32.2 Hz), 38.6 (s), 42.34 (s), 68.17 (s). .sup.31P- NMR (162 MHz, CDCl.sub.3): ppm 37.81 (s). Colourless oil; 115 mg, 83% [00025] 2 A .sup.1H-NMR (400 MHz, CDCl.sub.3): ppm 1.09 (dt, 9H, J = 18.2, 7.6 Hz), 1.33 (s, 9H), 1.46 (m, 2H), 1.73 (dq, 6H, J = 9.8, 7.6 Hz), 1.95 (m, 2H), 2.69 (m, 2H), 3.26 (m, 1H), 3.92 (2H, br s). .sup.13C-NMR (100 MHz, CDCl.sub.3): ppm 8.96 (s), 18.06 (d, J = 32.2 Hz), 28.40 (s), 39.67 (s), 40.95 (s), 79.05 (s), 154.80 (s). .sup.31P-NMR (162 MHz, CDCl.sub.3): ppm 37.74 (s). Yellow oil; 95 mg, 55% [00026] 3 A .sup.1H-NMR (400 MHz, CDCl.sub.3): ppm 1.27 (dt, 9H, J = 18.4, 7.6 Hz), 1.90 (dq, 6H, J = 9.8, 7.6 Hz), 6.82 (t, 1H, J = 4.8 Hz), 8.34 (d, 2H, J = 4.8 Hz). .sup.13C-NMR (100 MHz, CDCl.sub.3): ppm 9.03 (s), 18.13 (d, J = 33.6 Hz), 115.30 (s), 156.48 (s), 180.86 (s). .sup.31P- NMR (162 MHz, CDCl.sub.3): ppm 36.72 (s). Colourless oil; 105 mg, 38% [00027] 4 A .sup.1H-NMR (400 MHz, DMSO-d6): ppm 1.16 (dt, 9H, J = 18.7, 7.6 Hz), 1.96 (dq, 6H, J = 10.4, 7.6 Hz), 7.24 (dd, 1H, J = 8.6, 4.6 Hz), 7.50 (dd, 1H, J = 8.6, 1.5 Hz), 8.72 (dd, 1H, J = 4.6, 1.5 Hz). .sup.13C-NMR (100 MHz, CDCl.sub.3): ppm 9.07 (s), 18.11 (d, J = 33.6 Hz), 125.01 (s), 130.15 (s), 146.84 (s), 172.48 (s). .sup.31P-NMR (162 MHz, CDCl.sub.3): ppm 36.66 (s). Brown solid; 47 mg, 34% [00028] 5 B .sup.1H-NMR (400 MHz, DMSO-d6): ppm 1.16 (dt, 9H, J = 18.7, 7.6 Hz), 1.94 (dq, 6H, J = 10.1, 7.6 Hz), 6.97 (m, 2H), 7.22 (br s, 2H), 11.98 (br s, 1H). .sup.13C- NMR (100 MHz, DMSO-d6): ppm 8.95 (s), 16.92 (d, J = 34.4 Hz), 120.15 (s). .sup.31P-NMR (162 MHz, DMSO-d6): ppm 38.08 (s). White solid; 78 mg, 52% [00029] 6 A .sup.1H-NMR (400 MHz, CDCl3): ppm 1.20 (dt, 9H, J = 18.4, 7.6 Hz), 1.33 (m, 2H), 1.52 (m, 2H), 1.84 (dq, 6H, J = 9.8, 7.6 Hz), 1.97 (m, 2H), 2.17 (m, 2H), 3.23 (m, 1H), 3.58 (m, 1H). .sup.13C-NMR (100 MHz, DMSO-d6): ppm 9.00 (s), 17.09 (d, J = 33.6 Hz), 36.04 (s), 40.67 (s), 42.01 (s), 68.39 (s). .sup.31P-NMR (162 MHz, DMSO-d6): ppm 38.67 (s). Pale yellow oil; 128 mg, 90% [00030] 7 C .sup.1H-NMR (400 MHz, CDCl3): ppm 1.20 (dt, 9H, J = 18.2 Hz, 7.6 Hz), 1.82 (dq, 6H, J = 9.8, 7.6 Hz), 2.05 (s, 3H), 3.32 (dd, 1H, J = 13.1, 4.8 Hz), 3.45 (dd, 1H, J = 13.1, 4.8 Hz), 3.73 (s, 3H), 4.77 (dt, 1H, J = 7.6, 4.8 Hz), 6.66 (d, 1H, J = 7.6 Hz). .sup.13C- NMR (100 MHz, CDCl3): ppm 8.93 (s), 17.96 (d, J = 32.9 Hz), 23.32 (s), 30.04 (s), 52.29 (s), 54.82 (s), 169.81 (s), 171.66 (s). .sup.31P-NMR (162 MHz, CDCl3): ppm 36.67 (s). White solid; 72 mg, 45% [00031] 8 A .sup.1H-NMR (400 MHz, CDCl3): ppm 1.26 (dt, 9H, J = 18.7, 7.6 Hz), 1.92 (dq, 6H, J = 10.1, 7.6 Hz), 7.02 (dd, 1H, J = 8.1, 5.1 Hz), 7.52 (dd, 1H, J = 8.1, 1.5 Hz), 8.32 (dd, 1H, J = 5.1, 1.5 Hz). .sup.13C-NMR (100 MHz, CDCl3): ppm 9.15 (s), 18.03 (d, J = 34.4 Hz), 99.99 (s), 115.64 (s), 117.58 (s), 144.32 (s), 144.82 (s). .sup.31P-NMR (162 MHz, CDCl3): ppm 36.44 (s). Pale yellow oil; 136 mg, 91% [00032] 9 B .sup.1H-NMR (400 MHz, DMSO-d6): ppm 2.30 (d, 3H, J = 10.4 Hz), 6.99 (m, 2H), 7.27 (m, 2H), 7.50-7.60 (m, 6H), 7.82-7.90 (m, 4H), 12.08 (br s. 1H). .sup.13C- NMR (100 MHz, DMSO-d6): ppm 12.48 (d, J = 36.6 Hz), 120.30 (s), 129.2 (d, J = 11 Hz), 131.44 (d, J = 40.3 Hz), 131.73 (d, J = 13.9 Hz), 132.80 (d, J = 13.9 Hz). .sup.31P-NMR (162 MHz, DMSO-d6): ppm 24.41 (s). White solid; 142 mg, 89% [00033] 10 C .sup.1H-NMR (400 MHz, CDCl3): ppm 1.97 (s, 3H), 2.12 (d, 3H, J = 9.6 Hz), 3.39 (dd, 1H, J = 13.4, 4.5 Hz), 3.55 (dd, 1H, J = 13.4, 4.5 Hz), 3.61 (s, 3H), 4.86 (dt, 1H, J = 7.8, 4.5 Hz), 6.73 (d, 1H, J = 7.8 Hz), 7.44-7.54 (m, 6H), 7.60-7.69 (m, 4H). .sup.13C- NMR (100 MHz, CDCl3): ppm 14.41 (d, J = 35.9 Hz), 23.24 (s), 30.47 (s), 52.27 (s), 54.52 (s), 129.27 (d, J = 10.2 Hz), 131.67 (d, J = 2.2 Hz), 132.64 (d, J = 2.9 Hz), 132.78 (d, J = 2.2 Hz), 169.81 (s), 171.66 (s). .sup.31P-NMR (162 MHz, CDCl3): ppm 23.30 (s). White solid; 127 mg, 77% [00034] 11 A .sup.1H-NMR (400 MHz, DMSO-d6): ppm 2.41 (d, 3H, J = 10.6 Hz), 7.21 (dd, 1H, J = 8.1, 5.1 Hz), 7.50- 7.65 (m, 6H), 7.80-7.95 (m, 5H), 8.31 (dd, 1H, J = 5.1, 1.5 Hz). .sup.13C-NMR (100 MHz, DMSO-d6): ppm 12.28 (d, J = 37.3 Hz), 116.35 (s), 118.32 (s), 129.32 (d, J = 11.7 Hz), 130.68 (s), 131.26 (s), 131.85 (d, J = 2.9 Hz), 132.78 (d, J = 13.2 Hz), 143.59 (s), 144.77 (s). .sup.31P-NMR (162 MHz, DMSO-d6): ppm 24.85 (s). White solid; 108 mg, 60% [00035] 13 A .sup.1H-NMR (400 MHz, DMSO-d6) ppm 1.92 (d, 6H, J = 10.9 Hz), 6.97-6.99 (m, 2H), 7.24 (br s, 2H), 7.54-7.57 (m, 3H), 7.94-7.99 (m, 2H), 11.98 (br s, 1H). .sup.13C-NMR (100 MHz, DMSO-d6): ppm 14.46 (d, J = 36.1 Hz), 120.21 (s), 128.92 (d, J = 11.1 Hz), 131.4 (s), 132.04 (d, J = 13.1 Hz), 132.49 (s), 133.06 (s) White solid; 70 mg, 54% [00036] 14 A .sup.1H-NMR (400 MHz, CDCl.sub.3): ppm 1.91 (d, 6H, J = 10.6 Hz), 7.04 (dd, 1H, J = 7.8, 4.8 Hz), 7.52-7.56 (m, 4H), 7.78-7.83 (m, 2H), 8.34 (dd, 1H, J = 4.8, 1.3 Hz). .sup.13C-NMR (100 MHz, CDCl.sub.3): ppm 15.83 (d, J = 37.2 Hz), 115.75 (s), 117.65 (s), 129.32 (d, J = 12.7 Hz), 131.91 (d, J = 14.1 Hz), 100.45 (s), 144.86 (s), 157.45 (s), 175.48 (s). .sup.31P-NMR (162 MHz, CDCl.sub.3): ppm 10.06 (s) Orange gum; 65 mg, 50% [00037] 15 A .sup.1H-NMR (400 MHz, CDCl.sub.3): ppm 1.81 (d, 6H, J = 10.1 Hz), 2.01 (s, 3H), 3.34-3.38 (dd, 1H, J = 13.4, 4.5 Hz), 3.48-3.52 (dd, 1H, J = 13.4, 4.5 Hz), 3.68 (s, 3H), 4.82 (m, 1H), 6.69 (br s, 1H), 7.49-7.53 (m, 3H), 7.70-7.75 (m, 2H). .sup.13C-NMR (100 MHz, CDCl.sub.3): ppm 15.7 (d, J = 35.2 Hz), 15.77 (d, J = 35.2 Hz), 23.31 (s), 30.40 (s), 52.34 (s), 54.65 (s), 129.24 (d), J = 11.1 Hz), 131.71 (d, J = 8.0 Hz), 131.83 (d, J = 2.0 Hz), 169.82 (s), 171.69 (s). .sup.31P- NMR (162 MHz, CDCl.sub.3): ppm 11.19 (s) White gum; 89 mg, 64% [00038] 16 A .sup.1H-NMR (400 MHz, CDCl.sub.3): ppm 1.19 (dt, 9H, J = 18.4, 7.6 Hz), 1.83 (dq, 6H, J = 9.9, 7.6 Hz), 2.03 (s, 3H), 3.09 (dd, 1H, J = 12.9, 7.6 Hz), 3.44 (dd, 1H, J = 12.9, 4.8 Hz), 4.46 (m, 1H), 5.65 (br s, 1H), 6.85 (br s, 1H), 7.06 (br s, 1H) .sup.13C-NMR (100 MHz, CDCl.sub.3): ppm 9.06 (s), 18.04 (d, J = 33.2 Hz), 23.37 (s), 30.19 (s), 57.05 (s), 170.12 (s), 173.64 (s). .sup.31P-NMR (162 MHz, CDCl.sub.3): ppm 36.87 (s) White solid; 92 mg, 88% [00039] 17 A .sup.1H-NMR (400 MHz, CDCl.sub.3): ppm 1.18 (dt, 9H, J = 18.2, 7.6 Hz), 1.81 (dq, 6H, J = 9.8, 7.6 Hz), 2.60 (t, 2H, J = 6.1 Hz), 3.10-3.14 (m, 2H), 3.61-3.67 (m, 30H), 3.76 (t, 2H, J = 6.1 Hz). .sup.13C-NMR (100 MHz, CDCl.sub.3): ppm 8.98 (s), 18.06 (d, J = 33.2 Hz), 26.78 (s), 35.14 (s), 66.69 (s), 69.9 9s), 70.23 (s), 70.46 (s), 70.51 (s), 70.55 (s), 70.61 (s), 173.91 (s) .sup.31P-NMR (162 MHz, CDCl.sub.3): ppm 36.87 (s) Colourless gum; 58 mg, 75% [00040] 18 A .sup.1H-NMR (400 MHz, CDCl.sub.3): ppm 1.21 (dt, 9H, J = 18.2, 7.6 Hz), 1.83 (dq, 6H, J = 9.9, 7.6 Hz), 3.13-3.18 (m, 2H), 3.39 (s, 3H), 3.55- 3.58 (m, 2H), 3.65-3.70 (m, 24H). .sup.13C-NMR (100 MHz, CDCl.sub.3): ppm 8.98 (s), 18.08 (d, J = 32.2 Hz), 26.78 (s), 59.06 (s), 69.92 (s), 70.56 (s), 71.93 (s). .sup.31P-NMR (162 MHz, CDCl.sub.3): ppm 37.9 (s) Colourless gum; 60 mg, 88% [00041] 19 C .sup.1H-NMR (400 MHz, CDCl3): ppm 1.16 (dt, 9H, J = 18.7, 7.6 Hz), 1.97 (m, 6H), 7.00 (dd, 1H, J = 7.3, 5.1 Hz), 7.54 (d, 1H, J = 7.3 Hz), 8.06 (br s, 1H) .sup.31P-NMR (162 MHz, CDCl3): ppm 39.37 (br s) Brown solid; 28 mg, 18% [00042] 20 B .sup.1H-NMR (400 MHz, DMSO-d6): ppm 1.29 (dd, 18H, J = 15.9, 7.1 Hz), 2.45 (m, 3H), 6.96 (dd, 2H, J = 5.8, 3.0 Hz), 7.20 (dd, 2H, J = 5.8, 3.0 Hz), 11.91 (br s, 1H). .sup.13C-NMR (100 MHz, DMSO-d6): ppm 20.18 (d, J = 32.0 Hz), 23.14 (d, J = 29.3 Hz), 120.15 (s). .sup.31P-NMR (162 MHz, DMSO-d6): ppm 69.68 (s) White solid; 98 mg, 76% [00043] 24 C .sup.1H-NMR (400 MHz, CDCl.sub.3): ppm 1.21-1.35 (m, 9H), 1.39-1.52 (m, 6H), 1.69-1.75 (m, 3H), 1.77-2.01 (m, 15H), 2.03 (s, 3H), 3.11 (dd, 1H, J = 12.9, 7.6 Hz), 3.48 (dd, 1H, J = 12.9, 4.8 Hz), 4.45 (ddd, 1H, J = 7.8, 6.6, 4.8 Hz), 5.42 (br s, 1H), 6.78 (br d, 1H, J = 6.6 Hz), 7.03 (br s, 1H). .sup.31P-NMR (162 MHz, CDCl.sub.3): ppm 57.31 (s) White solid; 60 mg, 93% [00044] 25 C .sup.1H-NMR (400 MHz, CDCl.sub.3): ppm 1.90 (s, 3H), 3.38 (dd, 1H, J = 13.4, 4.5 Hz), 3.51 (s, 3H), 3.57 (dd, 1H, J = 13.4, 4.0 Hz), 4.86 (dt, 1H, J = 8.1, 4.5 Hz), 6.73 (br d, 1H, J = 8.1 Hz), 7.43-7.56 (m, 15H). .sup.31P-NMR (162 MHz, CDCl.sub.3): ppm 38.77 (s) White solid; 116 mg, 90% [00045] 26 D .sup.1H NMR (400 MHz, CDCl.sub.3): ppm 6.65 (br d, 1H, J = 7.3 Hz), 4.79 (dt, 1H, J = 7.8, 4.8 Hz), 3.75 (s, 3H), 3.45 (dd, 1H, J = 13.1, 4.8 Hz), 3.32 (dd, 1H, J = 13.1, 4.8 Hz), 2.06 (s, 3H), 1.96 (m, 1H), 1.49 (d, 6H, J = 9.9 Hz), 1.25 (d, 3H, J = 6.8 Hz), 1.20 (d, 3H, J = 6.8 Hz). .sup.31P-NMR (162 MHz, CDCl.sub.3): ppm 22.25 (s). Colourless gum; 52 mg, 84% [00046] 27 D .sup.1H NMR (400 MHz, CDCl.sub.3): ppm 6.68 (br d, 1H, J = 6.8 Hz), 4.77 (m, 1H), 3.74 (s, 3H), 3.43 (dd, 1H, J = 13.1, 2.3 Hz), 3.31 (dd, 1H, J = 13.1, 2.3 Hz), 2.05 (s, 3H), 1.88-1.78 (m, 2H), 1.51 (d, 6H, J = 10.1 Hz), 1.26-1.15 (m, 3H). .sup.31P-NMR (162 MHz, CDCl.sub.3): ppm 11.55 (s). Pale yellow gum; 10.5 mg, 54% [00047] 28 C .sup.1H-NMR (400 MHz, CDCl.sub.3): ppm 1.19 (dt, 9H, J = 18.4, 7.6 Hz), 1.28 (t, 3H, J = 7.3 Hz), 1.82 (dq, 6H, J = 9.9, 7.6 Hz), 2.04 (s, 3H), 3.33 (dd, 1H, J = 13.1, 4.5 Hz), 3.43 (dd, 1H, J = 13.1, 4.8 Hz), 4.19 (dq, 2H, J = 8.6, 7.3 Hz), 4.73 (dt, 1H, J = 7.3, 4.8 Hz), 6.65 (br d, 1H, J = 7.3 Hz). .sup.31P-NMR (162 MHz, CDCl.sub.3): ppm 36.51 (s) Colourless gum; 210 mg, 84% [00048] 29 C .sup.1H-NMR (400 MHz, CDCl.sub.3): ppm 1.90 (s, 3H), 3.41 (dd, 1H, J = 13.4, 4.5 Hz), 3.56 (s, 3H), 3.58 (dd, 1H, J = 13.4, 4.0 Hz), 4.89 (dt, 1H, J = 8.0, 4.3 Hz), 6.83 (br d, 1H, J = 8.0 Hz), 7.34-7.39 (m, 1H), 7.43-7.51 (m, 6H), 7.61-7.69 (m, 4H), 7.73-7.82 (m, 2H), 8.76-8.80 (m, 1H). .sup.31P- NMR (162 MHz, CDCl.sub.3): ppm 34.57 (s) White solid; 104 mg, 81%

Example 2

[0270] ##STR00049##

[0271] The appropriated diselenide (0.23 mmol) was dissolved in EtOH (4 mL) and the reaction cooled to 0 C. NaBH.sub.4 (17 mg, 0.46 mmol) was added in one portion and the pale yellow solution stirred at 0 C. for 20 min. The chlorophosphine gold (I) compound (0.46 mmol) was then added in one portion and the reaction warmed to rt and stirred at this temperature for 3 hour. The reaction mixture was diluted with DCM (30 mL) and subsequently washed with saturated NH.sub.4Cl (aq., 20 mL), saturated NaHCO.sub.3 (aq., 20 mL) and finally water (20 mL). The organic phase was passed through a phase separator cartridge and the solvent removed in vacuo to give a brown oil which was purified by column chromatography (Biotage Isolera 4) eluting with neat EtOAc to 1:1 EtOAc-WIPE 129 to provide the title compound.

[0272] The following compounds were made using these methods:

TABLE-US-00003 TABLE 2 Compound Analytical Data Structure Number Yield/Physical appearance [00050] 12 .sup.1H-NMR (400 MHz, CDCl3): ppm 1.21 (dt, 9H, J = 18.2, 7.6 Hz), 1.83 (dq, 6H, J = 9.8, 7.6 Hz), 2.05 (s, 3H), 3.24 (dd, 1H, J = 12.1, 4.8 Hz), 3. 34 (dd, 1H, J = 12.1, 4.8 Hz), 3.74 (s, 3H), 4.81 (dt, 1H, J = 7.6, 4.8 Hz), 6.57 (d, 1H, J = 7.6 Hz). .sup.13C-NMR (100 MHz, DMSO-d6): ppm 8.81 (s), 15.67 (s), 17.07 (d, J = 32.2 Hz), 22.35 (s), 51.66 (s), 56.88 (s), 169.06 (s), 171.66 (s). .sup.31P-NMR (162 MHz, DMSO-d6): ppm 39.62 (s). White solid; 191 mg, 67% [00051] 21 .sup.1H-NMR (400 MHz, CDCl3): ppm 1.20 (dt, 9H, J = 18.2, 7.6 Hz), 1.28 (m, 2H), 1.66 (m, 2H), 1.82 (dq, 6H, J = 9.6, 7.6 Hz), 1.92 (m, 2H), 2.24 (m, 2H), 3.36 (m, 1H), 3.58 (m, 1H). .sup.13C-NMR (100 MHz, CDCl3): ppm 8.90 (s), 17.29 (d, J = 32.2 Hz), 32.69 (s), 36.98 (s), 40.67 (s), 68.27 (s). .sup.31P-NMR (162 MHz, DMSO-d6): ppm 40.33 (s) Colourless gum; 48 mg, 87% [00052] 22 .sup.1H-NMR (400 MHz, DMSO-d6): ppm 1.79 (s, 3H), 2.24 (d, 3H, J = 9.9 Hz), 2.95 (dd, 1H, J = 11.9, 7.3 Hz), 3.08 (dd, 1H, J = 11.9, 6.0 Hz), 3.58 (s, 3H), 4.46 (dt, 1H, J = 7.6, 6.0 Hz), 7.49-7.58 (m, 6H), 7.72-7.80 (m, 4H), 8.19 (d, 1H, J = 7.6 Hz). .sup.13C-NMR (100 MHz, DMSO-d6): ppm 12.47 (d, J = 35.1 Hz), 16.26 (s), 22.33 (s), 51.70 (s), 56.83 (s), 129.15 (d, J = 11.7 Hz), 131.43 (d, J = 2.9 Hz), 132.00 (d, J = 54.2 Hz), 132.55 (d, J = 13.9 Hz), 169.12 (s), 171.67 (s). .sup.31P-NMR (162 MHz, DMSO-d6): ppm 25.21 (s) Clear gum; 47 mg, 85% [00053] 23 .sup.1H-NMR (400 MHz, DMSO-d6): ppm 1.25 (dd, 18H, J = 15.9, 7.1 Hz), 1.83 (s, 3H), 2.40 (m, 3H), 2.84 (dd, 1H, J = 11.6, 7.6 Hz), 3. 01 (dd, 1H, J = 11.6, 6.3 Hz), 3.60 (s, 3H), 4.39 (dt, 1H, J = 7.6, 6.3 Hz), 8.14 (d, 1H, J = 7.6 Hz). .sup.13C-NMR (100 MHz, DMSO-d6): ppm 15.56 (s), 19.94 (s), 22.32 (s), 23.17 (d, J = 27.1 Hz), 51.59 (s), 57.16 (s), 168.95 (s), 171.69 (s). .sup.31P-NMR (162 MHz, DMSO-d6): ppm 68.95 (s) White solid; 23 mg, 44%

Example 3

[0273] Growth Media

[0274] Tryptic Soy Broth

TABLE-US-00004 Formula/Litre Pancreatic Digest of Casein 17.0 g Enzymatic Digest of Soybean 3.0 g Sodium Chloride 5.0 g Di-potassium hydrogen Phosphate 2.5 g Glucose 2.5 g

[0275] Directions for use: Dissolve 30 g of the medium in one litre of purified water, mix thoroughly, and then autoclave at 121 C. for 15 minutes.

[0276] Luria Broth

TABLE-US-00005 Formula/Litre Tryptone 10.0 g Yeast Extract 5.0 g NaCl 5.0 g

[0277] Directions for use: Dissolve components in 1 litre of distilled or deionized water and sterilize by autoclaving at 121 C. for 15 minutes.

[0278] Mueller Hinton II Broth (Cation-Adiusted)

TABLE-US-00006 Formula/Litre Beef Extract 3.0 g Acid Hydrolysate of Casein 17.5 g Starch 1.5 g *Adjusted and/or supplemented as required with appropriate salts to provide 20-25 mg/L of calcium and 10-12.5 mg/L of magnesium and as additionally required to meet performance criteria.

[0279] Directions for use: Dissolve components in 1 litre of distilled or deionized water andand sterilize by autoclaving at 121 C. for 15 minutes.

[0280] Brain Heart Infusion Broth

TABLE-US-00007 Formula/Litre Brain Heart Infusion solids 12.5 g Beef heart infusion solids 5 g Proteose peptone 10 g Glucose 2 g Sodium Chloride 5 g Di-sodium Phosphate 2.5 g

[0281] Directions for use: Dissolve components in 1 litre of purified water. Heat the mixture with frequent agitation to completely dissolve the medium, and sterilize by autoclaving at 121 C. for 15 minutes.

[0282] Growth Assay for S. aureus. (NCTC8325)

[0283] Stock solution of the test compounds (20 mg/ml) in dimethyl sulfoxide (DMSO) were serially diluted in DMSO and each diluted compound added in duplicate to a 96-well plate to a final DMSO concentration of 2% (v/v). An overnight culture of S. aureus (Oxford strain) grown in tryptic soy broth (TSB) was diluted to approximately 510.sup.7 cfu/ml and 150 l of this sample was added to each well of the 96-well plates. Control wells included an untreated control with bacteria in TSB in the presence of 2% DMSO and a negative sample (containing 150 l TSB growth media in the presence of 2% DMSO). Plates were incubated in a shaking incubator at 37 C. for 22 hours and bacterial growth assessed by absorbance at a wavelength of 595 nm. The minimum inhibitory concentration (MIC) was defined as the lowest concentration of compound that inhibited growth compared to the no-treatment control.

[0284] Variation of Growth Assays for:

[0285] Klebsiella pneumoniae (NCTC 13443), Vibrio cholerae or E. coli (ATCC 25922): use of 1/100 overnight dilution to set up assay, medium used: Luria broth (LB); incubation without shaking.

[0286] P. aeruginosa (ATCC 27853): use of 1/100 overnight dilution to set up assay, medium used: Cation adjusted Mueller Hinton broth (CaMHB); incubation without shaking.

[0287] Enterococcus feacalis (ATCC29212): use of 1/100 overnight dilution to set up assay, medium used: brain heart infusion broth containing 0.5% yeast extract; incubation without shaking.

TABLE-US-00008 S. aureus E. faecalis K. pneumoniae E. coli P. aeruginosa V. cholerae MIC MIC MIC MIC MIC MIC Compound (g/mL) (g/mL) (g/mL) (g/mL) (g/mL) (g/mL) 1 0.8 50 1.3 2 0.8 1.6 >100 50 100 2.5 3 0.4-0.8 1.6 6.3-12 12.5 12.5-25 1.3 4 1.6 3.1 12.5 12.5-25 25 1.6 5 1.6 1.6 12.5 6.3-12.5 50 1.6 6 0.8 1.6 50 12.5 25-50 1.6 7 1.3-1.6 1.6 100 25 50 1.6-3.1 8 1.3-1.6 1.6 25-50 12.5 25-50 1.56 9 3.1-6.3 6.3-12.5 >100 >100 >100 3.1-6.3 10 3.1 6.3-12.5 50-100 50-100 50 3.1-6.3 11 3.1-6.3 12.5 >100 >100 >100 3.1-6.3 12 1.5-3 3.1 >100 >100 >100 >100 13 3.1 25 25 14 3.1 25 50 15 3.1 50 100 16 0.8 100 25-50 17 1.6 >100 100 18 1.6 >100 50 19 <0.8 12.5 12.5 20 1.6 50-100 25 21 0.8 >100 >100 22 3.1-6.3 >100 >100 23 3.1-6.3 >100 >100 24 12.5 >100 >100 >100 12.5 25 6.3 >100 >100 >100 12.5 26 1.6 25 12.5-25 50 27 0.8-1.6 6.3 6.3 12.5-25 28 0.8 50-100 50-100 29 3.1 >100 100

[0288] CHO Toxicity Assay

[0289] Cell counting kit-8 (Sigma, CCK-8) assays were performed to assess the effect of compounds on cell viability. The assay is based on the reduction of a water-soluble tetrazolium salt (WST-8) by cellular dehydrogenases to a formazan dye which can be detected spectroscopically. 96-well plates were seeded with chinese hamster ovary cells (CHO) cells at 710.sup.3 cells per well in Dulbecco's modified Eagle's medium nutrient mixture F-12 Ham (containing 15 mM HEPES, NaHCO.sub.3, pyridoxine and L-glutamine) supplemented with 10% fetal bovine serum (FBS). The following day serial dilutions of compounds (dissolved and diluted in DMSO) were added to the cells in duplicates. Control included an untreated control where cells were grown in the presence of 1% DMSO and a medium only control (plus 1% DMSO). After 24 hours CCK-8 reagent (10 l) was added to each well and cell viability was assessed by measuring the absorbance at a wavelength of 450 nm after 2.5-3 hours. Only living cells can reduce the tetrazolium salts into coloured formazan products. Results were expressed as 50% growth inhibition (TD.sub.50) values compared to untreated control.

[0290] The therapeutic index was calculated as the ratio of the dose that produces growth inhibition in 50% of CHO cells divided by the dose where 50% of S. aureus growth is inhibited.

TABLE-US-00009 CHO cell Compound TD .sub.50 (g/mL) Therapeutic Index 1 0.5 1.7 2 0.7 2.3 3 0.6 3 4 1.4 3.7 5 1.5 3.5 6 1.5 4.5 7 2.6 8.7 8 1.6 4 9 2.6 1.6 10 1.2 1.1 11 2.0 1.3 12 6.5 5.3

[0291] HepG2 Cell Inhibition Assay

[0292] Cell counting kit-8 (Sigma, CCK-8) assays were performed to assess the effect of compounds on cell viability. The assay is based on the reduction of a water-soluble tetrazolium salt (WST-8) by cellular dehydrogenases to a formazan dye which can be detected spectroscopically. 96-well plates were seeded with the human hepatocyte cell line (HepG2) at approximately 810.sup.3 cells per well in Minimum Essential Medium Eagle (EMEM) with Earle's salts and sodium bicarbonate supplemented with 10% heat-inactivated foetal bovine serum 2 mM glutamine and 1% non-essential amino acids (NEAA). The following day serial dilutions of compounds (dissolved and diluted in DMSO) were added to the cells in duplicates. Control included an untreated control where cells were grown in the presence of 1% DMSO and a medium only control (plus 1% DMSO). After 24 hours CCK-8 reagent (10 l) was added to each well and cell viability was assessed by measuring the absorbance at a wavelength of 450 nm after 2-3 h hours. Only living cells can reduce the tetrazolium salts into coloured formazan products. Results were expressed as 50% growth inhibition (TD.sub.50) values compared to untreated control. The therapeutic index was calculated as the ratio of the dose that produces growth inhibition in 50% of HepG2 cells divided by the dose where 50% of S. aureus growth is inhibited.

TABLE-US-00010 HepG2 cell Therapeutic Index Compound TD.sub.50 (g/mL) (HepG2) 13 8.5 6 14 9 6 15 6 4 16 9 >11 17 18 >22 18 9 >11 20 6 >8 22 10 4 23 12 13

[0293] Efficacy Studies in the Galleria mellonella Model

[0294] G. mellonella larvae at 5th or 6th instar stage were purchased from a commercial supplier and used within 3 days. Prior to infection larvae were kept at room temperature. Larvae were infected with bacteria (various Gram positive and negative bacteria, including S. aureus, K. pneumoniae, E. coli and P. aeruginosa) using a sterile Hamilton syringe. Bacteria cultures were grown overnight, washed 3 in PBS and resuspended in PBS. Larvae were wiped with 70% ethanol and 10 l of bacteria solution (to cause 80% death within 3-4 days) was injected into the bottom right proleg of the larvae. Larvae injected with 10 l of PBS were used as negative controls. Larvae were then placed in petri dishes (1 dish per condition) containing filter paper at the bottom of the dish at 37 C. After various time points post infection (1-6 h), larvae were taken from the incubator wiped again with 70% ethanol and injected with 10 l of various concentrations of compound, dissolved in either 5% dimethyl sulfoxide, 5% ethanol or 5% 1-methyl-2-pyrrolidinone into a proleg on the left hand-side. Control larvae received 10 l of 5% solvent. Ten larvae were injected for each condition. To assess the toxicity of the compound, larvae were injected with various concentrations of compound alone. Larvae were returned to a 37 C. incubator and checked daily. Larvae were considered dead when no movement occurred when touched with a blunt pair of forceps. Black or discoloured larvae which still showed movement were considered to be alive. Numbers of dead larvae were recorded each day.

[0295] Biofilm Prevention Assay

[0296] The effect of a test compound on the formation of a S. aureus biofilm may be assessed using a biofilm prevention assay as described by Merritt et al. Current Protocols in Microbiology, 2011, 1B.1.1-1B1.18 with slight modifications. Briefly, S. aureus NCTC 8325, MRSA (RPAH18) and MRSA (MW2) are grown overnight in Tryptic soy broth (TSB) and diluted to between 1/50 and 1/100 before 150 L is added to the wells of a flat bottomed 96-well plate. Three microliters of auranofin at the appropriate dilution in DMSO are added to the wells in duplicate. Controls included a serial dilution of lincomycin in ethanol (to assess plate to plate variation), a positive control with bacteria alone in TSB with 2% DMSO and a negative (no bacteria) control with 150 L TSB containing 2% DMSO. Plates are sealed with AeraSeal and incubated at 37 C. for 24 hours. The plates are then washed three times with PBS, dried at 60 C. for 1 hour and stained with crystal violet for 1 hour. The plates are again washed three times with water, dried and scanned prior to the addition of 33% acetic acid to re-solubilize the crystal violet stain bound to the adherent cells. Absorbance is then measured at 595 nm and expressed as a percentage of the bacteria only control.

[0297] The effect of a test compound on preformed S. aureus biofilms can also be assessed. Briefly S. aureus NCTC 8325 is plated in 96-well plates as described in above and incubated 37 C. for 24 hours. Biofilms are then washed 3 times with TSB and 150 L of fresh TSB and 3 L of auranofin at the appropriate dilution in DMSO was added to the wells in duplicate. Plates are again sealed with AeraSeal and reincubated 37 C. for 24 hours. Biofilm is then detected as described above.

[0298] Persister Cell Assay

[0299] To determine whether S. aureus persister cells are susceptible to treatment with a test compound, a persister cell (or SCV) isolate hemB mutant of NCTC 8325-4 may be used (Von Eiff et al., (1997) J Bacteriol 179:4706-4712). This persister cell variant displays varying resistance to erythromycin and the aminoglycosides gentamicin and kanamycin. Growth assays are performed essentially as described above with the bacteria being grown in TSB. Disc assays were also performed by plating bacteria on TSB agar. Discs impregnated with an amount of test compound were placed on top of the agar. The plates were incubated overnight at 37 C. and any zone of bacterial inhibition was observed.

Abbreviations

[0300] aq. Aqueous

[0301] br Broad

[0302] d Doublet

[0303] DCM Dichloromethane

[0304] DMSO Dimethyl sulfoxide

[0305] Et Ethyl

[0306] EtOAc Ethyl acetate

[0307] EtOH Ethanol

[0308] Et.sub.2O Diethyl ether

[0309] FA Formic acid

[0310] g Gram

[0311] h Hours

[0312] .sup.iPr Isopropyl

[0313] J Coupling constant

[0314] LC-MS Liquid chromatography-mass spectrometry

[0315] Me Methyl

[0316] MeCN Acetonitrile

[0317] MeOH Methanol

[0318] mg Milligram

[0319] min Minutes

[0320] mL Millilitre

[0321] mmol Millimole

[0322] ppm Parts per million

[0323] ppt Precipitate

[0324] q Quartet

[0325] rt Room temperature

[0326] s Singlet

[0327] TLC Thin layer chromatography

[0328] t Triplet

[0329] WIPE Water/isopropanol/Ethyl acetate (1:2:9)

REFERENCES

[0330]

TABLE-US-00011 doi Gli{hacek over (s)}i, BD & Djuran MI, Dalton Trans., 2014, 10.1039/c4dt00022f 43, 5950-5969 Medeira, JM, et al., Inflammopharmacology, 10.1007/s10787-012- 2012, 20(6), 297-306 0149-1 Jackson-Rosario, S, et al., J. Biol. Inorg. Chem., 10.1007/s00775-009- 2009, 14(4), 507-519 0466-z Novelli, F, et al., Farmaco, 1999, 54, 232-236 10.1016/S0014- 827X(99)00019-1 Shaw, CF, Chem Rev., 1999, 99(9), 2589-2600 10.1021/cr980431o Rhodes, MD, et al., J. Inorg. Biochem., 1992, 10.1016/0162- 46, 129-142 0134(92)80016-O Fricker, SP, Transition Met. Chem., 1996, 10.1007/BF00139037 21, 377-383