PANDYA VRAJESH (IN)
WO1993023384A1 | 1993-11-25 | |||
WO2017156519A1 | 2017-09-14 |
We claim: 1. Compounds of general Formula (I), their stereoisomers, their suitable pharmaceutically acceptable salts, Wherein, Q represents O, NR6, S(O)p; p = 0-2 integer; Y is selected from OR3, NR3R4, NHC(O)R5; R1 is selected from H, F, Cl, CH3, CN, OH and OCH3; m is selected from 1-4; R2 is selected from H, F, CH3, OH; n is selected from 1-8; R3 and R4 is independently selected from H, (C1-C6)alkyl, (C3-C6)cycloalkyl, aryl, heterocyclyl and heteroaryl, each of which is substituted or unsubstituted; R3 and R4 taken together with the nitrogen to which they are attached to form a 4- to 8- membered heterocyclyl or heteroaryl with 1 to 3 additional heteroatoms selected from O, S, or N, which is substituted or unsubstituted; wherein substitutions on (C1-C6)alkyl, (C3-C6)cycloalkyl, aryl, heterocyclyl and heteroaryl groups selected from halo, hydroxyl, (C1-C6)alkyl, (C1-C6)alkoxy, (C1-C6)acyloxy, haloalkyl, NO2, CN and NH2; R5 is selected from aminoalkyl, hydroxyalkyl, aryl and heteroaryl each of which is substituted or unsubstituted; wherein substitutions on (C1-C6)alkyl, aryl, heterocyclyl and heteroaryl groups selected from halo, hydroxyl, (C1-C6)alkyl, (C1-C6)alkoxy, (C1-C6)acyloxy, haloalkyl, NO2, CN and NH2; R6 = H, CN, (C1-C6)alkyl, haloalkyl, -COCH3; -COO(C1-C6)alkyl. 2. The compound as claimed in claim 1 having Formula (I-a) or their suitable pharmaceutically acceptable salts Wherein, Q, R1, R2 and Y are as defined in claim 1. 3. The compound as claimed in claim 2, wherein Q is O; Y is selected from NR3R4, NHC(O)R5; R1 is F; m is selected form 1-2; R2 H. 4. The compound as claimed in claim 1 having Formula (I-b) or their suitable pharmaceutically acceptable salts, Wherein, Q, R1, R2 and Y are as defined in claim 1. 5. The compound as claimed in claim 4, wherein Q is O; Y is selected from NR3R4, NHC(O)R5; R1 is F; m is selected form 1-2; R2 is H. 6. Compounds of Formula (I) or their suitable pharmaceutically acceptable salts as claimed in claim 1 are selected from: 5-((1H-1,2,3-triazol-1-yl)methyl)-3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1- yl)phenyl)oxazolidin-2-one; (R)-5-((1H-1,2,3-triazol-1-yl)methyl)-3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin- 1-yl)phenyl)oxazolidin-2-one; (S)-5-((1H-1,2,3-triazol-1-yl)methyl)-3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin- 1-yl)phenyl)oxazolidin-2-one; N-((3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2-oxooxazolidin-5- yl)methyl)-2-hydroxyacetamide; (R)-N-((3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2- oxooxazolidin-5-yl)methyl)-2-hydroxyacetamide; (S)-N-((3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2- oxooxazolidin-5-yl)methyl)-2-hydroxyacetamide; 2-amino-N-((3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2- oxooxazolidin-5-yl)methyl)acetamide; (R)-2-amino-N-((3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2- oxooxazolidin-5-yl)methyl)acetamide; (S)-2-amino-N-((3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2- oxooxazolidin-5-yl)methyl)acetamide; 3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-5-((isoxazol-3- ylamino)methyl)oxazolidin-2-one; (R)-3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-5-((isoxazol-3- ylamino)methyl)oxazolidin-2-one; (S)-3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-5-((isoxazol-3- ylamino)methyl)oxazolidin-2-one; 5-((1H-1,2,3-triazol-1-yl)methyl)-3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1- yl)phenyl)oxazolidin-2-one; (R)-5-((1H-1,2,3-triazol-1-yl)methyl)-3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1- yl)phenyl)oxazolidin-2-one; (S)-5-((1H-1,2,3-triazol-1-yl)methyl)-3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1- yl)phenyl)oxazolidin-2-one; N-((3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2-oxooxazolidin-5- yl)methyl)-2-hydroxyacetamide; (R)-N-((3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2-oxooxazolidin-5- yl)methyl)-2-hydroxyacetamide; (S)-N-((3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2-oxooxazolidin-5- yl)methyl)-2-hydroxyacetamide; 2-amino-N-((3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2- oxooxazolidin-5-yl)methyl)acetamide; (R)-2-amino-N-((3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2- oxooxazolidin-5-yl)methyl)acetamide; (S)-2-amino-N-((3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2- oxooxazolidin-5-yl)methyl)acetamide; 3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-5-((isoxazol-3- ylamino)methyl)oxazolidin-2-one; (R)-3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-5-((isoxazol-3- ylamino)methyl)oxazolidin-2-one; (S)-3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-5-((isoxazol-3- ylamino)methyl)oxazolidin-2-one. 7. Pharmaceutical composition comprising compound of Formula (I) or Formula (I- a) or Formula (I-b) or their suitable pharmaceutically acceptable salts as claimed in claim 1, 2 and 4 and suitable pharmaceutically acceptable excipients. 8. Use of the compounds as claimed in claim 1, 2 and 4 for the treatment of mammalian infections, by administering a therapeutically effective & non-toxic amount of the compound of Formula (I) or Formula (I-a) or Formula (I-b) or their suitable pharmaceutically acceptable salts, or their suitable pharmaceutically acceptable compositions to the mammals. 9. Use of the compounds as claimed in claim 8 for the treatment of mammalian infections wherein mammalian infections is caused by Gram-positive bacteria. 10. Method of treating mammalian infections in a subject which comprising administering to a patient in need thereof an effective amount of a compound of Formula (I) or Formula (I-a) or Formula (I-b) or their suitable pharmaceutically acceptable salts as claimed in claim 1, 2 and 4 or their suitable pharmaceutical composition. 11. Method of treating mammalian infections as claimed in claim 10 wherein mammalian infections is caused by Gram-positive bacteria. |
The compound of the general Formula (I) can also be prepared by following general scheme 2. Compound (VII) can also be reacted with appropriate amine derivatives to get compounds of the general Formula (I, when Y = NR 3 R 4 ). Compoun d of the general can be reacted with triazole in presence of Formula (VII) b ase such as Na 2 CO 3 , K 2 CO 3 etc. in solvents such as DMF, CH 3 CN etc. to get compound (I , wh en Y = triazole). Alternatively, compound (V II I ) c an be reacte d with Norbornadiene or vinyl acetate under refluxing conditio n i n p resence or ab s e n ce of solvent such as Dioxane to get triazole derivative (I) . Compound (VII) can be reacted with (IX) in presence of base such as Na 2CO 3 , K 2 CO 3 etc. in solvents such as DMF, CH 3 C N e tc. f ollowed by deprotection using TFA in D CM to get compound (I, when Y = aminoisoox az ole ) . Scheme 3: Synthesis of comp o unds of general Formula (I-a & I-b) The compound (I) prepared following scheme 1 and scheme 2 can be converted into its corresponding enantiomers (I-a) and (I-b) using chiral preparative HPLC purification technique. Scheme 4: Synthesis of compounds of general Formula (I-a)
Alternatively, the compound of the general Formula (I-a) can be prepared by following general scheme 4. Compounds of the Formula (I-a, when Y = OH) can be obtained by treating (VI) with n-butyl lithium and R-glycidyl butyrate in THF. It was then converted into mesylate derivatives (X) using methane sulfonyl chloride and TEA in solvents such as THF, CH 3 CN, DCM etc., which was then reacted with sodium azide in DMF at high temperature to get azide derivative (XI). Reduction of (XI) using Triphenyl phosphine in mixture of THF and water gave compounds (I-a, when Y = NH 2 ). Alternatively, reduction can also be achieved using catalytic hydrogenation using H 2 /Pd-C system. It was further reacted with appropriate acid derivative using general amide bond formation techniques as described in Tetrahedron 2005, 61, 10827 to get compounds of the Formula (I-a) with amide linkage. Scheme 5: Synthesis of compounds of general Formula (I-a)
The compound of the general Formula (I-a) can also be prepared by following general scheme 5. Compound (X) can be reacted with appropriate amine derivatives to get compounds of the general Formula (I-a, when Y = NR 3 R 4 ). Compound of the general Formula (X) can be reacted with triazole in presence of base such as Na 2 CO 3 , K 2 CO 3 etc. in solvents such as DMF, CH 3 CN etc. to get compound (I-a, when Y = triazole). Alternatively, compound (XI) can be reacted with Norbornadiene or vinyl acetate under refluxing condition in presence or absence of solvent such as Dioxane to get triazole derivative (I-a). Compound (X) can be reacted with (IX) in presence of base such as Na 2 CO 3 , K 2 CO 3 etc. in solvents such as DMF, CH 3 CN etc. followed by deprotection using TFA in DCM to get compound (I-a, when Y = aminoisooxazole). The invention is explained in greater detail by the examples given below, which are provided by way of illustration only and therefore should not be construed to limit the scope of the invention. The chemical shifts (δ) in NMR spectra are reported in parts per million (ppm) relative to Tetramethyl silane (TMS), in either CDCl 3 or DMSO-d 6 solution. Mass spectra (ESI-MS) were obtained on Shimadzu LC-MS 2010-A spectrometer. List of Abbreviations CH 3 CN: Acetonitrile CDCl 3 : Deuterated chloroform DIPEA: Disopropyl ethyl amine DMF: Dimethyl formamide DCM: Dichloromethane DMSO-d 6 : Hexadeuterodimethyl sulfoxide EDC.HCl: N-(3-Dimethyl aminopropyl)-N’-ethyl carbodiimide hydrochloride EtOH: Ethanol EtOAc: Ethyl acetate HOBT: 1-Hydroxy benzotriazole K 2 CO 3 : Potassium carbonate MeOH: Methanol Na 2 CO 3 : Sodium carbonate Na 2 SO 4 : Sodium sulfate NaH: Sodium Hydride NaHCO 3 : Sodium bicarbonate Pd/C: palladium carbon SnCl2.2H2O: Stannous chloride dihydrate TEA: Triethyl amine TFA: Trifluoroacetic acid THF: Tetrahydrofuran 1 H NMR: Proton Nuclear Magnetic Resonance h: Hour(s) RT: room temperature [25-30 °C] min: Minute(s) J: Coupling constant in units of Hz Hz: Hertz Preparation of compounds EXAMPLE 1 Preparation of 5-((1H-1,2,3-triazol-1-yl)methyl)-3-(3,5-difluoro-4-(4-(oxet an-3- yl)piperazin-1-yl)phenyl)oxazolidin-2-one Step 1: tert-butyl 4-(oxetan-3-yl)piperazine-1-carboxylate To a stirring solution of tert-butyl piperazine-1-carboxylate (4.99 g, 26.8 mmol) and oxetan-3-one (1.93 g, 26.8 mmol) in DCM was added Sodium triacetoxyborohydride (8.5 g, 40.2 mmol) at 0-5°C and stirred for 16 h at 25-30°C. Reaction mixture was diluted with DCM and washed with aq NaHCO 3 . Organic layer was separated, dried and evaporated under reduced pressure to get the product. ESI-MS (m/z) : 243.16 (M+H) + . Step 2: 1-(2,6-difluoro-4-nitrophenyl)-4-(oxetan-3-yl)piperazine To a stirring solution of product of step 1 (7.12 g, 29.42 mmol) in DCM was added TFA (13.6 ml, 176.3 mmol) at 0-5°C and stirred for 3 h at 25-30°C. After completion of reaction, DCM was evaporated under reduced pressure to get the crude product which was diluted with DMF (70 mL). To this was added K 2 CO 3 (9.2 g, 66.8 mmol) and 1,2,3- trifluoro-5-nitrobenzene (4.26 g, 24.1 mmol) and stirred for 4 h at 80°C. Reaction mixture was then diluted with water and solid obtained was filtered to get the title product. ESI-MS (m/z): 300.1 (M+H) + . Step 3: 3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)aniline To a stirring solution of product of step 2 (6.0 g, 20.05 mmol) in THF was added Pd/C (cat.) at RT and stirred it for 16 h under hydrogen atmosphere. After completion of reaction, it was filtered through celite and filtrate was evaporated to get the title product. ESI-MS (m/z): 270.13 (M+H) + . Step 4: benzyl (3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)carbam ate To a stirring solution of product of step 3 (16.3 g, 60.5 mmol) in THF was added NaHCO 3 (15.25 g, 18.2 mmol) and benzyl chloroformate (11.36 g, 66.63 mmol) at 0-5°C. The reaction mixture was stirred at 25-30°C for 2 h. Reaction mixture was diluted with EtOAc and water. Organic layer was separated, dried and evaporated under reduced pressure to get the product. ESI-MS (m/z) : 404.16 (M+H) + . Step 5: 5-(chloromethyl)-3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin -1-yl)phenyl) oxazolidin-2-one To a stirring solution of product of step 4 (1 g, 2.479 mmol) in dry THF was added n- butyl lithium (9.22 ml (2.5 M), 23.05 mmol) followed by rac-epichlorohydrin (0.213 mL, 2.73 mmol) at -78°C. The resultant solution was stirred at 50°C for 16 h. The reaction mixture was diluted with water and EtOAc. Organic layer was separated, dried over Na 2 SO 4 , and concentrated to get the title product. ESI-MS (m/z): 388.3 (M+H) + . Step 6: 5-(azidomethyl)-3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin- 1-yl)phenyl) oxazolidin-2-one To stirring solution of product of step 5 (1.2 g, 3.09 mmol) in DMF (40 ml) was added sodium azide (1.0 g, 15.47 mmol). Reaction mixture was stirred at 80 0 C for 3 h. After complete conversion of starting material, the reaction mixture was diluted with cold water and obtained white solid was filtered. ESI-MS (m/z): 395.3 (M+H) + . Step 7: 5-((1H-1,2,3-triazol-1-yl)methyl)-3-(3,5-difluoro-4-(4-(oxet an-3-yl)piperazin- 1-yl)phenyl)oxazolidin-2-one To stirring solution of product of step 6 (600 mg, 1.521 mmol) in Dioxane was added norbornadiene (0.93 mL, 9.13 mmol). Reaction mixture was stirred at 100 0 C for 16 h. After complete conversion of starting material, the reaction mixture was concentrated and purified by column NMR (DMSO-d 6 ): 8.17 (d, J = 0.8 Hz, 1H), 7.77 (d, J = 0.8 Hz, 1H), 7.23-7.18 (m, 2H), 5.16-5.12 (m, 1H), 4.82 (d, J = 5.2 Hz, 2H), 4.55 (t, J = 6.4 Hz, 2H), 4.45 (t, J = 6.0 Hz, 2H), 4.19 (t, J = 9.2 Hz, 1H), 3.87-3.84 (m, 1H), 3.47-3.44 (m, 1H), 3.09 (s, 4H), 2.36 (s, 4H). ESI-MS (m/z): 421.18 (M+H) + . EXAMPLE 2 Preparation of (R)-5-((1H-1,2,3-triazol-1-yl)methyl)-3-(3,5-difluoro-4-(4-( oxetan-3- yl)piperazin-1-yl)phenyl)oxazolidin-2-one Step 1: (R)-3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl) -5- (hydroxymethyl)oxazolidin-2-one To a stirring solution of product step (6.2 g, 15.38 mmol) in dry THF was added n-butyl lithium (9.22 ml (2.5 M), 23.05 mmol) at -78°C. The resultant solution was stirred at -78 °C for 1 h and then (R)-glycidyl butyrate (2.44 g, 16.91 mmol) was dropwise added at -78°C. The reaction mixture was stirred for an additional 1 h at -78°C. The reaction mixture was allowed to warm to RT and stirred for 16 h. The reaction mixture was diluted with water and EtOAc. Organic layer was separated, dried over Na 2 SO 4 , and concentrated to get the title product. 1 H NMR (DMSO-d6): 7.33-7.27 (m, 2H), 5.21 (t, 1H), 4.72-4.69 (m, 1H), 4.56-4.53 (m, 2H), 4.47-4.44 (m, 2H), 4.04 (t, 1H), 3.81-3.77 (m, 1H), 3.69-3.64 (m, 1H), 3.57-3.51 (m, 1H), 3.48-3.45 (m, 1H), 3.09 (s, 4H), 2.36 (s, 4H). ESI-MS (m/z): 370.15 (M+H) + . Step 2: (R)-(3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl )-2- oxooxazolidin-5-yl)methyl methanesulfonate To a stirring solution of product obtained above in step 1 (3.5 g, 9.48 mmol) in DCM was added TEA (1.98 ml, 14.21 mmol) and methanesulfonyl chloride (0.89 ml, 11.37 mmol) at 0-5°C. Reaction mixture was stirred for 2 h at 25-30°C. After completion of reaction it was diluted with DCM and washed with water. DCM layer was separated, dried over Na 2 SO 4 and evaporated to get the title product which was directly used for next step. Step 3: (R)-5-(azidomethyl)-3-(3,5-difluoro-4-(4-(oxetan-3-yl)pipera zin-1- yl)phenyl)oxazolidin-2-one To a stirring solution of product obtained above in step 2 (4.0 g, 8.95 mmol) in DMF (40 ml) was added sodium azide (2.9 g, 44.7 mmol). Reaction mixture was stirred at 80 0 C for 5 h. After complete conversion of starting material, the reaction mixture was diluted with cold water and solid obtained was filtered. ESI-MS (m/z): 395.16 (M+H) + . Step 4: (R)-5-((1H-1,2,3-triazol-1-yl)methyl)-3-(3,5-difluoro-4-(4-( oxetan-3- yl)piperazin-1-yl)phenyl)oxazolidin-2-one To a stirring solution of step g, 5.32 mmol) in Dioxane was added norbornadiene (3.3 mL, 31.9 mmol). Reaction mixture was stirred at 100 0 C for 16 h. After complete conversion of starting material, the reaction mixture was concentrated and purified by column chromatography. 1 H NMR (DMSO-d 6 ): 8.17 (d, J = 0.8 Hz, 1H), 7.77 (d, J = 1.2 Hz, 1H), 7.24-7.18 (m, 2H), 5.16-5.12 (m, 1H), 4.82 (d, J = 5.2 Hz, 2H), 4.55 (t, J = 6.6 Hz, 2H), 4.45 (t, J = 6.2 Hz, 2H), 4.19 (t, J = 9.2 Hz, 1H), 3.88-3.84 (m, 1H), 3.47-3.44 (m, 1H), 3.09 (s, 4H), 2.36 (s, 4H). ESI-MS (m/z): 421.18 (M+H) + . EXAMPLE 3 Preparation of (S)-3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl) -5- ((isoxazol-3-ylamino)methyl)oxazolidin-2-one
Step 1: tert-butyl (R)-((3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)pheny l)-2- oxooxazolidin-5-yl)methyl)(isoxazol-3-yl)carbamate To a stirring solution of product of step 2 (Example-2) (0.6 gm, 1.341 mmol) in DMF (6 ml) was added tert-butyl isoxazol-3-ylcarbamate (0.346 gm, 1.877 mmol) and K 2 CO 3 (0.371 gm, 2.68 mmol) at RT. Reaction mixture was stirred for 16 h at 100 o C. Reaction mixture was diluted with water and the precipitated solid was filtered to get title product. ESI-MS (m/z): 536.15 (M+H) + . Step 2: (S)-3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl) -5-((isoxazol-3- ylamino)methyl)oxazolidin-2-one To a stirring solution of product obtained above in step 1 (0.66 gm, 1.232 mmol) in DCM (6 mL) was added TFA (1.9 mL, 24.64 mmol) at 0 o C. Reaction mixture was stirred for 2 h then diluted with DCM (30 mL) and washed with aq. NaHCO 3. Organic layer was separated, dried and evaporated under reduced pressure to get the crude product which was purified by preparative HPLC to get title product. (DMSO-d 6 ): 8.40 (s, 1H), 8.39-7.25 (m, 2H), 6.55 (t, J = 6.0 Hz, 1H), 5.99 (d, J = 2.0 Hz, 1H), 4.89-4.86 (m, 1H), 4.56-4.53 (m, 2H), 4.46-4.44 (m, 2H), 4.11 (t, J = 9.0 Hz, 1H), 3.78-3.75 (m, 1H), 3.47- 3.41 (m, 3H), 3.09 (m, 4H), 2.36 (m, 4H). ESI-MS (m/z): 436.10 (M+H) + . EXAMPLE 4 Preparation of (S)-N-((3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phe nyl)-2- oxooxazolidin-5-yl)methyl)-2-hydroxyacetamide Step 1: (S)-5-(aminomethyl)-3-(3,5-difluoro-4-(4-(oxetan-3-yl)pipera zin-1- yl)phenyl)oxazolidin-2-one To stirring solution of product of step 3 (Example-2) (0.4 g, 1.014 mmol) in mixture of THF (10 mL) and EtOH (2 mL) was added Pd/C (30 mg) followed by sodium borohydride (0.23 gm, 6.09 mmol). The reaction mixture was stirred at RT for 1 h and passed it through hyflow. Filtrate was washed with water (30 mL) and extracted by DCM. Organic layer was separated, dried and evaporated under reduced pressure to get the product. 1 H NMR (DMSO-d 6 ): 7.32-7.25 (m, 2H), 4.72-4.61 (m, 3H), 4.59-4.53 (m, 2H), 4.04 (t, 1H), 3.84-3.80 (m, 1H), 3.49-3.43 (m, 1H), 3.09 (s, 4H), 2.86-2.74 (m, 2H), 2.36 (s, 4H), 1.95 (bs, 2H). ESI-MS (m/z): 369.10 (M+H) + . Step 2: (S)-N-((3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phe nyl)-2- oxooxazolidin-5-yl)methyl)-2-hydroxyacetamide To a stirring solution of product obtained above in step 1 (0.5 gm, 1.357 mmol) and HOBT (0.27 gm, 1.764 mmol) in DMF (5 ml) was added Glycolic acid (0.26 gm, 3.39 mmol) followed by DIPEA (0.71 ml, 4.07 mmol) and EDC.HCl (0.78 gm, 3.39 mmol). Reaction mixture was stirred for 16 h at RT. Reaction mixture was diluted with water and the precipitated solid was filtered to get the crude product which was purified by preparative HPLC to get title NMR (DMSO-d 6 ): 8.07 (t, J = 6.2 Hz, 1H), 7.30-7.22 (m, 2H), 5.56 (bs, 1H), 4.79-4.73 (m, 1H), 4.56-4.53 (m, 2H), 4.47-4.44 (m, 2H), 4.08 (t, J = 9.0 Hz, 1H), 3.83 (s, 2H), 3.79-3.75 (m, 1H), 3.51-3.40 (m, 3H), 3.09 (s, 4H), 2.36 (s, 4H). ESI-MS (m/z): 427.17 (M+H) + . EXAMPLE 5 Preparation of (S)-2-amino-N-((3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin- 1- yl)phenyl)-2-oxooxazolidin-5-yl)methyl)acetamide Step 1: tert-butyl (S)-(2-(((3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)p henyl)-2- oxooxazolidin-5-yl)methyl)amino)-2-oxoethyl)carbamate To a stirring solution of step gm, 2.71 mmol) and HOBT (0.54 gm, 3.53 mmol) in DMF (10 ml) was added Boc-Gly-OH (0.95 gm, 5.43 mmol) followed by DIPEA (1.42 ml, 8.14 mmol) and EDC.HCl (1.56 gm, 8.14 mmol). Reaction mixture was stirred for 16 h at RT. Reaction mixture was diluted with water and the precipitated solid was filtered to get title product which was used for next step. Step 2: (S)-2-amino-N-((3-(3,5-difluoro-4-(4-(oxetan-3-yl)piperazin- 1-yl)phenyl)-2- oxooxazolidin-5-yl)methyl)acetamide To a stirring solution of product obtained above in step 1 (1.4 gm, 2.66 mmol) in DCM (15 mL) was added TFA (4.1 mL, 53.3 mmol) at 0 o C. Reaction mixture was stirred for 2 h then diluted with DCM (30 mL) and washed with aq.NaHCO 3. Organic layer was separated, dried and evaporated under reduced pressure to get the crude product which was purified by preparative HPLC to get title product. NMR (DMSO-d 6 ): 8.17 (bs, 1H), 7.28-7.25 (m, 2H), 4.78-4.71 (m, 1H), 4.56-4.53 (m, 2H), 4.47-4.44 (m, 2H), 4.07 (t, J = 9.0 Hz, 1H), 3.75 (m, 1H), 3.49-3.45 (m, 3H), 3.10 (s, 6H), 2.36 (s, 4H), 1.81 (bs, 2H). ESI-MS (m/z): 426.20 (M+H) + . EXAMPLE 6 Preparation of (R)-5-((1H-1,2,3-triazol-1-yl)methyl)-3-(3-fluoro-4-(4-(oxet an-3- yl)piperazin-1-yl)phenyl)oxazolidin-2-one Step 1: 1-(2-fluoro-4-nitrophenyl)-4-(oxetan-3-yl)piperazine To a stirring solution of product of step 1 (Example-1) (1.0 g, 4.13 mmol) in DCM (10 mL) was added TFA (1.91 ml, 24.76 mmol) at 0-5°C and stirred it for 3 h at 25-30°C. After completion of reaction, DCM was evaporated under reduced pressure to get the crude product which was diluted with DMF (5 mL). To this was added K 2 CO 3 (1.41 g, 10.20 mmol) and 1,2-difluoro-4-nitrobenzene (0.58 g, 3.67 mmol) and stirred for 4 h at 80°C. Reaction mixture was then diluted with water obtained solid was filtered to get the title product. ESI-MS (m/z): 282.13 (M+H) + . Step 2: 3-fluoro-4-(4-(oxetan-3- 1- aniline To a stirring solution of product of step 1 (0.83 g, 2.95 mmol) in THF was added Pd/C (cat.) at RT and stirred it for 16 h under hydrogen atmosphere. After completion of reaction, it was filtered through celite and filtrate was evaporated to get the title product. ESI-MS (m/z): 252.15 (M+H) + . Step 3: benzyl (3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)carbamate To a stirring solution of product of step 2 (0.73 g, 2.90 mmol) in THF was added NaHCO 3 (0.73 g, 8.71 mmol) and benzyl chloroformate (1.29 g, 3.78 mmol) at 0-5°C. The reaction mixture was stirred at 25-30°C for 2 h. After completion of reaction it was diluted with EtOAc and water. Organic layer was separated, dried and evaporated under reduced pressure to get the product. ESI-MS (m/z): 386.17 (M+H) + . Step 4: (R)-3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-5- (hydroxymethyl)oxazolidin-2-one To a stirring solution of product of step 3 (1.5 g, 3.89 mmol) in dry THF (40 mL) was added n-butyl lithium (2.33 ml (2.5 M), 5.84 mmol) at -78°C. The resultant solution was stirred at -78 °C for 1 h and then (R)-glycidyl butyrate (0.62 g, 4.28 mmol) was dropwise added at -78°C. The reaction mixture was stirred for an additional 1 h at -78°C. The reaction mixture was allowed to warm to RT and stirred for 16 h. The reaction mixture was diluted with water and EtOAc. Organic layer was separated, dried over Na 2 SO 4 , and concentrated to get the title product. 1 H NMR (DMSO-d 6 ): 7.53-7.50 (m, 1H), 7.49-7.18 (m, 1H), 7.08-7.04 (m, 1H), 5.21 (s, 1H), 4.71-4.65 (m, 1H), 4.58-4.54 (m, 2H), 4.47-4.44 (m, 2H), 4.04 (t, J = 9.0 Hz, 1H), 3.81-3.77 (m, 1H), 3.68-3.64 (m, 1H), 3.57-3.50 (m, 1H), 3.48-3.44 (m, 1H), 3.00 (s, 4H), 2.33 (s, 4H). ESI-MS (m/z): 352.24 (M+H) + . Step 5: (R)-(3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2- oxooxazolidin-5- yl)methyl methanesulfonate To a stirring solution of product of step 4 (1.35 g, 3.84 mmol) in DCM was added TEA (1.61 ml, 11.53 mmol) and methanesulfonyl chloride (0.39 ml, 4.99 mmol) at 0-5°C. Reaction mixture was stirred for 2 h at 25-30°C. After completion of reaction it was diluted with DCM and washed with water. DCM layer was separated, dried over Na 2 SO 4 and evaporated to get the title product which was directly used for next step. Step 6: (R)-5-(azidomethyl)-3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin- 1- yl)phenyl)oxazolidin-2-one
To stirring solution of product of step 5 (1.6 g, 3.73 mmol) in DMF (10 ml) was added Sodium Azide (1.4 g, 22.35 mmol). Reaction mixture was stirred at 80 0 C for 5 h. After complete conversion of starting material, the reaction mixture was diluted with cold water and solid obtained was filtered. ESI-MS (m/z): 377.4 (M+H) + . Step 7: (R)-5-((1H-1,2,3-triazol-1-yl)methyl)-3-(3-fluoro-4-(4-(oxet an-3-yl)piperazin- 1-yl)phenyl)oxazolidin-2-one To stirring solution of product of step 6 (0.4 g, 1.06 mmol) in Dioxane was added norbornadiene (0.59 gm, 6.38 mmol). Reaction mixture was stirred at 100 0 C for 16 h. After complete conversion of starting material, the reaction mixture was concentrated and purified by column chromatography. 1 H NMR (DMSO-d 6 ): 8.17 (d, J = 0.8 Hz, 1H), 7.77 (d, J = 0.8 Hz, 1H), 7.42-7.37 (m, 1H), 7.13-7.03 (m, 2H), 5.15-5.09 (m, 1H), 4.82 (d, J = 4.8 Hz, 2H), 4.57-4.54 (m, 2H), 4.47-4.44 (m, 2H), 4.20 (t, J = 9.2 Hz, 1H), 3.87-3.83 (m, 1H), 3.49-3.34 (m, 1H), 3.00 (m, 4H), 2.33 (s, 4H). ESI-MS (m/z): 403.18 (M+H) + . EXAMPLE 7 Preparation of (S)-N-((3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl) -2- oxooxazolidin-5-yl)methyl)-2-hydroxyacetamide
Step 1: (S)-5-(aminomethyl)-3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin- 1- yl)phenyl)oxazolidin-2-one 5 To stirring solution of product of step 6 (Example-6) (0.4 g, 1.06 mmol) in mixture of THF (10 mL) and EtOH (3 mL) was added Pd/C (Cat.) followed by sodium borohydride (0.24 gm, 6.38 mmol). The reaction mixture was stirred at RT for 1 h and passed it through hyflow. Filtrate was washed with water (30 mL) and extracted by DCM. Organic layer was separated, dried and evaporated under reduced pressure to get the 10 NMR (DMSO-d 6 ): 7.52-7.48 (m, 1H), 7.21-7.18 (m, 1H), 7.09-7.04 (m, 1H), 4.63-4.45 (m, 3H), 4.47-4.44 (m, 2H), 4.02 (t, J = 8.8 Hz, 1H), 3.84-3.80 (m, 1H), 3.50-3.44 (m, 1H), 3.00 (s, 4H), 2.87-2.76 (m, 2H), 2.33 (s, 4H), 1.89 (bs, 2H). ESI-MS (m/z): 351.19 (M+H) + . Step 2: (S)-N-((3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl) -2-oxooxazolidin- 15 5-yl)methyl)-2-hydroxyacetamide To a stirring solution of product of step 1 (0.5 gm, 1.43 mmol) and HOBT (0.28 gm, 1.85 mmol) in DMF (5 ml) was added Glycolic acid (0.27 gm, 3.57 mmol) followed by DIPEA (0.75 ml, 4.28 mmol) and EDC.HCl (0.82 gm, 4.28 mmol). Reaction mixture was stirred for 16 h at RT. Reaction mixture was diluted with water and the precipitated solid was filtered to get the crude product which was purified by preparative HPLC to get title product. 1 H NMR (DMSO-d 6 ): 8.07 (t, J = 6.0 Hz, 1H), 7.49-7.45 (m, 1H), 7.19-7.16 (m, 1H), 7.09-7.04 (m, 1H), 5.55 (t, J = 5.6 Hz, 1H), 4.77-4.71 (m, 1H), 4.58-4.54 (m, 2H), 4.47-4.44 (m, 2H), 4.08 (t, J = 8.8 Hz, 1H), 3.83 (d, J = 6.0 Hz, 2H), 3.79-3.75 (m, 1H), 3.49-3.41 (m, 3H), 3.00 (s, 4H), 2.33 (s, 4H). ESI-MS (m/z): 409.16 (M+H) + . EXAMPLE 8 Preparation of (S)-2-amino-N-((3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl )phenyl)- 2-oxooxazolidin-5-yl)methyl)acetamide Step 1: tert-butyl (S)-(2-(((3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)pheny l)-2- oxooxazolidin-5-yl)methyl)amino)-2-oxoethyl)carbamate To a stirring solution of product of step 1 (Example-7) (0.5 gm, 1.427 mmol) and HOBT (219 mg, 1.427 mmol) in DMF (5 ml) was added Boc-Gly-OH (0.5 gm, 2.85 mmol) followed by DIPEA (0.75 ml, 4.28 mmol) and EDC.HCl (821 mg, 4.28 mmol). Reaction mixture was stirred for 16 h at RT. Reaction mixture was diluted with water and the precipitated solid was filtered to get title product. ESI-MS (m/z): 508.25 (M+H) + . Step 2: (S)-2-amino-N-((3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl )phenyl)-2- oxooxazolidin-5-yl)methyl)acetamide To a stirring solution of product obtained above in step 1 (0.7 gm, 1.38 mmol) in DCM (10 mL) was added TFA (2.1 mL, 27.6 mmol) at 0 o C. Reaction mixture was stirred for 2 h then diluted with DCM (20 mL) and washed with aq.NaHCO 3. Organic layer was separated, dried and evaporated under reduced pressure to get the crude product which was purified by preparative HPLC to get title NMR (DMSO-d 6 ): 8.18 (bs, 1H), 7.49-7.45 (m, 1H), 7.18-7.16 (m, 1H), 7.09-7.04 (m, 1H), 5.76-4.69 (m, 1H), 4.58- 4.54 (m, 2H), 4.47-4.44 (m, 2H), 4.08 (t, J = 9.0 Hz, 1H), 3.75-3.71 (m, 1H), 3.50-3.45 (m, 3H), 3.17 (s, 2H), 2.99 (m, 4H), 2.42 (m, 4H), 1.99 (bs, 2H). ESI-MS (m/z): 408.17 (M+H) + . EXAMPLE 9 Preparation of (S)-3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-5-( (isoxazol- 3-ylamino)methyl)oxazolidin-2-one Step 1: tert-butyl (R)-((3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-2 - oxooxazolidin-5-yl)methyl)(isoxazol-3-yl)carbamate To a stirring solution of product of step 5 (Example-6) (0.25 gm, 0.582 mmol) in DMF (3 ml) was added tert-butyl isoxazol-3-ylcarbamate (0.129 gm, 0.699 mmol) and K 2 CO 3 (0.161 gm, 1.164 mmol) at RT. Reaction mixture was stirred for 16 h at 100 o C. Reaction mixture was diluted with water and the precipitated solid was filtered to get title product. ESI-MS (m/z): 518.22 (M+H) + . Step 2: (S)-3-(3-fluoro-4-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)-5-( (isoxazol-3- ylamino)methyl)oxazolidin-2-one To a stirring solution of product obtained above in step 1 (0.3 gm, 0.58 mmol) in DCM (5 mL) was added TFA (0.89 mL, 11.59 mmol) at 0 o C. Reaction mixture was stirred for 2 h then diluted with DCM (15 mL) and washed with aq.NaHCO 3. Organic layer was separated, dried and evaporated under reduced pressure to get the crude product which was purified by preparative HPLC to get title NMR (DMSO-d 6 ): 8.39 (d, J = 1.6 Hz, 1H), 7.52-7.47 (m, 1H), 7.19-7.16 (m, 1H), 7.09-7.04 (m, 1H), 6.56 (t, J = 6.2 Hz, 1H), 6.00 (d, J = 2.0 Hz, 1H), 4.89-4.84 (m, 1H), 4.58-4.54 (m, 2H), 4.47-4.44 (m, 2H), 4.11 (t, J = 9.0 Hz, 1H), 3.79-3.75 (m, 1H), 3.50-3.38 (m, 3H), 3.00 (m, 4H), 2.33 (m, 4H). ESI-MS (m/z): 418.16 (M+H) + . Biological evaluation: Minimum inhibitory concentration (MIC) determination: Following strains were used for MIC testing: Staphylococcus aureus (MRSA) ATCC 33591 Staphylococcus aureus (VRS2) NR-46411 Streptococcus pneumoniae (PRSP) ATCC 700904 MIC protocol: MIC determination was done by using the reference broth microdilution method as described by the Clinical and Laboratory Standards Institute (CLSI). Briefly, bacterial cells were cultured on Mueller Hinton agar plates. Stock solutions of compounds and positive controls were prepared in DMSO. Subsequent dilutions of compounds were prepared in cation adjusted Mueller Hinton broth (CAMHB). Compounds were tested by serial double dilution in 96 well plates. Inoculum densities were maintained at 5 X 10 4 cells per well. Plates were incubated at 37 ⁰C for 20-24 hrs before being read at 620 nm in Multiskan reader (Thermo). Linezolid was taken as positive control. All QC results were within specified ranges as published in CLSI document M100–S25 Mitochondrial protein synthesis (MPS) modulators assay: Human hepatocyte cell line, HepG2 was used to assess the mitochondrial protein synthesis inhibition of test compounds. The cells were plated at 6000 cell /well in 96 well tissue culture plates and allowed to grow for 16 h. To these cells, test compounds were added in desired concentrations and incubated for 96h. Chloramphenicol was used in the assay as MPS inhibition control. After 96 h, the cells were fixed with 4% paraformaldehyde for 20min, then treated with 0.5% acetic acid to stop alkaline phosphatase activity. The cells were then treated with permeabilization buffer (1% triton x-100) for 30min followed by blocking with the blocking buffer (AbCAM mitogenesis in cell ELISA kit #ab110217) for 2 h. The cells were then probed for COX-1 and SDH-A using the antibodies provided in the kit. The protein levels were measured in the kinetic mode using Spectramax (Molecular Devices, US) and the ratio of COX-1 to SDH-A expression was calculated. The ratio with respect to the concentration of the test compounds were utilized to derive the half-maximal inhibitory concentration using GraphPad Prism.
Compounds of the present invention show antibacterial activity against various Gram- positive bacterial strains as reflected in their MIC values described in Table 1. Further, compounds have shown lower potential for mitochondrial protein synthesis inhibition as reflected in higher MPS IC 50 of compounds of the present invention in MPS assay compared with Linezolid. Hence, compounds of the present invention have improved safety profile over Linezolid. Table 1: The novel compounds of Formula (I) or Formula (I-a) or Formula (I-b) or their suitable pharmaceutically acceptable salts of the present invention can be formulated into suitable pharmaceutically acceptable compositions by combining with suitable excipients by techniques and processes and concentrations as are well known. The compounds of Formula (I) or Formula (I-a) or Formula (I-b) or their suitable pharmaceutically acceptable salts, or pharmaceutical compositions containing them are useful as a medicament for the mammalian infections and suitable for humans and other warm blooded animals, and may be administered either by oral, topical or parenteral administration. The quantity of active component, that is, the novel compounds of Formula (I) or Formula (I-a) or Formula (I-b) or their suitable pharmaceutically acceptable salts according to this invention, in the pharmaceutical composition and unit dosage form thereof may be varied or adjusted widely depending upon several factors such as the particular application method, the potency of the particular compound and the desired concentration. The novel compounds of Formula (I) or Formula (I-a) or Formula (I-b) or their suitable pharmaceutically acceptable salts of the present invention can be formulated into suitable pharmaceutically acceptable compositions by combining with suitable excipients by techniques and processes and concentrations as are well known. The pharmaceutical compositions further comprise an effective amount of an antibacterial agent. The dosage of antibacterial agent may vary within wide limits and should be adjusted, in each particular case, to the individual conditions. 5 Use of the novel compounds of Formula (I) or Formula (I-a) or Formula (I-b) or their suitable pharmaceutically acceptable salts of the present invention use for the treatment of mammalian infection caused by Gram-positive bacteria. In some embodiments, the mammalian infection caused by Gram-positive bacteria includes but not limited to skin infections, lung infections and tissue infections. 10 In some embodiments, the present invention includes a method for the treatment of mammalian infection caused by Gram-positive bacteria at least one of but not limited to skin infections, lung infections and tissue infections by administering to a subject in need thereof a therapeutically effective amount of a compound or salt of the novel compound of Formula (I) or Formula (I-a) or Formula (I-b) or their suitable pharmaceutically 15 acceptable salts.
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