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Synthesis of quinoline acetohydrazide-hydrazone derivatives evaluated as DNA gyrase inhibitors and potent antimicrobial agents

P. Sridhara, Manikandan Alagumuthub, Sivakumar Arumugamb, Sabbasani Rajasekhara Reddya,*

aDepartment of Chemistry, Scholl of Advanced Sciences, VIT University, Vellore-632014, IndiabSchool of Bio-Science and Technology, VIT University, Vellore-632014, India.

*Corresponding author e-mail: sekharareddy@vit.ac.in or sekharareddyiitm@gmail.com

Tel: +91-9884968303 Fax: +91-416-2243092, 2240411

Supporting Information File

Table of contents Page No.

1. Graphical representation (Scheme 1) 2

2. Table 1. Anti-bacterial activity results (Zone of inhibition details) 2

3. Compound 8 Spectra (H1 NMR and Mass) 3

4. Confirmation Spectra of (1H NMR, 13C NMR, FTIR, Mass& HRMS) 9a-n 4-25

5. DNA gyrase A and B PDB structures 26

6. Table 2. DNA gyrase inhibition assay 27

Electronic Supplementary Material (ESI) for RSC Advances.This journal is © The Royal Society of Chemistry 2016

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Scheme 1:

F NH2F N O

O

O

17

6 steps

FNO

O

NH

NH2

FNO

O

NH

N R

8 9a- 9n

9a. R = 4-OMe9b. R = 2,4-OMe9c. R = 2,5-OMe9d. R = 2,6-OMe9e. R = 3,4-OMe9f. R = OEt9g. R = OPr9h. R = 3,4,5-OMe9i. R = 4-F9j. R = 4-OCF39k. R = 4-CF39l. R= 3-CF39m.R = 2,4-F9n. R = 3,4-F

Hydrazine hydrateEthanol

Ethanol

Scheme 1: Synthesis of novel Quinoline acetohydrazide derivatives 9a-9n

Experimental Conditions: a)cinnamoyl chloride, aq. NaHCO3, isopropyl acetate, room temperature, 30 min; b) AlCl3, chlorobenzene, 90 °C, 1 h; c) MeI, KtOBu, DMSO, 70 °C, 2.5 h; d) NBS, benzoyl peroxide, xylene, 70 °C, 1.5 h; e) KCN, DMF, 60 °C, 16 h; f) TMSiCl, MeOH, 70 °C, 2.5 h; g) NH2-NH2, ethanol, reflux, 20 h; h) benzaldehydes, a-n, ethanol, reflux, 4 h.

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Table 1-In vivo efficacy of quinoline acetohydrazide derivatives 9a-9n for demonstrating antibacterial activity against selected pathogens

Zone of inhibition (mM)**Entry CompoundsE.coli P.aeruginosa S.aureus S.pyogenes

1 9a 10 10 7 112 9b 9 11 8 93 9c 8 9 7 104 9d 12 12 9 115 9e 11 10 7 116 9f 12 10 7 117 9g 11 11 9 128 9h 16 17 14 169 9i 17 17 13 1510 9j 16 15 13 1711 9k 17 16 14 1712 9l 16 17 15 1713 9m 21 20 18 2014 9n 20 19 18 1915 Ampicillin 19 18 16 1816 Control* - - - -

*DMSO, **Diameter of well (bore size)- 6 mm; Culture strains of bacteria were maintained on nutrient agar slant at 37±0.5 °C for 24 h; All plates were incubated at 37±0.5 °C for 24 h.

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F N O

NH

O

NH2

Compound 8

Fig. 1:1H NMR spectrum of 2-(7-fluoro-2-methoxyquinolin-8-yl) acetohydrazide

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Fig. 2: Mass spectra of Compound 8

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Fig.3: 1H NMR spectra of 9a

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Fig.4. 13C NMR spectra of 9a

8

F N ONH

O

NO

Exact Mass: 367.13

Fig. 5. Mass spectra of 9a

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Fig.6. HRMS spectra of 9a

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Fig. 7. 1H NMR spectra of 9b

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Fig. 8. Mass spectra of 9b

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Fig. 9. 1H NMR spectra of 9c

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Fig. 10. Mass spectra of 9c

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Fig. 11. 1H NMR spectra of 9d

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Fig. 12. Mass spectra of 9d

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Fig. 13. 1H NMR spectra of 9e

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F N ONH

O

N

O

O

Exact Mass: 397.14

9e

Fig. 14. Mass spectra of 9e

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Fig. 15. 1H NMR spectra of 9f

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Fig. 16. Mass spectra of 9f

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Fig. 17. HRMS spectra of 9f

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Fig. 18. 1H NMR spectra of 9g

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Fig. 19. Mass spectra of 9g

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Fig. 20. HRMS spectra of 9g

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Fig. 21. 1H NMR spectra of 9h

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Fig. 22. Mass spectra of 9h

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Fig. 23. HRMS spectra of 9h

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Fig. 24. 1H NMR spectra of 9i

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Fig. 25. Mass spectra of 9i

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Fig. 26. IR spectra of 9i

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Fig. 27. HRMS spectra of 9i

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Fig. 28. 1H NMR spectra of 9j

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Fig. 29. 13C NMR spectra of 9j

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Fig. 30. Mass spectra of 9j

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Fig. 31. IR spectra of 9j

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Fig. 32. HRMS spectra of 9j

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Fig. 33. 1H NMR spectra of 9k

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Fig. 34. 13C NMR spectra of 9k

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Fig. 35. Mass spectra of 9k

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Fig. 36. HRMS spectra of 9k

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Fig. 37. 1H NMR spectra of 9l

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Fig. 38. 13C NMR spectra of 9l

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Fig. 39. Mass spectra of 9l

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Fig. 40.1H NMR spectra of 9m

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Fig.41. 13C NMR spectra of 9m

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Fig. 42. Mass spectrum of 9m

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Fig. 43. IR spectra of 9m

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Fig.44. HRMS spectra of 9m

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Fig. 45. 1H NMR spectra of 9n

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F N ONH

O

NF

F

Exact Mass: 373.10

Fig. 46. Mass spectrum of 9n

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Figure 47. PyMOL veiw of DNA gyrase A (PDB ID: 1ZI0)

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Figure 48. PyMOL veiw of DNA gyrase B (PDB ID: 2ZJT)

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Table 2. In vivo efficacy of quinoline acetohydrazide derivatives 9a-n for demonstrating antibacterial activity against selected pathogens

IC50(mg/mL)Entry CompoundsS.aureus

1 9a 19.712 9b 18.243 9c 23.454 9d 19.285 9e 12.846 9f 11.477 9g 9.268 9h 6.149 9i 1.3810 9j 1.9811 9k 1.4412 9l 1.0513 9m 0.1414 9n 0.1915 Clorobiocin 0.04