SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF INDOLE DERIVATIVE BEARING THE PYRAZOLE MOIETY

SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF INDOLE DERIVATIVE BEARING THE PYRAZOLE MOIETY

Imaduddin Quazi ^*1, V. Girija   Sastry ² and Javed Akhtar Ansari ³

Department of Pharmaceutical Chemistry ¹, Faculty of Pharmacy, MESCO College of Pharmacy (Affiliated to Osmania University), Hyderabad - 50006, TS, India.

Department of Pharmaceutical Chemistry ², Faculty of Pharmacy, University College of Pharmaceutical Sciences, Andhra University, Visakhapatnam, AP, India.

Department of Pharmacology ³, Faculty of Pharmacy, Mesco College of Pharmacy, (Affiliated to Osmania University), Hyderabad - 50006, India.

ABSTRACT: Series of 1 of  1-[(3,5 diphenyl substituted ) -4,5-dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl) ethan-1-one (5a-5j)  derivatives were synthesized by the reaction between indole 3 acetic acid hydrazide and various chalcones (3a-3j). The Chalcones were prepared by Claisen-Schmidt condensation reaction in which substituted aromatic aldehydes was treated with simple acetophenone(aromatic ketones) in presence of 20% base(NaOH) and indole 3 acetic acid hydrazide was prepared by reaction between 3 indole acetic acid with hydrazide. The synthesized new compounds were identified by spectral studies and elemental analysis, and were evaluated in vitro for their antimicrobial activity using standard agar diffusion method and using four bacterial strains (Bacillus, Pseudomonas, Escherichia coli and Staphylococcus) and two fungal strains (Sclerotium rolfsii & Macrophomina phaseolina) most of compounds such 5c.5a,5b,5f,5g  i.e 1-[5-(4-Chloro phenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl] - 2 - (3H-indol-3-yl) ethan-1-one (5c), 1-(3, 5-diphenyl-4,5-dihydro-1H-pyrazol-1-yl) -2-(3H-indol-3-yl) ethan-1-one (5a), 1-[5-(4-methoxyphenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl) ethan - 1-one( 5b), 1-[5-(4 dimethyl amino phenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl)ethan-1-one(5e), 1-[5-(4 Hydroxyl 3 Methoxy  phenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl)ethan-1-one(5g). Shows good activity against gram positive and gram negative bacteria. All the compound exhibits moderate to average antifungal activity.

Antimicrobial, Antifungal, Chalcone, 3 Indole Acetic Hydrazide, Indole, Pyrazoline

INTRODUCTION: It has been delineated that the morbidity, mortality, and costs connected to the healing of infectious diseases have been amplified by antimicrobial resistance. The multiple resistance in bacterial strains that have propagated so widely has never been at anytime of such great importance.

The increased use of antibiotics, extensive movement of people, and increased industrial and economic development are the important factors constraining this hazard ¹. The rapid global pre-eminent issue is the resistance of pathogenic microorganisms to approachable antibiotics, anxiolytics, sedatives, hypnotics and anti-convulsants. Secondly, the primary and opportunistic fungal infections persist to increase very quickly as the number of resistant patients is amplifying ². The multiple biological and pharmacological properties of heterocyclic compounds have evoked recognition ³. The delineation of new compounds to treat resistant bacteria has become of the most significant aim of antibacterial research currently. This is because the antibiotic resistance as a consequence of improper and irrational utilization of antimicrobial medicines, renders suitable conditions for resistant bacteria to become prominent. As a result of this resistance of pathogenic bacteria towards available antibiotics happens to be a worldwide problem ⁴. The pyrazole moiety is a resourceful lead molecule in the pharmaceutical progress and has a broad range of biological activities antibacterial, antifungal   and pharmacological activities such as anti-inflammatory, antitubercular, anticancer, Analgesic ⁵. Pyrazole moiety fused indole also shows the potent antibacterial activity ⁶. It has been reported that indole derivatives bearing pyrazole nucleus are good antioxidant ⁶. Indole derivatives such as indole -2-carboxamide are potent and broad spectrum antivral agents ⁷.

A large number of heterocyclic compounds containing the indole ring are associated with diverse pharmacological properties such as Analgesic, Antiallergic, Antibacterial, Anticonvulsant, Antifungal, Antihistaminic, Anti-inflammatory, Anticancer, Anthelminthic, Anti hypertensive, Cardiovascular, Antioxidant ⁸. The present investigation was undertaken to develop an efficient method for synthesizing indole derivatives having pyrazoline moiety can be potent anti microbial agent.

MATERIALS AND METHODS: The used chemicals were supplied by S.D. Fine Chemicals, Spectrochem lab awra (India). Melting points were determined by open   tube capillary process and are uncorrected.

Pureness of  the compounds was checked on thin layer chromatography  (TLC) plates (silica gel G) in the solution system toluene-ethyl formate- formic acid (5:4:1, v/v/v)and N-hexane-ethylacetate (4:1, v/v), the  spots were to be found under iodine vapors and UV  light. IR spectra were obtained on a Shimadzu spectrometer (KBr pellets). ¹HNMR  spectroscopy were recorded on a Avance- 300 MHz spectrometer using TMS as internal standard in DMSO-d6/ CDCl3 and mass   spectra under electron impact conditions (EI) were recorded at 70 eV ionizing voltage  and are presented as m/z.

Experimental Procedure:

Synthesis of (2E)-3-(substituted phenyl)-1-phenylprop-2-en- 1-one (3A – 3 J): Derivatives were synthesized by condensing acetophenone with appropriate substituted aromatic aldehydes according to Claisen-Schmidt condensation ^9-15. To a solution of acetophenone (0.01 mole) in ethanol (100ml), there was added solution of aromatic aldehyde (0.01 mole) in ethanol (100) (if doesn’t dissolve warm it), it was stirred for 2-3 minutes. After 10 minutes  drop by drop 10% of KOH solution  was added  till turbidity was formed (don’t add excess) stirring was continued till the solid separated. Product was filtered and was washed with water. In case if product was not obtained stirring was continued for 10-12 hours. After that, it was kept in the refrigerator for 6-7 hours.  Then, it was acidified with hydrochloric acid (10%) and allowed it to stand at room temperature. Solid separated was collected, dried and crystallized with the suitable solvent (ethanol).

Synthesis of (2E)-3-(substituted phenyl)-1-phenylprop-2-en- 1-one (3A – 3 J) (2E)-1, 3-diphenylprop-2-en-1-one (3A): White solid, (60 % yield); mp= 55 ˚C IR: (KBR cm^-1): υ=3058 (CH), 1660 (C=O). ¹HNMR (DMSO-d6), δ (ppm):  7.54(1H ×2, d J = 6Hz, 7.8Hz CH=HC), 7.6-8. (10 H, m, Ar-H). EI-MS:  m/z: 208 (m+1)

Anal Calcd for C₁₅H₁₂O (208.25): C, 86.51; H, 5.81.  Found C, 86.61; H, 5.80.

(2E)-3-(4-methoxyphenyl)-1-phenylprop-2-en-1-one (3 B). White solid, (75 yield); mp= 80 ˚C IR: (KBR cm^-1): υ = 3030 (CH), 1654(C=O).¹ HNMR (DMSO-d₆), δ (ppm):  6.9 (1H× 2 d J = 6.39Hz, 6.68Hz CH=CH), 7.5-8. (9H, m, Ar- H), 3.88 (3 H s, CH₃). EI-MS:  m/z: 239 (m+1).

Anal Calcd   for C₁₆ H₁₄ 0₂ (238.38): C, 80.65; H, 5.92. Found C, 80.40; H, 5.89.

(2E) - 3 - (4-chlorophenyl)-1-phenylprop-2-en-1-one (3C): White solid, (65%   yield); mp= 85˚C;

IR: (KBr cm^-1): υ = 3030 (CH), 1676 (C=O). ¹HNMR (DMSO-d ₆), δ (ppm):  7.5 (1H× 2, d J = 8.4Hz, 8.1Hz CH=CH), 7.7-8.16 (9 H, m, Ar-H). EI-MS: m/z: 242 (m+1)

Anal Calcd for C₁₅H₁₁0Cl (242.70): C, 74.23; H, 4.57. Found C, 74.44; H, 4.57.

4 (2E)-3-(2-chlorophenyl)-1-phenylprop-2-en-1-one (3D):  White solid, (75 yield); mp= 80˚C; IR: (KBr cm^-1): υ = 3030 (CH), 1676 (C=O), ¹HNMR (DMSO-d ₆), δ (ppm):  7.56 (1H× 2, d J= 8.3Hz, 8.1Hz HC=CH) ,7.52-8.1 (9H,m, Ar-H). EI-MS: m/z: 242 (m+1).

Anal Calcd for C₁₅H₁₁0Cl (242.70): C, 74.23; H, 4.57. Found C, 74.44; H, 4.57.

(2E)-3-(2-4-chlorophenyl)-1-phenylprop-2-en-1-one (3E): Yellow solid, (55% yield); mp= 70˚CIR: (KBr cm^-1): υ = 3030 (CH), 1676 (C=O). ¹ HNMR (DMSO-d ₆), δ (ppm):  7.57 (1H× 2, d J= 8.2Hz, 8.0 Hz CH=CH), 7.7-8 (8H, m, Ar-H). EI-MS: m/z: 278 (m+1).

Anal Calcd   for   C₁₅H₁₀Cl₂O (277.14): C, 65.01; H, 3.64. Found: C, 64.77; H, 3.61.

(2E)-3-[4-(dimethylamino)phenyl]-1phenylprop-2-en-1-one (3F).   Yellowish –white Solid, (63% yield); mp= 90 ˚C IR: (KBr cm^-1): υ = 3030 (CH), 1660 (C=O). ¹ HNMR (DMSO-d ₆), δ (ppm):  6.7 (1H × 2, d J= 8.7Hz, 7.2Hz CH=CH), 7.323-8 (9H, m, Ar-H), 3.3 (6H,s, N (CH3₎₂ ). EI-MS: m/z:  252 (m+1).

Anal Calcd for C₁₇H₁₇NO   (251.32): C, 81.24; H, 6.82; N, 5.57. Found: C, 80.95; H, 6.74.

(2E)-3-(4-hydroxy-3-methoxyphenyl) – 1 -phenyl prop-2-en-1-one (3G). White solid, (80 yield); mp= 87˚C; IR: (KBr cm^-1): υ = 3030 (CH), 1676 (C=O), 3455(OH). ¹ HNMR (DMSO-d₆ ), δ  (ppm):  6.71 ( 1H× 2, d J=8.2Hz, 7.3Hz HC=CH) ,7.51-8 ( 8H,m, Ar-H),  10.19 (1 H, s ,OH), 3.4( 3 H, s,  OCH₃ ). EI-MS: m/z: 255 (m+1).

Anal Calcd for C₁₆H₁₄O₃ (254.28):  C, 75.57; H, 5.55.  Found: C, 75.36; H, 5.52.

(2E)-3-(4-bromophenyl)-1-phenylprop - 2 - en-1-one (3 H). Pink solid, (80 % yield); mp= 85 ˚C; IR: (KBr cm^-1): υ = 3030 (CH), 1676 (C=O). ¹HNMR (DMSO-d ₆), δ (ppm):  7.55 (1H× 2, d J= 6.1Hz, 7.89Hz CH=CH), 7.7-8.2 (9H, m, Ar-H). EI-MS: m/z:  288 (m+1).

Anal Calcd for C₁₅H₁₁0Br (287.15): C, 62.74; H, 3.86.  Found: C, 62.55; H, 3.84.

(2E)-1-phenyl-3-(3,4,5-trimethoxyphenyl) prop-2-en-1-one  (3 I). White solid, (70 yield); mp= 108 ˚C; IR: (KBr cm^-1): υ = 3030 (CH), 1676 (C=O). ¹HNMR (DMSO-d₆), δ   (ppm):  7.1 (1H × 2, d J= 6.40Hz, 6.68Hz CH=CH), 7.51-8 (7H, m, Ar-H), 3.23 (9H, s, OCH₃). EI-MS: m/z: 299 (m+1).

Anal Calcd for C₁₈H₁₈0₄ (298.33): C, 72.47; H, 6.08. Found: C, 72.30; H, 6.06.

(2E)-3-(4-nitrophenyl)-1-phenylprop-2-en-1-one (3 J). Red solid, (   85 yield); mp= 80˚C; IR:  (KBr cm^-1):  υ = 3030 (CH), 1676 (C=O), 1380 (N-O). ¹HNMR (DMSO-d₆), δ (ppm): 7.55 (1H× 2, d J=7.5Hz, 7.2Hz CH=CH), 7.58 -8 (9H,m, Ar-H). EI-MS: m/z: 254 (m+1)

Anal Calcd for   C₁₅H₁₁ N0₃ (253.25):  C, 71.14; H, 4.38; N, 5.53. Found: C, 70.92; H, 4.33; N, 5.51.

Synthesis of 3 Indole acetic hydrazide (4):0.001 mole of 3 indole acetic acid was dissolved in 100ml of absolute alcohol and 3 drops of sulphuric acid were added, refluxed it for 18 hours. Then TLC was taken and compared with starting compound using N-hexane-ethyl acetate (4:1) ratio. After completion of reaction content was neutralized with NaHCO₃ (Esterification reaction) filtered it to remove the salt, after that 0.003 mole hydrazine hydrate was added to above Ester and refluxed for 15 hours.  Product was obtained by filtration and recrystallized it from ethanol to give pure compound ^16-19. As white solid (75% yield);   mp =     142˚C; IR: (KBr cm^-1): υ = 3029 (CH), 1673 (C=O), 3374(N-H) ¹HNMR (DMSO-d ₆), δ (ppm):  3.73 (s 2H CH₂), 3.5 (s 1H, CH), 2.4 (s, 2H, NH),  7.51(s, 1H, NH), 10.87 (s 1H NH), 7.02-7.4 (4H,m, Ar-H).

Anal Calcd   for C₁₀H₁₁N₃O₃ (189.21) C, 63, 47; H, 5.85; N, 22.20. Found:  C, 63.23; H, 5.83; N, 22.12.

Synthesis of 1-[(3,5-diphenyl substituted)-4,5-dihydro-1H-pyrazol-1-yl] - 2 - (3H-indol-3-yl) ethan-1-one  (5 A- 5J): 0.001M of indole 3 acetic hydrazide was  reacted with 0.001M of  (2E)-3-(substituted)-1-phenylprop-2-en-1-one (chalcones 3A-3J) in 30 ml of glacial acetic acid. Mixture was refluxed for 24 hour. Excess of solvent was removed under reduced pressure. Reaction mixture was cooled and poured onto crushed ice (30g). Product obtained was filtered and recrystallized from methanol.^20-21

1-(3, 5-diphenyl-4,5-dihydro-1H-pyrazol-1-yl)-2-(3H-indol-3-yl)ethan-1-one(5A): White solid (70%yield); mp 135 ˚C; IR: (KBR cm^-1): υ = 3391(C-H),1701(C=O). ¹HNMR (DMSO-d ₆), δ   (ppm): 3.6(2H s- CH₂), 4.822 (1H, s –CH), 2.48(2H s- CH₂), 3.2 (1H s-CH) 7.49 (1H, s, CH) 6.88-7.33 (14 H, m, Ar-H). EI-MS: m/z: 380 (m+1).

Anal Calcd for C₂₅H₂₁N₃O (379.45): C, 79.13; H, 5.58; N, 11.07. Found:  C, 79.01; H, 5.56; N, 11.05.

1-[5-(4-methoxyphenyl)-3-phenyl- 4, 5 - dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl)ethan-1 - one ( 5B). White solid (yield 80); mp=120 ˚C; IR: (KBr cm^-1): υ=1665(C=O), 3364 (CH). ¹HNMR (DMSO-d ₆), δ  (ppm) : 3.8 (2H,s CH2 ), 5.5(1H,s CH), 2.48 (2H,s,CH2), 3.2(1H,S,CH) 7.50(1H,s CH), 3.7 (3H, S, OCH ₃), 7- 8 (13H,m, Ar-H  proton). EI-MS: m/z: 409 (m+1).

Anal Calcd for   C₂₆H₂₃N₃O (409.47): C, 76.26; H, 5.66, N, 10.26. Found: C, 76.35; H, 5.66; N, 10.27.

1-[5-(4-Chloro phenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl)ethan - 1 - one (5 C): White Solid (yield 85%); mp  170 ˚C; IR:  (KBr cm^-1):  υ = 17O4(C=O), 3390,(C-H),  794(C-CL). ¹HNMR (DMSO-d ₆), δ (ppm): 3.34 (2H, s,CH₂), 4.8 (1H, s, CH), 2.48 (2H,s, CH₂), 3.34(1 H,s CH) , 7.50  (1H,s CH), 7.56-8 ,  (13H,m, Ar-H). EI-MS:  m/z =: 414 (m+1)

Anal Calcd for C₂₅H_2OClN₃O (413.89) C, 72.55; H, 4.57; N, 10.15. Found: C, 72.52; H, 4.83; N, 10.15

1-[5-(2-Chloro phenyl)-3-phenyl-4, 5 - dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl) ethan-1-one (5D): White solid (55% yield); mp 180˚C; IR:  (KBr cm^-1): υ = 1698(C=O), 3391(C-H) 783 (C-CL). ¹HNMR (DMSO-d ₆), δ (ppm): 3.6(2H, s, CH₂), 4.5 (1H, s, CH), 2.48(2 H, s, CH₂), 3.33(1Hs CH), 7.50( 1H,s CH) , 6.94- 8  (13 H,m, Ar-H). EI-MS m/z: 414 (m+1).

Anal Calcd for C₂₅H_2OClN₃O (413.89) C, 72.55; H, 4.57; N, 10.15. Found: C, 72.52; H, 4.83; N, 10.15.

1-[5-(2,4 dichloro phenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl)ethan - 1 - one (5E): Whitish yellow (yield 60%) ; mp 210 ˚C;

IR:  (KBr cm^-1): υ= 1671(C=O), 3391(CH), 793(C-CL).¹HNMR (DMSO-d ₆), δ (ppm): 3.4(2H, s, CH₂), 5.1 (1H,s.CH ),  2.46 (2H,s, CH₂), 3.3 (1 H,s, CH), 7.52(1H,s, CH ), 6.5 - 7.5 (12 H, m, Ar-H ).

EI-MS: m/z: 449(m+1).

Anal Calcd for C₂₅H₁₉ Cl₂ N₃O (448.34):  C, 66.97; H, 4.27; N, 9.37. Found: C, 66.87; H, 4.26; N, 9.35.

1-[5-(4 dimethyl amino phenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-2-(3H - indol - 3-yl) ethan-1-one(5F) .Whitish yellow (yield 75%) ; mp  115 ˚C; IR:  (KBr cm^-1): υ = 1701(C=O), 3393 (CH),1248 (N-H). ¹HNMR (DMSO-d ₆), δ  (ppm):  3.46(2 H, s, CH2), 4.5 (1H, s.CH), 2.48 (2H,s, CH₂), 3.3(1H,s,CH) , 7.5 (1H,s,CH,), 3.03 (6, H,s,  N (CH ₃)_2,  6.5 to 7.5 (13H,m, Ar-H). EI-MS: m/z: 423 (m+1).

Anal Calcd for C₂₇H₂₆N₄ O (422.52):  C, 76.75; H, 6.20; N, 13.26. Found:  C, 76.66; H, 6.18; N, 13.24.

1-[5-(4 Hydroxyl 3 Methoxy phenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl]- 2 - (3H-indol-3-yl) ethan-1-one(5G). White (yield 65%); mp 160 ˚C

IR: (KBr cm^-1): υ=1660(C=O), 3397(CH), 3455 (OH). ¹HNMR (DMSO-d ₆), δ  (ppm): 3.6(2H, s, CH₂,), 4.54 (1 H,s, CH), 2.49(2H,s, CH₂), 3.5 (1H,s,CH), 7.5(1H,s,  CH),  3.8 (3 H,s, OCH₃), 10.81 (1H,s, OH),6.603- 7.49 (12H,m, Ar-H). Mass:  EI-MS m/z: 426 (m+1).

Anal Calcd for C₂₆H₂₃N₃O₃ (425.47):  C, 73.39; H, 5.45, N, 9.88. Found:  C, 73.30; H, 5.43; N, 9.86.

1-[5-(4Bromo phenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl) ethan - 1-one (5H): White (yield 80%); mp 240 ˚C; IR: (KBr cm^-1) : υ= 1660(C=O), 2915 (CH),684(C-Br). ¹HNMR (DMSO-d ₆), δ (ppm): 3.70 ( 2 H,s,  CH₂ ),  3.85 (1 H,s,  CH), 2.49 (2H,s, CH₂ ), 3.6(1H,s H), 7.49 (1H,s,CH), 7.2 to 8.1  (13H,m, Ar-H). Mass: EI-MS m/z: 459 (m+1).

Anal Calcd   for   C₂₅H₂₀BrN₃O (458.34:  C, 65.51; H, 4.4;   N, 9.17. Found:  C, 65.54; H, 4.38; N, 9.15.

1-[5-(3, 4, 5 methoxy phenyl)-3-phenyl-4,5-di hydro-1H-pyrazol – 1 - yl] - 2 - (3H-indol-3-yl) ethan-1-one(5I): White (yield 73%) ; mp 190 ˚C; IR: (KBr cm ^-1): υ = 1660 (C=O), 2991 (CH).

¹HNMR (DMSO-d ₆), δ (ppm):  3.7 (2 H,s,CH₂), 4.13 (1 H,s ,CH), 2.49(2H,s, CH₂), 3.38(1 H,s ,CH), 7.5 (1H,s, -CH), 3.85 (9H, s, OCH3), 7.52 - 8.16 (11H,m,  Ar –H). Mass:  EI-MS m/z: 467(m+1).

Anal Calcd for C₂₈H₂₇N₃O₄ (469.53): C, 71.62; H, 4.4; N, 9.17. Found:  C, 72.01; H, 4.52; N, 8.99.

1-[5-(4 Nitro phenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl)ethan-1-one(5J):   Brown  solid (yield 85); mp 130 ˚C IR: (KBr cm¹): υ = 1654 (C=O) ,2915 (CH) ,1331(N-0). ¹HNMR (DMSO-d ₆), δ (ppm): ¹HNMR (DMSO-d ₆), δ (ppm): 3.36 (2H,s,CH₂) 3.9 (1 H,s-CH) 2.51  (2 H,s, CH₂), 7.58 (1 H,s  CH ), 3.6 (1H,s,CH ), 7.58 - 8.3 (13H,m, Ar-H). MASS: EI-M S m/z: 425 (m+1).

Anal Calcd for C₂₅H₂₀N₄O₃ (424.45):  C, 70.74; H, 4.75; N, 13.20. Found: C, 70.65; H, 4.74; 13.18.

RESULTS AND DISCUSSION: Synthesis  2E)-3-(substituted phenyl)-1-phenylprop-2-en-  1-one  (3A – 3 J) The  present   compound such  as (2E)-3-(substituted phenyl)-1-phenylprop-2-en-1-one  3A – 3 J was prepared  by  Claisen-Schmidt  condensation  reaction in which substituted aromatic benzaldehyide is  reacted  with  simple aromatic  ketone   (acetophenone)  in the presence of 20% alkali such as sodium hydroxide or  potassium hydroxide, where the two  above component’s   were  stirred  in the solvent such as ethanol for 10 minutes. After that, alkali was added drop by drop   until product was Separated ^9-15. Detailed analysis of 1H NMR, IR, and Mass spectral data of all compound has been describe in this paper.

The IR spectrum compound 3A showed stretching bands at υ= 3058 cm-1 (CH), υ=1660 cm-1 (C=O), υ= 1571 (CH=CH), υ = 1448   (C=C), υ=1217   (C-O-C), υ= 748 cm-1 mono substituted benzene. 1H NMR Spectrum of compound 3A displays two signals i.e. doublet at δ =7.4 ppm which is attributed to (- CH=CH) and also multiplets of ten aromatic proton at δ 7.5-8ppm ^12-15. Mass spectrum revealed a molecular ion peak at m/z 243 (m+1).  Similarly, by using the above procedure 10 new derivatives i.e (3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H, 3I, 3J) were prepared and their structure was established on the basis of elemental analysis and spectral data. The required  indole  3 acetic acid hydrazine(4) is prepared by procedure as describe in literature ¹⁶  0.001 Mole of indole 3 acetic acid was dissolved in 100 ml absolute ethanol. 3 drops of sulphuric acid were added and refluxed for 18 hours. After completion of reaction (esterification)   0.003 mole of hydrazine hydrate was added and refluxed for 15 hours. Product was obtained by filtration. The structure of compound 4 was confirmed by spectral data of (IR, 1HNMR Mass). IR Spectra compound stretching band at υ = 3029 cm-1 (CH),   υ=1673 cm-1 (C=O), υ= 3374 cm-1 (N-H), 1H NMR of compound (4), exhibited singlet at 2.4, 8.11, 10.8 confirmed with the –NH2 NH and NH Protons of hydrazide [31]. Mass spectrum supports the molecular weight of the compound (4) i.e. m/z peak at 189 (m+1).

Synthesis of  1-[(3,5-diphenyl substituted)-4,5-dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl)ethan-1-one 5A-5J was done from procedure as  describe in literature ²¹ were  (2E)-3-(substituted phenyl)-1-phenylprop-2-en-1-one (chalcone) was  reacted with 3 indole acetic hydrazide in presence  of glacial acetic acid, refluxed  for 24 hours to form new indole derivative such as,  1-[(3,5-diphenyl substituted)-4,5-dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl)ethan-1-one The structure of all compounds has been supported by different spectral data (IR, 1H NMR, Mass). For example, compound (5A) IR spectra show characteristic absorption band at υ = 1701 cm-1, and υ=3391 cm-1 which assigned for (C=O) and (CH). 1H NMR spectra compound (5A) display singlet at δ = 3.6ppm and 4.88ppm for (C 4’ CH2 and C 5’ CH), and also multiplets of aromatic proton at δ = 7.5 to 8ppm. Mass spectrum of compound (5A) molecular ion peak at m/z =380 which is in agreement with its molecular weight. Singlet   of (C 4’ CH2 and C 5’ CH) was also confirmed on the basis of Literature ²⁰ in all 10 newly synthesized compounds i.e. (5A-5J). Both analytical and spectral data (IR and 1H NMR) of all synthesized compounds completely supports the purposed structure. Spectra of compounds such as (5A, 5B, 5C, 5D, 5E, 5F, 5G, 5H, 5I, 5J) has been described in experimental section.

Biological Activity:

Antimicrobial Activity:

Determination of Antibacterial activity by Agar cup method: Antibacterial activity was tested by standard agar diffusion method. Fresh bacterial culture having 5x10-5 colonies was mixed with nutrient agar medium and poured in to plates. Wells were made in the cooled agar plates (1cm).The compounds 10mg were dissolved in 2 ml DMSO and 100µl was loaded in the well. The activity or sensitivity was observed after 24-48 hours incubation at 37˚C ^22-23.

Determination of Antifungal activity by Disc diffusion method: Anti fungal activity studies were carried out using two fungi. Potato Dextrose Agar media was prepared and the fungal plugs were placed in the center of the plate and the compounds were put in the wells surrounding the plug and the zone of inhibition was measured after 72 hours.²²

1,3-diphenyl (Substituted)prop-2-en-1-one (2E)-1,3-diphenyl (Substituted)prop-2-en-1-one 1-ones  (3A-3J):

       Where                                     Ar

1. a)                                                 C₆H₅
2. b)                          C₆H₄ OCH₃ (4)
3. c)                                C₆H₄CL(4)
4. d)                                C₆H₄CL(2)
5. e)                               C₆H₃CL(2,4)
6. f)                                        C₆H₄N(CH₃)₂
7. g)                                C₆H₃OCH₃OH(3,4)
8. h)                                C₆H₄Br(4)
9. i)                               C₆H₂OCH₃(3,4.5)
10. j)                                C₆H₄ NO₂ (4)

 Scheme 2: Synthesis of 3 Indole acetic hydrazide (4):

Scheme 3: (5A-5J): Synthesis of 1-[(3,5-diphenyl substituted)-4,5-dihydro-1H-pyrazol-1-yl]-2-(3H-indol-3-yl)ethan-1-one  (5 A- 5J):

TABLE 1: ANTIMICROBIAL ACTIVITY RESULTS

TABLE 2: ANTI FUNGAL ACTIVITY

The antimicrobial activity, i.e. antibacterial and antifungal activity of 1-[(3,5diphenyl substituted) 4,5-dihydro-1H-pyrazol-1-yl]-2-(3H-indol - 3 - yl) ethan-1-one (5a-5j) was studied in vitro by agar cup & disc diffusion methods respectively against four bacterial strains (Bacillus, Pseudomonas, Escherichia coli and Staphylococcus) and two fungal strains (Sclerotium rolfsii and Macrophomina phaseolina) at different concentrations. The screening results indicate that the compounds 5c. Exhibited potent antibacterial activities against tested strains i.e Bacillus and Staphylococcus. And moderately active against other strain such as Escherichia coli, Pseudomonas, and other compounds such as 5a, 5b 5d, 5f, 5g exhibit good activity against gram positive bacteria whereas for gram negative bacteria compounds are less active. Which has shown in Table 1.  Whereas antifungal activity concern compounds 5c, 5e, 5f, 5j and 5i exhibit good activity against fungal strain Macrophomina phaseolina and Sclerotium rolfsii. Other compounds shows mark antifungal activity against above fungal strain.

CONCLUSION: Novel indole derivatives bearing pyrazoline moiety were synthesized and characterized. The structure of all compounds confirmed using different spectral studies. The antibacterial evaluation of all compounds demonstrates potent to moderate activity compare to standard drug streptomicin, while primary antifungal evaluation of all the compounds shows promising results against all employed strains as campared to standard drug Indofil-M 45.

ACKNOWLEDGMENT: The author (Quazi Imaduddin) wishes to express his thanks to Indian Institute of Chemical Technology Hyderabad, India for spectral study and Kalam institute (Hyderabad) for performing anti microbial activity.

CONFLICT OF INTEREST: None declared.

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How to cite this article:

Quazi I, Sastry VG and Ansari JA: Synthesis and antimicrobial activity of indole derivative bearing the pyrazole moiety. Int J Pharm Sci Res 2017; 8(3): 1145-52.doi: 10.13040/IJPSR.0975-8232.8(3).1145-52.

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