- Email: [email protected]
Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases
Journal of Saudi Chemical Society (2012) xxx, xxx–xxx
King Saud University
Journal of Saudi Chemical Society www.ksu.edu.sa www.sciencedirect.com
ORIGINAL ARTICLE
Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases Narsidas Parmar a,*, Shashikant Teraiya a, Rikin Patel a, Hitesh Barad a, Harshur Jajda b, Vasudev Thakkar b a b
Department of Chemistry, Sardar Patel University, Vallabh Vidyanagar 388 120, Dist. Anand, Gujarat, India Department of Biosciences, Sardar Patel University, Vallabh Vidyanagar 388 120, Dist. Anand, Gujarat, India
Received 30 October 2011; accepted 9 December 2011
KEYWORDS Bisketimine; Antifungal; Antibacterial; Acylation; FRAP assay; Monoketimine; o-, m- & p-Phenylenediamine
Abstract A series of nine new biologically active Schiff bases 5a–i were synthesized by a condensation of 4-acyl-5-pyrazolones 3a–c with aromatic diamines 4a–d, and characterized by elemental analysis, mass and spectroscopic data. All the compounds showed antibacterial activity against Bacillus subtilis and Escherichia coli, good antifungal activity against Phytophthora infestanse and Aspergillus niger, and ferric-reducing antioxidant power (FRAP). ª 2011 King Saud University. Production and hosting by Elsevier B.V. All rights reserved.
1. Introduction 5-Pyrazolone is a widely used precursor to a variety of compounds, documented well for their numerous applications such as products and intermediates in analytical, agricultural, biological, and pharmaceutical chemistry (Jung et al., 2002; Kimata et al., 2007; Varvounis et al., 2007; Bojan et al., 2009). Some of them also serve as important pharmaceutical agents including. antipyrine and its congeners. With * Corresponding author. Tel.: +91 2692 226857. E-mail address: [email protected] (N. Parmar). 1319-6103 ª 2011 King Saud University. Production and hosting by Elsevier B.V. All rights reserved. Peer review under responsibility of King Saud University. doi:10.1016/j.jscs.2011.12.014
Production and hosting by Elsevier
continuous evaluation for their pharmacological properties like analgesic (Gu¨rsoy et al., 2000), anti-inflammatory (Satyanarayana and Rao, 1995), antiarrhythmic, antifungal (Bekhit and Fahmy, 2003), potential antipyretic (Souza et al., 2002), antinociceptive (Tabarelli et al., 2004; Prokopp et al., 2006) and antioxidant activities (Godoy et al., 2004), the pyrazolone derivatives have still attracted medicinal chemist’s interest. Recently, acylpyrazolones have been reported to have a multidrug resistance modulating activity (Kimata et al., 2007). Benzoylpyrazolones, particularly, are potential antiprion agents (Chiba et al., 1998). From our laboratory, many reports exist on a ligational behaviour of pyrazolone based Schiff compounds. But, to the best of our knowledge, no reports exist on their biological evaluation. The presence of fragment –N‚CH–R in Schiff bases is known for its biological activity (Shemarova et al., 2000; Rehab et al., 2010). Many reports exist on structure–activity relationship of the class of these compounds (More et al., 2002; Bhendkar et al., 2004). Thus, it seems worthwhile to continue to investigate in this area. In the present work, we report synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff
Please cite this article in press as: Parmar, N. et al., Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases. Journal of Saudi Chemical Society (2012), doi:10.1016/j.jscs.2011.12.014
2 bases derived from a condensation reaction of 4-acyl-5-pyrazolones with aromatic diamines. 2. Experimental section 2.1. General All chemicals used were of laboratory reagent grade and used without further purification. Phenyl hydrazine was obtained from Sd. Fine Chem. Pvt. Ltd., Mumbai, India. Ethyl acetoacetate and calcium hydroxide were obtained from Samir Tech Chem. Pvt. Ltd., Vadodara, India. Diethyl ether and butyryl chloride were used as received from Merck, Mumbai, India. 1,4-Dioxane was supplied by Sisco Chem. Pvt. Ltd., Mumbai, India. Benzoyl chloride and Acetyl chloride were obtained from Chemport (India) Pvt. Ltd., Mumbai, India. 2.2. Analytical methods All melting points were taken in open capillaries and are uncorrected. IR spectra were recorded, in KBr disc, on PerkinElmer Spectrum GX FTIR spectrometer and are reported in wavenumbers (cm1). 1H NMR and 13C NMR spectra (ppm, d) were recorded on a Bruker Avance 400 spectrometer operating at 400 MHz for 1H NMR, and 100 MHz for 13C NMR using CDCl3 or DMSO d6 as solvent and reference. A degree of substitution (C, CH, CH2, and CH3) was determined by the DEPT-135 method. Carbon, Hydrogen and Nitrogen were estimated on a PerkinElmer 2400 Series II CHNS/O Elemental Analyzer. ESI mass spectra were measured on Thermo TSQ Quantum Access mass spectrometer at SICART, Vallabh Vidyanagar, Gujarat, India. Thin-layer chromatography (TLC, on aluminium plates coated with silica gel 60 F254, 0.25 mm thickness, Merck) was used for monitoring the progress of the reaction, purity and homogeneity of the synthesized compounds. 2.3. General procedure for the synthesis of Schiff bases (5a–i)
N. Parmar et al. 2.16 g of 3a, 2.78 g of 3b or 2.44 g of 3c), in the presence of a few drops of acetic acid, was refluxed for 3 h. After the completion of reaction as monitored by TLC, it was then cooled and allowed to stand overnight at room temperature. The coloured crystalline products 5a–i were obtained in good yield with excellent purity. It was washed with cold ethanol followed by drying at 60–90 C (Scheme 1, Table 1). The spectral characterizations of the compounds are given below: 2.3.2.1. 4-(1-(2-Aminophenylimino)ethyl)-3-methyl-1-phenyl1H-pyrazol-5-ol 5a. Recrystallized from ethanol (yield 60%), obtained as yellow crystals. mp 200–202 C. Anal. Calcd for C18H18N4O (306.36): C, 70.57; H, 5.92; N, 18.29. Found: C, 70.68; H, 5.85; N, 18.40; 1H-NMR (CDCl3) d; 2.27 (s, 3H, CH3), 2.42 (s, 3H, COCH3), 3.78 (s, 2H, NH2), 6.83–8.02 (m, 9H, Ar-H), 12.59 (s, 1H, OH); 13C NMR (CDCl3) d; 16.51, 17.33, 100.27, 116.70, 118.50, 118.86, 119.12, 122.21, 124.08, 127.45, 128.58, 129.13, 139.03, 142.24, 147.36, 165.64; IR mmax cm1(KBr): 3440, 3349, 1620, 1393, 1054; m/z (ESI) 306.7 (M+). 2.3.2.2. 4-((2-Aminophenylimino)(phenyl)methyl)-3-methyl-1phenyl-1H-pyrazol-5-ol 5b. Recrystallized from ethanol (yield 83%), obtained as orange crystals. mp 223–225 C. Anal. Calcd for C23H20N4O (368.43): C, 74.98; H, 5.47; N, 15.21. Found: C, 75.12; H, 5.50; N, 15.25; 1H NMR (DMSO-d6) d; 1.44 (s, 3H, CH3), 5.43 (s, 2H, NH2), 6.27–8.05 (m, 14H, ArH), 12.13 (s, 1H, OH); 13C NMR (DMSO-d6) d; 16.0, 100.97, 115.89, 116.18, 118.54, 122.53, 124.33, 128.28, 128.48, 128.66, 128.70, 128.88, 129.23, 130.61, 131.91, 139.58, 144.80, 147.90, 165.95; IR mmax cm1(KBr): 3407, 3333, 1630, 1396, 1054. m/z (ESI) 368.6 (M+). 2.3.2.3. 4-((3-Amino-2-methylphenylimino)(phenyl)methyl)-3methyl-1-phenyl-1H-pyrazol-5-ol 5c. Recrystallized from ethanol (yield 73%), obtained as yellow crystals. mp above 250 C. Anal. Calcd for C24H22N4O (382.45): C, 75.37; H, 5.80; N, 14.65. Found: C, 75.17; H, 5.83; N, 14.59; 1H NMR (CDCl3) d; 1.60 (s, 3H, CH3), 2.28 (s, 3H, CH3), 4.95 (s, 2H, NH2), 6.27–8.04 (m, 13H, Ar-H), 12.81 (s, 1H, OH); 13C
2.3.1. The preparation of 4-acyl-phenyl-3-methyl-5-pyrazolones 3a–c 4-Acyl-5-pyrazolones were prepared by reported methods. A corresponding acyl chloride (0.1 mol, 7.85 g acetyl chloride 2a, 15.20 g benzoyl chloride 2b and 10.60 g butyryl chloride 2c) was added to a well stirred, suspended with calcium hydroxide (12 g), solution of 5-pyrazolone 1 (0.1 mol, 17.4 g) in 1,4-dioxane (70–80 mL) at room temperature. Temperature increased for the first 5 min due to the exothermic nature of the reaction. After the complete addition, the resulted mass was treated according to the type of acylchloride taken. When butyryl chloride used, it was just stirred at room temperature for 45 min (Okafor et al., 1993). In all other cases, the mass was refluxed for 30 min (Jenson, 1956). Resulted mass obtained either in any ways, was then acidified by ice cold diluted hydrochloric acid (2 N, 200 mL), followed by a continuous stirring to cream colour crystals.
R
N
N Ph
O
+ RCOCl 2a-c
1
A mixture of an equimolar ethanolic hot solution (50 mL) of respective diamines 4a–d (1.08 g of 4a or 4b or 4d and 1.22 g of 4c) with corresponding acylpyrazolones 3a–c (0.01 mol,
Dioxane 70-80 ºC 3h
2a R = CH3 2b R = Ph 2c R = CH2CH2CH3
O N
OH
N Ph
3a-c H2 N
EtOH Reflux
X
NH2
4a-d
Path b
Path a R N N
N Ph
2.3.2. The synthesis of Schiff bases 5a–i
Ca(OH)2
5a-g
OH
X
R NH2
R N
N
N Ph
X
OH
N HO
5h-i
N
N
Ph
X = -C6H4(o/m/p)- , -(2-Me)(C6H3(m)-
Scheme 1
Synthesis of Schiff bases 5.
Please cite this article in press as: Parmar, N. et al., Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases. Journal of Saudi Chemical Society (2012), doi:10.1016/j.jscs.2011.12.014
Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases Table 1
3
Physicochemical properties of new synthesized Schiff bases 5h–i.
Entry
Compd.
R
X
Yield (%)
Time (h)
1 2 3 4 5 6 7 8 9
5a 5b 5c 5d 5e 5f 5g 5h 5i
CH3 Ph Ph, Ph C3H7 C3H7 C3H7 Ph C3H7
–C6H4(ortho)– –C6H4(ortho)– –(2-Me)C6H3(meta)– –C6H4(para)– –C6H4(ortho)– –(2-Me)C6H3(meta)– –C6H4(para)– –C6H4(meta)– –C6H4(meta)–
60 83 73 65 83 68 75 78 70
2.5 2.5 3.0 3.0 2.5 2.0 2.5 3.0 3.5
NMR (CDCl3) d; 12.31, 16.06, 101.13, 119.38, 124.47, 126.29, 126.35, 128.35, 128.46, 128.66, 128.78, 128.83, 130.24, 131.45, 136.79, 138.98, 142.84, 148.05, 163.91, 166.03; IR mmax cm1 (KBr): 3472, 3386, 1620, 1387, 1052; m/z (ESI) 382.9 (M+). 2.3.2.4. 4-((4-Aminophenylimino)(phenyl)methyl)-3-methyl-1phenyl-1H-pyrazol-5-ol 5d. Recrystallized from ethanol (yield 65%), obtained as yellow crystals. mp 172–174 C. Anal. Calcd for C23H20N4O (368.43): C, 74.98; H, 5.47; N, 15.21. Found: C, 75.17; H, 5.52; N, 15.34; 1H NMR (CDCl3) d; 1.60 (s, 3H, CH3), 3.52 (s, 2H, NH2), 6.63–8.02 (m, 14H, Ar-H), 12.89 (1H, s, OH); 13 C NMR (CDCl3) d; 15.91, 100.00, 117.53, 119.42, 121.97, 124.55, 125.14, 125.84, 127.43, 128.87, 131.51, 132.57, 138.92, 144.8, 147.90, 162.30, 165.67; IR mmax cm1 (KBr): 3409, 3332, 1631, 1388, 1053. m/z (ESI) 369.0 (M+). 2.3.2.5. 4-(1-(2-Aminophenylimino)butyl)-3-methyl-1-phenyl1H-pyrazol-5-ol 5e. Recrystallized from ethanol (yield 83%), obtained as yellow crystals. mp 183–185 C. Anal. Calcd for C20H22N4O (334.41): C, 71.83; H, 6.63; N, 16.75. Found: C, 72.03; H, 6.66; N, 16.78; 1H NMR (CDCl3) d; 0.90 (t, 3H, J 7.2 Hz, CH3), 1.58 (m, 2H, CH2), 2.44 (s, 3H, CH3), 2.57 (t, 2H, J 8.0 Hz, CH2), 3.87 (s, 2H, NH2), 6.79–8.02 (m, 9H, Ar-H), 12.58 (s, 1H, OH); 13C NMR (CDCl3) d; 14.24, 16.83, 22.69, 31,22, 99.76, 116.52, 118.84, 119.43, 122.33, 124.52, 128.03, 128.78, 129.45, 138.92, 142.26, 146.91, 166.23, 170.37; IR mmax cm1 (KBr): 3420, 3342, 1628, 1395, 1054; m/z (ESI) 334.7 (M+). 2.3.2.6. 4-(1-(3-Amino-2-methylphenylimino)butyl)-3-methyl1-phenyl-1H-pyrazol-5-ol 5f. Recrystallized from ethanol (yield 68%), obtained as white crystals. mp 182–183 C. Anal. Calcd for C21H24N4O (348.44): C, 72.39; H, 6.94; N, 16.08. Found: C, 72.58; H, 6.95; N, 16.12; 1H NMR (DMSO-d6) d; 0.81 (t, 3H, J 7.4 Hz, CH3), 1.46 (m, 2H, CH2), 1.96 (s, 3H, CH3), 2.37 (s, 3H, CH3), 2.56 (t, 2H, J 8.4 Hz, CH2), 5.20 (s, 2H, NH2), 6.51–8.01 (m, 8H, Ar-H), 12.75 (s, 1H, OH); 13C NMR (DMSO-d6) d; 12.25, 14.37, 16.93, 22.33, 30.78, 99.48, 114.38, 114.78, 117.42, 118.60, 124.32, 127.02, 129.16, 135.75, 139.51, 147.23, 148.55, 166.24, 169.62; IR mmax cm1 (KBr): 3446, 3358, 1624, 1383, 1051. m/z (ESI) 348.5 (M+). 2.3.2.7. 4-(1-(4-Aminophenylimino)butyl)-3-methyl-1-phenyl1H-pyrazol-5-ol 5g. Recrystallized from ethanol (yield 75%), obtained as yellow crystals. mp 181–183 C. Anal. Calcd for C20H22N4O (334.41): C, 71.83; H, 6.63; N, 16.75. Found: C, 71.67; H, 6.68; N, 16.71; 1H NMR (CDCl3) d; 0.95 (t, 3H, J
7.2 Hz, CH3), 1.59 (m, 2H, CH2), 2.44 (s, 3H, CH3), 2.63 (t, 2H, J 8.6 Hz, CH2), 4.73 (s, 2H, NH2), 6.81–8.01 (m, 9H, Ar-H), 12.85 (s, 1H, OH); 13C NMR (CDCl3) d; 14.17, 16.88, 22.92, 30.78, 99.05, 116.68, 116.74,119.41, 124.41, 126.49, 127.28, 128.51, 128.74, 139.04, 142.26, 146.80, 166.04, 168.67; IR mmax cm1 (KBr): 3372, 3338, 1612, 1390, 1054. m/z (ESI) 337.0 (M+). 2.3.2.8. N,N0 -bis-[1-(5-Hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yle)-phenyl-methylene]-benzene-1,3-diamine 5h. Recrystallized from ethanol (yield 78%), obtained as yellow crystals. mp 229–230 C. Anal. Calcd for C40H32N6O2 (628.72): C, 76.41; H, 5.13; N, 13.37. Found: C, 76.58; H, 5.10; N, 13.28; 1H NMR (CDCl3) d; 1.59 (s, 6H, CH3), 6.37– 8.02 (m, 24H, Ar-H), 12.79 (s, 2H, OH); 13C NMR (CDCl3) d; 15.95, 101.79, 119.32, 119.60, 121.68, 124.70, 128.46, 128.82, 128.98, 129.41, 130.80, 131.00, 138.29, 138.69, 148.07, 161.93 165.57; IR mmax cm1 (KBr): 3424, 1374, 1051; m/z (ESI) 629.2 (M+). 2.3.2.9. N,N’-bis[1-(5-Hydroxy-3-methyl-1-phenyl-1H-pyrazol4-yle)-butylidene]-benzene-1,3-diamine 5i. Recrystallized from ethanol (yield 70%), obtained as white crystals. mp 180– 182 C. Anal. Calcd for C34H36N6O2 (560.69): C, 72.83; H, 6.47; N, 14.99. Found: C, 72.90; H, 6.43; N, 15.11; 1H NMR (CDCl3) d; 0.97 (t, 6H, J 7.6 Hz, CH3), 1.62 (m, 4H, CH2), 2.48 (s, 6H, CH3), 2.74 (t, 4H, J 8.4 Hz, CH2), 7.17–8.01 (m, 14H, Ar-H), 13.22 (s, 2H, OH); 13C NMR (CDCl3) d; 14.11, 16.91, 22.90, 30.75, 100.16, 119.43, 123.75, 124.73, 125.31, 128.79, 130.82, 138.43, 138.66, 146.83, 165.95, 167.55; IR mmax cm1(KBr): 3424, 1374, 1054; m/z (ESI) 560.8 (M+). 2.4. Biological evaluation of the synthesized compounds 5a–i 2.4.1. Antimicrobial activity Biological assays were carried out by the agar cup diffusion method (Venkatraman et al., 1999; Cruickshank et al., 1975). A nutrient agar cup was prepared by dissolving a weighed ingredient in water at 7–6 pH. An aliquot (25 mL) was then dispensed in different test tubes followed by plugging them with sterilized cotton wool. By a gentle shaking, poured a well mixed incubated 0.5–0.6 mL 24 h old culture into a sterilized petri dish (25 mL each) and was allowed to set for 1.5 h. Cups were made by punching agar surface with a sterile cork bore and punched part of the agar media was removed by scooping. Each cup was added a sample solution (400 lg/mL DMF). Plates were then incubated at 35 C for 24–48 h to observe
Please cite this article in press as: Parmar, N. et al., Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases. Journal of Saudi Chemical Society (2012), doi:10.1016/j.jscs.2011.12.014
4
N. Parmar et al.
growth. Inhibition zones were measured in millimetres. Streptomycin and griseofulvin were used as standard antibacterial and antifungal drugs respectively. Solvent was screened for its activity. The corrections in biological activity of the compound, due to solvent dimethylformamide (DMF) were also applied in the calculation. DMF gave zero inhibition against Bacillus subtilis as well as Escherichia coli, but showed 3.0 mm against Phytophthora infestanse and Aspergillus niger. 2.4.2. Antioxidant activity Ferric reducing antioxidant power (FRAP) was measured by a modified method of Benzie and Strain (Benziea and Strainb, 1996). The antioxidant potentials of the compounds were estimated as their power to reduce the TPTZ–Fe(III) complex to TPTZ–Fe(II) complex (FRAP assay), which is simple, fast, and reproducible. FRAP working solution was prepared by mixing a 25.0 mL, 10 mM TPTZ solution in 40 mM HCl, 20 mM FeCl3Æ6H2O and 25 mL, 0.3 M acetate buffer at pH 3.6. A mixture of 40.0 lL, 0.5 mM sample solution and 1.2 mL FRAP reagent was incubated at 37 C for 15 min. Absorbance of intensive blue colour [Fe(II)–TPTZ] complex was measured at 593 nm. The ascorbic acid was used as a standard antioxidant compound. The results are expressed as ascorbic equivalent (mmol/100 g of dried compound). 3. Results and discussion 3.1. Chemistry 4-Acetyl/benzoyl-5-pyrazolones 3a–b were obtained by a method reported elsewhere (Jenson, 1956) (Scheme 1). Similarly, 4butyryl-5-pyrazolone 3c was obtained from butyrylchloride 2c but at modified room temperature method (Okafor et al., 1993). Yields were 75% (3a), 72% (3b) and 67% (3c). Equimolar 3a–c with diamines 4a–d in the presence of a few drops of acetic acid under refluxing ethanol gave Schiff bases 5a–g (Table 1, entries 1–7; Scheme 1, Path a). Schiff bases 5a–g that formed from o- or p-phenylenediamines were monoketiminic and bisketiminic 5h–i from m-phenylenediamine (Table 1,
entries 8–9; Scheme 1, Path b). IR, 1H NMR and 13C NMR spectroscopic data are in good agreement with their proposed structure. A displacement of a mOH band from region 3650– 3500 cm1 to 3350–2800 cm1 may be due to an internal hydrogen bridge OH N‚C (Ueno and Martell, 1956; Faniram et al., 1974). The band sometimes remained undetected if a strong hydrogen bond exists. So, Schiff bases are relatively planar with an adequate intramolecular distance favouring hydrogen bond formation (Freedman, 1961). Electronegative group attached to nitrogen favours the intra/intermolecular hydrogen bonding (Freedman, 1961). The compounds exist in enolic form (Scheme 1). Greater the electron density on C‚N, weaker this bond becomes and its stretching frequency appears at a lower wave number. IR spectra of compounds 5a–g show a doublet in the 3500–3000 cm1 range due to NH2 which is absent in 5h–i. All the compounds 5a–i show bands in the 3500–3000 cm1 range, and 1055 cm1 attributed to phenolic OH and C‚N groups respectively. The bands at 1595 and 1320 cm1 are attributable to cyclic mC‚N and a mC–O respectively. 1 H NMR spectra of 5e show three peaks; a triplet at d 0.90, a multiplet at 1.58, and a triplet at 2.57 ppm which are attributed to n-propyl hydrogens. A singlet peak appearing around d 2.44 ppm is due to methyl protons attached to pyrazolone unit. The NH2 protons resonate as a broad singlet at d 3.8 ppm, whereas signal due to phenolic proton was observed around d 12 ppm. Aromatic protons appeared as multiplet in the d 6.79–8.04 ppm range. Absence of a broad singlet d 3–4 ppm in compounds 5h–i is due to bisketimino of Schiff base.13C NMR spectra of 5h–i are in good agreement with their proposed structure. It showed that a peak in the d 12– 17 ppm range is due to CH3 carbon. The compound CH2 gives two negative signals; one at d 22 and second at 30 ppm in DEPT-135. A distinctive peak in d 166–170 ppm range is assigned to carbon attached to the oxygen atom. A signal at d100 ppm indicates the carbon at position-4 of the pyrazole ring. All the aromatic carbon signals appeared in d 110.08– 160.74 ppm range confirming the proposed structure of 5a–i. The mass spectra agreed with the molecular ion signals corresponding to the respective molecular formula of the
Table 2 Antimicrobial and antioxidant activities of compounds 5a–ia. The bold values indicate highest values of respective properties i.e. antimicrobial, antifungal or antioxident, among the compounds. Compound
5a 5b 5c 5d 5e 5f 5g 5h 5i DMF Streptomycinb Griseofulvinb a b c
Antibacterial activity
Antifungal activity
Antioxidant activity
B. subtilis Gram +ve
E. coli Gram ve
P. infestanse
A. niger
FRAP value (mmol/100 g)
0.0 2.0 4.0 0.0 0.0 4.0 4.0 5.0 0.0 0.0 10.0 NT
3.0 5.0 3.0 3.0 3.0 4.0 3.0 2.5 2.5 0.0 10.0 NT
5.0 9.0 6.0 7.0 9.0 6.0 7.0 8.0 7.0 3.0 NTc 9.0
6.0 6.0 2.0 5.0 5.0 5.0 5.0 2.0 5.0 3.0 NT 9.0
13.2 30.6 17.9 95.0 20.5 25.6 37.0 31.8 75.4 NT NT NT
400 lg/mL in DMF, Inhibition zone measured in mm. 100 lg/mL in DMF, Inhibition zone measured in mm. NT = Not tested.
Please cite this article in press as: Parmar, N. et al., Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases. Journal of Saudi Chemical Society (2012), doi:10.1016/j.jscs.2011.12.014
Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases synthesized compounds. For example, mass spectra of compound 5a gave molecular ion peak at 306.7 (M+) corresponding to the molecular formula C18H18N4O. The observed values of C H N elemental analysis are in good agreements with the calculated data. 3.2. Biological evaluation 3.2.1. Antimicrobial activity The antimicrobial screening test results exhibited a poor activity compared to other standard drugs. From activity data (Table 2), it shows that compounds 5b and 5h exhibited moderate activity against E. coli and B. subtilis respectively in comparison to standard antibiotic streptomycin. On the other hand antifungal study shows excellent activity against P. infestanse and Aspergillus fumigates. Compared to a standard griseofulvin, compounds 5b, 5e and 5h exhibited excellent activity against P. infestanse. Thus, from the structural examination, it concludes that Schiff bases, particularly, from 4-butyryl-5-pyrazolone possess good antibacterial and antifungal activities which may be due to electronegative alkyl group (Waksman, 1947). 3.2.2. Antioxidant activity A capacity to transfer a single electron i.e. the antioxidant power of all compounds was determined by a FRAP assay. The FRAP value was expressed as an equivalent of standard antioxidant ascorbic acid (mmol/100 g of dried compound). FRAP values indicate that all the compounds have a ferricreducing antioxidant power. The compounds 5d and 5i showed relatively high antioxidant activity while compound 5a shows poor antioxidant power (Table 2). 4. Conclusion In summary, we afforded two types of Schiff base compounds; a bisketimine and monoketimine depending upon the nature of aromatic diamines. m-phenylenediamine gave bisketiminic Schiff bases, while o- or p-, and 2-methyl-m-phenylenediamine afforded a monoketiminic one. All synthesized compounds are active against gram positive bacteria – B. subtilis and P. infestanse. Schiff bases derived from butyrylpyrazolone showed good antibacterial and antifungal activities. While those from acetylpyrazolones showed substantially a low antioxidant activity, very high antioxidant power was shown by the Schiff bases from 4-butyryl-5-pyrazolones.
Acknowledgements The authors are grateful to Heads, Department of Chemistry, and Department of Biosciences, Sardar Patel Univ., V. V. Nagar, for providing research facilities.
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.jscs.2011.12.014.
5
References Bekhit, A‘.A., Fahmy, H.T., 2003. Design and synthesis of some substituted 1H-pyrazolyl oxazolidines or 1H-pyrazolylthiazolidines as anti-inflammatory-antimicrobial agents. Arch. Pharm. (Weinheim) 336, 111–118. doi:10.1002/ardp.20039000(org). Benziea, I.F.F., Strainb, J.J., 1996. The Ferric Reducing Ability of Plasma (FRAP) as a measure of ‘‘Antioxidant Power’’: the FRAP assay. Anal. Biochem. 239, 70–76. doi:10.1006/abio.1996.0292. Bhendkar, A.K., Vijay, K., Rant, A.W., 2004. Synthesis of some novel Schiff bases of 2- aminopyrimidine and their antimicrobial activity. Acta Ciencia Indica Chem. 30, 29. Bojan, B., Marijan, K., Slovenko, P., 2009. A simple approach to pyrazol-3-ones via diazenes. Tetrahedron 65, 8690–8696. doi:10.1016/j.tet.2009.08.047. Chiba, P., Holzer, W., Landau, M., Bachmann, G., Lorenz, K., Plagens, B., Hitzler, M., Richter, E., Ecker, G., 1998. Substituted 4Acylpyrazoles and 4-Acylpyrazolones: synthesis and multidrug resistance-modulating activity. J. Med. Chem. 41, 4001–4011. doi:10.1021/ jm980121. Cruickshank, R., Duguid, J.P., Marmion, B.P., Swain, R.H.A., 1975, Twelfth ed. In: Medical Microbiology, 2 Churchill Livingstone, London, p. 190. Faniram, J.A., Patel, K.S., Bailar Jr., J.C., 1974. Infrared spectra of N,N0 -bis(salicylidene)-1,1-(dimethyl)ethylenediamine and its metal complexes. J. Inorg. Nucl. Chem. 36 (7), 1547–1551. doi:10.1016/ 0022-1902(74)80621-4. Freedman, H.H., 1961. Intramolecular H-Bonds I. A spectroscopic study of the hydrogen bond between hydroxyl and nitrogen. J. Am. Chem. Soc. 83 (13), 2900–2905. doi:10.1021/ ja01474a026. Godoy, M.C., Fighera, M.R., Souza, F.R., Flores, A.E., Rubin, M.A., Oliveira, M.R., Zanatta, N., Martin, M.A.P., Bonacorso, H.G., Mello, C.F., 2004. Alpha 2-adrenoceptors and 5-HT receptors mediate the antinociceptive effect of new pyrazolines, but not of dipyrone. Eur. J. Pharmacol. 496 (1-3), 93–97. doi:10.1016/ j.ejphar.2004.05.045. Gu¨rsoy, A., Demirayak, S., Capan, G., Erol, K., Vural, K., 2000. Synthesis and preliminary evaluation of new 5-pyrazolinone derivatives as analgesic agents. Eur. J. Med. Chem. 35, 359–364. doi:10.1016/S0223-5234(00)00117-3 PMid:10785562. Jenson, B.S., 1956. The Synthesis of 1-Phenyl-3-methyl-4-acyl-pyrazolones-5. Acta. Chem. Scand. 13, 1668–1670. doi:10.3891/acta.chem.scand.13-1668. Jung, J.C., Watkins, E.B., Avery, M.A., 2002. Synthesis of 3substituted and 3, 4-disubstituted pyrazolin-5-ones. Tetrahedron 58, 3639–3646. doi:10.1016/S0040-4020(02)00306-X. Kimata, A., Nakagawn, H., Ohyama, R., Fukuuchi, T., Ohata, S., Suzuki, T., Miyata, N., 2007. New series of antiprion compounds: pyrazolone derivatives have the potent activity of inhibiting protease-resistant prion protein accumulation. J. Med. Chem. 50, 5053–5056. doi:10.1021/jm070688. More, S.V., Dongarkhadekar, D.V., Chavan, R.N., Jadhav, W.N., Bhusare, S.R., Pawar, R.P., 2002. Synthesis and antibacterial activity of new Schiff bases, 4-thiazolidinones and 2-azetidinones. J. Indian Chem. Soc. 79, 768–769. Okafor, E.C., Adiukwu, P.U., Uzoukwu, B.A., 1993. Sykoheses and characterization of 4-iso-Butyryl and 4-iso-valeroyl derivatives of 1-FHE NTL-3-Methyl-pyrazolone-5 and their Uranium(VI), Tkorium(IV), Lanthanum(III), Iron(III), Lead(II) and Calciun(II) Complexes. Synth. React. Inorg. Met. Org. Chem. 23 (1), 97–111. doi:10.1080/ 15533179308016620. Prokopp, C.R., Rubin, M.A., Sauzem, P.D., de Souza, A.H., Berlese, D.B., Lourega, R.V., Muniz, M.N., Bonacorso, H.G., Zanatta, N., Martins, M.A.P., Mello, C.F., 2006. A pyrazolyl-thiazole derivative causes antinociception in mice. Braz. J. Med. Biol. Res. 39 (6), 795. doi:10.1590/S0100-879X2006000600013.
Please cite this article in press as: Parmar, N. et al., Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases. Journal of Saudi Chemical Society (2012), doi:10.1016/j.jscs.2011.12.014
6 Rehab, A., Barbara, K., Nora, A.K., Thomas, V., El-Ansary, A., 2010. Antibacterial effect of some benzopyrone derivatives. Eur. J. Med. Chem. 45, 372–378. doi:10.1016/ j.ejmech.2009.10.001. Satyanarayana, K., Rao, M.N.A., 1995. Synthesis of 4-[5-(substituted aryl)-4, 5-dihydro-1H pyrazol-3-yl]-3-phenyl-sydnones as antiinflammatory, antiarthritic and analgesic agents. Eur. J. Med. Chem. 30, 641–645. doi:10.1016/0223-5234(96) 88280-8. Shemarova, I.V., Maizel, E.B., Voznyi, I.V., Stepanova, N.P., Khovanskikh, A.E., 2000. Synthesis of new derivatives of pyrazolone and nicotinic acid and study of their effect on cytochrome P450. Activity Pharm. Chem. J. 34 (10), 530–532. doi:10.1023/ A:1010355129735. Souza, F.R., Souza, V.T., Ratzlaff, V., Borges, L.P., Oliveira, M.R., Bonacorso, H.G., Zanatta, N., Martins, M.A.P., Mello, C.F., 2002. Hypothermic and antipyretic effects of 3-methyl-and 3-phenyl-5hydroxy-5-trichloromethyl-4,5-dihydro-1H-pyrazole-1-carboxyamides in mice. Eur. J. Pharmacol. 451 (2), 141. doi:10.1016/ S0014-2999(02)02225-2.
N. Parmar et al. Tabarelli, Z., Rubin, M.A., Berlese, D.B., Sauzem, P.D., Missio, T.P., Teixeira, M.V., Sinhorin, A.P., Martins, M.A.P., Zanatta, N., Bonacorso, H.G., Mello1, C.F., 2004. Antinocice-ptive effect of novel pyrazolines in mice. Braz. J. Med. Bio. Res. 37, 1531. doi:10.1590/S0100-879X2004001000013. Ueno, K., Martell, A.E., 1956. Infrared studies on synthetic oxygen carriers. J. Phys. Chem. 60, 1270–1275. doi:10.1021/j150543a029. Varvounis, G., Fiamegos, Y., Pilidis, G., 2007. Pyrazol-3-ones. Part III: reactivity of the ring substituents 95, 27–141. doi:10.1016/ S0065-2725(07)95002-3. Venkatraman, R., Davis, K., Shelby, A., Zubkowski, J.D., Valente, E.J., 1999. syn,E-1-cyclopentano-4-ethyl-3-thiosemicarbazone and syn,E-1-cyclopentano-4-phenyl-3-thio-semicarbazone. J. Chem. Chrystallogr. 29 (4), 429–434. doi:10.1023/A:1009515111029. Waksman, S.A., 1947. Microbial Antagonism and antibiotic substances. Commonwealth fund third ed. New York.
Please cite this article in press as: Parmar, N. et al., Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases. Journal of Saudi Chemical Society (2012), doi:10.1016/j.jscs.2011.12.014
King Saud University
Journal of Saudi Chemical Society www.ksu.edu.sa www.sciencedirect.com
ORIGINAL ARTICLE
Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases Narsidas Parmar a,*, Shashikant Teraiya a, Rikin Patel a, Hitesh Barad a, Harshur Jajda b, Vasudev Thakkar b a b
Department of Chemistry, Sardar Patel University, Vallabh Vidyanagar 388 120, Dist. Anand, Gujarat, India Department of Biosciences, Sardar Patel University, Vallabh Vidyanagar 388 120, Dist. Anand, Gujarat, India
Received 30 October 2011; accepted 9 December 2011
KEYWORDS Bisketimine; Antifungal; Antibacterial; Acylation; FRAP assay; Monoketimine; o-, m- & p-Phenylenediamine
Abstract A series of nine new biologically active Schiff bases 5a–i were synthesized by a condensation of 4-acyl-5-pyrazolones 3a–c with aromatic diamines 4a–d, and characterized by elemental analysis, mass and spectroscopic data. All the compounds showed antibacterial activity against Bacillus subtilis and Escherichia coli, good antifungal activity against Phytophthora infestanse and Aspergillus niger, and ferric-reducing antioxidant power (FRAP). ª 2011 King Saud University. Production and hosting by Elsevier B.V. All rights reserved.
1. Introduction 5-Pyrazolone is a widely used precursor to a variety of compounds, documented well for their numerous applications such as products and intermediates in analytical, agricultural, biological, and pharmaceutical chemistry (Jung et al., 2002; Kimata et al., 2007; Varvounis et al., 2007; Bojan et al., 2009). Some of them also serve as important pharmaceutical agents including. antipyrine and its congeners. With * Corresponding author. Tel.: +91 2692 226857. E-mail address: [email protected] (N. Parmar). 1319-6103 ª 2011 King Saud University. Production and hosting by Elsevier B.V. All rights reserved. Peer review under responsibility of King Saud University. doi:10.1016/j.jscs.2011.12.014
Production and hosting by Elsevier
continuous evaluation for their pharmacological properties like analgesic (Gu¨rsoy et al., 2000), anti-inflammatory (Satyanarayana and Rao, 1995), antiarrhythmic, antifungal (Bekhit and Fahmy, 2003), potential antipyretic (Souza et al., 2002), antinociceptive (Tabarelli et al., 2004; Prokopp et al., 2006) and antioxidant activities (Godoy et al., 2004), the pyrazolone derivatives have still attracted medicinal chemist’s interest. Recently, acylpyrazolones have been reported to have a multidrug resistance modulating activity (Kimata et al., 2007). Benzoylpyrazolones, particularly, are potential antiprion agents (Chiba et al., 1998). From our laboratory, many reports exist on a ligational behaviour of pyrazolone based Schiff compounds. But, to the best of our knowledge, no reports exist on their biological evaluation. The presence of fragment –N‚CH–R in Schiff bases is known for its biological activity (Shemarova et al., 2000; Rehab et al., 2010). Many reports exist on structure–activity relationship of the class of these compounds (More et al., 2002; Bhendkar et al., 2004). Thus, it seems worthwhile to continue to investigate in this area. In the present work, we report synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff
Please cite this article in press as: Parmar, N. et al., Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases. Journal of Saudi Chemical Society (2012), doi:10.1016/j.jscs.2011.12.014
2 bases derived from a condensation reaction of 4-acyl-5-pyrazolones with aromatic diamines. 2. Experimental section 2.1. General All chemicals used were of laboratory reagent grade and used without further purification. Phenyl hydrazine was obtained from Sd. Fine Chem. Pvt. Ltd., Mumbai, India. Ethyl acetoacetate and calcium hydroxide were obtained from Samir Tech Chem. Pvt. Ltd., Vadodara, India. Diethyl ether and butyryl chloride were used as received from Merck, Mumbai, India. 1,4-Dioxane was supplied by Sisco Chem. Pvt. Ltd., Mumbai, India. Benzoyl chloride and Acetyl chloride were obtained from Chemport (India) Pvt. Ltd., Mumbai, India. 2.2. Analytical methods All melting points were taken in open capillaries and are uncorrected. IR spectra were recorded, in KBr disc, on PerkinElmer Spectrum GX FTIR spectrometer and are reported in wavenumbers (cm1). 1H NMR and 13C NMR spectra (ppm, d) were recorded on a Bruker Avance 400 spectrometer operating at 400 MHz for 1H NMR, and 100 MHz for 13C NMR using CDCl3 or DMSO d6 as solvent and reference. A degree of substitution (C, CH, CH2, and CH3) was determined by the DEPT-135 method. Carbon, Hydrogen and Nitrogen were estimated on a PerkinElmer 2400 Series II CHNS/O Elemental Analyzer. ESI mass spectra were measured on Thermo TSQ Quantum Access mass spectrometer at SICART, Vallabh Vidyanagar, Gujarat, India. Thin-layer chromatography (TLC, on aluminium plates coated with silica gel 60 F254, 0.25 mm thickness, Merck) was used for monitoring the progress of the reaction, purity and homogeneity of the synthesized compounds. 2.3. General procedure for the synthesis of Schiff bases (5a–i)
N. Parmar et al. 2.16 g of 3a, 2.78 g of 3b or 2.44 g of 3c), in the presence of a few drops of acetic acid, was refluxed for 3 h. After the completion of reaction as monitored by TLC, it was then cooled and allowed to stand overnight at room temperature. The coloured crystalline products 5a–i were obtained in good yield with excellent purity. It was washed with cold ethanol followed by drying at 60–90 C (Scheme 1, Table 1). The spectral characterizations of the compounds are given below: 2.3.2.1. 4-(1-(2-Aminophenylimino)ethyl)-3-methyl-1-phenyl1H-pyrazol-5-ol 5a. Recrystallized from ethanol (yield 60%), obtained as yellow crystals. mp 200–202 C. Anal. Calcd for C18H18N4O (306.36): C, 70.57; H, 5.92; N, 18.29. Found: C, 70.68; H, 5.85; N, 18.40; 1H-NMR (CDCl3) d; 2.27 (s, 3H, CH3), 2.42 (s, 3H, COCH3), 3.78 (s, 2H, NH2), 6.83–8.02 (m, 9H, Ar-H), 12.59 (s, 1H, OH); 13C NMR (CDCl3) d; 16.51, 17.33, 100.27, 116.70, 118.50, 118.86, 119.12, 122.21, 124.08, 127.45, 128.58, 129.13, 139.03, 142.24, 147.36, 165.64; IR mmax cm1(KBr): 3440, 3349, 1620, 1393, 1054; m/z (ESI) 306.7 (M+). 2.3.2.2. 4-((2-Aminophenylimino)(phenyl)methyl)-3-methyl-1phenyl-1H-pyrazol-5-ol 5b. Recrystallized from ethanol (yield 83%), obtained as orange crystals. mp 223–225 C. Anal. Calcd for C23H20N4O (368.43): C, 74.98; H, 5.47; N, 15.21. Found: C, 75.12; H, 5.50; N, 15.25; 1H NMR (DMSO-d6) d; 1.44 (s, 3H, CH3), 5.43 (s, 2H, NH2), 6.27–8.05 (m, 14H, ArH), 12.13 (s, 1H, OH); 13C NMR (DMSO-d6) d; 16.0, 100.97, 115.89, 116.18, 118.54, 122.53, 124.33, 128.28, 128.48, 128.66, 128.70, 128.88, 129.23, 130.61, 131.91, 139.58, 144.80, 147.90, 165.95; IR mmax cm1(KBr): 3407, 3333, 1630, 1396, 1054. m/z (ESI) 368.6 (M+). 2.3.2.3. 4-((3-Amino-2-methylphenylimino)(phenyl)methyl)-3methyl-1-phenyl-1H-pyrazol-5-ol 5c. Recrystallized from ethanol (yield 73%), obtained as yellow crystals. mp above 250 C. Anal. Calcd for C24H22N4O (382.45): C, 75.37; H, 5.80; N, 14.65. Found: C, 75.17; H, 5.83; N, 14.59; 1H NMR (CDCl3) d; 1.60 (s, 3H, CH3), 2.28 (s, 3H, CH3), 4.95 (s, 2H, NH2), 6.27–8.04 (m, 13H, Ar-H), 12.81 (s, 1H, OH); 13C
2.3.1. The preparation of 4-acyl-phenyl-3-methyl-5-pyrazolones 3a–c 4-Acyl-5-pyrazolones were prepared by reported methods. A corresponding acyl chloride (0.1 mol, 7.85 g acetyl chloride 2a, 15.20 g benzoyl chloride 2b and 10.60 g butyryl chloride 2c) was added to a well stirred, suspended with calcium hydroxide (12 g), solution of 5-pyrazolone 1 (0.1 mol, 17.4 g) in 1,4-dioxane (70–80 mL) at room temperature. Temperature increased for the first 5 min due to the exothermic nature of the reaction. After the complete addition, the resulted mass was treated according to the type of acylchloride taken. When butyryl chloride used, it was just stirred at room temperature for 45 min (Okafor et al., 1993). In all other cases, the mass was refluxed for 30 min (Jenson, 1956). Resulted mass obtained either in any ways, was then acidified by ice cold diluted hydrochloric acid (2 N, 200 mL), followed by a continuous stirring to cream colour crystals.
R
N
N Ph
O
+ RCOCl 2a-c
1
A mixture of an equimolar ethanolic hot solution (50 mL) of respective diamines 4a–d (1.08 g of 4a or 4b or 4d and 1.22 g of 4c) with corresponding acylpyrazolones 3a–c (0.01 mol,
Dioxane 70-80 ºC 3h
2a R = CH3 2b R = Ph 2c R = CH2CH2CH3
O N
OH
N Ph
3a-c H2 N
EtOH Reflux
X
NH2
4a-d
Path b
Path a R N N
N Ph
2.3.2. The synthesis of Schiff bases 5a–i
Ca(OH)2
5a-g
OH
X
R NH2
R N
N
N Ph
X
OH
N HO
5h-i
N
N
Ph
X = -C6H4(o/m/p)- , -(2-Me)(C6H3(m)-
Scheme 1
Synthesis of Schiff bases 5.
Please cite this article in press as: Parmar, N. et al., Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases. Journal of Saudi Chemical Society (2012), doi:10.1016/j.jscs.2011.12.014
Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases Table 1
3
Physicochemical properties of new synthesized Schiff bases 5h–i.
Entry
Compd.
R
X
Yield (%)
Time (h)
1 2 3 4 5 6 7 8 9
5a 5b 5c 5d 5e 5f 5g 5h 5i
CH3 Ph Ph, Ph C3H7 C3H7 C3H7 Ph C3H7
–C6H4(ortho)– –C6H4(ortho)– –(2-Me)C6H3(meta)– –C6H4(para)– –C6H4(ortho)– –(2-Me)C6H3(meta)– –C6H4(para)– –C6H4(meta)– –C6H4(meta)–
60 83 73 65 83 68 75 78 70
2.5 2.5 3.0 3.0 2.5 2.0 2.5 3.0 3.5
NMR (CDCl3) d; 12.31, 16.06, 101.13, 119.38, 124.47, 126.29, 126.35, 128.35, 128.46, 128.66, 128.78, 128.83, 130.24, 131.45, 136.79, 138.98, 142.84, 148.05, 163.91, 166.03; IR mmax cm1 (KBr): 3472, 3386, 1620, 1387, 1052; m/z (ESI) 382.9 (M+). 2.3.2.4. 4-((4-Aminophenylimino)(phenyl)methyl)-3-methyl-1phenyl-1H-pyrazol-5-ol 5d. Recrystallized from ethanol (yield 65%), obtained as yellow crystals. mp 172–174 C. Anal. Calcd for C23H20N4O (368.43): C, 74.98; H, 5.47; N, 15.21. Found: C, 75.17; H, 5.52; N, 15.34; 1H NMR (CDCl3) d; 1.60 (s, 3H, CH3), 3.52 (s, 2H, NH2), 6.63–8.02 (m, 14H, Ar-H), 12.89 (1H, s, OH); 13 C NMR (CDCl3) d; 15.91, 100.00, 117.53, 119.42, 121.97, 124.55, 125.14, 125.84, 127.43, 128.87, 131.51, 132.57, 138.92, 144.8, 147.90, 162.30, 165.67; IR mmax cm1 (KBr): 3409, 3332, 1631, 1388, 1053. m/z (ESI) 369.0 (M+). 2.3.2.5. 4-(1-(2-Aminophenylimino)butyl)-3-methyl-1-phenyl1H-pyrazol-5-ol 5e. Recrystallized from ethanol (yield 83%), obtained as yellow crystals. mp 183–185 C. Anal. Calcd for C20H22N4O (334.41): C, 71.83; H, 6.63; N, 16.75. Found: C, 72.03; H, 6.66; N, 16.78; 1H NMR (CDCl3) d; 0.90 (t, 3H, J 7.2 Hz, CH3), 1.58 (m, 2H, CH2), 2.44 (s, 3H, CH3), 2.57 (t, 2H, J 8.0 Hz, CH2), 3.87 (s, 2H, NH2), 6.79–8.02 (m, 9H, Ar-H), 12.58 (s, 1H, OH); 13C NMR (CDCl3) d; 14.24, 16.83, 22.69, 31,22, 99.76, 116.52, 118.84, 119.43, 122.33, 124.52, 128.03, 128.78, 129.45, 138.92, 142.26, 146.91, 166.23, 170.37; IR mmax cm1 (KBr): 3420, 3342, 1628, 1395, 1054; m/z (ESI) 334.7 (M+). 2.3.2.6. 4-(1-(3-Amino-2-methylphenylimino)butyl)-3-methyl1-phenyl-1H-pyrazol-5-ol 5f. Recrystallized from ethanol (yield 68%), obtained as white crystals. mp 182–183 C. Anal. Calcd for C21H24N4O (348.44): C, 72.39; H, 6.94; N, 16.08. Found: C, 72.58; H, 6.95; N, 16.12; 1H NMR (DMSO-d6) d; 0.81 (t, 3H, J 7.4 Hz, CH3), 1.46 (m, 2H, CH2), 1.96 (s, 3H, CH3), 2.37 (s, 3H, CH3), 2.56 (t, 2H, J 8.4 Hz, CH2), 5.20 (s, 2H, NH2), 6.51–8.01 (m, 8H, Ar-H), 12.75 (s, 1H, OH); 13C NMR (DMSO-d6) d; 12.25, 14.37, 16.93, 22.33, 30.78, 99.48, 114.38, 114.78, 117.42, 118.60, 124.32, 127.02, 129.16, 135.75, 139.51, 147.23, 148.55, 166.24, 169.62; IR mmax cm1 (KBr): 3446, 3358, 1624, 1383, 1051. m/z (ESI) 348.5 (M+). 2.3.2.7. 4-(1-(4-Aminophenylimino)butyl)-3-methyl-1-phenyl1H-pyrazol-5-ol 5g. Recrystallized from ethanol (yield 75%), obtained as yellow crystals. mp 181–183 C. Anal. Calcd for C20H22N4O (334.41): C, 71.83; H, 6.63; N, 16.75. Found: C, 71.67; H, 6.68; N, 16.71; 1H NMR (CDCl3) d; 0.95 (t, 3H, J
7.2 Hz, CH3), 1.59 (m, 2H, CH2), 2.44 (s, 3H, CH3), 2.63 (t, 2H, J 8.6 Hz, CH2), 4.73 (s, 2H, NH2), 6.81–8.01 (m, 9H, Ar-H), 12.85 (s, 1H, OH); 13C NMR (CDCl3) d; 14.17, 16.88, 22.92, 30.78, 99.05, 116.68, 116.74,119.41, 124.41, 126.49, 127.28, 128.51, 128.74, 139.04, 142.26, 146.80, 166.04, 168.67; IR mmax cm1 (KBr): 3372, 3338, 1612, 1390, 1054. m/z (ESI) 337.0 (M+). 2.3.2.8. N,N0 -bis-[1-(5-Hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yle)-phenyl-methylene]-benzene-1,3-diamine 5h. Recrystallized from ethanol (yield 78%), obtained as yellow crystals. mp 229–230 C. Anal. Calcd for C40H32N6O2 (628.72): C, 76.41; H, 5.13; N, 13.37. Found: C, 76.58; H, 5.10; N, 13.28; 1H NMR (CDCl3) d; 1.59 (s, 6H, CH3), 6.37– 8.02 (m, 24H, Ar-H), 12.79 (s, 2H, OH); 13C NMR (CDCl3) d; 15.95, 101.79, 119.32, 119.60, 121.68, 124.70, 128.46, 128.82, 128.98, 129.41, 130.80, 131.00, 138.29, 138.69, 148.07, 161.93 165.57; IR mmax cm1 (KBr): 3424, 1374, 1051; m/z (ESI) 629.2 (M+). 2.3.2.9. N,N’-bis[1-(5-Hydroxy-3-methyl-1-phenyl-1H-pyrazol4-yle)-butylidene]-benzene-1,3-diamine 5i. Recrystallized from ethanol (yield 70%), obtained as white crystals. mp 180– 182 C. Anal. Calcd for C34H36N6O2 (560.69): C, 72.83; H, 6.47; N, 14.99. Found: C, 72.90; H, 6.43; N, 15.11; 1H NMR (CDCl3) d; 0.97 (t, 6H, J 7.6 Hz, CH3), 1.62 (m, 4H, CH2), 2.48 (s, 6H, CH3), 2.74 (t, 4H, J 8.4 Hz, CH2), 7.17–8.01 (m, 14H, Ar-H), 13.22 (s, 2H, OH); 13C NMR (CDCl3) d; 14.11, 16.91, 22.90, 30.75, 100.16, 119.43, 123.75, 124.73, 125.31, 128.79, 130.82, 138.43, 138.66, 146.83, 165.95, 167.55; IR mmax cm1(KBr): 3424, 1374, 1054; m/z (ESI) 560.8 (M+). 2.4. Biological evaluation of the synthesized compounds 5a–i 2.4.1. Antimicrobial activity Biological assays were carried out by the agar cup diffusion method (Venkatraman et al., 1999; Cruickshank et al., 1975). A nutrient agar cup was prepared by dissolving a weighed ingredient in water at 7–6 pH. An aliquot (25 mL) was then dispensed in different test tubes followed by plugging them with sterilized cotton wool. By a gentle shaking, poured a well mixed incubated 0.5–0.6 mL 24 h old culture into a sterilized petri dish (25 mL each) and was allowed to set for 1.5 h. Cups were made by punching agar surface with a sterile cork bore and punched part of the agar media was removed by scooping. Each cup was added a sample solution (400 lg/mL DMF). Plates were then incubated at 35 C for 24–48 h to observe
Please cite this article in press as: Parmar, N. et al., Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases. Journal of Saudi Chemical Society (2012), doi:10.1016/j.jscs.2011.12.014
4
N. Parmar et al.
growth. Inhibition zones were measured in millimetres. Streptomycin and griseofulvin were used as standard antibacterial and antifungal drugs respectively. Solvent was screened for its activity. The corrections in biological activity of the compound, due to solvent dimethylformamide (DMF) were also applied in the calculation. DMF gave zero inhibition against Bacillus subtilis as well as Escherichia coli, but showed 3.0 mm against Phytophthora infestanse and Aspergillus niger. 2.4.2. Antioxidant activity Ferric reducing antioxidant power (FRAP) was measured by a modified method of Benzie and Strain (Benziea and Strainb, 1996). The antioxidant potentials of the compounds were estimated as their power to reduce the TPTZ–Fe(III) complex to TPTZ–Fe(II) complex (FRAP assay), which is simple, fast, and reproducible. FRAP working solution was prepared by mixing a 25.0 mL, 10 mM TPTZ solution in 40 mM HCl, 20 mM FeCl3Æ6H2O and 25 mL, 0.3 M acetate buffer at pH 3.6. A mixture of 40.0 lL, 0.5 mM sample solution and 1.2 mL FRAP reagent was incubated at 37 C for 15 min. Absorbance of intensive blue colour [Fe(II)–TPTZ] complex was measured at 593 nm. The ascorbic acid was used as a standard antioxidant compound. The results are expressed as ascorbic equivalent (mmol/100 g of dried compound). 3. Results and discussion 3.1. Chemistry 4-Acetyl/benzoyl-5-pyrazolones 3a–b were obtained by a method reported elsewhere (Jenson, 1956) (Scheme 1). Similarly, 4butyryl-5-pyrazolone 3c was obtained from butyrylchloride 2c but at modified room temperature method (Okafor et al., 1993). Yields were 75% (3a), 72% (3b) and 67% (3c). Equimolar 3a–c with diamines 4a–d in the presence of a few drops of acetic acid under refluxing ethanol gave Schiff bases 5a–g (Table 1, entries 1–7; Scheme 1, Path a). Schiff bases 5a–g that formed from o- or p-phenylenediamines were monoketiminic and bisketiminic 5h–i from m-phenylenediamine (Table 1,
entries 8–9; Scheme 1, Path b). IR, 1H NMR and 13C NMR spectroscopic data are in good agreement with their proposed structure. A displacement of a mOH band from region 3650– 3500 cm1 to 3350–2800 cm1 may be due to an internal hydrogen bridge OH N‚C (Ueno and Martell, 1956; Faniram et al., 1974). The band sometimes remained undetected if a strong hydrogen bond exists. So, Schiff bases are relatively planar with an adequate intramolecular distance favouring hydrogen bond formation (Freedman, 1961). Electronegative group attached to nitrogen favours the intra/intermolecular hydrogen bonding (Freedman, 1961). The compounds exist in enolic form (Scheme 1). Greater the electron density on C‚N, weaker this bond becomes and its stretching frequency appears at a lower wave number. IR spectra of compounds 5a–g show a doublet in the 3500–3000 cm1 range due to NH2 which is absent in 5h–i. All the compounds 5a–i show bands in the 3500–3000 cm1 range, and 1055 cm1 attributed to phenolic OH and C‚N groups respectively. The bands at 1595 and 1320 cm1 are attributable to cyclic mC‚N and a mC–O respectively. 1 H NMR spectra of 5e show three peaks; a triplet at d 0.90, a multiplet at 1.58, and a triplet at 2.57 ppm which are attributed to n-propyl hydrogens. A singlet peak appearing around d 2.44 ppm is due to methyl protons attached to pyrazolone unit. The NH2 protons resonate as a broad singlet at d 3.8 ppm, whereas signal due to phenolic proton was observed around d 12 ppm. Aromatic protons appeared as multiplet in the d 6.79–8.04 ppm range. Absence of a broad singlet d 3–4 ppm in compounds 5h–i is due to bisketimino of Schiff base.13C NMR spectra of 5h–i are in good agreement with their proposed structure. It showed that a peak in the d 12– 17 ppm range is due to CH3 carbon. The compound CH2 gives two negative signals; one at d 22 and second at 30 ppm in DEPT-135. A distinctive peak in d 166–170 ppm range is assigned to carbon attached to the oxygen atom. A signal at d100 ppm indicates the carbon at position-4 of the pyrazole ring. All the aromatic carbon signals appeared in d 110.08– 160.74 ppm range confirming the proposed structure of 5a–i. The mass spectra agreed with the molecular ion signals corresponding to the respective molecular formula of the
Table 2 Antimicrobial and antioxidant activities of compounds 5a–ia. The bold values indicate highest values of respective properties i.e. antimicrobial, antifungal or antioxident, among the compounds. Compound
5a 5b 5c 5d 5e 5f 5g 5h 5i DMF Streptomycinb Griseofulvinb a b c
Antibacterial activity
Antifungal activity
Antioxidant activity
B. subtilis Gram +ve
E. coli Gram ve
P. infestanse
A. niger
FRAP value (mmol/100 g)
0.0 2.0 4.0 0.0 0.0 4.0 4.0 5.0 0.0 0.0 10.0 NT
3.0 5.0 3.0 3.0 3.0 4.0 3.0 2.5 2.5 0.0 10.0 NT
5.0 9.0 6.0 7.0 9.0 6.0 7.0 8.0 7.0 3.0 NTc 9.0
6.0 6.0 2.0 5.0 5.0 5.0 5.0 2.0 5.0 3.0 NT 9.0
13.2 30.6 17.9 95.0 20.5 25.6 37.0 31.8 75.4 NT NT NT
400 lg/mL in DMF, Inhibition zone measured in mm. 100 lg/mL in DMF, Inhibition zone measured in mm. NT = Not tested.
Please cite this article in press as: Parmar, N. et al., Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases. Journal of Saudi Chemical Society (2012), doi:10.1016/j.jscs.2011.12.014
Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases synthesized compounds. For example, mass spectra of compound 5a gave molecular ion peak at 306.7 (M+) corresponding to the molecular formula C18H18N4O. The observed values of C H N elemental analysis are in good agreements with the calculated data. 3.2. Biological evaluation 3.2.1. Antimicrobial activity The antimicrobial screening test results exhibited a poor activity compared to other standard drugs. From activity data (Table 2), it shows that compounds 5b and 5h exhibited moderate activity against E. coli and B. subtilis respectively in comparison to standard antibiotic streptomycin. On the other hand antifungal study shows excellent activity against P. infestanse and Aspergillus fumigates. Compared to a standard griseofulvin, compounds 5b, 5e and 5h exhibited excellent activity against P. infestanse. Thus, from the structural examination, it concludes that Schiff bases, particularly, from 4-butyryl-5-pyrazolone possess good antibacterial and antifungal activities which may be due to electronegative alkyl group (Waksman, 1947). 3.2.2. Antioxidant activity A capacity to transfer a single electron i.e. the antioxidant power of all compounds was determined by a FRAP assay. The FRAP value was expressed as an equivalent of standard antioxidant ascorbic acid (mmol/100 g of dried compound). FRAP values indicate that all the compounds have a ferricreducing antioxidant power. The compounds 5d and 5i showed relatively high antioxidant activity while compound 5a shows poor antioxidant power (Table 2). 4. Conclusion In summary, we afforded two types of Schiff base compounds; a bisketimine and monoketimine depending upon the nature of aromatic diamines. m-phenylenediamine gave bisketiminic Schiff bases, while o- or p-, and 2-methyl-m-phenylenediamine afforded a monoketiminic one. All synthesized compounds are active against gram positive bacteria – B. subtilis and P. infestanse. Schiff bases derived from butyrylpyrazolone showed good antibacterial and antifungal activities. While those from acetylpyrazolones showed substantially a low antioxidant activity, very high antioxidant power was shown by the Schiff bases from 4-butyryl-5-pyrazolones.
Acknowledgements The authors are grateful to Heads, Department of Chemistry, and Department of Biosciences, Sardar Patel Univ., V. V. Nagar, for providing research facilities.
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.jscs.2011.12.014.
5
References Bekhit, A‘.A., Fahmy, H.T., 2003. Design and synthesis of some substituted 1H-pyrazolyl oxazolidines or 1H-pyrazolylthiazolidines as anti-inflammatory-antimicrobial agents. Arch. Pharm. (Weinheim) 336, 111–118. doi:10.1002/ardp.20039000(org). Benziea, I.F.F., Strainb, J.J., 1996. The Ferric Reducing Ability of Plasma (FRAP) as a measure of ‘‘Antioxidant Power’’: the FRAP assay. Anal. Biochem. 239, 70–76. doi:10.1006/abio.1996.0292. Bhendkar, A.K., Vijay, K., Rant, A.W., 2004. Synthesis of some novel Schiff bases of 2- aminopyrimidine and their antimicrobial activity. Acta Ciencia Indica Chem. 30, 29. Bojan, B., Marijan, K., Slovenko, P., 2009. A simple approach to pyrazol-3-ones via diazenes. Tetrahedron 65, 8690–8696. doi:10.1016/j.tet.2009.08.047. Chiba, P., Holzer, W., Landau, M., Bachmann, G., Lorenz, K., Plagens, B., Hitzler, M., Richter, E., Ecker, G., 1998. Substituted 4Acylpyrazoles and 4-Acylpyrazolones: synthesis and multidrug resistance-modulating activity. J. Med. Chem. 41, 4001–4011. doi:10.1021/ jm980121. Cruickshank, R., Duguid, J.P., Marmion, B.P., Swain, R.H.A., 1975, Twelfth ed. In: Medical Microbiology, 2 Churchill Livingstone, London, p. 190. Faniram, J.A., Patel, K.S., Bailar Jr., J.C., 1974. Infrared spectra of N,N0 -bis(salicylidene)-1,1-(dimethyl)ethylenediamine and its metal complexes. J. Inorg. Nucl. Chem. 36 (7), 1547–1551. doi:10.1016/ 0022-1902(74)80621-4. Freedman, H.H., 1961. Intramolecular H-Bonds I. A spectroscopic study of the hydrogen bond between hydroxyl and nitrogen. J. Am. Chem. Soc. 83 (13), 2900–2905. doi:10.1021/ ja01474a026. Godoy, M.C., Fighera, M.R., Souza, F.R., Flores, A.E., Rubin, M.A., Oliveira, M.R., Zanatta, N., Martin, M.A.P., Bonacorso, H.G., Mello, C.F., 2004. Alpha 2-adrenoceptors and 5-HT receptors mediate the antinociceptive effect of new pyrazolines, but not of dipyrone. Eur. J. Pharmacol. 496 (1-3), 93–97. doi:10.1016/ j.ejphar.2004.05.045. Gu¨rsoy, A., Demirayak, S., Capan, G., Erol, K., Vural, K., 2000. Synthesis and preliminary evaluation of new 5-pyrazolinone derivatives as analgesic agents. Eur. J. Med. Chem. 35, 359–364. doi:10.1016/S0223-5234(00)00117-3 PMid:10785562. Jenson, B.S., 1956. The Synthesis of 1-Phenyl-3-methyl-4-acyl-pyrazolones-5. Acta. Chem. Scand. 13, 1668–1670. doi:10.3891/acta.chem.scand.13-1668. Jung, J.C., Watkins, E.B., Avery, M.A., 2002. Synthesis of 3substituted and 3, 4-disubstituted pyrazolin-5-ones. Tetrahedron 58, 3639–3646. doi:10.1016/S0040-4020(02)00306-X. Kimata, A., Nakagawn, H., Ohyama, R., Fukuuchi, T., Ohata, S., Suzuki, T., Miyata, N., 2007. New series of antiprion compounds: pyrazolone derivatives have the potent activity of inhibiting protease-resistant prion protein accumulation. J. Med. Chem. 50, 5053–5056. doi:10.1021/jm070688. More, S.V., Dongarkhadekar, D.V., Chavan, R.N., Jadhav, W.N., Bhusare, S.R., Pawar, R.P., 2002. Synthesis and antibacterial activity of new Schiff bases, 4-thiazolidinones and 2-azetidinones. J. Indian Chem. Soc. 79, 768–769. Okafor, E.C., Adiukwu, P.U., Uzoukwu, B.A., 1993. Sykoheses and characterization of 4-iso-Butyryl and 4-iso-valeroyl derivatives of 1-FHE NTL-3-Methyl-pyrazolone-5 and their Uranium(VI), Tkorium(IV), Lanthanum(III), Iron(III), Lead(II) and Calciun(II) Complexes. Synth. React. Inorg. Met. Org. Chem. 23 (1), 97–111. doi:10.1080/ 15533179308016620. Prokopp, C.R., Rubin, M.A., Sauzem, P.D., de Souza, A.H., Berlese, D.B., Lourega, R.V., Muniz, M.N., Bonacorso, H.G., Zanatta, N., Martins, M.A.P., Mello, C.F., 2006. A pyrazolyl-thiazole derivative causes antinociception in mice. Braz. J. Med. Biol. Res. 39 (6), 795. doi:10.1590/S0100-879X2006000600013.
Please cite this article in press as: Parmar, N. et al., Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases. Journal of Saudi Chemical Society (2012), doi:10.1016/j.jscs.2011.12.014
6 Rehab, A., Barbara, K., Nora, A.K., Thomas, V., El-Ansary, A., 2010. Antibacterial effect of some benzopyrone derivatives. Eur. J. Med. Chem. 45, 372–378. doi:10.1016/ j.ejmech.2009.10.001. Satyanarayana, K., Rao, M.N.A., 1995. Synthesis of 4-[5-(substituted aryl)-4, 5-dihydro-1H pyrazol-3-yl]-3-phenyl-sydnones as antiinflammatory, antiarthritic and analgesic agents. Eur. J. Med. Chem. 30, 641–645. doi:10.1016/0223-5234(96) 88280-8. Shemarova, I.V., Maizel, E.B., Voznyi, I.V., Stepanova, N.P., Khovanskikh, A.E., 2000. Synthesis of new derivatives of pyrazolone and nicotinic acid and study of their effect on cytochrome P450. Activity Pharm. Chem. J. 34 (10), 530–532. doi:10.1023/ A:1010355129735. Souza, F.R., Souza, V.T., Ratzlaff, V., Borges, L.P., Oliveira, M.R., Bonacorso, H.G., Zanatta, N., Martins, M.A.P., Mello, C.F., 2002. Hypothermic and antipyretic effects of 3-methyl-and 3-phenyl-5hydroxy-5-trichloromethyl-4,5-dihydro-1H-pyrazole-1-carboxyamides in mice. Eur. J. Pharmacol. 451 (2), 141. doi:10.1016/ S0014-2999(02)02225-2.
N. Parmar et al. Tabarelli, Z., Rubin, M.A., Berlese, D.B., Sauzem, P.D., Missio, T.P., Teixeira, M.V., Sinhorin, A.P., Martins, M.A.P., Zanatta, N., Bonacorso, H.G., Mello1, C.F., 2004. Antinocice-ptive effect of novel pyrazolines in mice. Braz. J. Med. Bio. Res. 37, 1531. doi:10.1590/S0100-879X2004001000013. Ueno, K., Martell, A.E., 1956. Infrared studies on synthetic oxygen carriers. J. Phys. Chem. 60, 1270–1275. doi:10.1021/j150543a029. Varvounis, G., Fiamegos, Y., Pilidis, G., 2007. Pyrazol-3-ones. Part III: reactivity of the ring substituents 95, 27–141. doi:10.1016/ S0065-2725(07)95002-3. Venkatraman, R., Davis, K., Shelby, A., Zubkowski, J.D., Valente, E.J., 1999. syn,E-1-cyclopentano-4-ethyl-3-thiosemicarbazone and syn,E-1-cyclopentano-4-phenyl-3-thio-semicarbazone. J. Chem. Chrystallogr. 29 (4), 429–434. doi:10.1023/A:1009515111029. Waksman, S.A., 1947. Microbial Antagonism and antibiotic substances. Commonwealth fund third ed. New York.
Please cite this article in press as: Parmar, N. et al., Synthesis, antimicrobial and antioxidant activities of some 5-pyrazolone based Schiff bases. Journal of Saudi Chemical Society (2012), doi:10.1016/j.jscs.2011.12.014