Bioorganic & Medicinal Chemistry Letters xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters journal homepage: www.elsevier.com/locate/bmcl
Synthesis and biological evaluation of pyrazolylthiazole carboxylic acids as potent anti-inflammatory–antimicrobial agents Poonam Khloya a, Satish Kumar a, Pawan Kaushik b, Parveen Surain c, Dhirender Kaushik b, Pawan K. Sharma a,⇑ a b c
Department of Chemistry, Kurukshetra University, Kurukshetra 136119, India Institute of Pharmaceutical Sciences, Kurukshetra University, Kurukshetra 136119, India Department of Microbiology, Kurukshetra University, Kurukshetra 136119, India
a r t i c l e
i n f o
Article history: Received 16 August 2014 Revised 23 January 2015 Accepted 4 February 2015 Available online xxxx Keywords: Pyrazole Thiazole Anti-inflammatory activity Antimicrobial activity
a b s t r a c t Current Letter presents design, synthesis and biological evaluation of a novel series of pyrazolylthiazole carboxylates 1a–1p and corresponding acid derivatives 2a–2p. All 32 novel compounds were tested for their in vivo anti-inflammatory activity by carrageenan-induced rat paw edema method as well as for in vitro antimicrobial activity. All the tested compounds exhibited excellent AI activity profile. Three compounds 1p (R = Cl, R1 = Cl), 2c (R = H, R1 = F) and 2n (R = Cl, R1 = OCH3) were identified as potent anti-inflammatory agents exhibiting edema inhibition of 93.06–89.59% which is comparable to the reference drug indomethacin (91.32%) after 3 h of carrageenan injection while most of the other compounds displayed inhibition P80%. In addition, pyrazolylthiazole carboxylic acids (2a–2p) also showed good antimicrobial profile. Compound 2h (R = OCH3, R1 = Cl) showed excellent antimicrobial activity (MIC 6.25 lg/mL) against both Gram positive bacteria comparable with the reference drug ciprofloxacin (MIC 6.25 lg/mL). Ó 2015 Elsevier Ltd. All rights reserved.
Inflammation is the immune response of tissues to external injury which can be categorized as acute or chronic. The former is the initial response of the body to harmful stimulus identified by the increased movement of macrophages and neutrophils in infected tissues while chronic inflammation is due to progressive movement of the mononucleated cells at the injury site leading to destruction of tissues by cell death.1 Anti-inflammatory drugs are known to inhibit one or more isoforms of cyclooxygenase (COX) enzyme that catalyzes the conversion of arachidonic acid (AA) into prostaglandins (PGs) and thromboxanes. COX enzyme is a rate-limiting enzyme that exists in two isoforms; constitutive (COX-1) and inducible (COX-2). COX1 is believed to be a housekeeping enzyme constitutively present in platelets and all tissues. It produces PGs involved in important physiological functions, such as gastric mucosal cytoprotection, renal homeostasis, and platelet aggregation. COX-2 is an inducible, short lived enzyme present in brain, kidney and endothelial cells and facilitates the release of PGs in the inflammatory process.2–4 Conventional non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin and ibuprofen are nonselective inhibitors of both the isoforms of COX thereby leading to a number of renal and ⇑ Corresponding author. Tel.: +91 9416457355; fax: +91 1744 238277. E-mail address: [email protected] (P.K. Sharma).
gastrointestinal (GI) side effects.5 To overcome the gastrointestinal side effects, selective COX-2 inhibitors such as celecoxib,6 rimonabant,7 valdecoxib,8 rofecoxib,9 deracoxib10 etc., which block the production of PGs in inflammatory cells,11 have been developed since 1999. Success of these ‘coxibs’ led to an increased attention towards development of more candidates like the approved COX2 selective inhibitors which are typical models of the diarylheterocycles template.12 Resistance of microbes to existing antimicrobial drugs is a cause of serious concern. Considering the obvious advantages of monotherapy against inflammation as well as microbial infection, research efforts are underway to develop dual anti-inflammatory–antimicrobial drugs with minimum GI side effects and high safety margin.13 Thiazole14–17 and pyrazole nuclei18–23 are ubiquitous motifs representing an interesting array of heterocyclic compounds exhibiting a wide range of biological activities such as antimicrobial, antiinflammatory, antitubercular, anticonvulsant, antitumor etc. Motivated by these findings, and in continuation of our ongoing research program in the field of 4-functionalized pyrazole analogues24–27 and other biologically active heterocyclic compounds28–34 we present in this Letter, design, synthesis and evaluation of pyrazolylthiazole carboxylic acids (2a–2p) and their ester analogues (1a–1p) as dual anti-inflammatory–antimicrobial agents (Fig. 1). Thiazole ring possessing carboxylic group have been incorporated at N-1 position
http://dx.doi.org/10.1016/j.bmcl.2015.02.004 0960-894X/Ó 2015 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Khloya, P.; et al. Bioorg. Med. Chem. Lett. (2015), http://dx.doi.org/10.1016/j.bmcl.2015.02.004
2
P. Khloya et al. / Bioorg. Med. Chem. Lett. xxx (2015) xxx–xxx
Functionalization at 4-position of pyrazole
R1
O
O
OH
O N
4-carbothioamidepyrazoles (10), which were prepared by multistep synthesis. Ethyl 3-aryl-3-oxopropanoates 5 were prepared by the base catalyzed carbethoxylation of the appropriately substituted acetophenones 3 with diethyl carbonate 4. Bromination of 5 was achieved by grinding ethyl 3-aryl-3-oxopropanoates 5 with NBS36 without solvent leading to the exclusive formation of monobrominated pure products 6 in excellent yield. 4-Carbothioamidepyrazoles 10 were synthesized starting from appropriate acetophenones using a multistep strategy involving hydrazone synthesis, Vilsmeier– Haack reaction followed by oxidative amination and subsequent thiolysis of 4-cyanopyrazoles 9 by using H2S gas under basic conditions in the presence of triethylamine as reported recently by our group.25 The target compounds pyrazolylthiazole carboxylates 1a–1p were synthesized by the condensation of appropriate 4-carbothioamidepyrazoles 10 with substituted ethyl 2-bromo-3-aryl3-oxopropanoates (6) in the presence of catalytic amount of glacial acetic acid in refluxing ethanol for 5–6 h. Pyrazolylthiazole carboxylates 1a–1p were converted into corresponding pyrazolylthiazole carboxylic acids 2a–2p following basic hydrolysis of the ester group using sodium hydroxide (NaOH) solution under reflux for 3–4 h in good yield. The newly synthesized target compounds (1a–1p and 2a–2p) were characterized by rigorous analysis of their IR, 1H NMR, 13C NMR and mass spectral data. IR spectra of pyrazolylthiazole
R1
N
S
S R2
R2 N N
N N
1a-1p
2a-2p
Figure 1. Pyrazolylthiazole carboxylates 1a–1p and corresponding carboxylic acids 2a–2p.
of pyrazole ring35 in the past but here in this Letter, to the best of our knowledge, we have introduced the thiazolecarboxylic acid functionality at 4-position of pyrazole ring (1a–1p and 2a–2p) for the first time (Fig. 1). The synthetic strategy adopted for the synthesis of the target compounds is depicted in Scheme 1. The basic requirements for the synthesis of pyrazolylthiazole carboxylic acids (2) were the formation of ethyl 2-bromo-3-aryl-3-oxopropanoates (6) and
Br
O
O
O
O
OC2H5
(a)
+ C2H5O
4
OC2H5
R1
R1
5
6
O
NHNH2 +
N N
N N
(c, d, e) reference 19
7
2
R2
CN
8
9
2
R
R S
NH2 10
N N R2
(h)
R2 N
(g)
(f)
N N
N
S
S OH
OCH2CH3
O
O R1
R1 1
Comp No.
O
(b)
OC2H5
R1 3
O
a
2
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
H OCH3
F
Cl
H
OCH3
F
Cl
H
OCH3
F
Cl
H
OCH3
F
Cl
H
H
H
OCH3
OCH3
OCH3
OCH3
F
F
F
F
Cl
Cl
Cl
Cl
1, 2 R1 2
R
H
Scheme 1. Reagents and conditions: (a) NaH, benzene, diethyl carbonate reflux; (b) NBS, grinding; (c) ethanol–water, reflux; (d) POCl3/DMF, 50–60 °C, 6 h; (e) I2/NH3, THF stir overnight; (f) H2S, NEt3, pyridine, 10–12 h; (g) ethyl 2-bromo-3-aryl-3-oxopropanoate 6, ethanol, 1–2 drops of glacial acetic acid, reflux; (h) NaOH/H2O/C2H5OH, reflux.
Please cite this article in press as: Khloya, P.; et al. Bioorg. Med. Chem. Lett. (2015), http://dx.doi.org/10.1016/j.bmcl.2015.02.004
3
P. Khloya et al. / Bioorg. Med. Chem. Lett. xxx (2015) xxx–xxx Table 1 In vivo anti-inflammatory (AI) activity of compounds (1a–1p and 2a–2p) in carrageenan induced rat paw edema assay (acute inflammatory model) Volume of edemaa (mL) and % AIb
Compounds 1h Swelling Control Indomethacin 1a 1b 1c 1d 1e 1f 1g 1h 1i 1j 1k 1l 1m 1n 1o 1p 2a 2b 2c 2d 2e 2f 2g 2h 2i 2j 2k 2l 2m 2n 2o 2p a b
Swelling
93.69 90.99 80.18 73.87 80.18 90.19 86.48 83.78 86.48 76.57 80.18 85.58 84.68 89.89 90.99 83.78 83.78 87.37 82.88 82.88 87.38 81.98 82.88 82.88 83.78 87.38 80.18 79.27 70.27 71.17 86.48 73.87 76.57
1.21 ± 0.16 0.14 ± 0.05* 0.30 ± 0.06* 0.29 ± 0.08* 0.22 ± 0.09* 0.15 ± 0.11* 0.20 ± 0.01* 0.19 ± 0.14* 0.18 ± 0.06* 0.38 ± 0.11* 0.32 ± 0.10* 0.27 ± 0.07* 0.25 ± 0.05* 0.22 ± 0.03* 0.22 ± 0.03* 0.35 ± 0.06* 0.47 ± 0.11* 0.27 ± 0.08* 0.39 ± 0.10* 0.25 ± 0.07* 0.16 ± 0.04* 0.21 ± 0.05* 0.16 ± 0.04* 0.24 ± 0.11* 0.22 ± 0.07* 0.26 ± 0.05* 0.22±0.05* 0.40 ± 0.07* 0.57 ± 0.22* 0.64 ± 0.16* 0.46 ± 0.11* 0.19 ± 0.04* 0.33 ± 0.10* 0.23 ± 0.06*
3h Inhibition (%)
Swelling
88.42 75.20 76.03 81.81 87.60 83.47 84.29 85.12 68.59 73.55 79.33 79.33 81.81 81.81 71.07 61.15 77.68 67.76 79.33 86.77 82.64 86.77 86.77 81.81 78.51 81.81 66.94 52.89 47.10 61.98 89.29 72.72 80.99
1.73 ± 0.09 0.15 ± 0.03* 0.28 ± 0.06* 0.24 ± 0.10* 0.31 ± 0.06* 0.24 ± 0.12* 0.33 ± 0.08* 0.27 ± 0.11* 0.31 ± 0.13* 0.38 ± 0.11* 0.33 ± 0.02* 0.39 ± 0.07* 0.32 ± 0.06* 0.34 ± 0.11* 0.32 ± 0.07* 0.25 ± 0.08* 0.50 ± 0.13* 0.12 ± 0.04* 0.28 ± 0.06* 0.24 ± 0.05* 0.18 ± 0.04* 0.20 ± 0.06* 0.21 ± 0.09* 0.20 ± 0.06* 0.31 ± 0.17* 0.28 ± 0.05* 0.37 ± 0.09* 0.56 ± 0.14* 0.61 ± 0.12* 0.75 ± 0.14* 0.69 ± 0.19* 0.16 ± 0.05* 0.49 ± 0.10* 0.43 ± 0.08*
4h Inhibition (%)
Swelling
Inhibition (%)
91.32 83.81 86.12 82.08 87.23 80.92 84.39 82.08 78.03 80.92 77.45 81.50 80.34 81.50 85.54 71.09 93.06 83.81 86.12 89.59 88.43 87.86 88.43 82.08 83.81 78.61 67.63 64.73 56.14 60.11 90.75 71.67 75.14
1.88 ± 0.20 0.16 ± 0.05* 0.24 ± 0.06* 0.34 ± 0.14* 0.42 ± 0.13* 0.22 ± 0.10* 0.24 ± 0.08* 0.17 ± 0.04* 0.37 ± 0.06* 0.53 ± 0.08* 0.45 ± 0.09* 0.32 ± 0.09* 0.23 ± 0.05* 0.26 ± 0.07* 0.28 ± 0.10* 0.21 ± 0.07* 0.19 ± 0.04* 0.18 ± 0.07* 0.30 ± 0.01* 0.22 ± 0.07* 0.17 ± 0.03* 0.22 ± 0.05* 0.23 ± 0.08* 0.19 ± 0.06* 0.18 ± 0.04* 0.20 ± 0.07* 0.18 ± 0.04* 0.36 ± 0.10* 0.47 ± 0.13* 0.37 ± 0.11* 0.54.0.11* 0.21 ± 0.03* 0.38 ± 0.10* 0.28 ± 0.08*
91.48 87.23 81.91 88.29 87.23 90.95 90.95 80.31 71.80 76.06 82.97 87.76 86.17 85.10 88.92 89.89 90.42 84.04 88.29 90.95 88.29 87.76 89.89 90.42 89.36 90.42 80.85 75.00 80.31 71.27 88.82 79.78 85.10
Significantly different compared to respective control values, P 21 mm against S. aureus as compared to standard drug (24.0 mm). For antifungal activity profile, best antibacterial candidate of the study 2h and 2m were found to also act as the most active antifungal agents with 2h showing zone of inhibition 27.6 mm (MIC 6.25 lg/mL) against both the fungal strain and 2m showing zone of inhibition 26.6 mm (MIC 6.25 lg/mL), 24.6 mm (MIC 6.25 lg/mL) against S. cerevisiae and C. albicans respectively which is better than the reference drug amphotericin B exhibiting 19.3 mm and 16.6 mm zone of inhibition with MIC 6.25 lg/mL. Seven compounds 2a–2d, 2i and 2o–2p displayed zone of inhibition >20 mm against S. cerevisiae while seven other compounds 1g, 1k, 2c, 2i, 2l, 2n and 2p showed zone of inhibition >20 mm against C. albicans. However, none of compounds were active against Gram negative bacteria. In conclusion, synthesis of pyrazolylthiazole carboxylates and their corresponding acids was achieved in good yield and the same were evaluated for their in vivo anti-inflammatory activity as well as for in vitro antimicrobial activity. Compounds 1p (R = Cl, R1 = Cl), 2c (R = H, R1 = F) and 2n (R = Cl, R1 = OCH3) showed significant AI activity ranging from 93.06% to 89.59% comparable to the reference drug indomethacin 3 h after carrageenan injection while 4 h after carrageenan injection, nine compounds 1e–1f, 1o–1p, 2c, 2f–2g, 2i and 2h showed AI activity ranging from 90.95% to 89.36% inhibition comparable to indomethacin (91.48%). In case of antimicrobial profile, it was found that two compounds 2h and 2m were found to be the most active antimicrobial agents while other compounds also exhibited good activity. Thus 2h can be considered as promising potent dual anti-inflammatory–antimicrobial agent.
5
(Haryana), India for the award of Senior Research Fellowships. The authors are thankful to Sophisticated Analytical Instrument Facility, Central Drug Research Institute, Lucknow for providing Mass spectra. Supplementary data Supplementary data (biological assay, experimental procedure and spectroscopic characterization of compounds 1a–1p and 2a–2p) associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.bmcl.2015.02.004. References and notes 1. 2. 3. 4. 5. 6.
7.
8. 9. 10. 11.
12. 13.
14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35.
Acknowledgements 36.
Dinarello, C. A. Cell 2010, 45, 935. Ormrod, D.; Wellington, K.; Wagstaff, A. J. Drugs 2002, 62, 2059. Vane, J. R. Am. J. Med. 1998, 104, 2S. Cryer, B.; Feldman, M. Am. J. Med. 1998, 104, 413. Smith, M. L.; Hawcroft, G.; Hull, M. A. Eur. J. Med. Chem. 2000, 36, 664. Penning, T.; Talley, J.; Bertenshaw, S.; Carter, J.; Callins, P.; Doctor, S.; Graneto, M.; Lee, L.; Malecha, J.; Miyashiro, J.; Rogers, R.; Rogeier, D.; Yu, S.; Anderson, G.; Burton, E.; Cogburn, J.; Gregory, S.; Koboldt, C.; Perkins, W.; Seibert, K.; Veenhuizen, A.; Zhang, Y.; Isakson, P. J. Med. Chem. 1997, 40, 1347. Rinaldi-Carmona, M.; Barth, F.; Heaulme, M.; Shire, D.; Calandra, B.; Congy, C.; Martinez, J.; Neliat, G.; Caput, D.; Ferrara, P.; Soubrie, P.; Breliere, J. C.; Le Fur, G. FEBS Lett. 1994, 350, 240. Nussmeier, N. A.; Whelton, A. A.; Brown, M. T.; Langford, R. M.; Hoeft, A.; Parlow, J. L.; Boyce, S. W.; Verburg, K. M. N. Engl. J. Med. 2005, 352, 1081. Scheen, A. J. Rev. Med. Liege 2004, 59, 565. Sessions, J. K.; Reynolds, L. R.; Budsberg, S. C. Am. J. Vet. Res. 2005, 66, 812. Song, Y.; Connor, D. T.; Sercel, A. D.; Sorenson, R. J.; Double-day, R.; Unangst, P. C.; Roth, B. D.; Beylin, V. G.; Gilbertsen, R. B.; Chan, K.; Schrier, D. J.; Guglietta, A.; Bornemeier, D. A.; Dyer, R. D. J. Med. Chem. 1999, 42, 1161. Palomer, A.; Cabre, F.; Pascual, J.; Campos, J.; Trujillo, M. A.; Entrena, A.; Callo, M. A.; Garcia, L.; Mauleon, D.; Espinosa, A. J. Med. Chem. 2002, 45, 1402. Giulia, M.; Luisa, M.; Paola, F.; Silvia, S.; Angelo, R.; Luisa, M.; Francesco, B.; Roberta, L.; Chiara, M.; Valeria, M.; Paolo, L. C.; Elena, T. Bioorg. Med. Chem. 2004, 12, 5465. Rostom, S. A. F. Bioorg. Med. Chem. 2006, 14, 6469. Chang, S.; Zhang, Z.; Zhuang, X.; Luo, J.; Cao, X.; Li, H.; Tu, Z.; Lu, X.; Ren, X.; Ding, K. Bioorg. Med. Chem. Lett. 2012, 22, 1208. Bondock, S.; Naser, T.; Ammar, Y. A. Eur. J. Med. Chem. 2013, 62, 270. EI-Sayed, M. A. A.; Abdel-Aziz, N. I.; Abdel-Aziz, A. A. M.; EI-Azab, A. S.; Asiri, Y. A.; EI-tahir, K. E. H. Bioorg. Med. Chem. 2011, 19, 3416. Li, M.; Zhao, B. X. Eur. J. Med. Chem. 2014, 85, 311. Pinna, G.; Loriga, G.; Lazzari, P.; Ruiu, S.; Falzoi, M.; Frau, S.; Pau, A.; Murineddu, G.; Asproni, B.; Pinna, G. A. Eur. J. Med. Chem. 2014, 82, 281. Mert, S.; Kasimogullari, R.; Ica, T.; Colak, F.; Altun, A.; Ok, S. Eur. J. Med. Chem. 2014, 78, 86. Ningaiah, S.; Bhadraiah, U. K.; Doddaramappa, S. D.; Keshavamurthy, S.; Javarasetty, C. Bioorg. Med. Chem. Lett. 2014, 24, 245. Wang, S. F.; Zhu, Y. L.; Zhu, P. T.; Makawana, J. A.; Zhang, Y. L.; Zhao, M. Y.; Lv, P. C.; Zhu, H. L. Bioorg. Med. Chem. 2014, 22, 6201. Tewari, A. K.; Singh, V. P.; Yadav, P.; Gupta, G.; Singh, A.; Goel, R. K.; Shinde, P.; Mohan, G. C. Bioorg. Chem. 2014, 56, 8. Sharma, P. K.; Kumar, S.; Kumar, P.; Kaushik, P.; Kaushik, D.; Dhingra, Y.; Aneja, K. R. Eur. J. Med. Chem. 2010, 45, 2650. Sharma, P. K.; Chandak, N.; Kumar, P.; Sharma, C.; Aneja, K. R. Eur. J. Med. Chem. 2011, 46, 241. Khloya, P.; Kumar, P.; Mittal, A.; Aggarwal, N. K.; Sharma, P. K. Org. Med. Chem. Lett. 2013, 3, 1. Khloya, P.; Celik, G.; Ram, S.; Vullo, V.; Supuran, C. T.; Sharma, P. K. Eur. J. Med. Chem. 2014, 76, 284. Chandak, N.; Kumar, P.; Kaushik, P.; Varshney, P.; Sharma, C.; Kaushik, D.; Jain, S.; Aneja, K. R.; Sharma, P. K. J. Enzyme Inhib. Med. Chem. 2014, 29, 476. Chandak, N.; Bhardwaj, J. K.; Sharma, R. K.; Sharma, P. K. Eur. J. Med. Chem. 2013, 59, 203. Kumar, P.; Chandak, N.; Nielsen, N.; Sharma, P. K. Bioorg. Med. Chem. 2010, 15, 4336. Ram, S.; Celik, G.; Khloya, P.; Vullo, D.; Supuran, C. T.; Sharma, P. K. Bioorg. Med. Chem. 2014, 22, 1873. Kumar, S.; Namkung, W.; Verkman, A. S.; Sharma, P. K. Bioorg. Med. Chem. 2012, 20, 4237. Chandna, N.; Kumar, S.; Kaushik, P.; Kaushik, D.; Roy, S. K.; Gupta, G. K.; Jachak, S. M.; Kapoor, J. K.; Sharma, P. K. Bioorg. Med. Chem. 2013, 21, 4581. Sharma, P. K.; Sawhney, S. N. Bioorg. Med. Chem. Lett. 1997, 7, 2427. Atobe, M.; Naganuma, K.; Kawanishi, M.; Morimoto, A.; Kasahara, K. I.; Ohashi, S.; Suzuki, H.; Hayashi, T.; Miypshi, S. Bioorg. Med. Chem. Lett. 2013, 23, 6569. Pravst, I.; Zupan, M.; Stavber, S. Green Chem. 2006, 8, 1001.
One of the authors (Poonam Khloya) is grateful to the Haryana State Council for Science and Technology (HSCST), Panchkula Please cite this article in press as: Khloya, P.; et al. Bioorg. Med. Chem. Lett. (2015), http://dx.doi.org/10.1016/j.bmcl.2015.02.004
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters journal homepage: www.elsevier.com/locate/bmcl
Synthesis and biological evaluation of pyrazolylthiazole carboxylic acids as potent anti-inflammatory–antimicrobial agents Poonam Khloya a, Satish Kumar a, Pawan Kaushik b, Parveen Surain c, Dhirender Kaushik b, Pawan K. Sharma a,⇑ a b c
Department of Chemistry, Kurukshetra University, Kurukshetra 136119, India Institute of Pharmaceutical Sciences, Kurukshetra University, Kurukshetra 136119, India Department of Microbiology, Kurukshetra University, Kurukshetra 136119, India
a r t i c l e
i n f o
Article history: Received 16 August 2014 Revised 23 January 2015 Accepted 4 February 2015 Available online xxxx Keywords: Pyrazole Thiazole Anti-inflammatory activity Antimicrobial activity
a b s t r a c t Current Letter presents design, synthesis and biological evaluation of a novel series of pyrazolylthiazole carboxylates 1a–1p and corresponding acid derivatives 2a–2p. All 32 novel compounds were tested for their in vivo anti-inflammatory activity by carrageenan-induced rat paw edema method as well as for in vitro antimicrobial activity. All the tested compounds exhibited excellent AI activity profile. Three compounds 1p (R = Cl, R1 = Cl), 2c (R = H, R1 = F) and 2n (R = Cl, R1 = OCH3) were identified as potent anti-inflammatory agents exhibiting edema inhibition of 93.06–89.59% which is comparable to the reference drug indomethacin (91.32%) after 3 h of carrageenan injection while most of the other compounds displayed inhibition P80%. In addition, pyrazolylthiazole carboxylic acids (2a–2p) also showed good antimicrobial profile. Compound 2h (R = OCH3, R1 = Cl) showed excellent antimicrobial activity (MIC 6.25 lg/mL) against both Gram positive bacteria comparable with the reference drug ciprofloxacin (MIC 6.25 lg/mL). Ó 2015 Elsevier Ltd. All rights reserved.
Inflammation is the immune response of tissues to external injury which can be categorized as acute or chronic. The former is the initial response of the body to harmful stimulus identified by the increased movement of macrophages and neutrophils in infected tissues while chronic inflammation is due to progressive movement of the mononucleated cells at the injury site leading to destruction of tissues by cell death.1 Anti-inflammatory drugs are known to inhibit one or more isoforms of cyclooxygenase (COX) enzyme that catalyzes the conversion of arachidonic acid (AA) into prostaglandins (PGs) and thromboxanes. COX enzyme is a rate-limiting enzyme that exists in two isoforms; constitutive (COX-1) and inducible (COX-2). COX1 is believed to be a housekeeping enzyme constitutively present in platelets and all tissues. It produces PGs involved in important physiological functions, such as gastric mucosal cytoprotection, renal homeostasis, and platelet aggregation. COX-2 is an inducible, short lived enzyme present in brain, kidney and endothelial cells and facilitates the release of PGs in the inflammatory process.2–4 Conventional non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin and ibuprofen are nonselective inhibitors of both the isoforms of COX thereby leading to a number of renal and ⇑ Corresponding author. Tel.: +91 9416457355; fax: +91 1744 238277. E-mail address: [email protected] (P.K. Sharma).
gastrointestinal (GI) side effects.5 To overcome the gastrointestinal side effects, selective COX-2 inhibitors such as celecoxib,6 rimonabant,7 valdecoxib,8 rofecoxib,9 deracoxib10 etc., which block the production of PGs in inflammatory cells,11 have been developed since 1999. Success of these ‘coxibs’ led to an increased attention towards development of more candidates like the approved COX2 selective inhibitors which are typical models of the diarylheterocycles template.12 Resistance of microbes to existing antimicrobial drugs is a cause of serious concern. Considering the obvious advantages of monotherapy against inflammation as well as microbial infection, research efforts are underway to develop dual anti-inflammatory–antimicrobial drugs with minimum GI side effects and high safety margin.13 Thiazole14–17 and pyrazole nuclei18–23 are ubiquitous motifs representing an interesting array of heterocyclic compounds exhibiting a wide range of biological activities such as antimicrobial, antiinflammatory, antitubercular, anticonvulsant, antitumor etc. Motivated by these findings, and in continuation of our ongoing research program in the field of 4-functionalized pyrazole analogues24–27 and other biologically active heterocyclic compounds28–34 we present in this Letter, design, synthesis and evaluation of pyrazolylthiazole carboxylic acids (2a–2p) and their ester analogues (1a–1p) as dual anti-inflammatory–antimicrobial agents (Fig. 1). Thiazole ring possessing carboxylic group have been incorporated at N-1 position
http://dx.doi.org/10.1016/j.bmcl.2015.02.004 0960-894X/Ó 2015 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Khloya, P.; et al. Bioorg. Med. Chem. Lett. (2015), http://dx.doi.org/10.1016/j.bmcl.2015.02.004
2
P. Khloya et al. / Bioorg. Med. Chem. Lett. xxx (2015) xxx–xxx
Functionalization at 4-position of pyrazole
R1
O
O
OH
O N
4-carbothioamidepyrazoles (10), which were prepared by multistep synthesis. Ethyl 3-aryl-3-oxopropanoates 5 were prepared by the base catalyzed carbethoxylation of the appropriately substituted acetophenones 3 with diethyl carbonate 4. Bromination of 5 was achieved by grinding ethyl 3-aryl-3-oxopropanoates 5 with NBS36 without solvent leading to the exclusive formation of monobrominated pure products 6 in excellent yield. 4-Carbothioamidepyrazoles 10 were synthesized starting from appropriate acetophenones using a multistep strategy involving hydrazone synthesis, Vilsmeier– Haack reaction followed by oxidative amination and subsequent thiolysis of 4-cyanopyrazoles 9 by using H2S gas under basic conditions in the presence of triethylamine as reported recently by our group.25 The target compounds pyrazolylthiazole carboxylates 1a–1p were synthesized by the condensation of appropriate 4-carbothioamidepyrazoles 10 with substituted ethyl 2-bromo-3-aryl3-oxopropanoates (6) in the presence of catalytic amount of glacial acetic acid in refluxing ethanol for 5–6 h. Pyrazolylthiazole carboxylates 1a–1p were converted into corresponding pyrazolylthiazole carboxylic acids 2a–2p following basic hydrolysis of the ester group using sodium hydroxide (NaOH) solution under reflux for 3–4 h in good yield. The newly synthesized target compounds (1a–1p and 2a–2p) were characterized by rigorous analysis of their IR, 1H NMR, 13C NMR and mass spectral data. IR spectra of pyrazolylthiazole
R1
N
S
S R2
R2 N N
N N
1a-1p
2a-2p
Figure 1. Pyrazolylthiazole carboxylates 1a–1p and corresponding carboxylic acids 2a–2p.
of pyrazole ring35 in the past but here in this Letter, to the best of our knowledge, we have introduced the thiazolecarboxylic acid functionality at 4-position of pyrazole ring (1a–1p and 2a–2p) for the first time (Fig. 1). The synthetic strategy adopted for the synthesis of the target compounds is depicted in Scheme 1. The basic requirements for the synthesis of pyrazolylthiazole carboxylic acids (2) were the formation of ethyl 2-bromo-3-aryl-3-oxopropanoates (6) and
Br
O
O
O
O
OC2H5
(a)
+ C2H5O
4
OC2H5
R1
R1
5
6
O
NHNH2 +
N N
N N
(c, d, e) reference 19
7
2
R2
CN
8
9
2
R
R S
NH2 10
N N R2
(h)
R2 N
(g)
(f)
N N
N
S
S OH
OCH2CH3
O
O R1
R1 1
Comp No.
O
(b)
OC2H5
R1 3
O
a
2
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
H OCH3
F
Cl
H
OCH3
F
Cl
H
OCH3
F
Cl
H
OCH3
F
Cl
H
H
H
OCH3
OCH3
OCH3
OCH3
F
F
F
F
Cl
Cl
Cl
Cl
1, 2 R1 2
R
H
Scheme 1. Reagents and conditions: (a) NaH, benzene, diethyl carbonate reflux; (b) NBS, grinding; (c) ethanol–water, reflux; (d) POCl3/DMF, 50–60 °C, 6 h; (e) I2/NH3, THF stir overnight; (f) H2S, NEt3, pyridine, 10–12 h; (g) ethyl 2-bromo-3-aryl-3-oxopropanoate 6, ethanol, 1–2 drops of glacial acetic acid, reflux; (h) NaOH/H2O/C2H5OH, reflux.
Please cite this article in press as: Khloya, P.; et al. Bioorg. Med. Chem. Lett. (2015), http://dx.doi.org/10.1016/j.bmcl.2015.02.004
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P. Khloya et al. / Bioorg. Med. Chem. Lett. xxx (2015) xxx–xxx Table 1 In vivo anti-inflammatory (AI) activity of compounds (1a–1p and 2a–2p) in carrageenan induced rat paw edema assay (acute inflammatory model) Volume of edemaa (mL) and % AIb
Compounds 1h Swelling Control Indomethacin 1a 1b 1c 1d 1e 1f 1g 1h 1i 1j 1k 1l 1m 1n 1o 1p 2a 2b 2c 2d 2e 2f 2g 2h 2i 2j 2k 2l 2m 2n 2o 2p a b
Swelling
93.69 90.99 80.18 73.87 80.18 90.19 86.48 83.78 86.48 76.57 80.18 85.58 84.68 89.89 90.99 83.78 83.78 87.37 82.88 82.88 87.38 81.98 82.88 82.88 83.78 87.38 80.18 79.27 70.27 71.17 86.48 73.87 76.57
1.21 ± 0.16 0.14 ± 0.05* 0.30 ± 0.06* 0.29 ± 0.08* 0.22 ± 0.09* 0.15 ± 0.11* 0.20 ± 0.01* 0.19 ± 0.14* 0.18 ± 0.06* 0.38 ± 0.11* 0.32 ± 0.10* 0.27 ± 0.07* 0.25 ± 0.05* 0.22 ± 0.03* 0.22 ± 0.03* 0.35 ± 0.06* 0.47 ± 0.11* 0.27 ± 0.08* 0.39 ± 0.10* 0.25 ± 0.07* 0.16 ± 0.04* 0.21 ± 0.05* 0.16 ± 0.04* 0.24 ± 0.11* 0.22 ± 0.07* 0.26 ± 0.05* 0.22±0.05* 0.40 ± 0.07* 0.57 ± 0.22* 0.64 ± 0.16* 0.46 ± 0.11* 0.19 ± 0.04* 0.33 ± 0.10* 0.23 ± 0.06*
3h Inhibition (%)
Swelling
88.42 75.20 76.03 81.81 87.60 83.47 84.29 85.12 68.59 73.55 79.33 79.33 81.81 81.81 71.07 61.15 77.68 67.76 79.33 86.77 82.64 86.77 86.77 81.81 78.51 81.81 66.94 52.89 47.10 61.98 89.29 72.72 80.99
1.73 ± 0.09 0.15 ± 0.03* 0.28 ± 0.06* 0.24 ± 0.10* 0.31 ± 0.06* 0.24 ± 0.12* 0.33 ± 0.08* 0.27 ± 0.11* 0.31 ± 0.13* 0.38 ± 0.11* 0.33 ± 0.02* 0.39 ± 0.07* 0.32 ± 0.06* 0.34 ± 0.11* 0.32 ± 0.07* 0.25 ± 0.08* 0.50 ± 0.13* 0.12 ± 0.04* 0.28 ± 0.06* 0.24 ± 0.05* 0.18 ± 0.04* 0.20 ± 0.06* 0.21 ± 0.09* 0.20 ± 0.06* 0.31 ± 0.17* 0.28 ± 0.05* 0.37 ± 0.09* 0.56 ± 0.14* 0.61 ± 0.12* 0.75 ± 0.14* 0.69 ± 0.19* 0.16 ± 0.05* 0.49 ± 0.10* 0.43 ± 0.08*
4h Inhibition (%)
Swelling
Inhibition (%)
91.32 83.81 86.12 82.08 87.23 80.92 84.39 82.08 78.03 80.92 77.45 81.50 80.34 81.50 85.54 71.09 93.06 83.81 86.12 89.59 88.43 87.86 88.43 82.08 83.81 78.61 67.63 64.73 56.14 60.11 90.75 71.67 75.14
1.88 ± 0.20 0.16 ± 0.05* 0.24 ± 0.06* 0.34 ± 0.14* 0.42 ± 0.13* 0.22 ± 0.10* 0.24 ± 0.08* 0.17 ± 0.04* 0.37 ± 0.06* 0.53 ± 0.08* 0.45 ± 0.09* 0.32 ± 0.09* 0.23 ± 0.05* 0.26 ± 0.07* 0.28 ± 0.10* 0.21 ± 0.07* 0.19 ± 0.04* 0.18 ± 0.07* 0.30 ± 0.01* 0.22 ± 0.07* 0.17 ± 0.03* 0.22 ± 0.05* 0.23 ± 0.08* 0.19 ± 0.06* 0.18 ± 0.04* 0.20 ± 0.07* 0.18 ± 0.04* 0.36 ± 0.10* 0.47 ± 0.13* 0.37 ± 0.11* 0.54.0.11* 0.21 ± 0.03* 0.38 ± 0.10* 0.28 ± 0.08*
91.48 87.23 81.91 88.29 87.23 90.95 90.95 80.31 71.80 76.06 82.97 87.76 86.17 85.10 88.92 89.89 90.42 84.04 88.29 90.95 88.29 87.76 89.89 90.42 89.36 90.42 80.85 75.00 80.31 71.27 88.82 79.78 85.10
Significantly different compared to respective control values, P 21 mm against S. aureus as compared to standard drug (24.0 mm). For antifungal activity profile, best antibacterial candidate of the study 2h and 2m were found to also act as the most active antifungal agents with 2h showing zone of inhibition 27.6 mm (MIC 6.25 lg/mL) against both the fungal strain and 2m showing zone of inhibition 26.6 mm (MIC 6.25 lg/mL), 24.6 mm (MIC 6.25 lg/mL) against S. cerevisiae and C. albicans respectively which is better than the reference drug amphotericin B exhibiting 19.3 mm and 16.6 mm zone of inhibition with MIC 6.25 lg/mL. Seven compounds 2a–2d, 2i and 2o–2p displayed zone of inhibition >20 mm against S. cerevisiae while seven other compounds 1g, 1k, 2c, 2i, 2l, 2n and 2p showed zone of inhibition >20 mm against C. albicans. However, none of compounds were active against Gram negative bacteria. In conclusion, synthesis of pyrazolylthiazole carboxylates and their corresponding acids was achieved in good yield and the same were evaluated for their in vivo anti-inflammatory activity as well as for in vitro antimicrobial activity. Compounds 1p (R = Cl, R1 = Cl), 2c (R = H, R1 = F) and 2n (R = Cl, R1 = OCH3) showed significant AI activity ranging from 93.06% to 89.59% comparable to the reference drug indomethacin 3 h after carrageenan injection while 4 h after carrageenan injection, nine compounds 1e–1f, 1o–1p, 2c, 2f–2g, 2i and 2h showed AI activity ranging from 90.95% to 89.36% inhibition comparable to indomethacin (91.48%). In case of antimicrobial profile, it was found that two compounds 2h and 2m were found to be the most active antimicrobial agents while other compounds also exhibited good activity. Thus 2h can be considered as promising potent dual anti-inflammatory–antimicrobial agent.
5
(Haryana), India for the award of Senior Research Fellowships. The authors are thankful to Sophisticated Analytical Instrument Facility, Central Drug Research Institute, Lucknow for providing Mass spectra. Supplementary data Supplementary data (biological assay, experimental procedure and spectroscopic characterization of compounds 1a–1p and 2a–2p) associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.bmcl.2015.02.004. References and notes 1. 2. 3. 4. 5. 6.
7.
8. 9. 10. 11.
12. 13.
14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35.
Acknowledgements 36.
Dinarello, C. A. Cell 2010, 45, 935. Ormrod, D.; Wellington, K.; Wagstaff, A. J. Drugs 2002, 62, 2059. Vane, J. R. Am. J. Med. 1998, 104, 2S. Cryer, B.; Feldman, M. Am. J. Med. 1998, 104, 413. Smith, M. L.; Hawcroft, G.; Hull, M. A. Eur. J. Med. Chem. 2000, 36, 664. Penning, T.; Talley, J.; Bertenshaw, S.; Carter, J.; Callins, P.; Doctor, S.; Graneto, M.; Lee, L.; Malecha, J.; Miyashiro, J.; Rogers, R.; Rogeier, D.; Yu, S.; Anderson, G.; Burton, E.; Cogburn, J.; Gregory, S.; Koboldt, C.; Perkins, W.; Seibert, K.; Veenhuizen, A.; Zhang, Y.; Isakson, P. J. Med. Chem. 1997, 40, 1347. Rinaldi-Carmona, M.; Barth, F.; Heaulme, M.; Shire, D.; Calandra, B.; Congy, C.; Martinez, J.; Neliat, G.; Caput, D.; Ferrara, P.; Soubrie, P.; Breliere, J. C.; Le Fur, G. FEBS Lett. 1994, 350, 240. Nussmeier, N. A.; Whelton, A. A.; Brown, M. T.; Langford, R. M.; Hoeft, A.; Parlow, J. L.; Boyce, S. W.; Verburg, K. M. N. Engl. J. Med. 2005, 352, 1081. Scheen, A. J. Rev. Med. Liege 2004, 59, 565. Sessions, J. K.; Reynolds, L. R.; Budsberg, S. C. Am. J. Vet. Res. 2005, 66, 812. Song, Y.; Connor, D. T.; Sercel, A. D.; Sorenson, R. J.; Double-day, R.; Unangst, P. C.; Roth, B. D.; Beylin, V. G.; Gilbertsen, R. B.; Chan, K.; Schrier, D. J.; Guglietta, A.; Bornemeier, D. A.; Dyer, R. D. J. Med. Chem. 1999, 42, 1161. Palomer, A.; Cabre, F.; Pascual, J.; Campos, J.; Trujillo, M. A.; Entrena, A.; Callo, M. A.; Garcia, L.; Mauleon, D.; Espinosa, A. J. Med. Chem. 2002, 45, 1402. Giulia, M.; Luisa, M.; Paola, F.; Silvia, S.; Angelo, R.; Luisa, M.; Francesco, B.; Roberta, L.; Chiara, M.; Valeria, M.; Paolo, L. C.; Elena, T. Bioorg. Med. Chem. 2004, 12, 5465. Rostom, S. A. F. Bioorg. Med. Chem. 2006, 14, 6469. Chang, S.; Zhang, Z.; Zhuang, X.; Luo, J.; Cao, X.; Li, H.; Tu, Z.; Lu, X.; Ren, X.; Ding, K. Bioorg. Med. Chem. Lett. 2012, 22, 1208. Bondock, S.; Naser, T.; Ammar, Y. A. Eur. J. Med. Chem. 2013, 62, 270. EI-Sayed, M. A. A.; Abdel-Aziz, N. I.; Abdel-Aziz, A. A. M.; EI-Azab, A. S.; Asiri, Y. A.; EI-tahir, K. E. H. Bioorg. Med. Chem. 2011, 19, 3416. Li, M.; Zhao, B. X. Eur. J. Med. Chem. 2014, 85, 311. Pinna, G.; Loriga, G.; Lazzari, P.; Ruiu, S.; Falzoi, M.; Frau, S.; Pau, A.; Murineddu, G.; Asproni, B.; Pinna, G. A. Eur. J. Med. Chem. 2014, 82, 281. Mert, S.; Kasimogullari, R.; Ica, T.; Colak, F.; Altun, A.; Ok, S. Eur. J. Med. Chem. 2014, 78, 86. Ningaiah, S.; Bhadraiah, U. K.; Doddaramappa, S. D.; Keshavamurthy, S.; Javarasetty, C. Bioorg. Med. Chem. Lett. 2014, 24, 245. Wang, S. F.; Zhu, Y. L.; Zhu, P. T.; Makawana, J. A.; Zhang, Y. L.; Zhao, M. Y.; Lv, P. C.; Zhu, H. L. Bioorg. Med. Chem. 2014, 22, 6201. Tewari, A. K.; Singh, V. P.; Yadav, P.; Gupta, G.; Singh, A.; Goel, R. K.; Shinde, P.; Mohan, G. C. Bioorg. Chem. 2014, 56, 8. Sharma, P. K.; Kumar, S.; Kumar, P.; Kaushik, P.; Kaushik, D.; Dhingra, Y.; Aneja, K. R. Eur. J. Med. Chem. 2010, 45, 2650. Sharma, P. K.; Chandak, N.; Kumar, P.; Sharma, C.; Aneja, K. R. Eur. J. Med. Chem. 2011, 46, 241. Khloya, P.; Kumar, P.; Mittal, A.; Aggarwal, N. K.; Sharma, P. K. Org. Med. Chem. Lett. 2013, 3, 1. Khloya, P.; Celik, G.; Ram, S.; Vullo, V.; Supuran, C. T.; Sharma, P. K. Eur. J. Med. Chem. 2014, 76, 284. Chandak, N.; Kumar, P.; Kaushik, P.; Varshney, P.; Sharma, C.; Kaushik, D.; Jain, S.; Aneja, K. R.; Sharma, P. K. J. Enzyme Inhib. Med. Chem. 2014, 29, 476. Chandak, N.; Bhardwaj, J. K.; Sharma, R. K.; Sharma, P. K. Eur. J. Med. Chem. 2013, 59, 203. Kumar, P.; Chandak, N.; Nielsen, N.; Sharma, P. K. Bioorg. Med. Chem. 2010, 15, 4336. Ram, S.; Celik, G.; Khloya, P.; Vullo, D.; Supuran, C. T.; Sharma, P. K. Bioorg. Med. Chem. 2014, 22, 1873. Kumar, S.; Namkung, W.; Verkman, A. S.; Sharma, P. K. Bioorg. Med. Chem. 2012, 20, 4237. Chandna, N.; Kumar, S.; Kaushik, P.; Kaushik, D.; Roy, S. K.; Gupta, G. K.; Jachak, S. M.; Kapoor, J. K.; Sharma, P. K. Bioorg. Med. Chem. 2013, 21, 4581. Sharma, P. K.; Sawhney, S. N. Bioorg. Med. Chem. Lett. 1997, 7, 2427. Atobe, M.; Naganuma, K.; Kawanishi, M.; Morimoto, A.; Kasahara, K. I.; Ohashi, S.; Suzuki, H.; Hayashi, T.; Miypshi, S. Bioorg. Med. Chem. Lett. 2013, 23, 6569. Pravst, I.; Zupan, M.; Stavber, S. Green Chem. 2006, 8, 1001.
One of the authors (Poonam Khloya) is grateful to the Haryana State Council for Science and Technology (HSCST), Panchkula Please cite this article in press as: Khloya, P.; et al. Bioorg. Med. Chem. Lett. (2015), http://dx.doi.org/10.1016/j.bmcl.2015.02.004
