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Home » Preclinical drugs » Synthesis, biological evaluation and docking analysis of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones as potential cyclooxygenase-2 (COX-2) inhibitors

Synthesis, biological evaluation and docking analysis of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones as potential cyclooxygenase-2 (COX-2) inhibitors



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COMPD HAS  cas no 1616882-93-9

MF……….C18 H11 F3 N2 O2
[1]​Benzopyrano[4,​3-​c]​pyrazol-​4(1H)​-​one, 3-​methyl-​1-​[4-​(trifluoromethyl)​phenyl]​-



Synthesis, biological evaluation and docking analysis of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones as potential cyclooxygenase-2 (COX-2) inhibitors

DOI: 10.1016/j.bmcl.2014.08.050

Jagdeep Grover, Vivek Kumar, M. Elizabeth Sobhia, Sanjay M. Jachak


As a part of our continued efforts to discover new COX inhibitors, a series of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones were synthesized and evaluated for in vitro COX inhibitory potential. Within this series, seven compounds (3ad, 3h, 3k and 3q) were identified as potential and selective COX-2 inhibitors (COX-2 IC50’s in 1.79–4.35 μM range; COX-2 selectivity index (SI) = 6.8–16.7 range). Compound 3b emerged as most potent (COX-2 IC50 = 1.79 μM; COX-1 IC50 >30 μM) and selective COX-2 inhibitor (SI >16.7). Further, compound 3b displayed superior anti-inflammatory activity (59.86% inhibition of edema at 5 h) in comparison to celecoxib (51.44% inhibition of edema at 5 h) in carrageenan-induced rat paw edema assay. Structure–activity relationship studies suggested that N-phenyl ring substituted with p-CF3 substituent (3b, 3k and 3q) leads to more selective inhibition of COX-2. To corroborate obtained experimental biological data, molecular docking study was carried out which revealed that compound 3b showed stronger binding interaction with COX-2 as compared to COX-1.


  • a Department of Natural Products, National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar (Mohali) 160062, Punjab, India
  • b Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar 160062, Punjab, India

Sanjay Corresponding author. Tel.: +91 172 2214683; fax: +91 172 2214692.


Cyclooxygenase (COX) or prostaglandin endoperoxide synthase (PGHS), catalyzes the conversion of arachidonic acid to inflammatory mediators such as prostaglandins (PGs), prostacyclins and thromboxanes. COX exists in mainly two isoforms: COX-1 and COX-2. Nonsteroidal anti-inflammatory drugs (NSAIDs), widely used for relief of fever, pain and inflammation, act by inhibiting COX catalyzed biosynthesis of inflammatory mediators.

However, the therapeutic use of classical NSAIDs is associated with well-known side effects at the gastrointestinal level (mucosal damage, bleeding) and, less frequently, at the renal level.

Two decades after the discovery of COX isoforms, it was recognized that selective inhibition of COX-2 might be endowed with improved anti-inflammatory properties and reduced gastrointestinal toxicity profiles than classical NSAIDs.

Overall, these selective COX-2 inhibitors (coxibs) have fulfilled the hope of possessing reduced risk in gastrointestinal events, but unfortunately cardiovascular concerns regarding the use of these agents have emerged that led to the withdrawal of rofecoxib (Vioxx) and valdecoxib (Bextra) from the market in 2004 and 2005, respectively.

Ongoing safety concerns pertaining to the use of non-selective NSAIDs have spurred development of coxibs with improved safety profile.


cas no 1616882-93-9

mf……….C18 H11 F3 N2 O2
[1]​Benzopyrano[4,​3-​c]​pyrazol-​4(1H)​-​one, 3-​methyl-​1-​[4-​(trifluoromethyl)​phenyl]​-


Full-size image (21 K)

Scheme 1.

Reagent and conditions: (a) Piperidine, rt, 20 min; (b) ArNHNH2, EtOH, reflux, 5 h; (c) K2CO3, acetone, reflux, 24 h.


3b R1=H R2= H 4-CF3-C6H4 90
3-Methyl-1-(4-(trifluoromethyl)phenylchromeno[4,3-c]pyrazol-4(1H)-one (3b):
White solid; yield 90%; mp: 224–225 °C;
1H NMR (CDCl3, 400 MHz): δ ppm 7.89 (d, 2H, J = 8.32 Hz, Ar-H), 7.73 (d, 2H, J = 8.24 Hz, Ar-H), 7.45–7.52 (m, 2H, H-6, H-7), 7.16 (dd, 1H, J = 1.4, 8.2 Hz, H-9), 7.10 (td, 1H, J = 1.56, 7.38 Hz, H-8), 2.69 (s, 3H, CH3);
13C NMR (CDCl3, 100 MHz): δ ppm 157.7, 153.3, 151.5, 142.3, 141.8, 131.9, 127.2, 127.1, 127.0, 124.0, 122.2, 118.3, 111.5, 107.1, 12.8;
HRMS (ESI) m/z: Calcd for C18H11F3N2O2Na [M + Na]+ 367.0670; found 367.0676.

Synthetic Communications (2014), 44(13), 1914-1923


Jagdeep Grovera, Somendu Kumar Roya & Sanjay Madhukar Jachaka*

pages 1914-1923


Unprecedented cyclization was observed during N-sulfonylation of 3-[1-(phenylhydrazono)-ethyl]-chromen-2-one in pyridine, affording 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones. To avoid use of noxious pyridine, reaction was tried in different basic conditions and the best results were obtained with potassium carbonate in acetone. A wide range of substrates bearing either electron-donating or electron-withdrawing substituents on phenylhydrazine ring were compatible with the developed methodology. Rapid access of starting material, 3-acetylcoumarin, excellent yields of products, and use of environmentally benign base and solvent for the cyclization make this strategy an efficient and convenient method for synthesis of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones.


Methyl-1-(4-(trifluoromethyl)phenylchromeno[4,3-c]pyrazol-4(1H)-one (4b):
yield 90%; mp: 224–225 °C;
1H NMR (CDCl3, 400 MHz):δppm 2.69 (s, 3H, CH3),
7.10(td, 1H,J= 1.56, 7.38 Hz, H-8),
7.16 (dd, 1H,J= 1.4, 8.2 Hz, H-9),
7.45–7.52 (m, 2H, H-6, H-7),
7.73 (d, 2H,J= 8.24 Hz, Ar-H),
7.89 (d, 2H,J= 8.32 Hz, Ar-H);
13C NMR (CDCl3, 100MHz):
δppm 12.8, 107.1, 111.5, 118.3, 122.2, 124.0,
127.0, 127.1, 127.2, 131.9, 141.8, 142.3,
151.5, 153.3, 157.7;
HRMS (ESI)m/z: Calcd for C18H11F3N2O2Na [M + Na]+367.0670; found367.0676.





1. Jones, G.; Willett, P.; Glen, R. C.; Leach, A. R.; Taylor, R. J. Mol. Biol. 1997, 267, 727.
2. Bernstein, F. C.; Koetzle, T. F.; Williams, G. J. B.; Meyer, E. F.; Brice, M. D.; Rodgers, J. R.; Kennard, O.; Shimanouchi, T.; Tasumi, M. J. Mol. Biol. 1977, 112, 535.

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DR ANTHONY MELVIN CRASTO, Born in Mumbai in 1964 and graduated from Mumbai University, Completed his Ph.D from ICT, 1991,Matunga, Mumbai, India, in Organic Chemistry, The thesis topic was Synthesis of Novel Pyrethroid Analogues, Currently he is working with AFRICURE PHARMA as ADVISOR, earlier assignment was with GLENMARK LIFE SCIENCES LTD, as CONSUlTANT, Retired from GLENMARK in Jan2022 Research Centre as Principal Scientist, Process Research (bulk actives) at Mahape, Navi Mumbai, India. Total Industry exp 32 plus yrs, Prior to joining Glenmark, he has worked with major multinationals like Hoechst Marion Roussel, now Sanofi, Searle India Ltd, now RPG lifesciences, etc. He has worked with notable scientists like Dr K Nagarajan, Dr Ralph Stapel, Prof S Seshadri, etc, He did custom synthesis for major multinationals in his career like BASF, Novartis, Sanofi, etc., He has worked in Discovery, Natural products, Bulk drugs, Generics, Intermediates, Fine chemicals, Neutraceuticals, GMP, Scaleups, etc, he is now helping millions, has 9 million plus hits on Google on all Organic chemistry websites. His friends call him Open superstar worlddrugtracker. His New Drug Approvals, Green Chemistry International, All about drugs, Eurekamoments, Organic spectroscopy international, etc in organic chemistry are some most read blogs He has hands on experience in initiation and developing novel routes for drug molecules and implementation them on commercial scale over a 32 PLUS year tenure till date Feb 2023, Around 35 plus products in his career. He has good knowledge of IPM, GMP, Regulatory aspects, he has several International patents published worldwide . He has good proficiency in Technology transfer, Spectroscopy, Stereochemistry, Synthesis, Polymorphism etc., He suffered a paralytic stroke/ Acute Transverse mylitis in Dec 2007 and is 90 %Paralysed, He is bound to a wheelchair, this seems to have injected feul in him to help chemists all around the world, he is more active than before and is pushing boundaries, He has 100 million plus hits on Google, 2.5 lakh plus connections on all networking sites, 100 Lakh plus views on dozen plus blogs, 227 countries, 7 continents, He makes himself available to all, contact him on +91 9323115463, email, Twitter, @amcrasto , He lives and will die for his family, 90% paralysis cannot kill his soul., Notably he has 38 lakh plus views on New Drug Approvals Blog in 227 countries...... , He appreciates the help he gets from one and all, Friends, Family, Glenmark, Readers, Wellwishers, Doctors, Drug authorities, His Contacts, Physiotherapist, etc He has total of 32 International and Indian awards

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