INTRODUCTION:

Coronavirus Disease 2019 is mainly caused by SARS-CoV-2 which was affected in more than 200 countries^1-3. According to World Health Organization, at the end of May 2021, there are more than 173 million peoples (28.8 million in India) are affected by COVID19 in the world, out of these more than 3.7 million people (3.4 lakhs in India) are died. The COVID-19 affected patients are mainly more asymptomatic^4-7. So it is worthy consideration, to understand about the SARS-CoV-2, SARS CoV and MERS-CoV discuss about the inactivation of pathogen^8-13.

The corona virus is vigorously spread from human to human. In the pandemic situation, to discover some drugs for COVID19 is very important^14,15.

Because of COVID19 cases are increased more aggressively in day by day, the determination of some drugs for treatment of COVID19 is most important task mainly for target-based inhibitors.

In our continuous research of searching the novel compounds for various biological activities^16-26 by using in-silico design and also by wet lab methods, we are designed some heterocyclic compounds and evaluation of biological activities. In Schrödinger suite LLC, there are various modules like Glide, Qikprop and Prime etc. are involved in computational methods like docking, ADMET screening and binding energy calculations etc to find the affinities and interactions which are responsible for SARS-CoV-2 Mpro inhibition. The in-silico studies may be provide key structural features to design of the potential drugs.

From the literatures, various biological activities of 9-Anilinoacridines have reported such as antimicrobial²⁷, anticancer^28-30, analgesic³¹, antioxidant³², antimalarial³³, antileishmanial³⁴, antinociceptive³⁵, and antiherpes³⁶ etc. The 9-anilinoacridine derivatives are reported as primary DNA-intercalating agent³⁷. Likewise, the biological activities of pyrazole derivatives are also reported^38-45 like anti-tumour, antimicrobial activities etc. In continuous of our previous research, we have designed 9-anilinoacridine analogs substituted with pyrazole moieties by docking studies by using the Schrodinger suit-2019-4 software. The outcomes of the research that some of the designed 9-anilinoacridines 1a-z have significant inhibitor against SARS CoV2 Mpro.

METHODS:

Molecular Docking:

The SARS-CoV-2 Mpro receptor 3D crystal structure which is co-crystallized with ligand 6-(ethylamino) pyridine-3-carbonitrile (5R82.pdb, Resolution: 1.3Å) was downloaded from RSCB protein data bank. Epic module in the Schrödinger suite 2019-4 was used to prepare protein with protein preparation wizard⁴⁶. The protein is prepared by deleting unnecessary waters beyond 5 Å, addition of hydrogens and refine bond orders. Prime module was used to fill the missing chain atoms. Protein energy was minimized by Optimized Potentials for Liquid Simulations-3 (OPLS3) force field with RMSD value 0.30 Å. Then grid box are generated for the centroid of active binding site. By using ligprep module, the ligands are prepared and docked in to active site of SARS CoV-2 Mpro by Extra precision (XP) mode using Glide module. The binding affinity modes with significant G score⁴⁷ have good binding affinities with receptor.

The in-silico ADMET properties for the designed compounds are calculated by qikprop module⁴⁷.

MM-GBSA Binding free energy:

The binding free energy of the receptor- ligand complex was predicted and post dock energy were performed by Prime MM-GB/SA (Molecular Mechanics-Generalized Born Surface Area) of Schrödinger suit 2019-4. The OPLS3 force ﬁeld was used to minimize energy for ligand-receptor complex and GB/SA with VSGB 2.0 solvent model⁴⁸.

RESULTS AND DISCUSSION:

Results of in-silico methods are summarized in Table 1-3 and Figure 1-6. From the results the SARS-CoV-2 main protease inhibitory of the compounds 1a-z are greatly depends on various substituents. The pyrazole substituted 9-anilinoacridines 1a-z structures of are given in the figure 1.

The docking of the ligands with receptor active sites are performed by using Glide module of Maestro-12.2 to determine the binding affinities of the designed ligands. The ligands 1a-z were subjected for docking towards SARS-CoV-2 Mpro (5R82) to check their inhibitory property. The molecules show RMSD value 0.3. From the Table 1, the ligands 1t and 1m are significantly inhibit SARS CoV-2 Mpro with G-score greater than -5.7, when compared to Hydroxy chloroquine (G Score: -5.47) and co-crystallized ligand 6-(ethylamino)pyridine-3-carbonitrile(G Score: -4.40). . The molecules 1t and 1m have significant affinity with receptor mainly due to the lipophilic parameter and H-bonding interactions.

Figure-1 Structures of compounds 1a-z

The results were summarized in Table1. The best binding affinity modes for all the docked ligands 1a-z against SARS-CoV-2 Mpro were shown in figure 2. Almost all the compounds are bounded in the same binding pocket.

Table-1 Docking studies for Pyrazole substituted 9-anilinoacridines with SARS-CoV-2 main protease (5R82)

Cpd	Glide score	Lipophilic EvdW	H Bond	XP Electro	Low MW	Rot Penal	XP Penalties
1t	-6.076	-5.424	-0.092	-1.566	0	0.136
1m	-5.74	-5.738	-0.971	-0.09	-0.072	0.185	0
1j	-5.352	-5.133	-0.724	-0.247	-0.065	0.184	0
1o	-5.289	-6.195	-0.145	-0.019	0	0.207	0
1v	-5.207	-5.845	-0.281	0.043	0	0.136	0
1g	-5.17	-6.148	-0.186	-0.007	-0.025	0.175	0
1q	-5.106	-5.989	-0.334	-0.032	0	0.15	0
1s	-5.069	-5.568	-0.101	0.041	0	0.164	0
1w	-5.055	-5.683	-0.042	-0.003	0	0.155	0
1d	-4.792	-5.498	-0.38	-0.017	-0.078	0.187	0
1y	-4.77	-5.823	-0.173	-0.142	0	0.162	0
1k	-4.656	-5.675	-0.169	-0.136	-0.065	0.184	0
1a	-4.535	-5.376	-0.122	0.042	0	0.145	0
1u	-4.411	-4.89	-0.651	-0.413	0	0.136	0
1b	-4.239	-5.261	-0.083	0.184	0	0.145	0
1f	-4.212	-3.766	-0.7	-0.221	-0.078	0.187	0
1h	-4.134	-4.789	-0.7	-0.262	-0.025	0.175	0
1i	-4.134	-4.789	-0.7	-0.262	-0.025	0.175	0
1l	-4.079	-5.901	-0.258	-0.056	0	0.165	0
1c	-3.856	-4.629	-0.197	-0.387	0	0.145	1
1x	-3.794	-4.978	-0.378	-0.346	0	0.141	0
1r	-3.661	-4.498	-0.648	-0.265	-0.018	0.174	0
1e	-3.652	-4.534	-0.7	-0.178	-0.078	0.187	0
Hydroxy chloroquine (Std)	-5.47	-3.15	-1.75	-0.69	-0.38	0.5	0
6-(ethylamino) pyridine-3-carbonitrile (Co-crystallized ligand)	-4.40	-2.9	-0.7	-0.19	-0.5	0.29	0

Fig-2 Docked poses of all compounds 1a-z with SARS-CoV-2 main protease (5R82)

From the results docking studies, many compounds have similar interactions with SARS-CoV-Mpro and the aminoacids GLN19, THR25, THR24, LEU27, THR26, HIE41, MET49, SER46, GLN189, ARG188, ASP187, VAL186, MET165, HIE164, ASN142 and GLY143 play major role in binding to the ligands. The 2D-ligand interaction of compounds 1t and 1m with SARS-CoV-2 are given in the figures 3.

Fig-3 Ligand Interaction of compound 1t & 1m with SARS-CoV-2 Mpro (5R82)

From the results, it was revealed that the molecules have shown agreeable Glide scores for compound 1t (-6.07 Kcal/mol) and compound 1m (-5.74 Kcal/mol) when compared to currently recommended drug for COVID19 Hydroxychloroquine (G Score -5.47). From the results, it was revealed that the compounds are showed hydrophobic and H-bond interactions with many amino acids between GLN19 and GLN189 in the binding pocket (figure 4). The compound 1m was exhibited hydrogen bonding interaction with THR118 (H-Bond lengh 2.44A^o) and ASN119 (H-Bond lengh 1.98 A^o) residues and also with some water molecules are given in the figure 5. The aromatic features of acridine and pyrazoles mainly contributed by the lipophilic interactions (figure 6).

Compound 1t (G Score: -6.08 )

Compound 1m(G Score: -5.74)

Compound 1j (G Score: -5.35)

Compound 1o(G Score: --5.29)

Figure- 4 Best affinity mode of docked compounds with SARS-CoV-2 Mpro (5R82)

Figure- 5 H-bonding interaction of compound 1m with SARS-CoV-2 Mpro (5R82)

Figure- 6 Hydrophilic/lipophilic map of compound 1t with SARS-CoV-2 Mpro (5R82)

The ADMET screening of the designed ligands are predicted in-silico by using qikprop module. From the results, the ADMET parameters for most the designed ligands are within the suggested values which are given in Table2.

The stability of docked complex was assessed by MM-GBSA binding free energy by the post scoring approach for SARS-CoV-2 Mpro (5R82) target and values are shown in the Table 3. From the MM-GBSA results, the dG bind values are in the range of -30.99 (cpd 1g) to -55.51Kcal/mol (cpd 1b) for significant active molecules and also dG lipophilic, dGvdw energy values which are positively contributing for total binding energy. The stability of docking complex is confirmed from the lowest binding energy poses which predicted by MM-GBSA free energy scoring function.

Table-2 In-silico ADMET screening for Pyrazole substituted 9-anilinoacridines

Compounds	Mol. Wt.	Dipole	Donor HB	Accpt HB	QPlog o/w	#metab	Rule of Five	%Human Oral Absorption
1a	491.389	6.387	2	2.5	7.016	2	1	100
1b	491.389	5.886	2	2.5	7.125	2	1	100
1c	491.389	4.139	2	2.5	7.129	2	1	100
1d	426.52	6.28	2	2.5	6.797	3	1	100
1e	426.52	6.672	2	2.5	6.873	3	1	100
1f	426.52	6.864	2	2.5	6.872	3	1	100
1g	442.519	7.985	2	3.25	6.716	3	1	100
1h	442.519	7.401	2	3.25	6.664	3	1	100
1i	442.519	7.401	2	3.25	6.664	3	1	100
1j	430.483	4.485	2	2.5	6.718	2	1	100
1k	430.483	4.006	2	2.5	6.789	2	1	100
1l	457.49	8.92	2	3.5	5.959	3	1	95.518
1m	428.492	7.246	3	3.25	5.731	3	1	100
1n	440.546	6.821	2	2.5	7.232	3	1	100
1o	456.546	5.888	2	3.25	7.082	3	1	100
1p	456.546	6.604	2	3.25	7.133	3	1	100
1q	481.383	6.373	2	2.5	7.412	2	1	100
1r	444.492	7.838	4	4	5.164	4	1	84.659
1s	458.518	7.818	3	4	5.985	4	1	100
1t	507.388	7.735	3	3.25	6.219	3	2	89.691
1u	507.388	6.302	3	3.25	6.555	3	2	89.131
1v	507.388	7.562	3	3.25	6.394	3	2	92.096
1w	472.545	5.443	2	4	6.819	4	1	100
1x	497.382	6.664	3	3.25	6.719	3	1	100
1y	460.965	4.058	2	2.5	7.297	3	1	100
1z	502.571	7.216	2	4.75	6.809	5	2	100
Hydroxychloroquine(std)	335.876	6.854	2	5.7	3.369	5	0	93.213
Recommended values	130-725	1-12.5	0– 6	2-20	-2-6.5	1 – 8	max 4	>80% is high <25% is poor

Table 3. Binding free energy calculation using Prime/MM-GBSA approach

Compd	MMGBSA_ dG_Bind	MMGBSA _dG_Bind_ Coulomb	MMGBSA _dG_Bind_ Covalent	MMGBSA_dG_Bind Hbond	MMGBSA _dG_Bind_ Lipo	MMGBSA_dG_Bind_vdW
1t	-40.8934	3.3008	-2.4885	0.0132	-17.0854	-47.1839
1m	-34.5511	2.0548	0.5712	2.3985	-19.4849	-42.2665
1j	-44.0509	-10.5992	-4.4535	1.7879	-12.3756	-32.9326
1o	-44.1076	-4.3237	8.9740	-0.0282	-17.7875	-50.3493
1v	-44.2857	-16.9709	16.0430	0.3358	-21.9537	-44.0201
1g	-30.9940	-5.3359	-1.9914	0.8414	-13.8936	-38.7015
1q	-44.2321	9.1512	-1.8337	0.0394	-14.2743	-43.0246
1s	-39.5822	-6.3367	3.5711	-1.2306	-15.8258	-30.7078
1w	-43.6721	2.8862	3.0545	1.3965	-13.8844	-54.1488
1d	-37.3820	16.1365	-4.0676	1.4202	-18.9833	-45.4262
1y	-35.4791	4.1133	3.1869	2.4399	-16.4169	-45.4761
1k	-40.6216	10.8215	-3.1261	1.0787	-17.1737	-39.1478
1a	-40.3259	-16.463	3.4383	-0.9626	-13.9651	-34.6412
1u	-33.9486	-13.2359	1.7711	0.4676	-16.0638	-28.4883
1b	-55.5076	-31.7170	6.7474	-2.6265	-15.2540	-35.6830
1f	-49.8973	-35.5645	15.5323	-2.0750	-16.6723	-33.6069
1h	-38.0701	-20.4441	0.78004	0.4122	-16.1061	-34.7814
1i	-38.0701	-20.4441	0.7800	0.4122	-16.1061	-34.7814
1l	-35.7492	15.5702	-8.3705	1.6287	-17.1136	-49.8675
1c	-36.9850	1.8875	-0.0108	2.8952	-15.5608	-39.4340
1x	-39.0372	-6.4394	3.1295	1.9501	-22.4468	-42.1313
1r	-35.7532	-8.6493	2.9639	0.1015	-13.6054	-26.4266
1e	-39.9204	-6.2329	-5.3781	1.1780	-15.3601	-40.0271
Hydroxy Chloroquine(std)	-26.9975	-4.9621	2.1824	0.0011	-9.2894	-33.0622

CONCLUSION:

The docking study of pyrazole substituted 9-anilinoacridines 1a-z revealed that the better arrangement in the dynamic site of SARS-CoV-2 main protease target. The in-silico investigation of some lead molecules helped for the recognizing and future determinations of in-vitro and in-vivo investigations. From in-silico study, the compounds 1t and 1m may be significantly inhibit SARS-CoV-2 Mpro and may be active against COVID19 and probably helpful after further development and refinement.

REFERENCES:

1. Wang D., Hu B., Hu C. Clinical Characteristics of 138 Hospitalized Patients with 2019 Novel Coronavirus-Infected Pneumonia in Wuhan, China. JAMA.; 2020, doi: 10.1001/jama.2020.1585.

2. Holshue M.L,. DeBolt C., Lindquist S, First Case of 2019 Novel Coronavirus in the United States. The New Engl J Med.; 2020, doi: 10.1056/NEJMoa2001191.

3. Yadi Zhou, Yuan Hou, Jiayu Shen, Yin Huang, William Martin, Feixiong Cheng, Network-based drug repurposing for novel coronavirus 2019-nCoV/SARS-CoV-2. Cell Discovery. 2020, 6:14-18.

4. Gu J., Han B., Wang J., COVID-19: Gastrointestinal manifestations and potential fecal-oral transmission. Gastroenterology. 2020. doi: https://doi.org/10.1053/j.gastro.2020.02.054.

5. Calisher C., Carroll D., Colwell R., Corley R.B., Daszak P., Drosten C., Enjuanes L., Farrar J., Field H., Golding J., Statement in support of the scientists, public health professionals, and medical professionals of China combatting COVID-19. Lancet. 2020, 395(10226):42–43.

6. To K.K., Tsang O.T., Chik-Yan Yip C. Consistent detection of 2019 novel coronavirus in saliva. Clinical Infectious Diseases. 2020, doi: 10.1093/cid/ciaa149.

7. Lu R., Zhao X., Li J. Genomic characterisation and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding. Lancet. 2020, doi: 10.1016/S0140-6736(20)30251-8.

8. Zhou P., Yang X.L., Wang X.G. A pneumonia outbreak associated with a new coronavirus of probable bat origin. Nature. 2020, doi: 10.1038/s41586-020-2012-7.

9. Huang Q., Herrman, A. Fast assessment of human receptor-binding capability of 2019 novel coronavirus (2019-nCoV). Bio Rxiv. 2020, doi: 10.1101/2020.02.01.930537

10. Zhang H., Kang Z.J., Gong H.Y., The digestive system is a potential route of 2019-nCov infection: a bioinformatics analysis based on single-cell transcriptomes. bioRxiv 927806. 2020, doi: 10.1101/2020.01.30.927806.

11. Kalirajan Rajagopal, Gowramma Byran, Srikanth Jupudi and R. Vadivelan. Activity of Phytochemical constituents of Black Pepper, Ginger and Garlic against Coronavirus (COVID19): An In-silico approach, Int J Health and Allied Sci. 2020, 9:S43- 50. DOI:10.4103/ijhas.IJHAS_55_20.

12. Rajagopal Kalirajan. Activity of some novel Chalcone substituted 9-anilinoacridines against Coronavirus (COVID19): A computational approach, Coronaviruses, 2020, 1(1):63-71. DOI : 10.2174/2666796701999200625210746.

13. Kalirajan Rajagopal, Potlapati Varakumar, Baliwada Aparna, Gowramma Byran and Srikanth Jupudi. Identification of some novel Oxazine substituted 9-anilinoacridines as SARS-CoV-2 inhibitors for COVID-19 by Molecular docking, Free energy calculation and molecular dynamics studies. J Biomol. Str Dyn. 2020, https://doi.org/10.1080/07391102.2020.1798285

14. Chang L., Yan Y., Wang L. Coronavirus Disease 2019: Coronaviruses and Blood Safety. Transfusion Med. Rev. 2020, https://doi.org/10.1016/j.tmrv.2020.02.003.

15. Huang C., Wang Y., Li X., Ren L., Zhao J., Hu Y. Clinical features of patients infected with 2019 novel coronavirus in Wuhan. China. Lancet. 2020, https://doi.org/10.1016/s0140-6736(20)30183-5.

16. Kalirajan R., Mohammed rafick M.H., Sankar S., Gowramma B. Green synthesis of some novel chalcone and isoxazole substituted 9-anilinoacridine derivatives and evaluation of their antimicrobial and larvicidal activities. Indian J Chem. 2018, 57B:583-90.

17. Gomathy Subramnian, Kalirajan Rajagopal, Farhath Sherin. Molecular Docking Studies, In silico ADMET Screening of Some Novel Thiazolidine Substituted Oxadiazoles as Sirtuin 3 Activators Targeting Parkinson’s Disease. Research J. Pharm. and Tech 2020; 13(6): 2708-2714. DOI: 10.5958/0974-360X.2020.00482.5

18. Kalirajan R., Muralidharan V., Jubie S., Gowramma B., Gomathy S., Sankar S., Elango K. Synthesis of some novel pyrazole substituted 9-anilinoacridine derivatives and evaluation for their antioxidant and cytotoxic activities. J Heterocycl Chem. 2012, 49:748-54.

19. Kalirajan R., Mohammed rafick M.H., Jubie S., Sankar S. Docking studies, synthesis, characterization and evaluation of their antioxidant and cytotoxic activities of some novel isoxazole substituted 9-anilinoacridine derivatives. The Sci World J. 2012, 165258, doi:10.1100/2012/165258.

20. Kalirajan R., Vivek kulshrestha, Sankar S., Jubie S. Docking studies, synthesis, characterization of some novel oxazine substituted 9-anilinoacridine derivatives and evaluation for their anti-oxidant and anticancer activities as topo isomerase II inhibitors. Eur J Med Chem. 2012,56,:217-224.

21. Kalirajan R,, Leela Rathore, Jubie S., Gowramma B., Gomathy S., Sankar S., Microwave assisted synthesis of some novel pyrazole substituted benzimidazoles and evaluation of their biological activities. Indian J Chem. 2011, 50B:1794-1801.

22. Kalirajan R., Sankar S., Jubie S., Gowramma B. Molecular Docking studies and in-silico ADMET Screening of Some novel Oxazine substituted 9-Anilinoacridines as Topoisomerase II Inhibitors. Indian J Pharm Edu and Res. 2017, 51(1):110-115.

23. Elizabeth Eldhose, Gowramma B., Manal Mohammed, Kalirajan R., Kaviarasan L., Translational Chemotherapy for triple negative Breast Cancer - A Review on significance of poly (ADP-ribose) polymerase 1 (PARP 1) inhibitors, Research J. Pharm. and Tech. 2019,12(6):3098-3104. doi: 10.5958/0974-360X.2019.00524.9.

24. Kalirajan R., Gaurav K., Pandiselvi A., Gowramm, B., Sanka, S. Novel Thiazine substituted 9-Anilinoacridines: Synthesis, Antitumour activity and Structure-Activity Relationships. Anti-Cancer Agents in Med Chem. 2019, 11:1350-1358. DOI :10.2174/1871520619666190408134224.

25. Kalirajan R., Vivek kulshrestha, Sankar S. Synthesis, Characterization and Evaluation for Antitumour Activity of Some Novel Oxazine Substituted 9-Anilinoacridines and their 3D-QSAR Studies. Indian J Pharm sci. 2018.80(5):921-929.

26. Kalirajan R., Pandiselvi A., Gowramma B., Balachandran P. In-silico design, ADMET screening, MM-GBSA binding free energy of some novel isoxazole substituted9-anilinoacridines as HER2 inhibitors targeting breast cancer. Current Drug Res Rev. 2019.11(2):118-128.

27. Nadaraj V., Selvi S.T., Mohan S. Microwave-induced synthesis and anti-microbial activities of 7,10,11,12-tetrahydrobenzo[c]acridin-8(9H)-one derivatives. Eur J Med Chem. 2009, 44:976-980.

28. Kapuriya N., Kapuriya K., Zhang X., Chou T.C., Kakadiya R, Synthesis and biological activity of stable and potent antitumor agents, aniline nitrogen mustards linked to 9-anilinoacridines via a urea linkage, Bioorg Med Chem. 2008, 16:5413-5423.

29. Yuan Wan Sun, Kuen Yuan Chen, Chul Hoon Kwon, Kun Ming Chen. CK0403. A 9 aminoacridine, is a potent anti cancer agent in human breast cancer cells. Mol Med Reports, 2016, 13:933-938.

30. Wakelin L.P.G., Bu X., Eleftheriou A., Parmar A., Hayek C., Stewart B.W. Bisintercalating threading diacridines: relationships between DNA binding, cytotoxicity, and cell cycle arrest, J Med Chem. 2003, 46(26):5790-5802.

31. Sondhi S.M., Johar M., Nirupama S., Sukla R., Raghubir R., Dastidar S.G. Synthesis of sulpha drug acridine derivatives and their evaluation for anti-anflammatory, analgesic and anticancer acvity. Indian J Chem, 2002, 41B:2659-2666,.

32. Dickens B.F., Weglicki W.B., Boehme P.A., Mak I.T. Antioxidant and lysosomotropic properties of acridine-propranolol: protection against oxidative endothelial cell injury. The J Mol CellCardiol. 2002, 34:129-137.

33. Anderson M.O., Sherrill J., Madrid P.B., Liou A.P., Weisman J.L., DeRisi J.L. Parallel synthesis of 9-aminoacridines and their evaluation against chloroquine-resistant Plasmodium falciparum. Bioorg Med Chem. 2006, 14:334-343.

34. Giorgio C.D., Shimi K., Boyer G., Delmas F., Galy J.P., Synthesis and antileishmanial activity of 6-mono-substituted and 3,6-di-substituted acridines obtained by acylation of proflavine. Eur J Med Chem. 2007,42:1277-1284.

35. Llama E.F., Campo C.D., Capo M., Anadon M. Synthesis and antinociceptive activity of 9-phenyl-oxy or 9-acyl-oxy derivatives of xanthene, thioxanthene and acridine. Eur J Med Chem. 1989, 24:391-396,.

36. Goodell J.R., Madhok A.A., Hiasa H., Ferguson D.M., Synthesis and evaluation of acridine- and acridone-based anti-herpes agents with topoisomerase activity. Bioorg Med Chem. 2006, 14:5467-80.

37. Rastogi K., Chang J.Y., Pan W.Y., Chen C.H., Chou T.C. Antitumor AHMA linked to DNA minor groove binding agents: synthesis and biological evaluation. J Med Chem. 2002, 45(20):4485-4493.

38. Kalirajan R., Sivakumar S.U., Jubie S., Gowramma B., Suresh B. Synthesis and biological evaluation of some heterocyclic derivatives of chalcones. Int J Chem tech res. 2009, 1(1): 27-34.

39. Kedar M.S, Shirbhate M.P, Rajani Chauhan, Suman Sharma, Amrita Verma. Design Synthesis and Evaluation of Anticancer Pyrazole Derivatives of Chalcone Scaffold. Research J. Pharm. and Tech. 2020; 13(1): 342-346.

40. Kulveer Singh, Suman Kumari, Y.K. Gupta. Synthesis and Antimicrobial Activity of New Pyrazoles and Chalcones Derived from Cyclic Imides. Research J. Pharm. and Tech 2017; 10(12): 4483-4488.

41. Babli Khatun, Venkatesh Kamath, Muddukrishna B. S., Aravinda Pai. Synthesis, Characterization and Anticancer Evaluation of Novel Analogues of Pyrazoles. Research J. Pharm. and Tech. 2021;14(4):2162-6.

42. Bhaskar S. Dawane, Baseer M Shaikh, Namdev T. Khandare, Gajanan G. Mandawad, Santosh S .Chobe, Shankaraiah G. Konda. Synthesis of Some Novel Substituted Pyrazole Based Chalcones and Their In-Vitro Antimicrobial Activity. Asian J. Research Chem. 3(1): Jan.-Mar. 2010; Page 90-93.

43. Kalpana Divekar, Shivakumar Swamy, Kavitha N., V. Murugan, Manish Devgun. Synthesis and Evaluation of Some New Pyrazole Derivatives as Antimicrobial Agents. Research J. Pharm. and Tech.3 (4): Oct.-Dec.2010; Page 1039-1043.

44. Yadav A.K., Mazhar Mehdi, Tasneem Fatima. Synthesis, Characterization and AntimicrobialActivity of Some new 1,4 Diaryl-3-Methyl-6-Imino-4,7-Dihydro-1,3-Thiazino (5,4-d) Pyrazoles. Asian J. Research Chem. 2018; 11(2):217-220.

45. Panneer Selvam T., Saravanan G., Prakash C. R., Dinesh Kumar P.. Microwave-Assisted Synthesis, Characterization and Biological Activity of Novel Pyrazole Derivatives. Asian J. Pharm. Res. 1(4): Oct. - Dec. 2011; Page 126-129.

46. Deepthi D. Kodical, Jainey P. James, Deepthi K, Pankaj Kumar, Chinchumol Cyriac, Gopika K.V. ADMET, Molecular docking studies and binding energy calculations of Pyrimidine-2-Thiol Derivatives as Cox Inhibitors. Research J. Pharm. and Tech 2020; 13(9):4200-4206.

47. Habeela Jainab N., Mohan Maruga Raja M. K.. In Silico Molecular Docking Studies on the Chemical Constituents of Clerodendrum phlomidis for its Cytotoxic Potential against Breast Cancer Markers. Research J. Pharm. and Tech 2018; 11(4): 1612-1618.

48. Li J., Abel R., Zhu K., Cao Y., Zhao S., Friesner R.A. The VSGB 2.0 model: A next generation energy model for high resolution protein structure modelling. Proteins. 2011, 79:2794-2812.

Received on 09.06.2021 Modified on 31.12.2021

Research J. Pharm. and Tech 2023; 16(2):529-534.

DOI: 10.52711/0974-360X.2023.00090

COVID-19 Activity of Some 9-Anilinoacridines substituted with Pyrazole against SARS CoV2 Main Protease: An In-silico Approach

Table 3. Binding free energy calculation using Prime/MM-GBSA approach