Synthesis and biological evaluation of various heterocyclic compounds

Abstract

Cancer is a huge global health concern and is the leading cause of human mortality exceeded only by cardiovascular diseases. Malignant tumor an alternative name to cancer which is a large group of diseases involving loss of control on normal cell growth and function with the capability of spreading to other body parts. A major problem in treating cancer is the fact that it is not a single disease. Different defects in cellular function lead to formation of more than 200 different types of cancer each needs particular diagnosis and treatment. In this study, a series of pyrazolo[3,4-b]pyridines have been designed and synthesized as anticancer compounds. The design based on investigation of the reported SAR studies, bioisosteric modifications of the lead compound and distinguishing the key interactions with the binding site in silico. Synthesis of the new compounds was then accomplished and their structures were confirmed by various spectral and microanalytical data. This study involved the synthesis and the characterization of the following novel compounds: 1. 3-(4-Chlorophenyl)-1,4-diphenyl-1H-pyrazolo[3,4-b]pyridine (VIa) 2. 3,4-Bis(4-chlorophenyl)-1-phenyl-1H-pyrazolo[3,4-b]pyridine (VIb) 3. 3-(4-Chlorophenyl)-1-phenyl-4-(p-tolyl)-1H-pyrazolo[3,4-b]pyridine (VIc) 4. 3-(4-Chlorophenyl)-4-(4-methoxyphenyl)-1-phenyl-1H-pyrazolo[3,4-b]pyridine (VId) 5. 3-(4-Chlorophenyl)-1-phenyl-4-(thiophen-2-yl)-1H-pyrazolo[3,4-b]pyridine (VIe) 6. 3-(4-Chlorophenyl)-1,4,6-triphenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile (VIIIa). 7. 3,4-Bis(4-chlorophenyl)-1,6-diphenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile (VIIIb). 8. 3-(4-Chlorophenyl)-4-(4-hydroxyphenyl)-1,6-diphenyl-1H-pyrazolo[3,4-b]pyridine-5- carbonitrile (VIIIc). 9. 3-(4-Chlorophenyl)-4-(4-methoxyphenyl)-1,6-diphenyl-1H-pyrazolo[3,4-b]pyridine-5- carbonitrile (VIIId). 10. 3-(4-Chlorophenyl)-4-(4-nitrophenyl)-1,6-diphenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile (VIIIe). 11. 3-(4-Chlorophenyl)-6-(4-methoxyphenyl)-1,4-diphenyl-1H-pyrazolo[3,4-b]pyridine-5- carbonitrile (VIIIf). 12. 3,4-Bis(4-chlorophenyl)-6-(4-methoxyphenyl)-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5- carbonitrile (VIIIg). 13. 3-(4-Chlorophenyl)-4-(4-hydroxyphenyl)-6-(4-methoxyphenyl)-1-phenyl-1H-pyrazolo[3,4- b]pyridine-5-carbonitrile (VIIIh). 14. 3-(4-Chlorophenyl)-4,6-bis(4-methoxyphenyl)-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5- carbonitrile (VIIIi). 15. 3-(4-Chlorophenyl)-6-(4-methoxyphenyl)-4-(4-nitrophenyl)-1-phenyl-1H-pyrazolo[3,4- b]pyridine-5-carbonitrile (VIIIj). 16. 3'-(4-Chlorophenyl)-2-oxo-1',6'-diphenyl-1',7'-dihydrospiro[indoline-3,4'-pyrazolo[3,4- b]pyridine]-5'-carbonitrile (Xa). 17. 5-Chloro-3'-(4-chlorophenyl)-2-oxo-1',6'-diphenyl-1',7'-dihydrospiro[indoline-3,4'-pyrazolo[3,4- b]pyridine]-5'-carbonitrile (Xb). 18. 3',6'-Bis(4-chlorophenyl)-2-oxo-1'-phenyl-1',7'-dihydrospiro[indoline-3,4'-pyrazolo[3,4- b]pyridine]-5'-carbonitrile (Xc). 19. 5-Chloro-3',6'-bis(4-chlorophenyl)-2-oxo-1'-phenyl-1',7'-dihydrospiro[indoline-3,4'- pyrazolo[3,4-b]pyridine]-5'-carbonitrile(Xd). 20. 3'-(4-Chlorophenyl)-6'-(4-methoxyphenyl)-2-oxo-1'-phenyl-1',7'-dihydrospiro[indoline-3,4'- pyrazolo[3,4-b]pyridine]-5'-carbonitrile (Xe). 21. 5-Chloro-3'-(4-chlorophenyl)-6'-(4-methoxyphenyl)-2-oxo-1'-phenyl-1',7'-dihydrospiro[indoline- 3,4'-pyrazolo[3,4-b]pyridine]-5'-carbonitrile (Xf).

The biological assessment was accomplished by testing the anticancer activity, enzyme inhibition activity, cell cycle and apoptosis assay. The anticancer activity of the newly synthesized compounds against HepG2 and Hela cell lines revealed that compound Xa has potent activity as anti- proliferative agents against HepG2 cell line with IC50 = 4.2 µM compared to reference compound (doxorubicin) with IC50 = 1.7 µM. On the other side, compound Xd has potent activity as anti- proliferative agents against Hela cell line with IC50 = 5.9 µM compared to cisplatin IC50 = 4.8 µM. Cell cycle and apoptosis assay of compounds (VIIIc and Xa) was performed at the Diagnostic and Confirmatory lab in the Holding Company for Biological Products and Vaccines (VACSERA), Giza, Egypt. Both compounds VIIIc and Xa promoted cell cycle disturbance and apoptosis in HepG2 cells as evidenced by the DNA flow cytometry and Annexin V-FITC/PI assays. Furthermore, (VIIIh) and (Xd) stood out as the most efficient anti-proliferative agents against NCI 60-cell line panel screening with mean GI % equals to 60.3 and 55.4%, respectively. The enzyme inhibition assay was performed at the Diagnostic and Confirmatory lab in the Holding Company for Biological Products and Vaccines (VACSERA), Giza, Egypt. The enzymatic inhibitory activity of the synthesized compounds was assessed against the cellular pathway regulator p38α kinase. Compounds VIIIc, VIIIh, Xa and Xd exhibited good inhibitory action against cellular pathway regulator p38α kinase with IC50 = 0.42, 0.41, 0.13 and 0.64 μM, respectively, which are comparable to those of SB 202190 (IC50 = 0.188 μM). Finally, Computer aided ADME study and toxicity prediction were also performed using Accelrys Discovery Studio® 2.5 software.