Abstract3-Amino-4,6-dimethylpyrazolopyridine was applied as a precursor for the synthesis of some new pyridopyrazolo-triazine and pyridopyrazolo-triazole derivatives through diazotization, followed by coupling with many 2-cyanoacetamide compounds, ethyl 3-(phenylamino)-3-thioxopropanoate, 3-oxo-N-phenylbutanethioamide, and α-bromo-ketone reagents [namely; 2-bromo-1-(4-fluorophenyl)ethan-1-one, 5-bromo-2-(bromoacetyl)thiophene, 3-(2-bromoacetyl)-2H-chromen-2-one and/or 3-chloroacetylacetone]. The prepared compounds were identified by spectroscopic analyses as IR, 1H NMR, and mass data. The anticancer activity of these pyrazolopyridine analogues was investigated in colon, hepatocellular, breast, and cervix carcinoma cell lines. The pyridopyrazolo-triazine compound 5a substituted with a carboxylate group gave a distinguished value of IC50 = 3.89 µM against the MCF-7 cell line compared to doxorubicin as a reference drug. Also, the pyridopyrazolo-triazine compound 6a substituted with the carbothioamide function gave good activity toward HCT-116 and MCF-7 cell lines with IC50 values of 12.58 and 11.71 µM, respectively. The discovered pyrazolopyridine derivatives were studied theoretically by molecular docking, and this study exhibited suitable binding between the active sides of pyrazolopyridine ligands and proteins (PDB ID: 5IVE). The pyridopyrazolo-triazine compound 6a showed the highest free binding energy (− 7.8182 kcal/mol) when docked inside the active site of selected proteins.

A new series of pyridine, thiazole, and pyrazole analogues were synthesized. The pyridone analogues 4a-e were synthesized by treating N-aryl-2-cyano-3-(4-(diphenylamino)phenyl)acrylamides 3a-e with malononitrile. Many 4-arylidene-thiazolidin-5-one analogues 6a-d were obtained by Knoevenagel reactions of 4-(diphenylamino)benzaldehyde (1) with their corresponding thiazolidin-5-one derivatives 5a-d. The structural elucidation of the products was proven by the collections of spectroscopic methods such as IR, 1H NMR, 13C NMR, and MS data. Their anti-cancer activity was examined against two cell lines, MDA-MB-231 (mammary carcinomas) and A-549 (lung cancer). Compared with cisplatin as a reference standard drug, 6-amino-4-(4-(diphenylamino)phenyl)-2-oxo-1-(p-tolyl)-1,2-dihydropyridine-3,5-dicarbonitrile (4b) and 6-amino-4-(4-(diphenylamino)phenyl)-1-(4-nitrophenyl)-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile (4e) exhibited better efficiency against the A-549 cell line, with IC50 = 0.00803 and 0.0095 μM, respectively. Also, these compounds 4b and 4e showed the most potency among the examined compounds against MDA-MB-231 with IC50 = 0.0103 and 0.0147 μM, respectively. The newly synthesized compounds were docked inside the active sites of the selected proteins and were found to demonstrate proper binding. 2-Cyano-2-(4,4-(diphenylamino)benzylidene)-5-oxo-3-phenylthiazolidin-2-ylidene)-N-(p-tolyl)acetamide (6c) offered the highest binding affinity (− 8.1868 kcal/mol) when docked into (PDB ID:2ITO), in addition to 2-cyano-N-(4-(diethylamino)phenyl)-2-(4-(4-(diphenylamino)benzylidene)-5-oxo-3-phenylthiazolidin-2-ylidene)acetamide (6a) gave the highest energy score (− 9.3507 kcal/mol) with (PDB ID:2A4L).

A new series of metal-free organic dyes (SM1-5) with dual anchors are synthesized for application in dye-sensitized solar cells (DSSC). Here, a simple triphenylamine (TPA) moiety serves as the electron donor, while di-cyanoacrylamide and di-thiazolidine-5-one units serve as the electron acceptors and anchoring groups. To understand the effect of dye structure on the photovoltaic characteristics of DSSCs, the photophysical and electrochemical properties, as well as molecular geometries calculated from density functional theory (DFT), are used for dyes SM1-5. The extinction coefficients of the organic dyes SM1-5 are high (5.36–9.54 104 M−1 cm−1), indicating a high aptitude for light harvesting. The photovoltaic studies indicated that using dye SM4 as a sensitizer showed a power conversion efficiency (PCE) of 6.09% (JSC = 14.13 mA cm−2, VOC = 0.624 V, FF = 68.89%). Interestingly, SM4 showed the highest values of VOC among all dyes, including N-719, due to its maximum dye coverage on the TiO2 surface, enhancing charge recombination resistance in the sensitized cell. The good agreement between the theoretically and experimentally obtained data indicates that the energy functional and basis set employed in this study can be successfully utilized to predict new photosensitizers' absorption spectra with great precision before synthesis. Also, these results show that bi-anchoring molecules have a lot of potentials to improve the overall performance of dye-sensitized solar cells.