SYNTHESIS AND BIOLOGICAL EVALUATION OF NOVEL PYRAZOLO[3,4-D]PYRIMIDINE DERIVATIVES OF EXPECTED ANTICANCER ACTIVITY

Farag Sherbiny

doi:10.21608/ajps.2021.153563

Abstract

A series of novel pyrazolo[3,4-d]pyrimidine derivatives have been designed based on chemical modifications on the general features of the reported and clinically used EGFR-TKIs such as repalcing of quinazoline moiety of reported EGFR-TKIs as erlotinib by pyrazolo[3,4-d]pyrimidine nucleus,introducing different hydrophobic moieties including phenyl, aromatic heterocyclic, fused aromatic or aliphatic structures , introducing different linkers which may be one atom , two atoms, three atoms, four atoms and five atoms and introducing of phenyl ring at position-3 of 1H-pyrazolo[3,4-d]pyrimidine nucleus to occupy the hydrophobic region II of ATP binding site. All the new synthesized compounds were biologically screened in vitro for their cytotoxic activities against four cancer cell lines namely, HepG-2, MCF-7, HCT-116, and Hela. The results of cytotoxic evaluation indicated that compound VI was found to be the most prominent broad-spectrum cytotoxic activity and significantly more potent than doxorubicin with IC50 values of 6.18, 6.48, 4.03, and 5.82μM against tested cell lines. In addition, compounds IXa,b displayed promising cytotoxic effect against all tested cell lines with IC50 values less than 30 μM compared with doxorubicin as a control drug. Besides, compound X possessed excellent anti-proliferative activities against the four cell lines with IC50 values ranging from 18 μM to 39.5 μM. Structural pharmacophoric features indicated that pyrazolo[3,4-d]pyrimidine scaffold having a four atoms linker as thiosemicarbazide moiety as compounds IXa,b which substituted with aliphatic moiety at the 4-position was more potent than those possessing one atom, two atoms, three atoms and five atoms linkers which lead to significant decrease in cytotoxic

Highlights

1- Introduction cancer is considered as the second cause of death in the world with every 1 in 6 deaths were attributed to cancer(Society, 2016)
The designed compounds were synthesized as outlined in Schemes 1 & 2. 2(bis(methylthio)- methylene)malononitrile I (Traxler et al, 1997a) was allowed to react with aniline to give 2-((methylthio)(phenylamino)methylene)malononitrile II (Li et al, 2014) compound II was reacted phenyl hydrazine to produce 5-Amino-3-(methylthio)1-phenyl-1H-pyrazolo-4-carbonitrile III (Traxler et al, 1997b) The IR spectrum of III demonstrated stretching bands at 3353, 3309, 3209 and 2206 cm-1 corresponding to NH2, NH and CN respectively
The new synthesized compounds were evaluated for their in vitro cytotoxic activity against four different cancer cell lines namely, hepatocellular carcinoma (HepG-2), human breast adenocarcinoma (MCF-7), colorectal carcinoma (HCT-116) and cervical cancer (Hela) via standard MTT method (Mosmann, 1983) (Denizot and Lang, 1986) (Thabrew et al, 1997), From the obtained anticancer results, it is evident that the screened compounds displayed different levels of cytotoxicity ranging from potent, moderate, weak, and inactive cytotoxicity against all tested cell lines

Summary

Rational Drug Design

We have carried out the chemical modifications on the general features of the reported and clinically used EGFR-TKIs as erlotinib 1(Sharma et al, 2016) (Mowafy et al, 2016). The modification comprises a replacement of the quinazoline moiety of erlotinib by 1H-pyrazolo[3,4-d]pyrimidine nucleus in an attempt to enhance the cytotoxic activity. The second modification was done by introducing different hydrophobic moieties including phenyl, aromatic heterocyclic, fused aromatic or aliphatic structures. The third modification was done by introducing different linkers may be one atom (e.g. imino group ascompound XI), two atoms (e.g. hydrazono group as compound XII), three atoms (e.g. ketohydrazinyl group as compounds X), four atoms (e.g. thiosemicarbazide moiety as compounds IX), five atoms e.g. cyclic structure (e.g. pyrrole and pyrazole ring as compound VII and VIII). The fourth modification was done introducing of phenyl ring at position-3 of 1H-pyrazolo[3,4-d]pyrimidine nucleus to occupy the hydrophobic region II of ATP binding site. The basic structural pharmacophoric requirements for erlotinib as reported EGFR-TK inhibitor

Chemistry

In Vitro Anticancer Screening

General

5-Conclusion: