Recent advances in the chemistry and biology of pyridopyrimidines

Overcoming Resistance in Cancer Therapy: Computational Exploration of PIK3CA Mutations, Unveiling Novel Non-Toxic Inhibitors, and Molecular Insights Into Targeting PI3Kα

Phosphoinositide-3-kinases (PI3 K) are pivotal regulators of cell signaling implicated in various cancers. Particularly, mutations in the PIK3CA gene encoding the p110α catalytic subunit drive oncogenic signaling, making it an attractive therapeutic target. Our study conducted in silico exploration of 31 PIK3CA mutations across breast, endometrial, colon, and ovarian cancers, assessing their impacts on response to PI3Kα inhibitors and identifying potential non-toxic inhibitors and also elucidating their effects on protein stability and flexibility. Specifically, we observed significant alterations in the stability and flexibility of the PI3 K protein induced by these mutations. Through molecular docking analysis, we evaluated the binding interactions between the selected inhibitors and the PI3 K protein. The filtration of ligands involved calculating chemical descriptors, incorporating Veber and Lipinski rules, as well as IC50 values and toxicity predictions. This process reduced the initial dataset of 1394 ligands to 12 potential non-toxic inhibitors, and four reference inhibitors with significant biological activity in clinical trials were then chosen based on their physico-chemical properties. This analysis revealed Lig5's exceptional performance, exhibiting superior affinity and specificity compared to established reference inhibitors such as pictilisib. Lig5 formed robust binding interactions with the PI3 K protein, suggesting its potential as a highly effective therapeutic agent against PI3 K-driven cancers. Furthermore, molecular dynamics simulations provided valuable insights into Lig5's stability and its interactions with PI3 K over 100 ns. These simulations supported Lig5's potential as a versatile inhibitor capable of effectively targeting various mutational profiles of PI3 K, thereby mitigating issues related to resistance and toxicity commonly associated with current inhibitors.

Ligand and structure based hierarchical virtual screening cascade for finding novel epidermal growth factor receptor inhibitors

The epidermal growth factor receptor (EGFR) tyrosine kinase plays an important role in tumor formation and growth by mediating cell growth and other physiological processes. Therefore, EGFR is a promising target for the treatment of cancer. In this work, we combined ligand-based and structure-based virtual screening methods to identify novel EGFR inhibitors from a library of more than 103 thousand compounds. We first obtained hundreds of compounds with similar physiochemical properties through 3D molecular shape and electrostatic similarity screening with potent inhibitors AEE788 and Afatinib as queries. Next, we identified compounds with strong binding affinities to the EGFR pocket through molecular docking, which makes good use of the structure information of the receptor. After molecular scaffold analysis, our bioassay confirmed 13 compounds with EGFR inhibitory activity and three compounds had IC50 values below 1000 nM. In addition, we collected 5371 EGFR inhibitors from online databases, and clustered them into 7 groups by K-means method using their ECFP4 fingerprints as input. Each cluster had typical molecular fragments and corresponding activity characteristics, which could guide the design of EGFR inhibitors, and we concluded that the fragments from some of the hits are indicated in the highly active scaffolds.

Design, synthesis and anti-osteosarcoma activity study of novel pyrido[2,3-d]pyrimidine derivatives by inhibiting DKK1-Wnt/β-catenin pathway

Osteosarcoma is a common primary malignant bone tumor in adolescents. Wnt/β-catenin has been proved to play a pro-oncogenic role and was overactivated in osteosarcoma. Therefore, this pathway has become an interesting therapeutic target for osteosarcoma. Herein we report the design, synthesis and biological activities of a series of novel pyrido[2,3-d]pyrimidine derivatives based on our previous work. Among these, the representative compound 2-{[1,3-dimethyl-7-(4-methylpiperazin-1-yl)-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidin-5-yl]amino}-N-[4-(trifluoromethoxy)phenyl]acetamide (7m) has exhibited good antiproliferative activity towards 143B and MG63 cells with good selectivity over non-cancerous HSF cells. In the assay of Ca2+ concentration, the compound 7m increased the intracellular Ca2+ concentration in 143B cells. In addition, the expression of DKK1 increased, and that of p-β-catenin decreased by 7m treatment. Finally, the Hoechst 33,342 staining, Annexin-FITC/PI staining and mitochondrial fluorescence staining have clearly demonstrated that compound 7m induced apoptosis in 143B cells.

Discovery of novel pyrido[3,2-d]pyrimidine derivatives as selective and potent PI3Kδ inhibitors

The δ isoform of class I PI3K (PI3Kδ) has been shown as a promising target for the treatment of hematologic malignancies and immune diseases. Herein, a series of pyrido[3,2-d]pyrimidine derivatives were designed, synthesized and evaluated for the preliminary bioactivity. Compared with idelalisib, compound S5 exhibited excellent enzyme activity against PI3Kδ (IC50  = 2.82 nM) and strong antiproliferation activity against SU-DHL-6 cells (IC50  = 0.035 μM). Besides, S5 inhibited the phosphorylation of Akt, which is downstream of PI3Kδ, in concentration-dependent manner. In view of the significant improvement in potency of PI3Kδ and selectivity over other PI3K isoforms, Compound S5 deserved further investigation as a promising PI3Kδ inhibitor.

Design, synthesis and biological evaluation of novel selective PI3Kδ inhibitors containing pyridopyrimidine scaffold

Aim: In our study compounds with pyrido[3,2-d]pyrimidine and pyrido[3,4-d]pyrimidine were designed, synthesized and evaluated for their biological activity against hematologic tumors. Methods: The biological activity of compounds was evaluated by ADP-Glo Luminescence assay, MTT [3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide] assay, western blotting and flow cytometry, respectively. Results: Compounds A1, A5 and A7 containing pyrido[3,2-d]pyrimidine inhibited phosphoinositide 3-kinase-δ (PI3Kδ) at subnanomolar levels and had good δ-isoform selectivity. A1, A5 and A7 showed significant inhibitory effects against SU-DHL-6 cells and effectively inhibited Akt phosphorylation in a good concentration-dependent manner. A7 induced apoptosis and caused cell cycle arrest in SU-DHL-6 cells. Docking studies showed that A1, A5 and A7 bound tightly to PI3Kδ through key hydrogen bonding interactions. Conclusion: This study suggests that employing pyrido[3,2-d]pyrimidine can facilitate the design of novel potent and selective PI3Kδ inhibitors.

Investigation of the radical scavenging potential of vanillin-based pyrido-dipyrimidines: experimental and in silico approach

Antioxidants have a significant contribution in the cell protection against free radicals which may induce oxidative stress, and permanently damage the cells causing different disorders such as tumors, degenerative diseases, and accelerated aging. Nowadays, a multi-functionalized heterocyclic framework plays an important role in drug development, and it is of great importance in organic synthesis and medicinal chemistry. Encouraged by the bioactivity of the pyrido-dipyrimidine scaffold and vanillin core, herein, we made an effort to thoroughly investigate the antioxidant potential of the vanillin-based pyrido-dipyrimidines A-E to reveal novel promising free radical inhibitors. The structural analysis and the antioxidant action of the investigated molecules were performed in silico by DFT calculations. Studied compounds were screened for their antioxidant capacity using in vitro ABTS and DPPH assays. All the investigated compounds showed remarkable antioxidant activity, especially derivative A exhibiting inhibition of free radicals at the IC50 value (ABTS and DPPH assay 0.1 mg ml-1 and 0.081 mg ml-1, respectively). Compound A has higher TEAC values implying its stronger antioxidant activity compared to a trolox standard. The applied calculation method and in vitro tests confirmed that compound A has a strong potential against free radicals and may be a novel candidate for application in antioxidant therapy.

Medicinal chemistry perspective of pyrido[2,3-d]pyrimidines as anticancer agents

Cancer is a major cause of deaths across the globe due to chemoresistance and lack of selective chemotherapy. Pyrido[2,3-d]pyrimidine is an emerging scaffold in medicinal chemistry having a broad spectrum of activities, including antitumor, antibacterial, CNS depressive, anticonvulsant, and antipyretic activities. In this study, we have covered different cancer targets, including tyrosine kinase, extracellular regulated protein kinases - ABL kinase, phosphatidylinositol-3 kinase, mammalian target of rapamycin, p38 mitogen-activated protein kinases, BCR-ABL, dihydrofolate reductase, cyclin-dependent kinase, phosphodiesterase, KRAS and fibroblast growth factor receptors, their signaling pathways, mechanism of action and structure-activity relationship of pyrido[2,3-d]pyrimidine derivatives as inhibitors of the above-mentioned targets. This review will represent the complete medicinal and pharmacological profile of pyrido[2,3-d]pyrimidines as anticancer agents, and will help scientists to design new selective, effective and safe anticancer agents.

Preparation and characterization of doped hollow carbon spherical nanostructures with nickel and cobalt metals and their catalysis for the green synthesis of pyridopyrimidines

Fused heterocyclic systems containing the pyrimidine ring structure perform a significant role in numerous biological and pharmaceutical processes. Their properties include antibacterial, antifungal, anti-fever, anti-tumor, and antihistamine. As pyridopyrimidines are important in the essential fields of pharmaceutical chemistry, efficient methods for preparing these heterocycles are presented. In this study, a method for producing improved hollow carbon sphere nanostructures with cobalt and nickel (Co-Ni@HCSs) is presented. The nanocatalyst was prepared and identified by applying Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET), and elemental mapping techniques. The Co-Ni@HCSs nanocatalyst was proved to be highly efficient in synthesizing pyranopyrimidine derivatives. The sizeable active site, economic catalyst loading, easy workup, reusability, green reaction conditions, and excellent yields of all derivatives are some of the significant features of this process. Also, applying response surface methodology (RSM) and the Box-Behnken design (BBD) techniques allowed us to determine the influential factors of the laboratory variables and identify the optimum conditions for superior catalytic activity. Finally, synthesized organic compounds were identified by utilizing melting point, FT-IR, and hydrogen-1 nuclear magnetic resonance (1H NMR) analyses.

Synthesis, characterization, thermal behavior, and antitumor activities of an Ag(I) complex based on 4-(2-hydroxyphenyl)-2-methylpyrimidine

A new Ag(I) coordination complex, Ag(C11H10N2O)2·NO3 (C11H10N2O = 4-(2-hydroxyphenyl)-2-methylpyrimidine) is successfully synthesized and characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction analysis. This complex features a three-dimensional framework consisting of hydrogen bonds, π–π stacking interactions, coordination interactions, and electrostatic interactions. Moreover, the thermal stability and non-isothermal thermal decomposition reaction kinetics of the complex are well investigated by the methods of Kissinger and Ozawa. Finally, the antitumor ability of the complex is evaluated against human lung cancer cells (NCI-H460), human hepatocellular cancer cells (HepG2), and human breast cancer cells (MCF7). The complex exhibits potent antitumor activities against HepG2 and MCF7 cancer cells.

Review on the Synthesis and Therapeutic Potential of Pyrido[2,3-d], [3,2-d], [3,4-d] and [4,3-d]pyrimidine Derivatives

The objective of this review is to list the structures composed of a pyridopyrimidine moiety which have shown a therapeutic interest or have already been approved for use as therapeutics. We consider all the synthetic protocols to prepare these pyridopyrimidine derivatives. The review is organized into four sections, successively pyrido[2,3-d]pyrimidines, pyrido[3,4-d]pyrimidines, pyrido[4,3-d]pyrimidines and pyrido[3,2-d]pyrimidines. For each compound we present the biological activity and the synthetic route reported. To produce this manuscript, the bibliographic research was done using Reaxys and Scifinder for each kind of pyridopyrimidine.

Visible-Light-Driven Multicomponent Cyclization by Trapping a 1,3-Vinylimine Ion Intermediate: A Direct Approach to Pyrimido[1,2-b]indazole Derivatives

Here we develop a novel visible-light-driven three-component cyclization by trapping an 1,3-vinylimine ion intermediate for the direct synthesis of pyrimido[1,2-b]indazole derivatives from bromodifluoroacetic acid derivatives, enaminones, and 3-aminoindazoles under mild conditions. Notably, the robust methodology provides a valuable opportunity for the introduction of aliphatic substituents and enables good compatibility of complex bioactive molecules. Furthermore, this is the first example of photoinduced multicomponent reaction by employing bromodifluoroacetic acid derivatives as a C1-synthon.

New C2- and N3-Modified Thieno[2,3-d]Pyrimidine Conjugates with Cytotoxicity in the Nanomolar Range

AIMS

The aim of the current study was to develop and explore a series of new cytotoxic agents based on the conjugation between the thieno[2,3-d]pyrimidine moiety and a second pharmacophore at the C2 or N3 position.

BACKGROUND

As the thieno[2,3-d]pyrimidine core is a bioisostere of the 4-anilinoquinazoline, various new thienopyrimidine derivatives were synthesized by modifying the structure of the clinically used anticancer quinazoline EGFR inhibitors of the first generation - gefitinib, and second generation - dacomitinib and canertinib. It was reported that some thieno[2,3-d]pyrimidine derivatives showed improved EGFR inhibitory activity. On the other hand, the benzimidazole heterocycle is present as a pharmacophore unit in the structure of many clinically used chemotherapeutic agents. Some 2-aminobenzimidazole derivatives, possessing anticancer activity, demonstrated EGFR inhibition and the benzimidazole derivative EGF816 is currently in the second phase of clinical trials.

OBJECTIVE

The objectives of the study were design of a novel series thieno[2,3-d]pyrimidines, synthesis of the compounds and investigation of their effects towards human cancer HT-29, MDA-MB-231, HeLa, HepG2 and to normal human Lep3 cell lines. (American Type Culture Collection, ATCC, Rockville, MD, USA) Methods: The synthetic protocol implemented cyclocondensation of 2-amino-thiophenes and nitriles in inert medium, aza-Michael addition to benzimidazole derivatives and nucleophylic substitution at the N3 place. MTS test was used in order to establish the cytotoxicity of the tested compounds. SAR analysis and in silico assessment of the inhibitory potential towards human oncogenic V^599EB-Raf were performed using Molinspiration tool and Molecular Operating environment software.

RESULTS

The MTS test data showed that almost all studied thieno[2,3-d]pyirimidines (9-13, 21-22 and 25) manifest high inhibiting effect on the cell proliferation at nanomolar concentrations, whereat compounds 9 (IC₅₀ = 130 nM) and 10 (IC₅₀ = 261 nM) containing amino acid moiety, and 21 (IC₅₀ = 108 nM) possesing two thienopyrimidine moieties attached to a 1,3-disubstituted benzimidazole linker, revealed many times lower toxicity against Lep3 cells compared to the cancer cells. Thienopyrimidines 11-13 possessed high selectivity against HeLa cells. Compound 13 showed high inhibitory activity against MDA-MB-231 and HepG2, with IC50 1.44 nM and 1.11 nM respectively. To outline the possible biological target of the studied coumpounds, their potential to interact with human oncogenic V^599EB-Raf was explored by a docking study. As a result, it was suggested that the benzimidazolyl and glycyl fragments could enhance the binding ability of the new compounds by increasing the number of hydrogen bond acceptors and by stabilizing the inactive form of the enzyme.

CONCLUSION

The thienopyrimidines tested in vitro towards human cancer HT-29, MDA-MB-231, HeLa, HepG2 and normal human Lep3 cell lines demonstrated cytotoxicity in nanomolar range. It was established that compounds 9, 10 and 21 showed many times lower toxicity against normal Lep3 cells that can provide a high selectivity towards all four cancer cell lines at small concentrations. Based on the analysis of the structure-activity relationship, the observed trends in the cytotoxicity could be related to the lipophilicity and the topological polar surface area of the tested compounds. The docking study on the potential of the new thieno[2,3-d]pyrimidine-4-ones to interact with mutant V^599EB-Raf showed that the compounds might be able to stabilize the enzyme in its inactive form.

Synthesis of biologically active heterocyclic compounds from allenic and acetylenic nitriles and related compounds

Cyclic and polycyclic compounds containing moieties such as imidazole, pyrazole, isoxazole, thiazoline, oxazine, indole, benzothiazole and benzoxazole benzimidazole are prized molecules because of the various pharmaceutical properties that they display. This led Prof. Landor and co-workers to engage in the synthesis of several of them such as alkylimidazolenes, oxazolines, thiazolines, pyrimidopyrimidines, pyridylpyrazoles, benzoxazines, quinolines, pyrimidobenzimidazoles and pyrimidobenzothiazolones. This review covers the synthesis of biologically active heterocyclic compounds by the Michael addition and the double Michael addition of various amines and diamines on allenic nitriles, acetylenic nitriles, hydroxyacetylenic nitriles, acetylenic acids and acetylenic aldehydes. The heterocycles were obtained in one step reaction and in most cases, did not give side products. A brief discussion on the biological activities of some heterocycles is also provided.

Aminations and arylations by direct C-O activation for the design of 7,8-dihydro-6H-5,8-ethanopyrido[3,2-d]pyrimidines

The design of some novel disubstituted 7,8-dihydro-6H-5,8-ethanopyrido[3,2-d]pyrimidine derivatives is reported. The series was developed from quinuclidinone, which afforded versatile platforms bearing one lactam function in position C-2 that were then used to create C-N or C-C bonds for S N Ar or palladium-catalyzed cross-coupling reactions by in situ C-O activation. The reaction conditions were optimized under microwave irradiation, and a wide range of amines or boronic acids were used to determine the scope and limitations of each method. To complete this study, the X-ray crystallographic data of 7,8-dihydro-6H-5,8-ethanopyrido[3,2-d]pyrimidine derivative 49 were used to formally establish the structures of the products.

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

Microwave-assisted (MWA) multicomponent reactions (MCRs) have successfully emerged as one of the useful tools in the synthesis of biologically relevant heterocycles. These reactions are strategically employed for the generation of a variety of heterocycles along with multiple point diversifications. Over the last few decades classical MCRs such as Ugi, Biginelli, etc. have witnessed enhanced yield and efficiency with microwave assistance. The highlights of MWA-MCRs are high yields, reduced reaction time, selectivity, atom economy and simpler purification techniques, such an approach can accelerate the drug discovery process. The present review focuses on the recent advances in MWA-MCRs and their mechanistic insights over the past decade and shed light on its advantage over the conventional approach.

Fused and Substituted Pyrimidine Derivatives as Profound Anti-Cancer Agents

The rationale behind drug design is the strategic utilization of heterocyclic fragments with specific physicochemical properties to form molecular targeted agents. Among the heterocyclic molecules, pyrimidine has proved to be a privileged pharmacophore for various biological cancer targets. The anti-cancer potential of small molecules with fused and substituted pyrimidines can be enhanced through bioisosteric replacements and altering their ADME parameters. Although several small molecules are used in cancer chemotherapy, oncology therapeutics has various limitations, especially in their routes of administration and their concurrent side effects. Such pernicious effects may be overcome, via selective biological targeting. In this review, the biological targets, to inhibit cancer, have been discussed. The structural activity relationship of fused and substituted pyrimidines was studied. Eco-friendly synthetic approaches for pyrimidine derivatives have also been discussed. This review will give an insight to scientists and researchers of medicinal chemistry discipline to design small molecules having a pyrimidine scaffold with high anti-cancer potential.

N,N-Diacylaminals as Emerging Tools in Synthesis: From Peptidomimetics to Asymmetric Catalysis

N,N-Diacylaminals are flexible molecular scaffolds that have commonly been utilized as amide surrogates in peptidomimetics. The singularities of this motif as an N-acyl imine equivalent and as hydrogen-bond donor have recently opened new synthetic opportunities, especially in the field of asymmetric catalysis. This concept article highlights this diverse synthetic potential and provides the elements necessary for further developments.

Pyrido[2,3-d]pyrimidin-7(8H)-ones: Synthesis and Biomedical Applications

Pyrido[2,3-d]pyrimidines (1) are a type of privileged heterocyclic scaffolds capable of providing ligands for several receptors in the body. Among such structures, our group and others have been particularly interested in pyrido[2,3-d]pyrimidine-7(8H)-ones (2) due to the similitude with nitrogen bases present in DNA and RNA. Currently there are more than 20,000 structures 2 described which correspond to around 2900 references (half of them being patents). Furthermore, the number of references containing compounds of general structure 2 have increased almost exponentially in the last 10 years. The present review covers the synthetic methods used for the synthesis of pyrido[2,3-d]pyrimidine-7(8H)-ones (2), both starting from a preformed pyrimidine ring or a pyridine ring, and the biomedical applications of such compounds.

Advances in the Solid-Phase Synthesis of Pyrimidine Derivatives

This Review describes the existing synthetic approaches for the solid-phase synthesis (SPS) of differently substituted and fused pyrimidine derivatives. These synthetic strategies are classified on the basis of the different synthetic routes leading to the particular type of pyrimidine heterocycle formed. The Review discusses the application of a variety of polystyrene derived supports for the construction of pyrimidine rings. The effect of microwave heating on the solid-phase synthesis is also addressed in the review.

Regioselective Synthesis of New 2,4-(Het)aryl-3H-pyrido[1',2':1,5]pyrazolo[4,3-d]pyrimidines Involving Palladium-Catalyzed Cross-Coupling Reactions

The design of some novel di-(het)arylated-3H-pyrido[1',2':1,5]pyrazolo[4,3-d]pyrimidine derivatives is reported. The series was developed from 1-aminopyridinium iodide, which afforded the key intermediate bearing two thiomethyl and amide functions, each of them useful for palladium catalyzed cross coupling reactions by alkyl sulfur release and C-O activation, respectively. The two regioselective and successive cross-coupling reactions were first carried out in C-4 by in situ C-O activation and next in C-2 by a methylsulfur release. Process optimization furnished conditions leading to products in high yields. The scope and limitations of the methodologies were evaluated and the final compounds characterized.

DIPEAc promoted one-pot synthesis of dihydropyrido[2,3-d:6,5-d′]dipyrimidinetetraone and pyrimido[4,5-d]pyrimidine derivatives as potent tyrosinase inhibitors and anticancer agents: in vitro screening, molecular docking and ADMET predictions

Efficient and rapid synthesis of 18 tyrosinase inhibitors with good to moderate anticancer activity and good oral drug like properties.

One pot synthesis, antimicrobial and antioxidant activities of fused uracils: pyrimidodiazepines, lumazines, triazolouracil and xanthines

Background

Uracil derivatives have a great attraction because they play an important role in pharmacological activities. Pyrimidodiazepines, lumazines, triazolopyrimidines and xanthines have significant wide spectrum activities including anticancer, antiviral as well as antimicrobial activities.

Results

A newly synthesized compounds pyrimido[4,5-b][1, 4]diazepines 5a–e, 6a–d, lumazines 7a–d, triazolo[4,5-d]pyrimidine 8 and xanthines 9, 10 was prepared in a good yields. The antimicrobial and antioxidant activities of compounds 5a, 5b, 6a, 6d and 8 exhibited a wide range activity against the pathogenic tested microbes (Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Candida albicans, and Saccharomyces cerevisiae). Compound 8 showed activity against the fungus Aspergillus niger. The highest antioxidant activity was noticed for compound 5a.

Conclusions

A series of novel pyrimido[4,5-b][1, 4]diazepines 5a–e, 6a–d, lumazines 7a–d, triazolo[4,5-d]pyrimidine 8 and xanthines 9, 10 was prepared from 5,6-diamino-1-(2-chlorobenzyl)uracil 3 in good yields. Compounds 5a–e, 6a–d were prepared by sequential manipulation of 3 with α,β-unsaturated ketones. Lumazines 7a–d were obtained from 3 by treatment with phenacyl bromides in the presence of TEA. Compound 8 was prepared by treatment of 3 with HNO₂, while xanthines 9, 10 were obtained from 3 by consecutive acetylation then intramolecular cyclodehydration or heating with malononitrile under solvent-free condition. The antimicrobial and antioxidant activity of this series was evaluated in vitro and they showed either weak or moderate activities.Graphical abstract

Steroidal[17,16-d]pyrimidines derived from dehydroepiandrosterone: A convenient synthesis, antiproliferation activity, structure-activity relationships, and role of heterocyclic moiety

A series of steroidal[17,16-d]pyrimidines derived from dehydroepiandrosterone were designed and prepared by a convenient heterocyclization reaction. The in vitro anticancer activities for these obtained compounds were evaluated against human cancer cell lines (HepG2, Huh-7, and SGC-7901), which demonstrated that some of these heterocyclic pyrimidine derivatives exhibited significantly good cytotoxic activities against all tested cell lines compared with 5-fluorouracil (5-FU), especially, compound 3b exhibited high potential growth inhibitory activities against all tested cell lines with the IC₅₀ values of 5.41 ± 1.34, 5.65 ± 1.02 and 10.64 ± 1.49 μM, respectively, which might be used as promising lead scaffold for discovery of novel anticancer agents.

Synthesis and Pharmacological Activities of Pyrano[2,3-d]pyrimidine and Pyrano[2,3-d]pyrimidine-5-one Derivatives as New Fused Heterocyclic Systems

Various fused oxazine such as 4-(4-methoxyphenyl)-3,7-dimethyl-1,4-dihydro-5H-pyrazolo [4′,3′:5,6]pyrano[2,3-d][1,3]oxazin-5-one2has been prepared and utilized as a starting material for novel pyrazolopyranopyrimidinones3,5,6, and7a–cand pyrazolopyranopyrimidines4,9,10, and11which are expected to possess considerable chemical and pharmacological activities. The structures of the new compounds have been elucidated by spectroscopic data and elemental analysis. The antioxidant and anticancer activities of synthesized products have been evaluated.

Controlled Dimroth Rearrangement in the Suzuki-Miyaura Cross Coupling of Triazolopyridopyrimidines

Polynitrogen heterocycles are often subject to Dimroth rearrangement which consists of ring opening, bond rotation, and ring closure. In this note, we report a synthesis of two new families of triazolopyridopyrimidines. Successful functionalization via a Suzuki-Miyaura coupling was performed with total control of triazole (Dimroth) isomerization based on the judicious choice of reaction conditions.

Recent developments in the chemistry of bicyclic 6-6 systems: chemistry of pyrido[4,3-d]pyrimidines

The present review reports the chemistry and biological importance of pyrido[4,3-d]pyrimidine analogues.

A catalyst free, multicomponent-tandem, facile synthesis of pyrido[2,3-d]pyrimidines using glycerol as a recyclable promoting medium

An efficient and green, one-pot synthesis of pyrido[2,3-d]pyrimidines, a biologically important heterocyclic scaffold, using glycerol as a promoter cum solvent.

Dual inhibitors of epidermal growth factor receptor and topoisomerase IIα derived from a quinoline scaffold

Based on the quinazoline bearing EGFR inhibitors, a series of thirty four compounds having a quinoline scaffold were synthesized and evaluated in vitro for EGFR kinase inhibitory and anticancer activities.

Efficient and convenient synthesis of pyrido [2,1-b]benzothiazole, pyrimidopyrido[2,1-b]benzothiazole and benzothiazolo[3,2-a][1,8]naphthyridine derivatives

New 3-aryl-pyrido[2,1-b][1,3]benzothiazole derivatives 2a–e were synthesized in excellent yields via the reaction of benzothiazoleacetonitrile (1) with different aromatic aldehydes. The treatment of 2-(benzo[d]thiazol-2-yl)-3-(pyridin-4-yl)acrylonitrile (6) with malononitrile afforded 1-amino-3-(pyridin-4-yl)-3H-pyrido[2,1-b][1,3]benzothiazole-2,4-dicarbonitrile (7), which was allowed to react with a variety of reagents to provide pyrimido[5′,4′:5,6]pyrido[2,1-b][1,3]benzothiazole 8, 9 and [1,3]benzothiazolo[3,2-a][1,8]naphthyridine 10, 15 derivatives. All synthesized products were confirmed by elemental analysis, IR, 1H-NMR, 13C-NMR, and mass spectral data.