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Pyrimidine is an important baseone of the base formed by hydrolysis of nucleosides. It is an interesting molecule in the medicinal chemistry because of its diversified biological activities. Alloxan which is an oxidation product of Uric acid is also a pyrimidine derivative of interest to a medicinal chemist. Several pyrimidines are reported as antimicrobial, analegesic, anti-inflammatory, antibacterial, and antiparasitic agents. Pyrimidine scaffold is considered as an interesting one due to its various pharmacological properties. In this scheme, an attempt is made to carry out synthesis of some new pyrimidine derivatives. The Starting material Chalcone is synthesized by condensation of various aromatic aldehyde and aromatic ketone. Chalcone is then treated with thiourea and KOH in presence of ethanol to yield pyrimidine derivatives. Then those pyrimidine derivatives were subjected to alkylation and acetylation. The synthesized compounds were characterized and confirmed by IR and 1HNMR spectroscopy and then evaluated for their anti-inflammatory activity. The anti-inflammatory activity of newly synthesized pyrimidine derivatives were carried out by the carrageenan induced rat hind paw edema method by taking Diclofenac sodium as standard.

Background 1,2,4-oxadiazole derivatives exhibited significant anti-cancer activity when they were evaluated, against human cancer cell lines. They also showed anti-inflammatory, analgesic, diabetic, immunosuppressive, α,β3-receptor antagonist, antimicrobial, anti-helminthic, histamine-H3 and antiparasitic properties. A pyrimidine analog, 5 fluoro-uracil is a chemotherapeutic drug used for treating multiple solid malignant tumors. But its application is limited, as it has side effects like low bioavailability and high toxicity. Molecular docking is an exemplary tool, helps in identifying target and designing a drug containing high bio-availability and minimum toxicity. Results A set of 1,2,4-oxadiazole linked 5-fluoruracil derivatives (7a–j) were synthesized and their structures were confirmed by 1HNMR, 13CNMR and Mass spectral analysis. Further, these compounds were investigated for their anticancer activity towards a panel of four human cancer cell lines such as (MCF-7, MDA MB-231), lung cancer (A549) and prostate cancer (DU-145) by using MTT method. Among them, compounds 7a, 7b, 7c, 7d and 7i demonstrated more promising anticancer activity than standard. Conclusion Synthesized derivatives (7a–j) of 1,2,4-oxadiazole linked 5-fluorouracil and investigated for their anticancer activity towards a panel of four human cancer cell lines.

Introduction and Aim:Epidermal Growth Factor Receptor tyrosine kinase is a well-known and widely studied cancer therapeutic target protein. Based on the reported anticancer activity of pyrimidines, a series of 13 compounds are designed. In the present studythe EGFR kinase domain is targeted with the designed 13 compounds. Materials and Methods:With missing residue in the kinase domain of EGFR crystallized structure, the domain is modelled using homology modelling, evaluated, energy-based optimization is carried out using OPLS in Gromacs. The default bindingsite was considered from the known EGFR kinase domain – Erlotinibcomplex crystallized structure. The molecular docking is carried out using AutodockVina, Insilico toxicity profiling and enrichment analysis of pathway is studied using Swiss-ADME and Enrich R. Results:Compounds 7, 9, 10 and 12 revealed a binding energy of -8.8, -8.3, -8.3 and -8.4 Kcal/mol and makes two h-bonds with MET-769. All the 13 compounds are under the range of Lipnski drug likeness, with high GI-absorption rate. Considering the metabolic enzyme activity, the entire series of compounds are predicted to inhibit the metabolizing enzyme CYP1A2, CYP2D6 and CYP3A4. Compounds 2, 3, 7, 8 and 13 acts as a substrate to CYP2C19 and compound 1, 3,4, 5, 6, 7, 8, 9, 10, 11, 12 and 13 act as a substrate to CYP2C9. Conclusion:The inhibition of metabolizing enzyme may affect the poor metabolizing and slowing down the excretion time of molecules from the body. The current in-silico molecular docking, in-silico PKPD study of compounds suggesting that they can be developed as putative lead compounds for developing new anti-cancer drugs.

5‐fluorouracil (5-FU), a pyrimidine analogue anticarcinogenic agent, is widely used in the solid tumors treatment. Use of the 5-FU causes cardiotoxicity. Our aim in this study investigations effects of Quercetin and Rutin on ECG parameters in the 5-FU-induced cardiotoxicity in rats. In the present study used male rats. Rats were divided randomly to eight group. The control group was given intragastric corn oil for 14 days. The 5-FU group rats were given ig corn oil for 14 days and injected intraperitoneal the single dose of 5-FU(50 mg/kg) on the eleventh day. The Q50+5-FU and Q100+5-FU groups were given ig 50 mg/kg and 100 mg/kg Q for 14 days, respectively and these groups were injected single dose of 5-FU(50 mg/kg) on the 11th days of Q application. The group Q100 was Q(100 mg/kg-ig) for 14 days. The Rutin50+5-FU and Rutin100+5-FU groups were injected ig 50 mg/kg and 100 mg/kg of the Rutin for 14 days, respectively. These groups were injected single dose of 5-FU(50 mg/kg) in the 11th days of Rutin application. The Rutin 100 group was given Rutin(100 mg/kg-ig) for 14 days. In the end of experimental application recorded to ECGs of the rats. 5-FU administration rats were observed that it was caused sinus tachycardia and ST elevation. Also, in the 5-FU group QRS segment was shorter and the duration and amplitude of the P was different from other groups. In both doses of Q and Rutin were prevented these changes and our findings were seen the consistent with the literature.

SecA, a key component of the bacterial Sec-dependent secretion pathway, is an attractive target for the development of new antimicrobial agents. We have previously reported pyrimidine analogs as SecA inhibitors. Herein, we report an extension of the earlier work in the synthesis and evaluation of a series of 15 5-cyanothiouracil derivatives as SecA inhibitors. All the compounds have been evaluated for their inhibition of SecA ATPase (EcSecAN68) and for their antimicrobial activity against Escherichia coli NR698 (a leaky mutant) and Bacillus anthracis Sterne. Twelve compounds showed IC50 of less than 6.3 μM when tested against EcSecAN68. In antimicrobial studies against E. coli NR698, six compounds showed MIC of

A highly efficient green protocol is described for the development of novel benzo[4,5]thiazolo[3,2-a]pyrimidine analogues through the one-pot fusion of the 2-amino-benzothiazole with different chos...

Aim: To synthesise biologically active thiazolidin-4-one by microwave irradiation method and evaluate against different species of bacteria, fungi and Plasmodium falciparum. Background: Microwave irradiation method is serviceable for rapid and sustainable synthesis. In this present study, Thiazolidin-4-one bearing pyrimidine derivatives have been synthesized by microwave irradiation method. Objective: Thiazolidin-4-one is a valuable motif because of its broad-spectrum biological evaluation. It is famous for many types of biological profiles, mainly antimicrobial, anti-tuberculosis, anti- convulsant, antihypertensive, hypoglycemic agent and antimalarial. This biological response leads our attention towards the change of Thiazolidin-4-one skeleton to enhance potential. Present study aims to carry out a rapid synthesis of Thiazolidin-4-one derivative of pyrimidine by microwave- assisted heating. Methods: 4-(4-substituted phenyl)-6-(substituted aryl) pyrimidin-2-amine was the key intermediate required for the synthesis of 3-(4-(Substituted phenyl)-6-(substituted aryl) pyrimidin-2-yl)-2-(4-hydroxy phenyl) thiozolidin-4-one (5A-J), which was prepared by using microwave irradiation. The structures of all newly synthesized motifs were characterized by spectral analysis (IR, 1H NMR, 13C NMR spectroscopy) and screened for antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pyogenes; antifungal activity against Candida albicans, Aspergillus niger, Aspergillus Clavatus; anti-tuberculosis activity against M. tuberculosis H37RV and antimalarial activity against Plasmodium falciparum. Results: Higher yield with less time-consuming method is the main advantage of Thiazolidin- 4-one bearing pyrimidine motifs synthesis. The excellent biological response of compounds 5B, 5C, 5D, 5G, 5H, 5I, and 5J was observed. Conclusion: As compared to conventional method, less time is required for the preparation of Thiazolidin- 4-one analogues by using advantageous microwave irradiation method. Thiazolidin-4-one derivatives showed improved biological activity.

Pyrimidine analogues can be considered as prodrugs, like their natural counterparts, they have to be activated within the cell. The intracellular activation involves several metabolic steps including sequential phosphorylation to its monophosphate, diphosphate and triphosphate. The intracellularly formed nucleotides are responsible for the pharmacological effects. This review provides a comprehensive overview of the clinical studies that measured the intracellular nucleotide concentrations of pyrimidine analogues in patients with cancer. The objective was to gain more insight into the parallels between the different pyrimidine analogues considering their intracellular pharmacokinetics. For cytarabine and gemcitabine, the intracellular pharmacokinetics have been extensively studied over the years. However, for 5-fluorouracil, capecitabine, azacitidine and decitabine, the intracellular pharmacokinetics was only very minimally investigated. This is probably owing to the fact that there were no suitable bioanalytical assays for a long time. Since the advent of suitable assays, the first exploratory studies indicate that the intracellular 5-fluorouracil, azacitidine and decitabine nucleotide concentrations are very low compared with the intracellular nucleotide concentrations obtained during treatment with cytarabine or gemcitabine. Based on their pharmacology, the intracellular accumulation of nucleotides appears critical to the cytotoxicity of pyrimidine analogues. However, not many clinical studies have actually investigated the relationship between the intracellular nucleotide concentrations in patients with cancer and the anti-tumour effect. Only for cytarabine, a relationship was demonstrated between the intracellular triphosphate concentrations in leukaemic cells and the response rate in patients with AML. Future clinical studies should show, for the other pyrimidine analogues, whether there is a relationship between the intracellular nucleotide concentrations and the clinical outcome of patients. Research that examined the intracellular pharmacokinetics of cytarabine and gemcitabine focused primarily on the saturation aspect of the intracellular triphosphate formation. Attempts to improve the dosing regimen of gemcitabine were aimed at maximising the intracellular gemcitabine triphosphate concentrations. However, this strategy does not make sense, as efficient administration also means that less gemcitabine can be administered before dose-limiting toxicities are achieved. For all pyrimidine analogues, a linear relationship was found between the dose and the plasma concentration. However, no correlation was found between the plasma concentration and the intracellular nucleotide concentration. The concentration-time curves for the intracellular nucleotides showed considerable inter-individual variation. Therefore, the question arises whether pyrimidine analogue therapy should be more individualised. Future research should show which intracellular nucleotide concentrations are worth pursuing and whether dose individualisation is useful to achieve these concentrations.

A series of some novel (E)-2-methyl/propyl-4-[(2-(substitutedbenzylidene)hydrazinyl]-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidines was synthesized and characterized by adopting an appropriate synthetic scheme. The effect of electron withdrawing and electron donating groups at the aromatic ring in presence of methyl and propyl substituents at the 2-position of the scaffold was evaluated for anthelmintic activity against adult Indian earthworms (Pheretima posthuma). Among 2-methyl-thieno[2,3-d]pyrimidine analogs, compounds with electron donating methoxy group either at para-position or at meta and para-positions of the aromatic ring showed potent anthelmintic activity at 100 μg/ml (284 and 261.8 μM concentrations) for compounds 5g and 5h with a mean paralytic time of 2.32, 2.22 min, and helminthicidal time of 22.38, 19.43 min, respectively. In contrast, the presence of electron withdrawing chloro group at ortho and para-position of the aromatic ring was found to be favorable for the anthelminthic activity of the compounds 5n and 5o (at concentration of 259.7 μM) with propyl group at the 2-position of the thieno[2,3-d]pyrimidine scaffold, exhibiting mean paralytic time of 2.5 min, 2.81 min and helminthicidal time of 21, 20.03 min, respectively. Anthelmintic activities of these four compounds 5g, 5h, 5n, and 5o (at the concentrations of 284, 261.8, 259.7, and 259.7 μM, respectively) were found to be on par with the standard drug piperazine adipate (time for paralysis and death at 6.25 and 24.5 min, respectively) at concentration of 100 μg/ml (431.03 μM). Overall, the potency of these compounds (5g, 5h, 5n, and 5o) is better than standard drug as they exhibited the same activity at 259.7–284 μM as that of a standard drug (which has shown the same activity at 431.03 μM). Further, the predicted ADME properties of all the synthesized compounds were found to be in the satisfactory ranges as predicted by SwissADME software and found to have drug-like properties. Thus, further modification of these compounds might lead to the discovery of more potent analogs.

5-fluorouracil (5-FU) refers to a fluorinated pyrimidine analogue that has been widely used as an anticancer agent for colon, head, and neck cancers. Detection of 5-FU and its metabolites; 5-fluoro...

Nucleoside analogues are a valuable experimental tool. Incorporation of these molecules into newly synthesized DNA (i.e. pulse-labeling) is used to monitor cell proliferation or to isolate nascent DNA. Some of the most common nucleoside analogues used for pulse-labeling of DNA in cells are the deoxypyrimidine analogues 5-ethynyl-2′-deoxyuridine (EdU) and 5-ethynyl-2′-deoxycytidine (EdC). Click chemistry enables conjugation of an azide molecule tagged with a fluorescent dye or biotin to the alkyne of the analog, which can then be used to detect incorporation of EdU and EdC into DNA. The use of EdC is often recommended because of the potential cytotoxicity associated with EdU during longer incubations. Here, by comparing the relative incorporation efficiencies of EdU and EdC during short 30-min pulses, we demonstrate significantly lower incorporation of EdC than of EdU in noninfected human fibroblast cells or in cells infected with either human cytomegalovirus or Kaposi's sarcoma-associated herpesvirus. Interestingly, cells infected with herpes simplex virus type-1 (HSV-1) incorporated EdC and EdU at similar levels during short pulses. Of note, exogenous expression of HSV-1 thymidine kinase increased the incorporation efficiency of EdC. These results highlight the limitations when using substituted pyrimidine analogues in pulse-labeling and suggest that EdU is the preferable nucleoside analogue for short pulse-labeling experiments, resulting in increased recovery and sensitivity for downstream applications. This is an important discovery that may help to better characterize the biochemical properties of different nucleoside analogues with a given kinase, ultimately leading to significant differences in labeling efficiency of nascent DNA.

Nevirapine (NVP) is widely used as a non-nucleoside reverse transcriptase inhibitor of HIV-1, however, it is associated with severe skin and liver injury. The mechanisms of these adverse reactions are not yet clear, but the metabolic activation of NVP is thought to be related to the injury process. Until now, several metabolic activation pathways of NVP have been reported. In this study, in order to identify the reactive metabolite of NVP mainly responsible for CYP inhibition and liver injury, we synthesized five NVP analogs designed to avoid the proposed bioactivation pathway and evaluated their metabolic stabilities, CYP3A4 time-dependent inhibitory activities, and cytotoxicity. As a result, only a pyrimidine analog of NVP, which could avoid the formation of a reactive epoxide intermediate, did not inhibit CYP3A4. Outside of this compound, the other synthesized compounds, which could avoid the generation of a reactive quinone-methide intermediate, inhibited CYP3A4 equal to or stronger than NVP. The pyrimidine analog of NVP did not induce cytotoxicity in HepG2 and transchromosomic HepG2 cells, expressing major four CYP enzymes and CYP oxidoreductase. These results indicated that the epoxide intermediate of NVP might play an important role in NVP-induced liver injury.

The chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus, and it is the causative agent of chikungunya fever (CHIKF). Although it has re-emerged as an epidemic threat, so far there are neither vaccines nor pharmacotherapy available to prevent or treat an infection. Herein, we describe the synthesis and structure-activity relationship studies of a class of novel small molecule inhibitors against CHIKV and the discovery of a new potent inhibitor (compound 6a). The starting point of the optimization process was N-ethyl-6-methyl-2-(4-(4-fluorophenylsulfonyl)piperazine-1-yl)pyrimidine-4-amine (1) with an EC50 of 8.68 μM, a CC50 of 122 μM, and therefore a resulting selectivity index (SI) of 14.2. The optimized compound 6a, however, displays a much lower micromolar antiviral activity (EC50 value of 3.95 μM), considerably better cytotoxic liability (CC50 value of 260 μM) and consequently an improved SI of greater than 61. Therefore, we report the identification of a promising novel compound class that has the potential for further development of antiviral drugs against the CHIKV. ispartof: ACS MEDICINAL CHEMISTRY LETTERS vol:11 issue:5 pages:906-912 ispartof: location:United States status: published

Purpose: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of deaths worldwide, pushing the urgent need for an efficient treatment. Nonstructural protein 15 (NSP15) is a promising target due to its importance for SARS-CoV-2’s evasion of the host’s innate immune response. Methods: Using the crystal structure of SARS-CoV-2 NSP15 endoribonuclease, we developed a pharmacophore model of the functional centers in the NSP15 inhibitor’s binding pocket. With this model, we conducted data mining of the conformational database of FDA-approved drugs. The conformations of these compounds underwent 3D fingerprint similarity clustering, and possible conformers were docked to the NSP15 binding pocket. We also simulated docking of random compounds to the NSP15 binding pocket for comparison. Results: This search identified 170 compounds as potential inhibitors of SARS-CoV-2 NSP15. The mean free energy of docking for the group of potential inhibitors were significantly lower than for the group of random compounds. Twenty-one of the compounds identified as potential NSP15 inhibitors were antiviral compounds used in the inhibition of a range of viruses, including MERS, SARS-CoV, and even SARS-CoV-2. Eight of the selected antiviral compounds in cluster A are pyrimidine analogues, six of which are currently used in a clinical setting. Four tyrosine kinase inhibitors were identified with potential SARS-CoV-2 inhibition, which is consistent with previous studies showing some kinase inhibitors acting as antiviral drugs. Conclusions: We recommended testing of these 21 selected antiviral compounds for the treatment of COVID-19.

This research presents the first example of the formation of a triplex via hydrogen bonding of a synthetic cyanuryl nucleoside (Cn) composed of a 6-membered ring compound (triazine-2,4,6-trione) which functions as a pyrimidine base. The Cn was able to form the triad via hydrogen bonding in two directions with two adenines, one in the antisense and one in the parallel chain. The thermal stability of the duplex between the antisense and sense chains was evaluated via its UV melting temperature. The melting curves of triplexes possessing the cyanuryl nucleoside (sense chain) and two adenines (antisense and parallel chains) were biphasic. To prove the formation of hydrogen bonding between the cyanuryl nucleoside and the adenine base toward the major groove, structural analysis via NMR was undertaken. A cyanuryl nucleoside containing three 15N in triazine-2,4,6-trione was synthesized first, and then the 15N cyanuryl nucleoside was incorporated into target sequences. The triplex containing the A·CnA triad was analyzed via 1H NMR, coupled and decoupled with 15N. This triad has two imino proton signals derived from the cyanuryl nucleoside, split according to the 15N coupling condition, at low field. These results are evidence of the formation of hydrogen bonds between the Cn and adenosine. The solution structure of the triplex was analyzed via NOE information from the imino proton. The cyanuryl nucleoside-containing triplex forms a right-handed helical structure similar to natural triplex DNA, albeit DNA having an enhanced pyrimidine analog in the sense chain capable of bidirectional hydrogen bonding with high sequence selectivity.

Multidrug-resistant (MDR) bacteria are widespread throughout the world and pose an increasingly serious threat to human and animal health. Besides implementing strict measures to prevent improper antibiotic use, it remains essential that novel antibiotics must be developed. These antibiotics need to exert their activity via mechanisms different from those employed by currently approved antibiotics. In this study, we used several 5-fluorouracil (5-FU) analogues as chemical probes and investigated the potential of these pyrimidine analogues as antibacterial agents. Several 5-FU derivatives exerted potent activity against strains of Gram-positive cocci (GPC) that are susceptible or resistant toward approved antibiotics, without showing cross-resistance. Furthermore, we have provided evidence that the pyrimidine analogues exerted anti-GPC activity via thymineless death by inhibition of thymidylate synthetase (ThyA) and/or inhibition of RNA synthesis. Interestingly, whole genome resequencing of in vitro-selected, pyrimidine analogue-resistant

A total of 66 novel heterofused pyrimidine analogues (pyrazolo[3,4-d]pyrimidine (7-43) and pyrido[2,3-d]pyrimidine (51a-l & 52a-h)) were synthesized by employing suitable methods. The desired structures of all the synthesized compounds were confirmed based on FT-IR, 1H NMR, 13C NMR and HRMS experimental data. Further, 19F NMR and 1H-15N HMBC of the representative compound were presented. All the final compounds were screened for their in vitro antitubercular (Mycobacterium tuberculosis; H37 Rv), antibacterial (S. aureus, B. subtilis, E. coli and P. aeruginosa) and antifungal (C. neoformans, C. albicans and A. niger) activities. Compounds 51d, 51j, 51k, 51l, and 51g displayed good antibacterial and antifungal activity (MIC = 12.5 μg/ml) against bacterial and fungal strains, while moderate inhibition (MIC = 59 μM) was observed for 51l against H37 Rv strain.

In this study, the acid chlorides of pyrazolo[3,4-d]pyrimidine compounds were prepared and reacted with a number of nucleophiles. The novel compounds were experimentally tested via enzyme assay and they showed cyclooxygenase-2 inhibition activity in the middle micro molar range (4b had a COX-1 IC50 of 26 µM and a COX-2 IC50 of 34 µM, 3b had a COX-1 IC50 of 19 µM and a COX-2 IC50 of 31 µM, 3a had a COX-2 IC50 of 42 µM). These compounds were analyzed via docking and were predicted to interact with some of the COX-2 key residues. Our best hit, 4d (COX-1 IC50 of 28 µM, COX-2 IC50 of 23 µM), appears to adopt similar binding modes to the standard COX-2 inhibitor, celecoxib, proposing room for possible selectivity. Additionally, the resultant novel compounds were tested in several in vivo assays. Four compounds 3a (COX-2 IC50 of 42 µM), 3d, 4d and 4f were notable for their anti-inflammatory activity that was comparable to that of the clinically available COX-2 inhibitor celecoxib. Interestingly, they showed greater potency than the famous non-steroidal anti-inflammatory drug, Diclofenac sodium. In summary, these novel pyrazolo[3,4-d]pyrimidine analogues showed interesting anti-inflammatory activity and could act as a starting point for future drugs.

Majority of breast cancers diagnosed today are estrogen receptor (ER)-positive, however, progesterone receptor-positive (PR-positive) is also responsible for breast cancer. Tumors that are ER/PR-positive are much more likely to respond to hormone therapy than tumors that are ER/PR-negative. Nearly 105 ERa inhibitors from literature when docked resulted in 31 compounds (pyrazolo[1,5-a]pyrimidine analogs and chromen-2-one derivatives) with better binding affinities. The maximum score obtained was -175.282 kcal/mol for compound, [2-(4- Fluoro-phenylamino)-pyridin-3-yl]-{4-[2-phenyl-7- (3, 4, 5-trimethoxy-phenyl)-pyrazolo[1,5-a]pyrimidine-5-carbonyl]-piperazin-1-yl}-methanone. The major H-bond interactions are observed with Thr347. In pursuit to identify novel ERa inhibitory ligands, virtual screening was carried out by docking pyrazole, bipyrazole, thiazole, thiadiazole etc scaffold analogs from literature.34 bipyrazoles from literature revealed Compound 2, ethyl 5-amino-1-(5-amino-3-anilino-4-ethoxycarbonyl-pyrazol-1-yl)-3-anilino-pyrazole-4-carboxylate, with -175.9 kcal/mol binding affinity with the receptor, where a favourable H-bond was formed with Thr347.On the other hand, screening 2035 FDA approved drugs from Drug Bank database resulted in 11 drugs which showed better binding affinities than ERa bound tamoxifen. Consensus scoring using 5 scoring schemes such as Mol Dock score, mcule, SwissDock, Pose&Rank and DSX respectively resulted in better rank-sumsfor Lomitapide, Itraconazole, Cobicistat, Azilsartanmedoxomil, and Zafirlukast.

Cancer is the second most dreaded disease worldwide. It is either acquired or inherited leading to the accompanying undesirable changes in the affected cells. Most existing chemotherapeutic drugs show enormous side effects. To minimize such effects, constant progress has been observed in the field of cancer by screening the anti-cancer effects of different chemical analogues. In the current study, we investigated the mechanism of action of a novel anticancer chromeno-pyrimidine analogue. We employed MTT, LDH assay to study cytotoxicity. DNA fragmentation, fluorescence imaging, and flow cytometric techniques have been carried out to study apoptosis, ROS generation, and cell cycle respectively. Wound healing assay and western blotting were used to evaluate the markers of epithelial-mesenchymal transition associated with metastasis. Molecular docking was used to predict possible protein targets that bind to this compound. The novel analogue induced apoptosis in lung adenocarcinoma cells and exhibited anti-metastatic activity. Increased expression of E-cadherin and inhibition of epithelial-mesenchymal transition was also observed. Docking studies with metastasis-related proteins such as Frizzled-7 (CRD), and Snail1 predict a high binding affinity of CP4b to both proteins. The novel analogue is therefore an anti-metastatic compound with EMT-inhibiting property and is hypothesized to act via binding to multiple targets in cancer cells.

We discovered 6-substituted thieno[2,3-d]pyrimidine compounds (3-9) with 3-4 bridge carbons and side-chain thiophene or furan rings for dual targeting one-carbon (C1) metabolism in folate receptor- (FR) expressing cancers. Synthesis involved nine steps starting from the bromo-aryl carboxylate. From patterns of growth inhibition toward Chinese hamster ovary cells expressing FRα or FRβ, the proton-coupled folate transporter or reduced folate carrier, specificity for uptake by FRs was confirmed. Anti-proliferative activities were demonstrated toward FRα-expressing KB tumor cells and NCI-IGROV1 ovarian cancer cells. Inhibition of de novo purine biosynthesis at both 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase and glycinamide ribonucleotide formyltransferase (GARFTase) was confirmed by metabolite rescue, metabolomics and enzyme assays. X-ray crystallographic structures were obtained with compounds 3-5 and human GARFTase. Our studies identify first-in-class C1 inhibitors with selective uptake by FRs and dual inhibition of enzyme targets in de novo purine biosynthesis, resulting in anti-tumor activity. This series affords an exciting new platform for selective multi-targeted anti-tumor agents.

SecA, a key component of the bacterial Sec-dependent secretion pathway, is an attractive target for the development of new antimicrobial agents. We have previously reported pyrimidine analogs as SecA inhibitors. Herein, we report an extension of the earlier work in the synthesis and evaluation of a series of 15 5-cyanothiouracil derivatives as SecA inhibitors. All the compounds have been evaluated for their inhibition of SecA ATPase (EcSecAN68) and for their antimicrobial activity against Escherichia coli NR698 (a leaky mutant) and Bacillus anthracis Sterne. Twelve compounds showed IC50 of less than 6.3 µM when tested against EcSecAN68. In antimicrobial studies against E. coli NR698, six compounds showed MIC of less than 12.5 µM with three being less than 6.3 µM. Against B. anthracis Sterne, three compounds showed MIC of less than 6.3 µM.

A series of nine novel thiazole linked chalcones, (E)-3-(4-methyl-2-(4(trifluoromethyl)phenyl)thiazol-5-yl)-1-phenylprop-2-en-1-one derivatives 7–15 were synthesized. To establish the structure–activity relationship (SAR), furthermore, the corresponding, ring-closed pyrimidine analogs 17–23 were synthesized. The derivatives thus obtained were evaluated for their anti-cancer activity against three genetically different colorectal cancer (CRC) cell lines. Thiazole derivatives 7, 9, and10 showed anti-cancer activity with GI50 values ranging from 0.19 to 100 µM. Importantly, compounds 7 and 10 outperformed the standard drug cisplatin in the tested cell lines and thus show promise for further optimization. Some of pyrimidine derivatives retain activity comparable to cisplatin in the HT-29 cell line, e.g. compounds 17 and 18 with IC50 of 25 µM, however, none of these compounds demonstrated improved antiproliferative activity as compared with the starting thiazole, thus the enone linker was critical for obtaining more active compounds in this series.

The synthetic halogenated pyrimidine analog, 5-bromo-2′-deoxyuridine (BrdU), is a marker of DNA synthesis. This exogenous nucleoside has generated important insights into the cellular mechanisms of the central nervous system development in a variety of animals including insects, birds, and mammals. Despite this, the detrimental effects of the incorporation of BrdU into DNA on proliferation and viability of different types of cells has been frequently neglected. This review will summarize and present the effects of a pulse of BrdU, at doses ranging from 25 to 300 µg/g, or repeated injections. The latter, following the method of the progressively delayed labeling comprehensive procedure. The prenatal and perinatal development of the cerebellum are studied. These current data have implications for the interpretation of the results obtained by this marker as an index of the generation, migration, and settled pattern of neurons in the developing central nervous system. Caution should be exercised when interpreting the results obtained using BrdU. This is particularly important when high or repeated doses of this agent are injected. I hope that this review sheds light on the effects of this toxic maker. It may be used as a reference for toxicologists and neurobiologists given the broad use of 5-bromo-2′-deoxyuridine to label dividing cells.

Fused pyrimidines, especially pyrazolo[3,4-d]pyrimidines, are among the most preferred building blocks for pharmacology studies, as they exhibit a broad spectrum of biological activity. In this study, new derivatives of pyrazolo[3,4-d]pyrimidine were synthesized by alkylation of the N1 nitrogen atom. We synthesized 3-iodo-1H-pyrazolo[3,4-d]pyrimidin-4-amine 2 from commercially available aminopyrazolopyrimidine 1 using N-iodosuccinimide as an iodinating agent. The synthesis of compound 2 started with nucleophilic substitution of 3-iodo-1H-pyrazolo[3,4-d]pyrimidin-4-amine with R-X (X: -OMs, -Br, -Cl), affording N-alkylated pyrazolo[3,4-d]pyrimidine. We performed this synthesis using a weak inorganic base and the mild temperature was also used for a two-step procedure to generate N-alkylated pyrazolo[3,4-d]pyrimidine derivatives. Also, all compounds were tested for their ability to inhibit acetylcholinesterase (AChE) and the human carbonic anhydrase (hCA) isoforms I and II, with Ki values in the range of 15.41 ± 1.39-63.03 ± 10.68 nM for AChE, 17.68 ± 1.92-66.27 ± 5.43 nM for hCA I, and 8.41 ± 2.03-28.60 ± 7.32 nM for hCA II. Notably, compound 10 was the most selective and potent CA I inhibitor with a significant selectivity ratio of 26.90.

This study synthesizes novel 6-amino-5-cyano-4-aryl-2-mercapto pyrimidines and condensed pyrimidines analogues in order to investigate their potential activity as anticancer agents. The compounds were synthesized via one-pot condensation of p-nitrobenzaldehyde or p-anisaldehyde with malononitrile and thiourea to prepare 6-amino-5-cyano-4-aryl-2-mercaptopyrimidines series (1-9a,b). The pyrimidine analogues were biologically screened In-vitro in HepG2 and MCF-7 compared to normal WI-38. Compound 8a showed higher antiproliferative activity to MCF-7 cells with sensitivity and minimal cytotoxic effect (IC50 53.3 µM- HepG2, 12.9 µM- MCF-7 and >100 µM- WI-38). Compound 8a was able to induce 40% of total antioxidants and 60% following treatment with 50 µM of H2O2 for 3hrs as external source of oxidative stress in MCF-7. 8a was able to significantly induce early stage apoptosis of 74.37% MCF-7 and cell cycle arrest with cells accumulation in subG0-G1 phase to 69.42% and reduction of cells in G2M phase to 3.6% and high apoptotic index. Compound 8a induced over-expression of Fas receptor and Cyto C genes. Molecular docking studies suggested that 8a can bind to both phosphodiesterase 4B and 4D binding pockets and inhibit their action through network of hydrophobic interactions in Q-P pockets with preferential selectivity to PDE4B through invariant Glu443. The chemical profile and the biological results suggest that 8a can be a promising anticancer agent.

Enterovirus A71 (EV-A71) is one of the aetiological agents for the hand, foot and mouth disease (HFMD) in young children and a potential cause of neurological complications in afflicted patients. Since its discovery in 1969, there remains no approved antiviral for EV-A71 and other HFMD-causing enteroviruses. We set out to address the lack of therapeutics against EV-A71 by screening an FDA-approved drug library and found an enrichment of hits including pyrimidine antimetabolite, gemcitabine which showed 90.2% of inhibition on EV-A71 infection. Gemcitabine and other nucleoside analogs, LY2334737 and sofosbuvir inhibition of EV-A71 infection were disclosed using molecular and proteomic quantification, and in vitro and in vivo efficacy evaluation. Gemcitabine displayed a significant reduction of infectious EV-A71 titres by 2.5 logs PFU/mL and was shown to target the early stage of EV-A71 viral RNA and viral protein synthesis process especially via inhibition of the RNA dependent RNA polymerase. In addition, the drug combination study of gemcitabine’s synergistic effects with interferon-β at 1:1 and 1:2 ratio enhanced inhibition against EV-A71 replication. Since gemcitabine is known to metabolize rapidly in vivo, other nucleoside analogs, LY2334737 and sofosbuvir conferred protection in mice against lethal EV-A71 challenge by potentially reducing the death rate, viral titers as well on virus-induced pathology in the limb muscle tissue of mice. Additionally, we found that gemcitabine is competent to inhibit other positive-sense RNA viruses of the Flaviviridae and Togaviridae family. Overall, these drugs provide new insights into targeting viral factors as a broad-spectrum antiviral strategy with potential therapeutic value for future development and are worthy of potential clinical application.

Objective: The present study was carried out to discover whether these pyrimidine derivatives have the potential to be used as epidermal growth factor receptor (EGFR) and carbonic anhydrase (CA) IX inhibitors through structure-based in silico study. Methods: Docking was performed on 6 pyrimidine analogs; cetuximab and curcumin were taken as reference drug. The structure of the target protein retrieved from the RCSB Protein databank and the protein-ligand docking was performed using Pyrx AutoDock wizard with MGL tools 1.5.6 by using Lamarckian algorithm. Results: All the compounds have shown lower binding energy and inhibition constant (Ki) value than reference drug cetuximab and curcumin. Out of the 6 inhibitors analyzed vkh has shown minimum binding energy against the target protein EGFR and CA IX respectively. Smaller Ki value shows stronger interaction. The scoring value of the interaction of vkh i. e-10.74 and-9.93 Kcal/mol and Ki 13.17ɳM and 53.04ɳM against the target protein EGFR and CA IX respectively while the reference drug cetuximab has shown binding energy-6.09 Kcal/mol with Ki value 34.44 µM and curcumin has shown binding energy-6.02 kcal/mol with Ki value 38.60 µM. Conclusion: It can be concluded that the molecule vkh could have potential to be used as an EGFR inhibitor and CA IX inhibitor.

The clinical evidence for the success of tyrosine kinase inhibitors in combination with microtubule-targeting agents prompted us to design and develop single agents that possess both epidermal growth factor receptor (EGFR) kinase and tubulin polymerization inhibitory properties. A series of 6-aryl/heteroaryl-4-(3′,4′,5′-trimethoxyanilino)thieno[3,2-d]pyrimidine derivatives were discovered as novel dual tubulin polymerization and EGFR kinase inhibitors. The 4-(3′,4′,5′-trimethoxyanilino)-6-(p-tolyl)thieno[3,2-d]pyrimidine derivative 6g was the most potent compound of the series as an antiproliferative agent, with half-maximal inhibitory concentration (IC50) values in the single- or double-digit nanomolar range. Compound 6g bound to tubulin in the colchicine site and inhibited tubulin assembly with an IC50 value of 0.71 μM, and 6g inhibited EGFR activity with an IC50 value of 30 nM. Our data suggested that the excellent in vitro and in vivo profile of 6g may be derived from its dual inhibition of tubulin polymerization and EGFR kinase.

The present study provides an overview of the chemistry and biological significance of pyrimido[4,5-d]pyrimidine and pyrimido[5,4-d]pyrimidine analogs as types of bicyclic [6 + 6] systems. The main sections include: (1) synthesis methods; (2) the reactivities of the substituents linked to the ring carbon and nitrogen atoms; and (3) biological applications. A discussion demonstrating the proposed mechanisms of unexpected synthetic routes is intended. The aim of this study is to discuss the synthetic significance of the titled compounds and to establish the biological characteristics of this class of compounds as studied to date, where the compounds have been applied on a large scale in the medical and pharmaceutical fields. This survey will help researchers in the fields of synthetic organic and medicinal chemistry to undertake and improve new approaches for the construction of new standard biological components.

The cyclin-dependent kinases (CDKs) play a crucial role in cell cycle progression and are validated targets of cancer therapy. Pyrazolopyrimidines are versatile scaffolds, which have been exploited for developing potential anticancer agents. We herein report the synthesis and in vitro CDK2/cyclin E kinase inhibitory activity of 34 novel 4,6-disubstituted pyrazolo [3,4-d]pyrimidines (9a-9s, 13a-13h, 14a-14d, 15a-15c). The structure-activity relationship (SAR) studies revealed that compounds with thiopentane/thiophenethyl group at C-6 and heteroatom-containing bicyclic moiety (benzofuran) at C-4 exhibited good CDK2 inhibitory activity. Further, the binding energies obtained for the active compounds from in silico molecular docking studies with CDK2 were found to be in consonance with the observed SAR and experimental results. In addition, some of the synthesized compounds showed anti-proliferative activity against K-562 (chronic myelogenous leukaemia) and MCF-7 (breast adenocarcinoma) cell lines in micromolar ranges. Further, the cytotoxicity studies on CHO cell line revealed that all the compounds are non-toxic to normal cells and are safe. Thus, the research findings revealed the anticancer potential of 4,6-disubstituted pyrazolo [3,4-d]pyrimidine derivatives which could be further considered for lead optimization.

New thiazolo[4,5-d]pyrimidine analogues were synthesized and biologically assessed in-vitro for their antineoplastic activity. The growth inhibitory effects of these compounds were assessed through the National Cancer Institute-United States of America (NCI-USA) anticancer screening program. Compound 5 (7-Chloro-3-(2,4-dimethoxyphenyl)-5-methylthiazolo[4,5-d]pyrimidine-2(3H)-thione) was found to have a potent and broad-spectrum cytotoxic action against NCI panel with GI50 (50% growth inhibition concentration) mean graph midpoint (MG-MID) = 2.88 µM. MTT assay was used to determine IC50 values of the most potent agent against HCT-116 colorectal carcinoma and WI-38 human lung fibroblast cell lines; 5.33 µM ± 0.69 and 21.69 µM ± 1.04, respectively. Flow cytometric analysis revealed that compound 5 triggered apoptosis and G2/M cell cycle arrest. The ability of compound 5 to inhibit CDK1 (Cyclin-Dependent Kinase 1)/Cyclin B complex was evaluated, and its IC50 value was 97 nM ± 2.33. Moreover, according to the gene expression analysis, compound 5 up-regulated p53, BAX, cytochrome c, caspases-3,-8 and-9 besides down-regulated Bcl-2. In conclusion, compound 5 exerted a potent pro-apoptotic activity through the activation of the intrinsic apoptotic pathway and arrested the cell cycle at the G2/M phase.

A series of Pyrazolo[1,5-a]Pyrimidine analogs were designed and synthesized as novel tubulin inhibitors. Among them, compounds 1a and 1b showed the highest antiproliferative activity against a panel of cancer cell lines with average IC50 values of 24.8 nM and 28 nM, respectively. We determined the crystal structures of 1a and 1b in complex with tubulin and confirmed their direct binding to the colchicine site. Compounds 1a and 1b also effectively inhibited tubulin polymerization in vitro, induced cell cycle arrest in G2/M phase, and inhibited cancer cell migration. In addition, compound 1b exhibited high metabolic stability in human liver microsomes. Finally, 1b was highly effective in suppressing tumor growth in a B16–F10 mouse melanoma model without apparent toxicity. In summary, these results suggest that 1b represents a promising tubulin inhibitor worthy of further investigation.

Novel fluorinated 2-amino-4-oxo-6-substituted pyrrolo[2,3- d]pyrimidine analogues 7-12 were synthesized and tested for selective cellular uptake by folate receptors (FRs) α and β or the proton-coupled folate transporter (PCFT) and for antitumor efficacy. Compounds 8, 9, 11, and 12 showed increased in vitro antiproliferative activities (∼11-fold) over the nonfluorinated analogues 2, 3, 5, and 6 toward engineered Chinese hamster ovary and HeLa cells expressing FRs or PCFT. Compounds 8, 9, 11, and 12 also inhibited proliferation of IGROV1 and A2780 epithelial ovarian cancer cells; in IGROV1 cells with knockdown of FRα, 9, 11, and 12 showed sustained inhibition associated with uptake by PCFT. All compounds inhibited glycinamide ribonucleotide formyltransferase, a key enzyme in the de novo purine biosynthesis pathway. Molecular modeling studies validated in vitro cell-based results. NMR evidence supports the presence of an intramolecular fluorine-hydrogen bond. Potent in vivo efficacy of 11 was established with IGROV1 xenografts in severe compromised immunodeficient mice.

Recently, it has been reported that large n JCC correlations can sometimes be observed in 1,1-ADEQUATE spectra with significant intensity, which opens the possibility of structural misassignment. In this work, we have focused on pyrimidine-based compounds, which exhibit multiple bond correlations in the 1,1-ADEQUATE experiment as a consequence of 3 JCC coupling constants greater than 10 Hz. Results are supported by both the experimental measurement of 3 JCC coupling constants in question using J-modulated-ADEQUATE and density functional theory calculations.

Tumor-targeted specificities of 6-substituted pyrrolo-[2,3-d]pyrimidine analogues of 1, where the phenyl side-chain is replaced by 3′,6′ (5, 8), 2′,5′ (6, 9), and 2′,6′ (7, 10) pyridyls, were analyzed. Proliferation inhibition of isogenic Chinese hamster ovary (CHO) cells expressing folate receptors (FRs) α and β were in rank order, 6 > 9 > 5 > 7 > 8, with 10 showing no activity, and 6 > 9 > 5 > 8, with 10 and 7 being inactive, respectively. Antiproliferative effects toward FRα- and FRβ-expressing cells were reflected in competitive binding with [(3)H]folic acid. Only compound 6 was active against proton-coupled folate receptor (PCFT)-expressing CHO cells (~4-fold more potent than 1) and inhibited [(3)H]methotrexate uptake by PCFT. In KB and IGROV1 tumor cells, 6 showed

Pyrimidines are nitrogen-containing heterocycles known for anticancer, anti-HIV, antifungal, and antibacterial activities. Pyrimidines, compounds bearing this heterocycle, are common in many medicinal drugs. Based on these findings, we have also reported the synthesis and biological activities of potential pyrimidine analogs. This review article provides a comprehensive insight into clinically approved pyrimidine-containing drugs and recent reports based on the broad-spectrum activities of pyrimidine analogs. Further, this review highlights the main aspects of pyrimidine analogs such as anticancer, sedative, antibiotic, antiviral, anti-inflammatory, analgesics, and anti-microbial activities, that make this molecule a more attractive scaffold for the discovery of newer drugs.

The inhibition of the enzyme TMP kinase (TMPKmt), is hypothesized as a significant therapy for tuberculosis. A series of designed pyrimidines were synthesized to inhibit the enzyme TMPKmt and evaluated for their enzyme-ligand interactions, antitubercular, physiochemical and ADMET properties. The pyrimidines were synthesized from chalcones and guanidine as the cyclizing agent. The molecular interactions were studied by Autodock 4.0 and physicochemical, druglikeness and ADMET properties were analysed by Molinspiration, Chemsketch program and admetSAR prediction tools. The confirmation of the synthesized titled compound’s structures was by spectral analysis. Also, they were screened for their antitubercular activity. In silico studies reports that their physicochemical, ADMET and druglikeness properties were found to be in standard limit, which infers that, these compounds may not have problems with oral bioavailability. Molecular docking studies showed that the pyrimidines have better enzyme inhibitory activity onTMPKmt.

This study was focused on the synthesis of new pyrimidines 4a,b, 5a,b and pyrazoles 6a, b as ATP mimicking tyrosine kinase inhibitors of the epidermal growth factor receptor (EGFR). The new compounds were assessed as cytotoxic candidates against human breast cancer cells (MCF-7) and hepatocellular carcinoma cells (HepG-2). All the new compounds appeared as more potent cytotoxic agents than erlotinib, while only compound 4a exhibited more potency than 5-flourouracil and 4b analogue was equipotent to it. Accordingly, the kinase suppression effect of 4a and 4b was further evaluated against EGFRWT, EGFRL858R and EGFRT790M. Both pyrimidine analogues 4a and 4b displayed outstanding inhibitory activity against EGFRWT and its two mutated isoforms EGFRL858R and EGFRT790M in comparing to erlotinib and osimertinib as reference drugs. Additionally, all the new analogues were subjected to antimicrobial assay. Interestingly, both 4a and 4b represented the most promising activity of wide spectrum antimicrobial effect against the examined microbes in comparison to gentamycin and ketoconazole as standard drugs. Moreover, docking results proved the good binding interactions of the compounds 4a and 4b with EGFRWT and EGFRT790M which were in accordance with the results of the in vitro enzyme assay. Additional in silico ADMET studies were performed for the new derivatives which represented their good oral absorption, good drug-likeness properties and low toxicity risks in human.

Pyrimidine dimerization is the dominant DNA photoreaction occurring in vitro and in vivo. Three types of dimers, cyclobutane pyrimidine dimers (CPDs), pyrimidine (6-4) pyrimidone photoproducts (6-4PPs), and the spore photoproduct (SP), are formed from the direct dimerization process; it is of significance to understand the photochemistry and photobiology of these dimers. Traditionally, pyrimidine dimerization was studied by using the natural pyrimidine residues thymine and cytosine, which share similar chemical structures and similar reactivity, making it sometimes less straightforward for one to identify the key pyrimidine residue that needs to be excited to trigger the photoreaction. We thus adopted synthetic chemistry to selectively modify the pyrimidine residues or to introduce pyrimidine analogs to the selected positions before UV irradiation is applied. By monitoring the subsequent outcomes from the photoreaction, we were able to gain unique mechanistic insights into the photochemistry of SP as well as of CPDs and 6-4PPs. Moreover, our approaches have resulted in several useful “tools” that can facilitate the understanding of lesion photobiology. Our results summarized in this account illustrate what organic synthesis/chemical analysis may allow us to achieve in future DNA lesion biology studies. 1 Introduction 2 Using the Deuterium Labeling Strategy to Understand SP Formation 3 Using Microcrystals to Reveal the Reaction Intermediates in SP Formation 4 Using a Phosphate Isostere to Understand the SP Structure 5 Synthesis of SP Phosphoramidite and SP Structural Studies 6 Using a Thymine Isostere to Understand CPD Formation 7 Using a Thymine Isostere to Understand 6-4PP Photoreaction 8 Understanding the Chemical Stability of SP 9 Understanding the Chemical Stability of 6-4PP10 Summary and Perspectives for Future Research

HIV-1 reverse transcriptase (RT) is one of the most important enzymes required for viral replication, thus acting as an attractive target for antiretroviral therapy. Pyrimidine analogues reportedly have selective inhibition on HIV-1 RT with favorable antiviral activities in our previous study. To further explore the relationship between inhibitory activity and pharmacophoric characteristics, field-based QSAR models were generated and validated using Schrodinger Suite (correlation coefficient of .8078, cross-validated value of 0.5397 for training set and Q2 of 0.4669, Pearson's r of .7357 for test set). Docking, pocket surfaces, and pharmacophore study were also investigated to define the binding pattern and pharmacophoric features, including (i) π-π interaction with residue Tyr181, Tyr188, and Trp229 and p-π interaction with His235 and (ii) hydrogen bond with residue Lys101 and halogen bond with residue Tyr188. The pharmacophore features of six-point hypothesis AADRRR.184, AAADRR.38, and AADRRR.26 further complimented to the docking and QSAR results. We also found that the protein-ligand complex exhibited high relative binding free energy. These observations could be potentially utilized to guide the rational design and optimization of novel HIV-1 RT inhibitors.

A series of novel 6-substituted pyrrolo[3,2-d]pyrimidine analogues (10a, 11a-13a, 15a, 17a, 18a, 27a and 28a) have been designed and synthesized as antifolate antitumor agents. The anti-proliferative activities of these compounds against HL60, A549, H1299, Hela, HCT116 and HT29 tumor cells were evaluated. Most of the compounds exhibited micromolar anti-proliferative potencies. Compound 15a, the most potent one, has GI50 value of 0.73, 1.72, and 8.92 μM against A549, H1299 and HL60 cells, respectively. The cell cycle distribution assay displayed that 15a could increase the accumulation of G2/M-phase cells. 15a showed low potency in induction of apoptosis. However, the inhibition of A549 cell colony formation was observed. These indicated that the tumor cell death relied on the irreversible effect of 15a on clonogenicity and cell proliferation. The identification of targeted pathway of 15a implied that the anti-proliferative potencies of 15a probably act through dual inhibition of thymidylate synthase (TS) and dihydrofolate reductase (DHFR).

The one-pot three-component reaction for the synthesis of pyrido[2,3-d]pyrimidine derivatives has been reported via initial Knoevenagel, subsequent addition and final heterocyclization of substituted aromatic aldehydes, cyanoacetamide and 6-aminouracil in N,N-dimethylformamide (DMF) solvent using 4-dimethylaminopyridine (DMAP) as new organocatalyst under ultrasound irradiation. The results showed that a series of aromatic aldehydes were successfully used to prepare the targeted pyrido[2,3-d]pyrimidine derivatives with good to excellent yields (81–93%) and there is no major effect on the yield of product by electron donating/withdrawing substituents. Short reaction time, environment friendly procedure, excellent yields, inexpensive and readily available catalyst are the advantages of this procedure. All synthesized compounds were characterized by IR, 1HNMR, 13CNMR and mass spectral data.

In this study, an efficient multicomponent one-pot route is described for the DABCO-catalyzed synthesis of tetrazolo[1,5-a]pyrimidines. This synthesis strategy is based on the reaction of malononitrile and aldehydes with 5-aminotetrazole monohydrate using 1,4-diazabicyclo[2.2.2]octane (DABCO) in i-PrOH under reflux conditions. This protocol is a simple, green, and low-cost technique to prepare new compounds with potential medicinal properties.

PI3Kα/mTOR ATP-competitive inhibitors are considered as one of the promising molecularly targeted cancer therapeutics. Based on lead compound A from the literature, two similar series of 2-substituted-4-morpholino-pyrido[3,2-d]pyrimidine and pyrido[2,3-d]pyrimidine analogs were designed and synthesized as PI3Kα/mTOR dual inhibitors. Interestingly, most of the series gave excellent inhibition for both enzymes with IC50 values ranging from single to double digit nM. Unlike many PI3Kα/mTOR dual inhibitors, our compounds displayed selectivity for PI3Kα. Based on its potent enzyme inhibitory activity, selectivity for PI3Kα and good therapeutic index in 2D cell culture viability assays, compound 4h was chosen to be evaluated in 3D culture for its IC50 against MCF7 breast cancer cells as well as for docking studies with both enzymes.

Promising 6-nitro-1,2,4-triazolo[1,5-a]pyrimidine analogues, structural analogues of synthetic inhibitors of adenosine receptors, were sorted out on the basis of quantum-chemical calculations. The compounds were synthesized by nitration and chlorodeoxygenation reactions. The in vivo activity of 6-nitroheterocycles was studied and the affinity to adenosine receptor A2A was demonstrated in regard to septic conditions.

Many anticancer and antiviral drugs are purine or pyrimidine analogues, which use membrane transporters to cross cellular membranes. Concentrative nucleoside transporters (CNTs) mediate the salvage of nucleosides and the transport of therapeutic nucleoside analogues across plasma membranes by coupling the transport of ligands to the sodium gradient. Of the three members of the human CNT family, CNT3 has the broadest selectivity and the widest expression profile. However, the molecular mechanisms of the transporter, including how it interacts with and translocates structurally diverse nucleosides and nucleoside analogues, are unclear. Recently, the crystal structure of vcCNT showed that the prokaryotic homologue of CNT3 forms a homotrimer. In this study, we successfully expressed and purified the wild type human homologue, hCNT3, demonstrating the homotrimer by size exclusion profiles and glutaraldehyde cross-linking. Further, by creating a series of cysteine mutants at highly conserved positions guided by comparative structure models, we cross-linked hCNT3 protomers in a cell-based assay, thus showing the existence of hCNT3 homotrimers in human cells. The presence and absence of cross-links at specific locations along TM9 informs us of important structural differences between vcCNT and hCNT3. Comparative modeling of the trimerization domain and sequence coevolution analysis both indicate that oligomerization is critical to the stability and function of hCNT3. In particular, trimerization appears to shorten the translocation path for nucleosides across the plasma membrane and may allow modulation of the transport function via allostery.