Synthesis and antiviral screening of some thieno[2,3-d]pyrimidine nucleosides

An assessment of EGFR and HER2 inhibitors with structure activity relationship of fused pyrimidine derivatives for breast cancer: a brief review

Epidermal growth factor receptor (EGFR) and its subtype human epidermal growth factor receptor 2 (HER2) gets activated when its endogenous ligand(s) bind to its ATP binding site of target receptors. In breast cancer (BC), EGFR and HER2 are two proteins are overexpressed which leads to overexpression of cells proliferation and decreases cell death/apoptosis. Pyrimidine is one of the most widely studied heterocyclic scaffolds for EGFR as well as HER2 inhibition. We gather some remarkable results for fused-pyrimidine derivatives on various cancerous cell lines (in-vitro) and animal (in-vivo) evaluation to highlight their potency. The heterocyclic (five, six-membered, etc.) moieties which are coupled with pyrimidine moiety are potent against EGFR and HER2 inhibitions. Hence structure-activity relationship (SAR) plays important role in study of heterocyclic moiety along pyrimidine and effects of substituents, groups for increase or decrease in the cancerous activity and toxicity. By thoughtful of fused pyrimidines SAR study, it facilitates in receiving excellent overview of the compounds by concerning of efficacy and potential summary for future EGFR inhibitors. Furthermore, we studied the in-silico interactions of synthesized compounds to evaluate binding affinity towards the key amino acids..Communicated by Ramaswamy H. Sarma.

Analysis of fluoro based pyrazole analogues as a potential therapeutics candidate against Japanese encephalitis virus infection

Japanese encephalitis virus (JEV) is the leading causative agent of encephalitis and its associated mortality among children. JEV modulates host cell machinery for its advantage, such as oxidative damage which subsequently leads to stress responsive pathways. The present study analyzes new series of dinitroaryl substituted derivatives (1a-1f), containing pyrazole moiety and explores its potential ensuing anti-JEV activity. Out of all synthesized derivatives, compounds 1b and 1f were selected based on minimal cytotoxicity. In vitro inhibition of more than 70% and 90% were observed with compounds 1b and 1f, respectively, in neuronal cells. Dose-response analyses highlighted 1f exhibiting better antiviral activity than 1b. The mice treated with compound 1b or 1f did not show any noticeable toxicity at a dose of 100mg/kg/day when administered intraperitoneally till 96th h. Inhibition of up to 41% and 70% JEV mRNA in spleen and 33% to 43% in brain tissue was observed with compounds 1b and 1f, respectively. Both the compounds suppressed JEV induced ROS generation by up-regulating the NQO1 and HO-1 proteins. Our result suggests the interlocked positive feedback loops of NRF2-SQSTM1 signaling pathway to be regulated by the synthesized compounds. The potential of these compounds can be further tested for broad-spectrum antiviral effects with other flaviviruses in the path towards the development of therapeutics.

A Review on Fused Pyrimidine Systems as EGFR Inhibitors and Their Structure–Activity Relationship

Epidermal growth factor receptor (EGFR) belongs to the family of tyrosine kinase that is activated when a specific ligand binds to it. The EGFR plays a vital role in the cellular proliferation process, differentiation, and apoptosis. In the case of cancer, EGFR undergoes uncontrolled auto-phosphorylation that results in increased cellular proliferation and decreased apoptosis, causing cancer promotion. From the literature, it shows that pyrimidine is one of the most commonly studied heterocycles for its antiproliferative activity against EGFR inhibition. The authors have collated some interesting results in the heterocycle-fused pyrimidines that have been studied using different cell lines (sensitive and mutational) and in animal models to determine their activity and potency. It is quite clear that the fused systems are highly effective in inhibiting EGFR activity in cancer cells. Therefore, the structure–activity relationship (SAR) comes into play in determining the nature of the heterocycle and the substituents that are responsible for the increased activity and toxicity. Understanding the SAR of heterocycle-fused pyrimidines will help in getting a better overview of the molecules concerning their activity and potency profile as future EGFR inhibitors.

Sublimation thermodynamics of nucleobases derived from fast scanning calorimetry

Fast scanning calorimetry was utilized to measure the sublimation thermodynamics of nucleobases. The results were rationalized at the molecular level.

Thieno[2,3-d]pyrimidine as a promising scaffold in medicinal chemistry: Recent advances

Thienopyrimidine scaffold is a fused heterocyclic ring system that structurally can be considered as adenine, the purine base that is found in both DNA and RNA-bioisosteres. Thienopyrimidines exist in three distinct isomeric forms. The current review discusses thieno[2,3-d]pyrimidine as a one of the opulent heterocycles in drug discovery. Its broad range of medical applications such as anticancer, anti-inflammatory, anti-microbial, and CNS protective agents has inspired us to study its structure-activity relationship (SAR), along with its relevant synthetic strategies. The present review briefly summarizes synthetic approaches for the preparation of thieno[2,3-d]pyrimidine derivatives. In addition, the promising biological activities of this scaffold are also illustrated with explanatory diagrams for their SAR studies.

Design, Synthesis, and Biological Activity of Tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine Derivatives as Anti-Inflammatory Agents

We designed and synthesized 26 prototype compounds and studied their anti-inflammatory activity and underlying molecular mechanisms. The inhibitory effects of the compounds on the production of nitric oxide (NO), cytokines, inflammatory-related proteins, and mRNAs in lipopolysaccharide (LPS)-stimulated macrophages were determined by the Griess assay, Enzyme linked immunosorbent assay (ELISA), Western blot analysis, and Reverse transcription-Polymerase Chain Reaction (RT-PCR), respectively. Our results indicated that treatment with A2, A6 and B7 significantly inhibited the secretion of NO and inflammatory cytokines in RAW264.7 cells without demonstrable cytotoxicity. It was also found that A2, A6 and B7 strongly suppressed the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase enzyme COX-2, and prevented nuclear translocation of nuclear factor κB (NF-κB) p65 by inhibiting the degradation of p50 and IκBα. Furthermore, the phosphorylation of mitogen-activated protein kinase (MAPKs) in LPS-stimulated RAW264.7 cells was significantly inhibited by A2, A6 and B7. These findings suggest that A2, A6 and B7 may operate as an effective anti-inflammatory agent through inhibiting the activation of NF-κB and MAPK signaling pathways in macrophages. Moreover, rat paw swelling experiments showed that these compounds possess anti-inflammatory activity in vivo, with compound A6 exhibiting similar activities to the reference drug Indomethacin.

Design, Synthesis, and Molecular Docking of Novel Pyrrolooxazepinediol Derivatives with Anti-Influenza Neuraminidase Activity

A series of novel pyrrolo[2,1-b][1,3]oxazepine-8,9-diol derivatives 12-15 were synthesized starting from l-tartaric acid, which was transformed into anhydride which then reacted with allylamine in xylene to afford the imide 2. The target molecules 12-15 were achieved via ring-closing metathesis with the Grubbs catalyst, followed by reduction of the carbonyl group and deprotection of hydroxyl groups. Finally, catalytic hydrogenation of the double bond afforded the title compounds 12-15. Molecular docking study of the title compounds 12-15 was carried out against neuraminidase as the target enzyme, in an attempt to understand the mechanism of action of the tested compounds as potential neuraminidase inhibitors. Molecular docking of the target compounds showed that all tested compounds bind to the active site of neuraminidase, with moderate to high binding energy. Compounds 12-15 were examined for their antiviral activity against H5N1 virus (A/chicken/Egypt/1/2008). Oseltamivir phosphate was used as a control for antiviral activity. The results show that compound 12 (EC₅₀  = 0.016 μg/mL) exhibited potent anti-influenza (H5N1) activity, which approximately equals that of oseltamivir (EC₅₀  = 0.012 μg/mL). Also, it had a therapeutic index similar to that of oseltamivir phosphate (∼20). The data also revealed that compounds 13, 14, and 15 had slightly lower antiviral activity and lower cytotoxicity than oseltamivir phosphate, with LD₅₀ of 0.188, 0.162, and 0.176 μg/mL, respectively. However, 13, 14, and 15 had lower therapeutic indices than 12. In conclusion, we were able to synthesize cheap and potent anti-H5N1 compounds.

Chromone-fused cytosine analogues: synthesis, biological activity, and structure-activity relationship

The preparation of a series of novel chromone-fused cytosine analogues, i.e., chromeno[2,3-d]pyrimidines has been carried out from substituted 2-amino-4-oxo-4H-chromene-3-carbonitriles with urea, thiourea, and guanidine under different reaction conditions. These chromone-fused cytosine analogues were evaluated for their in vitro activity against Mycobacterium tuberculosis H37Rv strain and different microbial pathogenic strains in cell culture for their structure-activity relationships, respectively. Among the synthesized compounds, 2d, 3a, and 4e showed better results against Mycobacterium tuberculosis H37Rv. The compounds 2a, 2b, and 3a showed potential antibacterial activity against E. coli and P. aeruginosa, while the majority of compounds were found to be active against S. aureus as compared to ampicillin. The synthesized cytosine analogues having an imine (-C&dbnd;NH) have been less sensitive to the bacterial and fungal strains but have a more beneficial effect on Mycobacterium tuberculosis H37Rv.

In search of uracil derivatives as bioactive agents. Uracils and fused uracils: Synthesis, biological activity and applications

This review article is an effort to summarize recent developments in researches providing uracil derivatives with promising biological potential. This article also aims to discuss potential future directions on the development of more potent and specific uracil analogues for various biological targets. Uracils are considered as privileged structures in drug discovery with a wide array of biological activities and synthetic accessibility. Antiviral and anti-tumour are the two most widely reported activities of uracil analogues however they also possess herbicidal, insecticidal and bactericidal activities. Their antiviral potential is based on the inhibition of key step in viral replication pathway resulting in potent activities against HIV, hepatitis B and C, the herpes viruses etc. Uracil derivatives such as 5-fluorouracil or 5-chlorouracil were the first pharmacological active derivatives to be generated. Poor selectivity limits its therapeutic application, resulting in high incidences of gastrointestinal tract or central nervous toxicity. Numerous modifications of uracil structure have been performed to tackle these problems resulting in the development of derivatives exhibiting better pharmacological and pharmacokinetic properties including increased bioactivity, selectivity, metabolic stability, absorption and lower toxicity. Researches of new uracils and fused uracil derivatives as bioactive agents are related with modifications of substituents at N(1), N(3), C(5) and C(6) positions of pyrimidine ring. This review is an endeavour to highlight the progress in the chemistry and biological activity of the uracils, predominately after the year 2000. In particular are presented synthetic methods and biological study for such analogues as: 5-fluorouracil or 5-chlorouracil derivatives, tegafur analogues, arabinopyranonucleosides of uracil, glucopyranonucleosides of uracil, liposidomycins, caprazamycins or tunicamycins, tritylated uridine analogues, nitro or cyano derivatives of uracil, uracil-quinazolinone, uracil-indole or uracil-isatin-conjugates, pyrimidinophanes containing one or two uracil units and nitrogen atoms in bridging polymethylene chains etc. In this review is also discussed synthesis and biological activity of fused uracils having uracil ring annulated with other heterocyclic ring.

Synthesis of Some 4,5-Dihydrothieno[3,2-e][1,2,4]Triazolo[4,3-a] Pyrimi-dine-2-Carboxamides as Anti-Inflammatory and Analgesic Agents

A new series 4,5-dihydrothieno[3,2-e][1,2,4]triazolo[4,3-a]pyrimidine-2-carboxamide was synthesized. Twenty one newly synthesized compounds were investigated for their anti-inflammatory and analgesic activity using acute and subacute formalin-induced paw edema models and diclofenac Na as a reference. The acute toxicity (ALD50) and ulcerogenic effects of the active compounds were also determined. The thienotriazolopyrimidines 10a, 10c and 11c were found to exhibit remarkable anti-inflammatory activity at both models in addition to good analgesic activity with a delayed onset of action. Moreover, the active compounds showed high GI safety level and are well tolerated by experimental animals with high safety margin (ALD50 > 0.4 g/kg). Docking study using Molecular Operating Environment (MOE) version 2008.10 into COX-2 has been made for derivatives of highest anti-inflammatory activity.

HIV-1 and HSV-1 virus activities of some new polycyclic nucleoside pyrene candidates

In continuation of our previous work, a novel series of polycyclic derivatives 2-8 incorporated heterocyclic and sugar moieties were synthesized by using pyren-1-aldehyde (1) as starting material and their tested as antiviral activities. Initially, the toxicity of the compounds was assayed via the determination of their EC(50). Some of the synthesized compounds were tested as antiviral activity against HIV-1 and HSV-1. The structure of the new compounds was confirmed by using chemical and spectroscopic evidences. The detailed of synthesis, spectroscopic data, antiviral activities of the synthesized compounds were reported.

Design, synthesis and biological evaluation of some novel thienopyrimidines and fused thienopyrimidines as anti-inflammatory agents

Some new substituted thienopyrimidine derivatives comprising thioxo, thioalkyl and pyrazolyl derivatives as well as fused thienotriazolopyrimidine and thienopyrimidinotriazine ring systems were prepared from 3-benzyl-2-hydrazino-5-methyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxamide 4. The designed compounds were evaluated for their anti-inflammatory activity. Compounds 4, 9, 10 and 13 showed the highest anti-inflammatory effect compared with the reference drug diclofenac sodium.

Thieno[2,3-d]pyrimidinedione derivatives as antibacterial agents

Several thieno[2,3-d]pyrimidinediones have been synthesized and examined for antibacterial activity against a range of gram-positive and gram-negative pathogens. Two compounds displayed potent activity (2-16 mg/L) against multi-drug resistant gram-positive organisms, including methicillin resistant, vancomycin-intermediate, vancomycin-resistant Staphylococcus aureus (MRSA, VISA, VRSA) and vancomycin-resistant enterococci (VRE). Only one of these agents possessed moderate activity (16-32 mg/L) against gram-negative strains. An examination of the cytotoxicity of these agents revealed that they displayed low toxicity (40-50 mg/L) against mammalian cells and very low hemolytic activity (2-7%). Taken together, these studies suggest that thieno[2,3-d]pyrimidinediones are interesting scaffolds for the development of novel gram-positive antibacterial agents.

Synthesis of new 5,6-dihydrobenzo[h]quinazoline 2,4-diamino substituted and antiplatelet/antiphlogistic activities evaluation

In pursuing our research on some 2,4-diamino-benzopyranopyrimidines and 2-amino-5,6-dihydrobenzo[h]quinazolines, previously reported as antiplatelet and analgesic/anti-inflammatory agents respectively, we designed and synthesized a new series of 5,6-dihydrobenzo[h]quinazoline 2,4-diamino substituted. The insertion of amino substituents at positions 2 and 4 of the benzoquinazoline scaffold resulted in compounds endowed with a potent ASA-like antiplatelet activity, combined with an anti-inflammatory activity comparable, in some cases, to that of indomethacin, used as a reference drug.

A facile synthesis and anti-avian influenza virus (H5N1) screening of some novel pyrazolopyrimidine nucleoside derivatives

Treatment of 5-amino-1-(9-methyl-5,6-dihydronaphtho[1',2':4,5]thieno[2,3-d]pyrimidin-11-yl)-1H-pyrazole-4-carbonitrile (1) with formic acid afforded pyrazolo[3,4-d]pyrimidin-4-one derivative 2. The sodium salt of the latter compound (generated in situ) was treated with some alkyl halides to afford the corresponding N-substituted compounds 3-7. The siloxy derivative 8 (generated also in situ from 2) was ribosylated and glycosylated to yield compounds 9 and 11, respectively. Deprotection of compounds 9 and 11 in methanolic ammonia produced the free nucleosides 10 and 12, respectively. Moreover, the prepared compounds were tested for antiviral activity against H5N1 virus [A/chicken/Egypt/1/2006] and some of them revealed moderate results compared with the other tested compounds.

Cationic schiff base amphiphiles and their metal complexes: Surface and biocidal activities against bacteria and fungi

A series of cationic surfactants containing schiff base groups was synthesized by condensation of four fatty amines namely: dodecyl, tetradecyl, hexadecyl and octadecyl amine and 4-diethyl aminobenzaldehyde (1-4), as well as their metal complexes with divalent transition metal ions including Co, Cu and Mn (5-16). The surface activities of the synthesized surfactants were influenced by their chemical structures and the type of the transition metals. The biological activity measurements of the parent cationic schiff bases showed high efficacy against Gram positive and Gram negative bacterial strains and fungi. While on complexation, the biocidal activity was increased remarkably. The biocidal activity of the tested compounds against sulfur reducing bacteria showed promising results in the field of biocide applications.

Iodine catalysed synthesis and antibacterial evaluation of thieno-[2,3-d]pyrimidine derivatives

A new route via iodine catalysed heterocyclisation of 2-amino-4,5-dimethylthiophene-3-carboxamide with aromatic aldehydes affording a series of thieno[2,3- d]pyrimidine derivatives in a single step have been developed. Some of these compounds exhibited antibacterial activities comparable to Streptomycin as reference drug.

Synthesis and antimicrobial activity of some cyclic and acyclic nucleosides of thieno[2,3-d]pyrimidines

The reaction of compounds 1, 2, 3, 4, or 13 with 2-chloroethyl methyl ether or 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide, afforded some acyclic and cyclic nucleosides of thieno[2,3-d]pyrimidine derivatives. Furthermore, cyclic C-nucleosides 24 and 25 were prepared from the reaction of 20, 21 or from 26, 27 with D-glucose. The antimicrobial evaluation of some prepared products showed promising antimicrobial activity.