Synthesis of novel benzo[4,5]thiazolo[1,2-a]pyrimidine-3-carboxylate derivatives and biological evaluation as potential anticancer agents

Design, synthesis, docking, and anticancer evaluations of new thiazolo[3,2-a] pyrimidines as topoisomerase II inhibitors

New thiazolopyrimidine derivatives 2, 3a-d, 4a-c, 5, 6a-c, and 7a,b were synthesised. All prepared compounds were evaluated by MTT cytotoxicity assay against three human tumour cell lines. Compounds 3c, 3d, 4c, 6a, 6b, and 7b exhibited potent to strong anticancer activity that was nearly comparable or superior to Doxorubicin. Compounds exhibiting significant cytotoxicity were further selected to study their inhibitory activity on the Topo II enzyme. Compound 4c was the most potent Topo II inhibitor with an IC₅₀ value of 0.23 ± 0.01 µM, which was 1.4-fold and 3.6-fold higher than the IC₅₀ values of Etoposide and Doxorubicin. Furthermore, compound 4c showed significant cell cycle disruption and apoptosis on A549 cells compared to control cells. Molecular docking of the most active compounds illustrated proper fitting to the Topo II active site, suggesting that our designed compounds are promising candidates for the development of effective anticancer agents acting through Topo II inhibition.

Design and Synthesis of New 4-(3,4,5-Trimethoxyphenyl)Thiazole-Pyrimidine Derivatives as Potential Antiproliferative Agents

A new series of 3,4,5-trimethoxyphenyl thiazole pyrimidines has been synthesized and biologically evaluated for its in vitro anticancer activity. Compounds 4a, 4b, and 4h with substituted piperazine showed the best antiproliferative activity. In the NCI-60 cell line screening, compound 4b showed promising cytostatic activity against multiple cell lines. Notably, it elicited a GI value of 86.28% against the NSCL cancer cell line HOP-92 at a 10 μM dose. Compounds 4a and 4h at 10 μM showed promising GI values of 40.87% and 46.14% against HCT-116 colorectal carcinoma and SK-BR-3 breast cancer cell lines, respectively. ADME-Tox prediction of compounds 4a, 4b, and 4h revealed their acceptable drug-likeness properties. In addition, compounds 4a, 4b, and 4h showed a high probability of targeting kinase receptors via Molinspiration and Swiss TargetPrediction.

Pyrimidine: a review on anticancer activity with key emphasis on SAR

Background

Cancer is a global health challenge, it impacts the quality of life and its treatment is associated with several side effects. Resistance of the cancer cells to the existing drugs has led to search for novel anticancer agents. Pyrimidine, a privileged scaffold, is part of living organisms and plays vital role in various biological procedures as well as in cancer pathogenesis. Due to resemblance in structure with the nucleotide base pair of DNA and RNA, it is recognized as valuable compound in the treatment of cancer.

Main text

Many novel pyrimidine derivatives have been designed and developed for their anticancer activity in the last few years. The present review aims to focus on the structure activity relationship (SAR) of pyrimidine derivatives as anticancer agent from the last decade.

Conclusion

This review intends to assist in the development of more potent and efficacious anticancer drugs with pyrimidine scaffold.

Graphical abstract

Design, Synthesis, Molecular Modeling and Antitumor Evaluation of Novel Indolyl-Pyrimidine Derivatives with EGFR Inhibitory Activity

Scaffolds hybridization is a well-known drug design strategy for antitumor agents. Herein, series of novel indolyl-pyrimidine hybrids were synthesized and evaluated in vitro and in vivo for their antitumor activity. The in vitro antiproliferative activity of all compounds was obtained against MCF-7, HepG2, and HCT-116 cancer cell lines, as well as against WI38 normal cells using the resazurin assay. Compounds 1-4 showed broad spectrum cytotoxic activity against all these cancer cell lines compared to normal cells. Compound 4g showed potent antiproliferative activity against these cell lines (IC₅₀ = 5.1, 5.02, and 6.6 μM, respectively) comparable to the standard treatment (5-FU and erlotinib). In addition, the most promising group of compounds was further evaluated for their in vivo antitumor efficacy against EAC tumor bearing mice. Notably, compound 4g showed the most potent in vivo antitumor activity. The most active compounds were evaluated for their EGFR inhibitory (range 53-79%) activity. Compound 4g was found to be the most active compound against EGFR (IC₅₀ = 0.25 µM) showing equipotency as the reference treatment (erlotinib). Molecular modeling study was performed on compound 4g revealed a proper binding of this compound inside the EGFR active site comparable to erlotinib. The data suggest that compound 4g could be used as a potential anticancer agent.

Importance of Fluorine in Benzazole Compounds

Fluorine-containing heterocycles continue to receive considerable attention due to their unique properties. In medicinal chemistry, the incorporation of fluorine in small molecules imparts a significant enhancement their biological activities compared to non-fluorinated molecules. In this short review, we will highlight the importance of incorporating fluorine as a basic appendage in benzothiazole and benzimidazole skeletons. The chemistry and pharmacological activities of heterocycles containing fluorine during the past years are compiled and discussed.

One-pot, catalyst-free synthesis of novel spiro[indole-3,4′-pyrano[2′,3′:4,5]pyrimido [2,1-b][1,3]benzothiazole] derivatives

The present report describes one-pot three-component condensation of isatins, malononitrile, and 2-hydroxy-4 H-pyrimido[2,1- b][1,3]benzothiazol-4-one in water–ethanol mixture at reflux to develop an efficient one-pot protocol for the synthesis of novel spiro[indole-3,4′-pyrano[2′,3′:4,5]pyrimido[2,1- b][1,3]benzothiazole] derivatives. The significant features of this protocol are short reaction times, avoidance of toxic catalysts, and provision of excellent yields, no column chromatographic purification, and use of ethanol-water as an environmentally benign solvent. The molecular structure of 4a has been supported by single-crystal X-ray diffraction.

One-pot synthesis of thiazolo[3,2-a]pyrimidine derivatives, their cytotoxic evaluation and molecular docking studies

An economical, simple and efficient one-pot method has been developed for the synthesis of thiazolo[3,2-a]pyrimidine hydrobromide derivatives. 2,4-diaryl-6,7,8,9-tetrahydro-4H-benzo[4,5]thiazolo[3,2-a]pyrimidine hydrobromides were synthesized by the α-bromination of cyclohexanone with N-Bromosuccinamide (NBS) and followed by cyclization with 3,4-dihydropyrimidine-2(1H)-thiones, respectively, in the presence of p-toluenesulfonic acid (PTSA) in acetonitrile. However when cyclohexanone was replaced by acetyl acetone and alpha-tetralone gave the corresponding 1-(3-methyl-5,7-diaryl-5H-thiazolo[3,2-a]pyrimidin-2-yl)ethan-1-one hydrobromide and 9,11-diaryl-6,11-dihydro-5H-naphtho[1',2':4,5]thiazolo[3,2-a]pyrimidine hydrobromide derivatives, respectively. The significant features of this method are novel, simple, inexpensive experimental procedure, short reaction time, and good yield. The some of the synthesized compounds were evaluated for cytotoxic activity against human lung adenocarcinoma cell line (A549), human breast carcinoma cell line (MCF-7), human cervical cancer cell line (HeLa) and human neuronal carcinoma cell lines (SKNSH). Tested compounds 5(b-e) showed the excellent anticancer activity against various cell lines. Particularly compound 5c with IC₅₀ value of 2.2 ± 0.6 μM against A549 and compound 5e with IC₅₀ value of 5.6 ± 0.4 μM against HeLa showed best cytotoxic effects. Furthermore, Molecular docking study was performed for some of the synthesized compounds 5(b-e) against topoisomerase-II by using Auto dock method. Docking results of the compounds 5c, 5d, and 5e exhibited higher cytotoxic activity than the standard doxorubicin.

A Review on Synthesis, Anticancer and Antiviral Potentials of Pyrimidine Derivatives

Background:

Pyrimidine is the six membered heterocyclic aromatic compound similar to benzene and pyridine containing two nitrogen atoms at 1st and 3rd positions. Pyrimidine is present throughout nature in various forms and is the building blocks of numerous natural compounds from antibiotics to vitamins and liposacharides. The most commonly recognized pyrimidines are the bases of RNA and DNA, the most abundant being cytosine, thymine or uracil.

Results:

Pyrimidine is a core structure in a wide variety of compounds that exhibits significant biological activity and also plays an important role in the drug discovery process. Various synthetic aspects indicated that pyrimidine derivatives are easy to synthesize and has diverse biological and chemical applications. The present review article aims to review the work reported on synthesis, anticancer and antiviral potentials of pyrimidine derivatives during new millennium.

Conclusion:

It may be concluded that the fused pyrimidine derivatives enhanced the anticancer potential against different human cancer cell lines and antiviral potential against different human immunodeficiency virus (HIV), herpes simplex virus (HSV-1) etc, which created interest among the medicinal chemists in the pyrimidine skeleton in medicinal chemistry. Thus, a tremendous scope for research is present in this direction for investigating pyrimidine derivatives as lead molecules.

Revealing quinquennial anticancer journey of morpholine: A SAR based review

Morpholine, a six-membered heterocycle containing one nitrogen and one oxygen atom, is a moiety of great significance. It forms an important intermediate in many industrial and organic syntheses. Morpholine containing drugs are of high therapeutic value. Its wide array of pharmacological activity includes anti-diabetic, anti-emetic, growth stimulant, anti-depressant, bronchodilator and anticancer. Multi-drug resistance in cancer cases have emerged in the last few years and have led to the failure of many chemotherapeutic drugs. Newer treatment methods and drugs are being developed to overcome this problem. Target based drug discovery is an effective method to develop novel anticancer drugs. To develop newer drugs, previously reported work needs to be studied. Keeping this in mind, last five year's literature on morpholine used as anticancer agents has been reviewed and summarized in the paper herein.

Potential anti-proliferative agents from 1,4-benzoxazinone-quinazolin-4(3H)-one templates

A novel synthetic protocol has been developed for the synthesis of 1,4-benzoxazinone-acetylphenylallyl quinazolin-4(3H)-one hybrids 7a-n by employing Pd-catalyzed CH arylation in presence of 5-10% phosphine ligand in good to excellent yields and evaluated for their anti-proliferative activity against three cancer cell lines such as A549 (lung), HeLa (cervical), MDA-MB-231 (breast). Compounds 7d, 7f, 7l and 7n exhibited promising anti-proliferative activity with GI₅₀ values ranging from 0.37 to 2.73 µM respectively against A549, HeLa, and MDA-MB-231, while compound 7f showed significant activity against MDA-MB-231 with GI₅₀ value 0.58 µM, 7j showed significant activity against A549 with GI₅₀ value 0.32 µM and 7l showed significant activity against HeLa with GI₅₀ value 0.37 µM. This is the first report on the synthesis and in vitro anti-proliferative evaluation of 1,4-benzoxazinone-acetylphenylallyl quinazolin-4(3H)-one hybrids.

A novel piperazine linked β-amino alcohols bearing a benzosuberone scaffolds as anti-proliferative agents

A new series of 1-((9-chloro-2,3-dimethyl-6,7-dihydro-5H-benzo[7]annulen-8-yl)methoxy)-3-(4-phenylpiperzin-1-yl) propan-2-ols (6a-k) have been designed, synthesized and their structures were established by spectroscopic data (FT-IR, ¹H NMR, ¹³C NMR, HRMS) and further confirmed by X-ray analysis. The newly synthesized compounds 6a-k were evaluated for their in vitro anti-proliferative activity against four cancer cell lines such as HeLa (cervical), MDA-MB-231 (breast), A549 (lung) and MIAPACA (pancreatic). Among the compounds tested, the compound 6e displayed most potent activity against four cancer cell lines with GI₅₀ values ranging from 0.010 to 0.097μM. The structure and anti-proliferative activity relationship was further supported by in silico molecular docking study of the active compounds against Colchicine binding site of β-tubulin.

Design, synthesis and docking studies of novel 1,2-dihydro-4-hydroxy-2-oxoquinoline-3-carboxamide derivatives as a potential anti-proliferative agents

A new series of 4-hydroxy-1-methyl-2-oxo-1,2-dihydroquinoline-3-carboxamide hybrids 8a-l have been designed and synthesized using peptide coupling agents with substituted N-phenyl piperazines and piperidines with good to excellent yields. The synthesized compounds were evaluated for their in vitro anti-proliferative activity against PANC 1, HeLa and MDA-MB-231. The compounds 8d, 8e, 8f, 8g, 8h and 8k exhibited considerable anti-proliferative activity with GI₅₀ values ranging from 0.15 to 1.4 μM. The structure and anti-proliferative activity relationship was further supported by in silico molecular docking study of the active compounds against tubulin protein.

An expeditious four-component domino protocol for the synthesis of novel thiazolo[3,2-a]thiochromeno[4,3-d]pyrimidine derivatives as antibacterial and antibiofilm agents

An efficient domino protocol has been developed for the synthesis of new pyrimidine scaffolds, through a one-pot four-component cascade transformation via [Bmim]HSO4 ionic liquid mediated reaction, using an equimolar mixture of thiochroman-4-one, benzaldehyde, thiourea and 3-bromo-1-phenylpropan-1-one leading to the formation of a double electrophilic pyrimidine-2(5H)-thione intermediate. The intermediate regioselectively undergoes cyclization through intramolecular NH bond activation followed by CS bond formation leading to highly functionalized thiazolo[3,2-a]thiochromeno[4,3-d]pyrimidines. The ionic liquid operates efficiently under mild conditions. The recyclability and scope for recovery of the ionic liquid makes this protocol environmentally benign. Further, the compounds 5d, 5g and 5k showed promising antimicrobial activity against the tested Gram-positive bacterial strains. Among them, the compound 5d was identified as a lead molecule exhibiting promising anti-biofilm activity towards Staphylococcus aureus MTCC 96, Bacillus subtilis MTCC 121, Staphylococcus aureus MLS16 MTCC 2940 and Micrococcus luteus MTCC 2470 with IC50 values of 2.1, 1.9, 2.4 and 5.3μg/mL, respectively. Further, the compound 5d showed increased levels of intracellular ROS accumulation in Staphylococcus aureus MTCC 96 suggesting that oxidative stress resulted in bacterial cell lysis and death.

Three-component, one-pot synthesis of benzo[6,7]cyclohepta[1,2-b]pyridine derivatives under catalyst free conditions and evaluation of their anti-inflammatory activity

An efficient three-component protocol is described for the synthesis of benzo[6,7]cyclohepta[1,2-b]pyridine derivatives using β-chloroacroleins, 1,3-dicarbonyls and ammonium acetate under catalyst free conditions by using ethanol as reaction media. The mild reaction conditions, operational simplicity and high yields are the advantages of this protocol and the broad scope of this one-pot reaction makes this procedure promising for practical usages. All the final compounds were screened for anti-inflammatory activity. Among the compounds tested, the compounds 5a, 5b, 5c, 5d, 5f, and 5k exhibited significant inhibition of IL-1β and MCP-1 secretion as a measure of anti-inflammatory activity.

Novel 2-Thioxanthine and Dipyrimidopyridine Derivatives: Synthesis and Antimicrobial Activity

Several fused imidazolopyrimidines were synthesized starting from 6-amino-1-methyl-2-thiouracil (1) followed by nitrosation, reduction and condensation with different aromatic aldehydes to give Schiff’s base. The dehydrocyclization of Schiff’s bases using iodine/DMF gave Compounds 5a–g. The methylation of 5a–g using a simple alkylating agent as dimethyl sulfate ((CH₃)₂SO₄) gave either monoalkylated imidazolopyrimidine 6a–g at room temperature or dialkylated derivatives 7a–g on heating 6a–g with ((CH₃)₂SO₄). On the other hand, treatment of 1 with different aromatic aldehydes in absolute ethanol in the presence of conc. hydrochloric acid at room temperature and/or reflux with acetic acid afforded bis-5,5′-diuracylmethylene 8a–e, which cyclized on heating with a mixture of acetic acid/HCl (1:1) to give 9a–e. Compounds 9a–e can be obtained directly by refluxing of Compound 1 with a mixture of acetic acid/HCl. The synthesized new compounds were screened for antimicrobial activity, and the MIC was measured.

Crystal structure of (2-methyl-4-phenyl-4H-benzo[4,5]thiazolo[3,2-a]pyrimidin-3-yl)(phenyl)methanone

In the title compound, C24H18N2OS, the pyrimidine ring has a flat envelope conformation with the methine C atom as the flap. The attached phenyl and benzoyl rings are inclined to the mean plane of the pyrimidine ring by 84.87 (8) and 75.33 (9)°, respectively. The benzothiazolo group is planar (r.m.s. deviation = 0.009 Å) and inclined to the mean plane of the pyrimidine ring by 3.27 (6)°. In the crystal, molecules are linked by pairs of C—H...N hydrogen bonds, forming inversion dimers.

Synthesis and evaluation of benzosuberone embedded with 1,3,4-oxadiazole, 1,3,4-thiadiazole and 1,2,4-triazole moieties as new potential anti proliferative agents

As an aspect of our ongoing research in search of new anti proliferative agents, a series of novel analogs of benzosuberone embedded with 1,3,4-oxadiazole, 1,3,4-thiadiazole and 1,2,4-triazole moieties were synthesized in excellent yields (82-93%). All the newly synthesized compounds were characterized by (1)H NMR, (13)C NMR, ESI/LC-MS, HRMS and evaluated for their in vitro anti proliferative activity against four human cancer cell lines (cervical, breast, pancreatic and alveolar). Among the synthesized compounds, 4b, 6a, 7d and 7l showed potent anti proliferative activity with GI50 values range of 0.079-0.957μM against four human cancer cell lines. However, it was revealed that the compound 7d have shown very close GI50 value 0.079μM as compared with positive control of colchicine against cervical cancer cell line.

Palladium(0)-catalyzed direct C–H hetero-arylation of 2-arylimidazo [1,2-a]pyridines with (E)-1-(5-bromothiophen-2-yl)-3-arylprop-2-en-1-ones and their anticancer activity

An efficient palladium(0)-catalyzed direct hetero-arylation of imidazo[1,2-a]pyridines at the C-3 position of the imidazole ring has been described.

Rational design, synthesis and anti-proliferative evaluation of novel 1,4-benzoxazine-[1,2,3]triazole hybrids

A series of novel 1,2,3-triazole-1,4-benzoxazine hybrids 5a-n were efficiently synthesized employing click chemistry approach and evaluated for anti-proliferative activity against four cancer cell lines such as HeLa (cervical), MIAPACA (pancreatic), MDA-MB-231 (breast) and IMR32 (neuroblastoma). Compounds 5n and 5g exhibited promising anti-proliferative activity with GI50 values ranging from 1.2 to 2.5 μM and 0.1-1.1 μM respectively against all cell lines, like HeLa, MDA-MB-231, MIAPACA and IMR32, while compound 5l showed significant activity against MDA-MB-231 and IMR32 with GI50 values ranging from 1.1 and 1.4 μM. This is the first report on the synthesis and in vitro anti-proliferative evaluation of 1,2,3-triazole-1,4-benzoxazine hybrids.

Rational design, synthesis and anti-proliferative evaluation of novel benzosuberone tethered with hydrazide-hydrazones

Two different series of novel analogues of benzosuberones (5a-m and 9a-w) tethered with hydrazone-hydrazides (functional group alterations: Head group to Tail group and vice versa) have been synthesized by the reaction of appropriate aldehydes with substituted hydrazides in excellent yields (87-94%) and their structures were confirmed by (1)H NMR, (13)C NMR, ESI-MS and HRMS. The newly synthesized compounds were evaluated for anti-proliferative activity against different human cancer cell lines (HeLa, MDA MB 231, MIAPACA and IMR32). Among the synthesized compounds, six compounds 5 a, 5 b, 5 d, 5 e, 5 f and 9 v exhibited potent anti-proliferative activity with GI50 values less than 0.01 μM against MIAPACA, MDA-MB-231 and IMR32 human cancer cell lines.