A review on potential heterocycles for the treatment of glioblastoma targeting receptor tyrosine kinases

Glioblastoma,the most aggressive form of brain tumor,poses significant challenges in terms of treatment success and patient survival.Current treatment modalities for glioblastoma include radiation therapy,surgical intervention,and chemotherapy.Unfortunately,the median survival rate remains dishearteningly low at 12–15 months.One of the major obstacles in treating glioblastoma is the recurrence of tumors,making chemotherapy the primary approach for secondary glioma patients.However,the efficacy of drugs is hampered by the presence of the blood-brain barrier and multidrug resistance mechanisms.Consequently,considerable research efforts have been directed toward understanding the underlying signaling pathways involved in glioma and developing targeted drugs.To tackle glioma,numerous studies have examined kinase-downstream signaling pathways such as RAS-RAF-MEKERK-MPAK.By targeting specific signaling pathways,heterocyclic compounds have demonstrated efficacy in glioma therapeutics.Additionally,key kinases including phosphatidylinositol 3-kinase(PI3K),serine/threonine kinase,cytoplasmic tyrosine kinase(CTK),receptor tyrosine kinase(RTK)and lipid kinase(LK)have been considered for investigation.These pathways play crucial roles in drug effectiveness in glioma treatment.Heterocyclic compounds,encompassing pyrimidine,thiazole,quinazoline,imidazole,indole,acridone,triazine,and other derivatives,have shown promising results in targeting these pathways.As part of this review,we propose exploring novel structures with low toxicity and high potency for glioma treatment.The development of these compounds should strive to overcome multidrug resistance mechanisms and efficiently penetrate the blood-brain barrier.By optimizing the chemical properties and designing compounds with enhanced drug-like characteristics,we can maximize their therapeutic value and minimize adverse effects.Considering the complex nature of glioblastoma,these novel structures should be rigorously tested and evaluated for their efficacy and safety profiles.

Assessment of electrostatic discharge sensitivity of nitrogen-rich heterocyclic energetic compounds and their salts as high energy-density dangerous compounds:A study of structural variables

Nitrogen-rich heterocyclic energetic compounds(NRHECs)and their salts have witnessed widespread synthesis in recent years.The substantial energy-density content within these compounds can lead to potentially dangerous explosive reactions when subjected to external stimuli such as electrical discharge.Therefore,developing a reliable model for predicting their electrostatic discharge sensitivity(ESD)becomes imperative.This study proposes a novel and straightforward model based on the presence of specific groups(-NH_(2) or-NH-,-N=N^(+)-O^(-)and-NNO_(2),-ONO_(2) or-NO_(2))under certain conditions to assess the ESD of NRHECs and their salts,employing interpretable structural parameters.Utilizing a comprehensive dataset comprising 54 ESD measurements of NRHECs and their salts,divided into 49/5 training/test sets,the model achieves promising results.The Root Mean Square Error(RMSE),Mean Absolute Error(MAE),and Maximum Error for the training set are reported as 0.16 J,0.12 J,and 0.5 J,respectively.Notably,the ratios RMSE(training)/RMSE(test),MAE(training)/MAE(test),and Max Error(training)/Max Error(test)are all greater than 1.0,indicating the robust predictive capabilities of the model.The presented model demonstrates its efficacy in providing a reliable assessment of ESD for the targeted NRHECs and their salts,without the need for intricate computer codes or expert involvement.

Binding interaction of phosphorus heterocycles with bovine serum albumin:A biochemical study

Interaction between bovine serum albumin(BSA) and phosphorus heterocycles(PHs) was studied using multispectroscopic techniques. The results indicated the high binding affinity of PHs to BSA as it quenches the intrinsic fluorescence of BSA. The experimental data suggested the fluorescence quenching mechanism between PHs and BSA as a dynamic quenching. From the UV–vis studies, the apparent association constant(K_(app)) was found to be 9.25×10~2, 1.27×10~4and 9.01×10~2L/mol for the interaction of BSA with PH-1, PH-2 and PH-3,respectively. According to the F?rster's non-radiation energy transfer(FRET) theory, the binding distances between BSA and PHs were calculated. The binding distances(r) of PH-1, PH-2 and PH-3 were found to be2.86, 3.03, and 5.12 nm, respectively, indicating energy transfer occurs between BSA and PHs. The binding constants of the PHs obtained from the fluorescence quenching data were found to be decreased with increase of temperature. The negative values of the thermodynamic parameters ΔH, ΔS and ΔG at different temperatures revealed that the binding process is spontaneous; hydrogen bonds and van der Waals interaction were the main force to stabilize the complex. The microenvironment of the protein-binding site was studied by synchronous fluorescence and circular dichroism(CD) techniques and data indicated that the conformation of BSA changed in the presence of PHs. Finally, we studied the BSA-PHs docking using Auto Dock and results suggest that PHs is located in the cleft between the domains of BSA.

CuI/Proline-catalyzed N-Arylation of Nitrogen Heterocycles

Ma＇s CuI/proline procedure for the catalytic cross coupling between nitrogen heterocycles and aryl halides was markedly improved. The key finding was that K3PO4 was a much better base than K2CO3 for the reaction. With this new reaction condition the cross coupling with aryl iodides could be accomplished in 1,4-dioxane instead of DMSO. This reactin also could be carried out in DMF. Furthermore, the coupling yields under the new conditions are usually higher than in Ma＇s original methods.

Synthesis and cytotoxic activity of heterocycle-substituted phthalimide derivatives

A series of heterocycle-substituted phthalimide derivatives were synthesized.Structurally diverse derivatives with heterocyclic rings,including furan,imidazo[1,2-a]pyridine,1,3,4-thiadiazine,imidazo[2,1-b][1,3,4]thiadiazine,pyrazole,1,2,4-triazolo[3,4- b][1,3,4]thiadiazine,thiazole and thiazoline,were obtained by the reactions ofα-bromoketone intermediate with various nucleophiles containing oxygen,nitrogen and sulfur atom.Their cytotoxic activity was also evaluated against five human cancer cell lines in vitro.

Ligand Exchange Reaction of Ferrocene with Heterocycles

The ligand exchange reaction with heterocycles containing nitrogen, oxygen or sulfur atoms was carried out. For the reaction with heterocycles, the order of the reactivity was S-heterocycles > N-heterocycles > O-heterocycles. Furthermore, when the results for the heterocycles were compared to those for the corresponding hydrocarbons, the hydrocarbons had a higher reactivity. These results mean that the reactivity would be mainly governed by the electron density of these arenes.

Cis-and Trans-Coordination Assembly of Nitrogen Heterocycle with Copper(Ⅱ) and Silver(Ⅰ)

After the preparation of 1,4-bis（4,5-dihydro-lH-imidazol-2-yl）benzene（bdib）, a nitrogen heterocycle with potential coordination manners of both cis- and trans-configuration forms, three complexes, including cis-[Cuz（bdib ）2（/L-OCH3）2]Cl2·2MeOH（1）, trans-[Cu（bdib）（AcO）2]n（2）, and cis-[Ag2（bdib）2]（NO3）2.2H20（3）, were successfully self-assembled. Complexes 1 and 2 crystallized in the monoclinic system with P21/n space group and complex 3 in the triclinic system with P1 space group.

Theoretical Design of High-spin Organic Molecules with —~*N—S— as a Spin-containing Fragment and Heterocycle as End Groups

Novel stable high-spin molecules possessing three different arranging fashions were designed with —^＊N—S— as a spin-containing （SC） fragment, an aromatic group, such as benzene （ 1 ）, pyridine （2）, pyridazine （3） , pyrimidine （4）, pyrazine （5） or triazine （6） as end groups （EG）, and phenyl as a ferromagnetic coupling （FC） unit. The effects of different EG on the spin multiplicities of the ground states and their stabilities were investigated by means of the AM1-CI approach. All the investigated molecules corresponded to the FC and possessed high-spin ground states. The spin on the two atoms of the SC fragment was not in agreement with the delocalization results in the specific stability of —^＊N—S—. In those molecules, the stabilities of the triplet states decreased when the distance between the atoms of central SC fragments （—N—） increased. The stabilities of the triplet states of compounds 1a-n, 1b-n and 1c-n, with heterocycles as EG were higher than those of the triplet states of those compounds with phenyl as EG. Furthermore, the stahilities of the triplet states of the compounds with pyrimidine and triazine as EG were higher than those with pyridine, pyridazine or pyrasine as EG.

Studies on Thiosemicarbazides and Related Heterocycles(ⅩⅩⅥ)──Synthesis of 3-[5'-amino-1'-(4"-chlorophenyl)-1',2',3'-triazol-4'-yl]-4-aryl-1,2,4-triazoline-5-thiones

The treatment of 5 amino 1 (4 chlorophenyl) 1,2,3 triazol 4 carbohydrazide with equimolecular aryl isothiocyanate gave new derivatives 1 a—l . Twelve title compounds were obtained in 42% to 87% yields when compounds 1 a—l were respectively treated with sodium hydroxide aqueous solution(2 mol/L). The products of Dimroth rearrangement were not observed in the experiment. The structures of all the compounds were confirmed by means of IR, 1H NMR, MS and elementary analysis.

Theoretical Design of High-spin Organic Molecules with Heterocycles as Ferromagnetic Coupling Units

Novel stable high spin molecules possessing three different arranged fashions are designed with - · N-N< as a spin-containing(SC) fragment, phenylene as an end group and various aromatic molecules, such as benzene(1), 2,6-pyridine(2), 3,5-pyridine(3), pyridazine(4), 4,6-pyrimidine(5), 2,6-pyrimidine(6), pyrazine(7) and triazine(8), as a ferromagnetic coupling(FC) unit. The effects of the different coupling units on the spin multiplicities of the ground states and their stabilities were investigated by means of AM1-CI approach. It has been found that the spin densities on the two atoms of the SC fragment are different from delocalization results in the specific stability of - · N-N<. In these molecules, the stabilities of the triplet states decrease when the distance between the atoms of central SC(-N-) increases. It is shown that the heterocycles as the coupling units have influence on the stabilities of the high-spin ground states. That the heteroatom lying in m -phenyl can improve ferromagnetic coupling, while the heteroatom lying in o -phenyl or p -phenyl is not in favor of the ferromagnetic coupling.

Synthesis of 2-methoxy-6-oxo-1, 4, 2-diazaphosphorinane-2-oxide, A New Potential Antitumor Phosphorus Heterocycle Compound

2-methoxy-6-oxo-1, 4, 2-diazaphosphorinane-2-oxide 8, phosphorus counterpart of 2, 6-dioxopiperazine, was synthesized as antitumor agent. The new phosphorus heterocycle compound 8 is the key intermediate in the synthesis of phosphorus counterpart of bisdioxopiperazine.

Cyclocondensation Reactions of Hydrazonoyl Chlorides with Some Azines: Synthesis of New Fused Heterocycles of Expected Microbiological Activity

New functionalized fused heterocycles, such as, 1,3,6,9,11-pentasubstituted-pyrido[3,2-f:6,5-f']bis([1,2,4]triazolo[4,3-a]-pyrimidin-5(1H)-ones (6) and 1,3-disubstituted-7-[(E)-2-(thiophen-2-yl)ethenyl]-1,4,9,9a-tetrahydro-6H-[1,2,4]triazino[4,3-b][1,2,4,5]-tetrazin-6-ones (16) were synthesized via reaction of the hydrazonoyl chlorides (1) with 1,3,6-triphenyl-9-thioxo-9,10-dihydro-pyrimido [4,5-b]pyrido[4,5-d][1,2,4]triazolo[4,3-a]pyrimidin-5,7(1H,8H)-di-one (5) and 4-amino-6-[(2-thiophen-2-yl)ethenyl]-3-thioxo-3,4-dihydro-[1,2,4]triazin-5(2H)-one (11), respectively. The mechanism and the regioselectivity of the studied reactions have been discussed. The biological activity of the products has been evaluated against some fungi and bacteria species. The tested compounds exhibited moderate activity against the bacteria species.

Microwave Irradiation Effect on the Ligand Exchange Reaction between Ferrocene and Heterocycles

The ligand exchange reaction is a typical reaction of ferrocenes. This reaction proceeds via the abstraction of a cyclopentadienyl ring by a Lewis acid followed by coordination of an aromatic compound to the resulting species. This reaction with conventional heating requires a long reaction time. Furthermore, the reactions with heterocycles are lower than those with the corresponding hydrocarbons, and do not produce any products in some cases. In this paper, the ligand exchange reaction of ferrocene and a heterocyclic aromatic compound during microwave irradiation and its effect are discussed. As a result, for some heterocycles, the decrease in the reaction time was confirmed. Furthermore, under the microwave irradiation conditions, the tendency in which the difference in their reactivities became low was confirmed.

The integration of dinitropyrazole and 1,3,4-oxadiazole:A novel hybrid heterocyclic skeleton for balancing energy and stability

In this study,a new energetic hybrid skeleton was constructed through the integration of nitropyrazole and 1,3,4-oxadiazole skeletons in a molecule.Furthermore,the energetic precursor(2),the azo-bridged compound(3),the neutral nitramine(4)and the corresponding energetic salts(5-7)were synthesized.Their physicochemical and energetic properties we re experimentally and theo retically evaluated.Among the developed compounds,the azo-bridged compound(3)and dihydroxylammoinium(6)display high detonation performances(3,D_(v)=8904 m/s,P=34.47 GPa;6,D_(v)=9025 m/s,P=34.66 GPa),moderate sensitivities(3,IS=16 J,FS=120 N;6,IS=20 J,FS=312 N)and good densities(3,1.87 g/cm^(3);6,1.81 g/cm^(3)),which indicates that they have the potential to replace the traditional high-energy explosive RDX.The results show that the integration of different energetic skeletons can achieve a good balance between energy and sensitivity.

Synthesis and Photophysical Properties of Novel Highly Stable Zero/Bis-Zero Methine Cyanine Dyes Based on N-Bridgehead Heterocycles

Cyanine dyes of zero/bis-zero methine incorporating imid-azo(1,2-a)Pyridine (quinoline) or pyrazino(1,2-a)pyridine (quinoline) with stable C-N bond were synthesized using keto-oxime methylene C-link heterocyclic quaternary salts [1-phenyl-3-methyl-pyrazolino-4-keto-oxime-α-methylene-bis-pyridin-(quinoin)-1(4)-di-ium-iodide(ethiodide) salts and 1-phenyl-3-methyl-pyrazolino- 4-ketooxime-α-methylene-N-2-methyl-bis pyridin (quinoin)-1(4)-di-ium-iodide(ethiodide) salts]. Such heterocyclic precursors and related dyes were identified by elemental and spectral analyses. The absorption spectra properties of such dyes were investigated in 95% Ethanol to attempt and throw some light on the influence of such new heterocyclic nuclei and to compare or evaluate spectral behaviors. The absorption spectra of dyes in different pure solvents were examined in the visible region showing solvatochromism and the colour changes of dyes with solvents having different polarities. This permits a selection of the optimal solvent (fractional solvent) when such dyes are applied as photosensitizers. The spectral behavior of some selected newly synthesized cyanine dyes is observed in mixed solvents of different polarities and progressively increasing quantities of one solvent over the other were studied and showed an increase in the absorbance of CT band with increasing proportion of that solvent. Evidence for hydrogen bond formation between the solute molecules and solvent molecules allows measurement of certain energies such as hydrogen bonding, orientation, and free energies.

Radical denitrogenative transformations of polynitrogen heterocycles:Building C–N bonds and beyond

Polynitrogen heterocycles are readily available and have recently arisen as versatile synthons for the formation of various C-C and C-X bonds,and medicinally active nitrogen-containing heterocycles.Several cascade reactions,including annulation,radical cascade,and borylation reactions,have been reported in which polynitrogen heterocycles are applied as arylation reagents.The success of these exceptional reactions illustrates the great synthetic potential of polynitrogen heterocycles,which provides a direct and useful approach to arylation reactions and the synthesis of nitrogen-containing heterocycles.The use of photocatalysts to effectively transfer energy from visible light to non-absorbing compounds has gained increasing attention as this method allows for the mild and efficient generation of radicals in a controlled manner.This approach has thus led to new methods that involve unique bond formation reactions.In addition,the use of free radical intermediates stabilized by transition metal catalysts is a powerful way to construct new chemical bonds.The aim of this review is to highlight the rapidly expanding area of radical-initiated denitrogenative cascade reactions of polynitrogen heterocycles and elaborate on their mechanisms from a new perspective by using photocatalysis and metal-based catalysis.

Spectroscopic studies of the interaction between phosphorus heterocycles and cytochrome P450

P450 fatty acid decarboxylase Ole T from Staphylococcus aureus(Ole TSA)is a novel cytochrome P450 enzyme that catalyzes the oxidative decarboxylation of fatty acids to yield primarily terminal alkenes and CO_(2) or minor a-andβ-hydroxylated fatty acids as side-products.In this work,the interactions between a series of cycloalkyl phosphorus heterocycles(CPHs)and Ole TSAwere investigated in detail by fluorescence titration experiment,ultraviolet-visible(UV-vis)and31 P NMR spectroscopies.Fluorescence titration experiment results clearly showed that a dynamic quenching occurred when CPH-6,a representative CPHs,interacted with Ole TSAwith a binding constant value of 15.2×104 M-1 at 293 K.The thermodynamic parameters(ΔH,ΔS andΔG)showed that the hydrogen bond and van der Waals force played major roles in the interaction between Ole TSAand CPHs.The UV-vis and31 P NMR studies indicated the penetration of CPH-6 into the interior environment of Ole TSA,which greatly affects the enzymatic activity of Ole TSA.Therefore,our study revealed an effective way to use phosphorus heterocyclic compounds to modulate the activity of cytochrome P450 enzymes.

A FACILE SYNTHESIS OF HETEROCYCLE SUBSTITUTED CHALCONE AND 5-NITROFURANYL OLEFIN DERIVATIVES

Reaction of heterocycle substituted telluronium salts with aroma- tic aldehydes under mild conditions gave corresponding chalcones.In the presence of dibutyl telluride,2-bromomethyl-5-nitrofuran condensed easily with aromatic aldehydes in THF to afford corresponding olefin derivatives as one-pot reaction.

Effects of oxygen content on the oxidation process of Si-containing steel during anisothermal heating

The oxidizing behavior of Si-containing steel was investigated in an O2 and N2 binary-component gas with oxygen contents ranging between 0.5 vol% and 4.0 vol% under anisothermal-oxidation conditions. A simultaneous thermal analyzer was employed to simulate the heating process of Si-containing steel in industrial reheating furnaces. The oxidation gas mixtures were introduced from the commencement of heating. The results show that the oxidizing rate remains constant in the isothermal holding process at high temperatures; therefore, the mass change versus time presents a linear law. A linear relation also exists between the oxidizing rate and the oxygen content. Using the linear regression equation, the oxidation rate at different oxygen contents can be predicted. In addition, the relationship between the total mass gain and the oxygen content is linear; thus, the total mass gain at oxygen contents between 0.5 vol%–4.0 vol% can be determined. These results enrich the theoretical studies of the oxidation process in Si-containing steels.

Theoretical design of high-spin biradical molecules with heterocycles as coupling unit

Computational studies of a class of potentially stable high-spin biradicals that two-atom-three-electron spin centers SC units connected by heterocycles FC and phenyl EG were described. The geometry and character of the spin exchange interaction were obtained by means of UB3LYP/6-31G*. The results show that the molecules possessing three different arranged fashions are designed with -·N-S as SC fragment, pyridine as FC and phenyl as EG, the spin densities on the two atoms of the SC fragment are different from the delocalization results in the specific stability of-·N-S. In these molecules, the stabilities of the triplet states decrease when the distance between the atoms of central SC (-N-) increases. Molecules with -·N-S as SC fragment, pyridine, pyrazine and triazine as FC and phenyl as EG are designed, the stability of triplet states for the molecule with pyridine as FC is the highest, and that for the molecule with pyrazine as FC is the lowest. Molecules with -·N-S, -·N-O and -·N-NH as SC fragment, pyridine as FC and phenyl as EG are designed, the stability of triplet states for the molecule with -·N-S as SC is the highest, that for the molecule with -·N-NH as SC is the lowest.