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In the realm of chemistry, increased energy consumption as a result of population development and industrialisation necessitates the usage of renewable energy sources. Nonrenewable energy sources emit not only greenhouse gases but also other toxic pollutants that harm all living creatures. This clearly necessitates the employment of an ecologically acceptable and cost-effective renewable energy source by the researchers. The Knoevenagel-Michael cyclocondensation of aldehyde derivatives, malononitrile, and barbituric acid/1,3-dimethylbarbituric acid via a three-condensation domino reaction can be used to create pyrano[2,3-d]pyrimidine scaffolds. This study establishes solar energy as a novel renewable energy source for the synthesis of pyrano[2,3-d]pyrimidine scaffolds under catalyst-solvent-free conditions, with excellent yields, reaction time savings, and atom economy. This reaction was carried out on a range of substrates with the use of a renewable energy source (sunlight) and a relatively simple experimental setup. The reaction was extremely fast, and there was no need for a solvent or chromatographic purification. According to a multigram scale reaction of model substrates, this reaction might be scaled up without affecting the outcome. Furthermore, the approach's broad applicability was proved by its usage to synthesis real-world pharmaceutical molecules. [ABSTRACT FROM AUTHOR]

In this work, the surface of Fe3O4 nanoparticles was functionalized with the glycine, furfural, and cobalt (II) nitrate hexahydrate to synthesize a novel support nanocatalyst (Fe3O4@gly@Furfural@Co(NO3)2). The characteristics of the nanocatalyst were confirmed by various techniques, such as energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectrometer, EDX mapping, scanning electron microscopy, X-ray diffraction, thermal gravimetric/derivative thermal gravimetric, vibrating sample magnetometer, and TEM. Finally, the performance of the nanocatalyst was investigated for the one-pot multicomponent synthesis of benzo[b]pyran and pyrano[2,3-d] pyrimidine derivatives. The good–excellent yield of the products was achieved in a green solvent under mild conditions at short reaction time. In addition, the green heterogeneous catalyst has features, such as environmental friendliness, easy separation from the reaction mixture by an external magnet, high catalytic activity, and reusability up to 6 stages without significant reduction of its catalytic activity. [ABSTRACT FROM AUTHOR]

In this study, MnCoFe2O4@ovalbumin nanoparticles were synthesized using MnCoFe2O4 MNPs and egg white nano-ovalbumin. The surface of MnCoFe2O4 MNPs was activated with trisodium citrate anhydrou to improve the fabrication of nano-ovalbumin on MCF MNPs. The structure of these nanoparticles was properly characterized by Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscope, X-ray powder diffraction, Energy-dispersive X-ray spectroscopy, Transmission electron microscopy, Thermogravimetric, and Vibrating sample magnetometer. The catalytic activity of the MnCoFe2O4@ovalbumin nanoparticles was evaluated for the synthesis of pyrimido[4,5-d]pyrimidine derivatives via multi-component reaction of aldehyde, barbituric acid, urea, or thiourea under solvent-free condition. The desired products were prepared using an environmentally friendly method. Short reaction time, high efficiency, and easy work-up are some advantages of this procedure. This heterogeneous nanocatalyst can be easily recovered by a magnetic field and used at least six times without considerable loss of its activity. Also, MCF@OVL MNPs exhibited a CO2 adsorption capacity about 9.35 mmol/g at 25 °C. [ABSTRACT FROM AUTHOR]

In this research, highly efficient protocols for the production of pyrido[2,3-d:6,5-d′]dipyrimidine and bis(pyrazolyl)methane derivatives using an acid ionic liquid namely [Et3N-SO3H][MeSO3] have been reported (bis(pyrazolyl)methanes have been produced via two methods, the pseudo three-component and the pseudo five-component reactions). [Et3N-SO3H][MeSO3] was superior than many of the reported catalysts in terms of two or more of these factors: turnover frequency (TOF), turnover number (TON), the reaction temperature, yield, the reaction time, simplicity in workup, and the reaction conditions. [ABSTRACT FROM AUTHOR]

Herein, a novel series of chromenopyrido[3,2-e]isothiazolo[2,3-a]pyrimidines were synthesized by a three-component reaction of 4-hydroxy coumarin, aromatic aldehydes, and 5-amino-2,3-dihydro-7H-thiazolo[3,2-a]pyrimidin-7-one under catalyst-free conditions in PEG 400 as a green solvent. The optimal reaction condition of this reaction was determined. The obtained product's structure was elucidated via NMR, IR, mass spectra, and elemental analysis techniques. This protocol has various advantages: excellent yields, short reaction times, no column chromatography, and green reaction media. [ABSTRACT FROM AUTHOR]

2-Cyanopyrazolo[1,5-a]pyrimidine derivative 3 reacted with some aromatic aldehydes, arenediazonium salts, hydrazine hydrate, and guanidine hydrochloride to create a series of novel pyrazolo[1,5-a]pyrimidine derivatives. Spectroscopic data confirmed the structure of the newly synthesized compounds. Some target compounds were tested in vitro for anticancer efficacy against three cancer cell lines: HepG-2, MCF-7, and Hela. On the most efficient anticancer compounds 6b,c, 6f, and 6h,i, the CDK-2 enzyme was evaluated. Using the HepG-2 cancer cell line, compounds 6b and 6i demonstrated the most effective inhibitory activity against CDK-2, with IC50 values of 0.199 ± 0.005 μg/ml and IC50 = 0.206 ± 0.007 μg/ml, respectively, compared to Dinaciclib and Roscovitine, which had IC50 values of 0.021 ± 0.002 and 0.230 ± 0.007 μg/ml, respectively. In cell cycle assay, compounds 6b, 6f and 6i arrest cell cycle at G2/M, G1/S and G2/M phases, respectively. Compound 6f has a stronger apoptosis induction effect (27.82%) than compounds 6b (7.92%) and 6i (19.21%). Also, silico studies (Molecular docking and Lipinski's rules) for compounds 6b, 6f and 6i were carried out. [ABSTRACT FROM AUTHOR]

Functionalized SBA-15 (immobilization of Pd on the modified SBA-15) has been used as an efficient catalyst for the preparation of spiroindolines by multi-component reactions of isatins, cyclic-1,3-diketones, and 6-amino-1,3-dimethyluracil under ultrasonic irradiation in water. The catalyst has been characterized by X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption analysis, temperature-programmed desorption (TPD), and thermogravimetric analysis (TGA). The advantages of this method include the reusability of the catalyst, low catalyst loading, excellent yields in short reaction times and easy separation of products, and use of ultrasonic irradiation as a valuable and powerful technology. [ABSTRACT FROM AUTHOR]

A series of new benzo[d][1,2,3]triazol-1-yl-pyrazole-based dihydro-[1,2,4]triazolo[4,3-a]pyrimidine derivatives 4a-p were synthesized and well characterized by using IR, 1H, 13C NMR and mass spectral data. Finally, the structure of the compound 4l was solved unambiguously by single-crystal X-ray diffraction (SXRD) which confirms all the structures 4a–p. The in vitro α-glucosidase inhibition, anticancer (A549 and MCF-7 cell lines) and antioxidant studies of the title compounds 4a–p were screened. Among all the compounds, 4g, 4h and 4n exhibited significant α-glucosidase inhibition activity with the IC50 values 20.12 ± 0.19 µM, 21.55 ± 0.46 µM and 24.92 ± 0.98 µM. Similarly, the compounds 4h, 4d and 4e showed potent anticancer activity against A549 (human lung carcinoma) cell line with IC50 values 3.64 µM, 4.73 µM and 4.56 µM, respectively, whereas the compounds 4c and 4o displayed potent anticancer activity against human breast cancer (MCF-7) cell line with IC50 values of 2.66 µM and 2.11 µM. In addition, the antioxidant activity revealed that the compounds 4e and 4h exhibited potent antioxidant activity (IC50: 4.25 µM and 5.40 µM). To determine the safety profile of the most active compounds 4c, 4d, 4e, 4g, 4h, 4n and 4o were tested against non-cancer HEK293 cell line (human embryonic kidney 293), results in the lower toxicity of these compounds. New benzo[d][1,2,3]triazol-1-yl-pyrazole-based dihydro-[1,2,4]triazolo[4,3-a]pyrimidines were synthesized. The target compounds were showed significant α-glucosidase inhibition, anticancer and antioxidant activities. [ABSTRACT FROM AUTHOR]

A new ionic liquid is synthesized, and its chemical structure is characterized by FTIR, 1D NMR and 2D NMR, and mass analyses. The thermal behavior and thermal stability of this ionic liquid are investigated. The results approved the formation of 4,4ʹ-trimethylene-N,Nʹ-dipiperidinium sulfate instead of 4,4ʹ-trimethylene-N,Nʹ-dipiperidinium hydrogen sulfate. Moreover, the synthesis of triazolo-pyrimidine derivatives was successfully conducted in the presence of new ionic liquid at room temperature under metal-free conditions, which demonstrated the catalytic efficiency of this ionic liquid. The workup was carried out without the utilization of high-cost column chromatography. After extraction of desired products, the residual ionic liquid could be recycled and reused in the next runs. New ionic liquid exhibited high catalytic activity even after fifth run with no significant change in the chemical structure. [ABSTRACT FROM AUTHOR]

We report synthesis of triphenyl(propyl-3-hydrogen sulfate)phosphonium bromide ([TPPHSP]Br) as a reusable green Brønsted-acidic ionic liquid catalyst and its application for synthesis of 5-arylidene barbituric acids and pyrano[2,3-d]pyrimidine derivatives by condensation reaction between aromatic aldehydes and barbituric acid or aromatic aldehydes, malononitrile, and barbituric acid in EtOH–H2O in reflux condition with good to excellent yield. The [TPPHSP]Br IL catalyst was characterized by Fourier-transform infrared (FT-IR) spectroscopy, 1H and 13C nuclear magnetic resonance (NMR), and thermogravimetric (TG) analysis and showed good catalytic activity and reusability. [ABSTRACT FROM AUTHOR]

Facile and efficient NaOH-promoted one-pot regioselective synthesis of 5,7-dimethyl-3-(arylamino)isoxazolo[5,4-d]pyrimidine-4,6(5H,7H)-diones and 5,7-dimethyl-3-(arylamino)-6-thioxo-6,7-dihydroisoxazolo[5,4-d]pyrimidin-4(5H)-ones as pharmaceutically interesting compounds has been developed based on a three-component reaction between aryl isothiocyanates, N,N-dimethylbarbituric acid or N,N-dimethyl-2-thiobarbituric acid, and hydroxylamine hydrochloride in N,N-dimethylformamide (DMF) at room temperature. This new protocol has advantages such as simple operation, regioselectivity, metal-free operation, high atom economy, moderate to high yield, easy work-up procedure, and applicability on the gram scale. [ABSTRACT FROM AUTHOR]

A green metal-free synthesis of spiro-fused 3,4′-pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine derivatives via deamination cyclization reactions of isatins, substituted 1H-pyrazol-5-amine, and 6-aminopyrimidine-2,4(1H,3H)-dione or 6-amino-1,3-dimethylpyrimidine-2,4(1H,3H)-dione in aqueous medium is reported. This is an efficient route for synthesis of the target products by deamination cyclization reaction. The other advantages of this process are high yield, easy separation, wide substrate range, and environmental friendliness. [ABSTRACT FROM AUTHOR]

This study includes the synthesis, characterization, electrochemical analysis and photoluminescence properties of a Schiff base ligand bearing a pyrimidine ring and its Co(II), Ni(II), Cu(II) and Pd(II) metal complexes. The Schiff base ligand was derived from the condensation reaction of a pyrimidine amine with 2-hydroxy-1-naphthaldehyde. The structures were characterized using FT-IR, UV-Vis, elemental analysis, magnetic susceptibility and electrolytic conductivity. The ligand and its metal complexes displayed strong violet emissions upon UV exposure. The photoluminescence quantum yield and excited-state decay were measured for the ligand and its complexes. The excited-state lifetime for the ligand was 3.70 ns and its quantum yield of luminescence was found to be 0.40. A reduction in photoluminescence intensity and quantum yield was observed upon metal ion complexation. The compounds synthesized were studied by cyclic voltammetry to probe the existence of electrochemical reduction and oxidation processes. [ABSTRACT FROM AUTHOR]

New series of pyrimidinone-5-carbonitriles 3a-i, 4a-e, 5a-c, 6 and 7 have been synthesized and explored for their activities as anticancer, antibacterial and antifungal agents. Investigation of the anticancer activity revealed that several newly synthesized derivatives displayed potent cytotoxic activity against different cancer cells. Among them, compound 3g was the most potent on the MCF-7, A549 and Caco-2 cell lines (IC50 = 1.42, 1.98 and 9.50 μM, respectively), as compared with 5-fluorouracil (IC50 = 1.71, 10.32 and 20.22 μM, respectively), while compound 3f was found especially effective against MCF-7 and Caco-2 cell lines (IC50 = 1.48 and 16.15 μM, respectively). Furthermore, the antimicrobial evaluation showed that compounds 3f and 3g have potent antibacterial activity against Gram-positive bacteria Staphylococcus aureus (MIC = 4 and 8 μg/mL, respectively) and promising activity against Escherichia coli (IZ. = 19 and 17 mm, respectively). Meanwhile, compound 4b displayed the highest activity toward Bacillus subtilis (MIC = 8 μg/mL). In particular, the results suggested that hydrazone derivatives bearing heterocyclic rings 3f and 3g are good lead compounds for the future design of more potent anticancer or antimicrobial agents. [ABSTRACT FROM AUTHOR]

A convenient and new method has been developed for the synthesis of highly substituted dihydro-2 H-dipyrimido[1,2- a,4,5- d]pyrimidine-2,4(3 H)-dione derivatives by one-pot three-component reactions of barbituric acid, aromatic aldehydes and 2-aminopyrimidine in ethanol under reflux condition without the support of any catalyst. The benefits of this protocol are catalyst-free, clean reaction procedure and providing excellent yields, and the use of ethanol as a solvent, which has been measured to be comparatively environmentally benign. Graphical Abstract: [ABSTRACT FROM AUTHOR]

A cellulose-based magnetic nano-composite supported SOH group was synthesized and characterized using Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy. Thereafter, its capability to promote the one-pot, three-component synthesis of pyrimido [4,5-b] quinolone and pyrido [2,3-d] pyrimidine derivatives was evaluated. The obtained results are indicative of excellent yields and short reaction times. The biopolymer based catalyst is readily recovered and reused several times without a decrease in yield. Graphical Abstract: [ABSTRACT FROM AUTHOR]

An efficient heterogeneous hybrid catalyst was developed by functionalization of halloysite clay nanotubes by γ-aminopropyltriethoxysilane and then immobilization of a Keggin type heteropolyacid, phosphotungstic acid. This hybrid catalyst was characterized by SEM/EDX, FTIR and XRD and its catalytic activity for the synthesis of pyrazolopyranopyrimidine derivatives via four-component domino reaction of barbituric acid, hydrazine hydrate, ethyl acetoacetate and benzaldehyde was investigated. The results indicated that the hybrid system can promote the reaction to afford the desired products in high yields and short reaction times. The superior catalytic activity of this system was confirmed when compared with those reported, previously. Moreover, this novel heterogeneous catalyst was found to be easily separable and recyclable. It was re-used at least three times with negligible loss of activity. Significantly, this protocol can be extended to nonconventional green heating sources such as microwave and ultrasonic irradiations. [ABSTRACT FROM AUTHOR]

A facile, eco-friendly, and highly efficient one-pot four-component protocol is demonstrated for the synthesis of the pyrano[2,3-c]pyrazole and pyrano[4′,3′:5,6]pyrazolo [2,3- d]pyrimidine derivatives using magnetized water as a new green solvent. Simplicity, short reaction time, high yield, easy work-up, and absence of hazardous organic solvents are the main advantages of this method . [ABSTRACT FROM AUTHOR]

Two series of 4-phenyl-5-cyanopyrimidin-6-one derivatives bearing various S-alkyl or S-acyl moieties at position 2 were prepared as cytotoxic agents. All compounds were tested for possible anti-cancer activity on two cell lines (MCF-7 and HCT-116). The MCF-7 cell line was found to be more sensitive than the HCT-116 cell line to the action of the compounds. Compound 8g was the most potent on the MCF-7 cell line with IC 18.3 nM/mL, whereas its IC on the normal cell line (MRC-5) was 64.38 nM/mL, indicating its safety and selectivity towards the MCF-7 cell line. On the other hand, compound 8d was the most potent compound on the HCT-116 cell line with IC 23.8 nM/mL. Compound 8g was screened against five kinases. The compound showed selective inhibitory activity against pim1 kinase with IC 11.62 µM. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A simple methodology has been developed for the synthesis of diverse members of multifunctionalized 4-hydroxy-2-methyl-6-(phenyl)pyrimidine-5-carbonitrile derivatives via multicomponent reaction of aromatic aldehydes, ethyl cyanoacetate, and acetamidine hydrochloride using a quantitative amount of NaOH in dry DMF at 80 °C in a single procedural step. The carbon skeleton of synthesized compounds resembles the bacimethrin, an antibiotic active against several yeast and bacteria. The anti-inflammatory activities of all the synthesized compounds were assessed on Wistar rats using diclofenac sodium as a standard reference. The compound AC1, 2, 5, 9, and AC10 showed promising anti-inflammatory activity (80-83 %) in comparison with diclofenac sodium (85 %) in the carrageenan-induced rat paw edema assay, which is the key finding of this article. Graphical Abstract: The synthesized 4-hydroxy-2-methyl-6-(phenyl)pyrimidine-5-carbonitrile derivatives shown promising anti-inflammatory activity (80-83 %) in comparison with diclofenac sodium (85 %) in the carrageenan-induced rat paw edema assay.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

1,3-Disulfonic acid benzimidazolium chloride ionic liquid ([Dsbim]Cl) was prepared, characterized and applied as an efficient, homogeneous and recyclable catalyst for the synthesis of 3,4-dihydropyrimidine-2-(1H)-ones/thiones through the one-pot three-component condensation of aromatic aldehydes, urea/thiourea and ethyl acetoacetate under solvent-free conditions. The key advantages of this novel protocol are its short reaction time, high yields, mild and clean conditions, practical simplicity and its capacity for reuse several times without a noticeable decrease in catalytic activity. [ABSTRACT FROM AUTHOR]

A new complex of yttrium-salpr was synthesized through the reaction of Y(NO)·6(HO) and salpr Schiff base (salpr = N,N′-bis(3-salicylidenaminopropyl) amine). The prepared complex was characterized by Mid and Far-IR, C-NMR, H-NMR, UV-Vis, XRF, and CHN. The obtained data suggested a binuclear structure for this compound. To our surprise, the catalytic activity of this complex was even lower than its precursor, Y(NO)·6(HO), in one-pot synthesis of dihydropyrimidinones under solvent-free conditions. As one of the reasons of this reduced activity should pertain to the binuclear structure of the complex that reduces the availability of yttrium in the reaction, the complex was immobilized on modified FeO nanoparticles, which not only increases the surface to the volume ratio of the compound, but also hinders the formation of binuclear structure due to site (Schiff base) isolation. These prepared nanoparticles depicted noticeably high catalytic activity as well as good recyclability and very easy separation. [ABSTRACT FROM AUTHOR]

A series of new indolizine 9a- c, 10a- c, diazepinoindolizine 7a- c, 8a- c, and pyrimidoindolizine 11 derivatives were synthesized and structures of the newly synthesized compounds were confirmed by spectral and elemental analyses. Antitumor activity evaluation was carried out using sulphorhodamine-B assay method against lung adenocarcinoma (A549), breast (MCF7), hepatoma (Hep3B) cancer cell lines and normal fibroblast cells. Compounds 7a, 9c, 10a,c and 11 showed to be the most active against the lung cancer cell line with IC in nanomole range (16-85 nmol/ml) and compound 11 was the best selective one (S. I. = 19). The most potent compounds against MCF7 are 8c, 9b,c, 10a,b, and 11. Their IC range is 4-46 nmol/ml and the best selectivity was assigned for compound 11 (S. I. = 133). As for the hepatoma cancer cell line, compounds 7a, 8a- c, 9a- c, and 10a,b were found to be the most potent with IC range 3-90 nmol/ml and compound 8c was the most selective one (S. I. = 42), the rest of the new compounds showed IC value >100 nmol/ml. Compound 10a showed a broad spectrum activity and selectivity against the tested cell lines with a much lesser effect on normal fibroblast cells (IC > 200 nmol/ml). [ABSTRACT FROM AUTHOR]

Two new series of thiazolo and imidazo N-(4-nitrophenyl)-7-methyl-5-aryl-pyrimidine-6 carboxamide derivatives were synthesized. All the synthesized compounds were evaluated for their antimicrobial activity against Gram-positive bacteria: Staphylococcus aureus MTCC 3160, Bacillus subtilis MTCC 441, Gram-negative bacterium: Escherichia coli MTCC 443 and antifungal activity against Candida albicans MTCC 227 and Aspergillus niger MTCC 281 and free radical scavenging activity. Compound 7e was found the most active antimicrobial comparable to standards taken. Compounds 7a, 7c, 9a, and 9d also showed significant antibacterial and antifungal activity. Further, compounds 7f, 9d, and 9h showed significant antioxidant activity with IC comparable with the standard compound. The synthesized compounds were confirmed for their structure by means of various spectrometric techniques like IR, H NMR, mass, and elemental analysis. [ABSTRACT FROM AUTHOR]

Two new series of methyl 7-methyl-5-(substituted-phenyl)-3,5-dihydro-2 H-substituted [3,2-α]pyrimidine-6-carboxylate derivatives of thiourea and guanidine were synthesized. These compounds were characterized and evaluated for their antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and antifungal Aspergillus niger and Candida albicans and free radical scavenging activity using DPPH reagent method. Compound 7f was found to be the most active antibacterial and antifungal agent comparable to the standard drugs ciprofloxacin and fluconazole. Further, the compounds 5e, 7g, and 7h were also found to have significant antimicrobial activity. Compound 5a was found to be the most active antioxidant among all the targeted compounds, while compounds 5b, 5g, 7b, and 7f also had significant antioxidant activity compared to standard ascorbic acid. [ABSTRACT FROM AUTHOR]

A series of novel fused tetrazolylbenzo[ h]chromenes 3a- f, 4a- f and 5a- f were prepared starting from 2-amino-benzo[ h]chromene-3-carbonitrile 1a-f. All structures of the newly synthesized compounds were confirmed by IR, NMR, mass spectral studies, and elemental analyses. The newly synthesized compounds were screened for their antibacterial and antifungal activity. Some of the derivatives have exhibited promising biological activity. [ABSTRACT FROM AUTHOR]

5-( P-tolyl)-2-[(3-bromo-4-methoxy benzylidene) hydrazino]-thiazole 3, 3-[(3-bromo-4-mehtoxy benzylidine) amino]-2-thiohydantion 5, and 4,6-disubstituted-3-[(3-bromo-4-methoxybenzyliden) amino]-2-thioxo pyrimidines 10 have been prepared via cyclization of 3-bromo-4-methoxy benzaldehyde thiosemicarbazone 2 with 4-methyl phenacyl bromide, ethyl chloroacetate, and dicarbonyl compounds in different conditions. Acetylation of 3 and 5 with acetic anhydride gave the corresponding monoacetyl derivatives 4 and 6, while the acetylation of 5 with acetic anhydride in the presence of fused sodium acetate gave diacetyl derivative 7. Condensation of compound 5 with benzaldehyde in the presence of piperidine yielded the corresponding 3-substituted-5-benzylindene 2-thiohydation 8. Acetylation of compound 8 with acetic anhydride gave the corresponding 1-acetyl-3-substituted-5-benzylidene-2-thiohydantion 9. The mass spectral fragmentation patterns of some prepared compounds are investigated in order to elucidate the structure of the synthesized nitrogen heterocycles. [ABSTRACT FROM AUTHOR]

Brønsted acidic ionic liquids, namely 2-pyrrolidonium hydrogensulfate, N-methyl-2-pyrrolidonium hydrogensulfate, N-methyl-2-pyrrolidonium dihydrogenphosphate, (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogensulfate, triphenyl(propyl-3-sulfonyl)phosphonium toluenesulfonate, l-prolinium sulfate, and l-prolinium nitrate, catalyzed efficient one-pot pseudo-four-component reaction of salicylaldehydes, malononitrile, and secondary amine for preparation of chromeno[2,3- d]pyrimidines under solvent-free conditions at room temperature. The catalysts show environmentally benign character and can be easily prepared, stored, and recovered without obvious significant loss of activity. [ABSTRACT FROM AUTHOR]

The conformational stability, relative IR intensities and harmonic vibrational wave numbers of 2-aminopyrimidine in the electronically ground state have been investigated by a comparison of the experimental and calculated spectroscopy. Two ab initio theories, Möller-Plesset second-order perturbation theory and density functional theory DFT-B3LYP methods, were used at different extended basis sets. The vibrational wave numbers calculated with DFT method were scaled using two different methods. The solvent effects on the structural parameters were also extensively studied. A comparison between the computed structural parameters of the investigated compound and the experimental data was shown. A good agreement between the theoretical results and the experimental data was found. [ABSTRACT FROM AUTHOR]

We describe syntheses and electrochemical properties of a new class of aminopyrimidinone derivatives: 2-amino-4-(3′,4′-dimethoxyphenyl)-6-pyrimidinone, 2-amino-4-(3′,4′-dihydroxyphenyl)-6-pyrimidinone, 2,4-diamino-5-(3′,4′-dimethoxyphenyl)-6-pyrimidinone, 2,4-diamino-5-(3′,4′-dihydroxyphenyl)-6-pyrimidinone, and 4-amino-5-(3′,4′-dihydroxyphenyl)-2,6-pyrimidinione, three of which possess a catechol unit as an oxidation-active moiety for developing electrochemically detectable abasic-site binders. These compounds were synthesized via a pyrimidine-ring forming reaction with guanidine. Cyclic voltammetry measurements revealed that the catechol-bearing derivatives showed oxidation potentials lower than that of DNA, indicating that they satisfied the requirements for the purpose. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A series of substituted-nicotinyl thiourea derivatives containing pyrimidine ring were synthesized in good to excellent yield using PEG-400 as solid-liquid phase transfer catalyst under ultrasonic irradiation. The structures of all newly synthesized compounds were elucidated and confirmed by IR, H NMR and elemental analysis. The preliminary biological tests show that some of the target compounds present good inhibitory activities against the root and stalk of dicotyledon plants and are safe for monocotyledon plants. [ABSTRACT FROM AUTHOR]

We present herein a new and efficient method for synthesis of bis-pyrazol pyrimidine derivatives by N-alkylation using a microwave-assisted synthetic process. Two new compounds, N-(4,6-bis(3,5-dimethyl-1 H-pyrazol-1-yl)methyl nicotinonitrile and 2,6-bis(3,5-dimethyl-1 H-pyrazol-1-yl)-4-methyl nicotinonitrile, were synthesized by the N-alkylation reaction. The novel compounds were characterized by Fourier transform infrared spectrometry, ultraviolet spectroscopy, elemental analysis, and nuclear magnetic resonance spectroscopy, etc. The microwave-assisted procedures have noteworthy advantages in terms of thermal efficiency over those carried out by conventional heating methods. Graphical abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Reactions of sulphate radical anion (SO·[sub 4][sup -]) with 4,6-dihydroxy-2-methyl pyrimidine (DHMP), 2,4-dimethyl-6-hydroxy pyrimidine (DMHP), 6-methyl uracil (MU) and 5,6-dimethyl uracil (DMU) have been studied by pulse radiolysis at pH 3 and at pH 10. The transient intermediate spectra were compared with those from the reaction of hydroxyl radical (·OH). It is proposed that SO·[sub 4][sup -] produces radical cations of these pyrimidines in the initial stage. These radical cations are short-lived except in the case of DMHP where a relatively longer lived radical cation is proposed to be formed. When there is a hydrogen atom attached to the N(1) or N(3) position, a deprotonation from these sites is highly favored. When there is no hydrogen attached to these sites, deprotonation from a substituted methyl group is favored. At acidic pH, deprotonation from nitrogen is observed for DHMP, MU and DMU. At basic pH, the radical cation reacts with OH[sup -] leading to the formation of OH adducts. [ABSTRACT FROM AUTHOR]

Pulse radiolysis technique has been used to investigate the reaction of oxide radical ion (O[sup .–]) with 4,6-dihydroxy-2-methyl pyrimidine (DHMP), 2,4-dimethyl-6-hydroxy pyrimidine (DMHP), 5,6-dimethyl uracil (DMU) and 6-methyl uracil (MU) in strongly alkaline medium. The second-order rate constants for the reaction of O[sup .–] with these compounds are in the range 2-5 × 10[sup 8] dm[sup 3] mol[sup –1] s[sup –1]. The transient absorption spectra obtained with DHMP have two maxima at 290 and 370 nm and with DMHP have maxima at 310 and 470 nm. The transient spectrum from DMU is characterized by its absorption maxima at 310 and 520 nm and that of MU by its single maximum at 425 nm. The intermediate species were found to react with N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) with high G(TMPD[sup .+]) values ranged between 3.9 × 10[sup –7] molJ[sup –1] and 4.8 × 10[sup –7] molJ[sup –1]. These radicals undergo decay by second-order kinetics (2k/ε = 1.0-1.7 × 10[sup 6] s[sup –1]). The reaction of O[sup .–] with the selected pyrimidines is proposed to proceed through a hydrogen abstraction from the methyl group forming allyl type radicals. These are mainly oxidizing radicals and hence readily undergo electron transfer reactions with TMPD. [ABSTRACT FROM AUTHOR]

The reactions of the OH adducts of cytosine and its derivatives with nitroxides namely TEMPO and TEMPOL have been followed by steady state γ-radiolysis and pulse radiolysis. Pulse radiolysis studies show that the transient OH adducts of cytosine and its derivatives react with TEMPO and TEMPOL by electron transfer reaction and not by adduct formation as was observed in the case of thymine. The second order rate constants for these electron transfer reactions are of the order of 10[sup 7] - 10[sup 8] dm[sup 3] mol[sup -1] s[sup -1]. [ABSTRACT FROM AUTHOR]