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An economic, sustainable, and straightforward environmentally friendly route for synthesis of 3-methyl-4-aryl-1,4-dihydropyrazolo[4ʹ,3ʹ:5,6]pyrano[2,3-d]pyrimidine-5,7(6H,8H)-diones via condensation of ethyl acetoacetate, hydrazine hydrate, barbituric acid, and aromatic aldehydes in the presence of catalytic amount of H3PMo7W5O40·24H2O under solvent-free condition was reported. This environmentally benign protocol offers selective synthesis of pyrazolopyranopyrimidine derivatives without any side product with excellent yield in shorter time.

In this research, a new heterogeneous catalyst is fabricated through covalent modification of iron-based metal–organic framework with ionic liquid. In more detail, using 2-aminoterephthalic acid and iron (III) chloride hexahydrate, amino-functionalized metal–organic framework has been synthesized and then reacted with 2,4,6-trichloro-1,3,5-triazine and 1,4-diazabicyclo[2.2.2]octane successively to furnish ionic liquid on metal–organic framework. The as-prepared catalyst was characterized by FTIR, TGA, BET, SEM/EDS, XRD and elemental mapping analysis and then employed for catalyzing synthesis of pyrano [2,3‐d]pyrimidines (with yields of 80–100%) from one-pot three-component reaction of aldehydes, barbituric acid and malononitrile in aqueous media. The catalytic test inferred high catalytic activity of the catalyst, superior to that of IL and metal–organic framework. Furthermore, the catalyst could be recovered and recycled for five reaction runs with preserving its morphology.

Aim and Objective: In the current study, environmentally benign and cost-effective procedures were suggested for the preparation of carboxy group functionalized imidazolium salts, including [Cmmim]BF4 - or [Cmmim]Br- as a new, reusable Brønsted acidic ionic liquid (BAIL) catalyst. Then, the catalytic performance of [Cmmim]BF4 - or [Cmmim]Br- were successfully inspected towards the three-components one pot preparation of pyrano[2,3-d]pyrimidinone derivatives 4a-4q. The mentioned procedures show short reaction times, easy work-up procedure, green conditions, high yields of the products, high potent of recovering, and reusing capability. The current study is useful and adequate for the application and development of imidazolium salts on the basis of green chemistry principles. Materials and Methods: An aromatic aldehyde (1 mmol), barbituric acid (1 mmol), and malononitrile (1 mmol) were placed in a round-bottomed flask containing ethanol (5 mL). BAILs A and B (0.1 mmol, 10 mol%) were added to the mixture. The suspension was magnetically stirred at room temperature for an appropriate time (Table 2). After completion of the reaction, which was monitored by TLC (n-hexane:ethyl acetate = 3:1), the pure product was filtered off to separate the catalyst, washed with water, and recrystallized from ethanol to afford the pure compound. After separation of the product, the catalyst was recovered by evaporation of water, washed with Et2O, dried under vacuum for 2 h, and reused for the same reaction. Results: The mentioned procedure shows short reaction times, easy work-up procedure, green conditions, high yields of the products, and high potent of recovering and reusing capability. Conclusion: In this study, we unveiled the synthesis of a new acetic acid functionalized ionic liquids [Cmmim]BF4 - BAIL A or [Cmmim]Br- BAIL B and their application for the preparation of pyrano[2,3-d]pyrimidinone derivatives via a three-component reaction among various aromatic aldehydes, barbituric acid, and malononitrile under mild and metal-free conditions. A wide range of pyrano[2,3-d]pyrimidinone derivatives bearing diverse functional groups was obtained in short reaction and excellent yields. Operational simplicity, recoverability, and reusability of catalysts, cheap and chemically stable reagents, high catalytic activity, easy work-up, and the eco-friendly procedure, make this method environmentally benign and cost-effective.

A 2,2′-Bipyridine-based ionic compound named 2,2′-bipyridinium dihydrogen phosphate was synthesized by addition of phosphoric acid to a solution of 2,2′-Bipyridine in dichloromethane. After the characterization using FT-IR, mass, 1H, 13C and 31P NMR techniques, it was used as a Bronsted dicationic acidic catalyst for the promotion of the synthesis of 2-arylidene malononitrile and 5-arylidene barbituric acid derivatives via Knoevenagel condensation reaction in water. Some of the advantages of this method are the utilization of an easy preparable, cost-effective and eco-friendly organic salt as a catalyst within high rates and yields of the reactions, simple and quick work-up and acceptable reusability of the catalyst.

An efficient methodology was developed to generate novel N,N′-dialkyl-2-thiobarbituric acid based sulfonamides S1–S4 in good to excellent yields (84%–95%). The synthesized compounds S1–S4 were docked to screen their in silico activities against two enzymes i.e., SARS-CoV-2 main protease enzyme with unliganded active site (2019-nCoV, coronavirus disease 2019, COVID-19) PDB ID: 6Y84 and SARS-CoV-2 Mpro PDB ID: 6LU7. Furthermore, some in silico physicochemical and physicokinetic properties were evaluated using the OSIRIS Property Explorer, Molinspiration property calculator, ADMET property calculator, and GUSAR to assess these compounds as potential candidates as lead compounds for the quest of SARS-CoV-2 main protease inhibitors. Molecular docking analyses of the synthesized compounds predicted that compound S3 is more potent as SARS-CoV-2 main protease inhibitor with binding energy –11.65 kcal/mol in comparison with reference inhibitor N3 (–10.95 kcal/mol), whereas compounds S1, S2, and S4 recorded comparable binding energies –9.89, –10.84, and –10.94 kcal/mol with reference inhibitor N3, which were much better than remdesivir (–9.85 kcal/mol). In case of SARS-CoV-2 Mpro, all compounds S1–S4 with docking energy values of –7.28, –8.38, –8.31, and –7.34 kcal/mol, respectively, were found to be potent in comparison with reference inhibitor N3 (–6.31 kcal/mol) and remdesivir (–6.33 kcal/mol). Ligand efficiency values against the target SARS-CoV-2 proteins, as well as α-glucosidase and DNA-(apurinic or apyrimidinic site) lyase inhibition results of these newly synthesized compounds, were also found to be promising.

A simple and efficient method for the synthesis of pyrazolopyranopyrimidines under solvent-free has been developed. The one-pot multicomponent condensation of arylaldehydes with hydrazine hydrate, ethyl acetoacetate and barbituric acid in the vicinity of a mesoporous basic nanomagnetic catalyst, namely DBU immobilized on Fe3O4@nSiO2@mSiO2 was synthesized in remarkably high yields and in short reaction times. Significantly, this catalyst can be easily separated from the reaction media by applying an external magnet, and can be reused for several cycles.

A heterogeneous organic–inorganic hybrid durable nanocatalyst γ-Al2O3@Silane-TMG was prepared by covalently functionalization of nano-γ-Al2O3 through anchored 3-chloropropyl- trimethoxysilane with 1,1,3,3-tetramethylguanidine (TMG). The structure of the catalyst was characterized by various techniques including FT-IR, XRD, SEM, EDX and TGA analyses. The synthesized nanocatalyst was successfully used in an efficient and green four-component synthesis of pyrazolopyranopyrimidine derivatives using ethyl acetoacetate, hydrazine hydrate, arylaldehydes and barbituric acid (or thiobarbituric acid) in H2O at 40 oC. This practical method produced the desired products at reduced reaction times (10–25 min) and high to excellent yields (85–98%). The main advantages of this practical method are the use of heterogeneous basic nanocatalyst, simple work-up procedure with no need to chromatographic purification, affording highly selective conversion and recyclability of the catalyst which could be used in 5 cycles with only a small decrease in its activity.

A facile one-pot multicomponent protocol for the synthesis of bio-active Pyrano[2,3-d]pyrimidine derivatives by a one- step condensation reaction of substituted aldehyde, malononitrile/methyl cyanoacetate, barbituric acid has been demonstrated using nano ZnO@PEG as a catalyst at room temperature. The present approach offers several advantages, such as shorter reaction time, higher yields, and environmental friendliness. Easy isolation of products, absence of column chromatographic purification, use of commercially available low-cost starting materials and reusability of the catalyst make the methodology viable in organic synthesis.

A set of C3N4 samples has been prepared by using melamine, cyanuric acid and barbituric acid as the precursors. The materials were subjected both to physical and chemical characterization and were used as photocatalysts for the selective oxidation of aromatic alcohols in water suspension under UV and visible irradiation. The photoactivity of the materials versus the partial oxidation of four substituted benzyl alcohols was investigated. The type and position of the substituents in the aromatic molecule influenced conversion and selectivity to the corresponding aldehyde. The presence of barbituric and cyanuric acids in the preparation method has changed the graphitic-C3N4 structure, and therefore both the characteristics of the material and the ability of light to activate the surface of the photocatalyst. The most active material prepared in the presence of melamine and cyanuric acid showed a remarkable selectivity towards the aldehyde even under visible irradiation.

A series of indolenine and barbituric acid zwitterion scaffolds were synthesized with a maximum yield of 98% via the formation of C–C single bonds. The structures were unambiguously elucidated by various spectroscopic techniques such as 1H, 13C NMR (1D and 2D), FT-IR and high-resolution mass spectrometry (HRMS). Single crystal X-ray crystallography analysis on 22, as the 22.DMF 1 : 1 solvate, confirms the presence of well-separated iminium and enolate centres, and also confirms that the BA ring is highly twisted with respect to the indolenine ring due to steric hindrance. The presence of N–H⋯O− and N–H⋯O− groups favours 1D-supramolecular assembly in the solid-state. The orange or yellow solutions of the zwitterion exhibit an intense molar absorption coefficient, e, ranging between 0.21 × 104 and 2.93 × 104 M−1 cm−1 in the UV-vis region. Furthermore, the Intramolecular Charge Transfer (ICT) peak of the zwitterion displays a hypsochromic shift in the absorption behavior when the polarity of the solvent increases. Moreover, treatment with a small amount of trifluoroacetic acid (TFA) with the DMF solution of 19 resulted in the protonation of the enolate of the BA ring. This fundamental work provides valuable structural design and information for the construction of supramolecular chemistry and synthetic dyes based on indolenine substituted BA derivatives.

A green and highly efficient synthesis of some new ?-amido-aroyl carbonyl derivatives has been achieved through a one-pot, three-component reaction of dimedone/barbituric acid derivatives, arylglyoxals, and amides in choline chloride/urea as a deep eutectic solvent (DES). The use of biodegradable materials, short reaction time and high yields of products introduced this protocol as an efficient environmentally friendly method. The DES could be easily recovered and reused about four times with satisfied catalytic activity.

Two pyran based bipodal D–π–A systems, CAPBA and CAPTBA, have been developed as Hg2+ ion selective colorimetric and fluorescent ratiometric probes. Both probes formed a 1 : 2 complex, with two mercury ions per probe. The stoichiometry of binding, limit of detection and binding constants were determined using absorption and fluorescence spectroscopy. The metal ion complexation proceeds with deprotonation of the NH protons of the barbituric acid or thiobarbituric acid moiety which was characterized using 1H NMR spectroscopy and MALDI-TOF mass spectrometry. Fluorescence lifetime studies ascertained the formation of a static complex. DFT computations at the B3LYP and CAM-B3LYP levels of theory corroborated the experimental findings and further supported the deprotonation process during complex formation. The complexation is found to be reversible on treatment with cysteamine hydrochloride.

In the last two decades, a large number of self-assembled materials were synthesized and they have already found their way into large-scale industry and science. Hydrogen-bond-based supramolecular adducts are found to have unique properties and to be perfect host structures for trapping target molecules or ions. Such chemical systems are believed to resemble living matter and can substitute a living cell in a number of cases. Herein, a report on an organic material based on supramolecular assembly of barbituric acid and melamine is presented. Surprisingly, the structure is found to host and stabilize radicals under mild conditions allowing its use for biological applications. The number of free radicals is found to be easily tuned by changing the pH of the environment and it increases when exposed to light up to a saturation level. We describe a preparation method as well as stability properties of melamine-barbiturate self-assembly, potentiometric titration, and hydrogen ions adsorption data and EPR spectra concerning the composite.

The oxidation of a heterocyclic compound—barbituric acid (BBA) by diperiodatoargentate(III) (DPA) was carried out in the absence and presence of ruthenium(III) catalyst in alkaline medium with a constant ionic strength of 0.20 mol dm–3 at 298 K. The reaction was monitored spectrophotometrically. The reaction was of first order with respect to [DPA] and was less than unity order with respect to [BBA] in both catalyzed and uncatalyzed cases. Positive and negative fractional order in [OH–] for uncatalyzed and Ru(III) catalyzed reaction respectively was observed, whereas perioadate has retarding effect in both the cases. A unity order with respect to [Ru(III)] was observed. The uncatalyzed reaction in alkaline medium has been shown to proceed via a DPA–BBA complex, which decomposes in a rate determining step to give the free radicals, which is followed by other fast steps to give the products. Whereas in catalyzed reaction, it has been shown to proceed via a Ru(III)–BBA complex, and similar other steps as in uncatalyzed reaction to give the products. The reaction constants involved in the various steps involved in the mechanisms were calculated for both the reactions. The catalytic constant (kC) was also calculated for catalyzed reaction at four temperatures. The activation parameters with respect to slow step of the mechanism and also the thermodynamic data for all the equilibrium steps were determined and discussed.

We have developed a SnO2/SiO2 catalyzed efficient and rapid protocol for the synthesis of pyrano[2,3-d]pyrimidinone derivatives by the three-component cyclocondensation of aromatic benzaldehydes, malononitrile, and barbituric acid in ethanol at room temperature. Nanocomposite SnO2/SiO2 catalytic materials were synthesized using the sol–gel method. The synthesized catalytic materials were well characterized by using a transmission electron microscope, X-ray diffraction spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, temperature-programmed desorption (NH3-TPD), and Brunauer–Emmett–Teller theory. This protocol has several advantages such as high yield, simple workup procedure, non-toxic, clean, and easy recovery and reusability of the catalytic system. An efficient catalytic system has been developed for the synthesis of pyrano[2,3-d]pyrimidinone derivatives from one-pot three-component cyclocondensation of aromatic benzaldehydes, malononitrile, and barbituric acid in ethanol at room temperature using 15 wt% SnO2/SiO2.

In this study, an efficient, rapid and simple plant-mediated green sol-gel auto-combustion procedure was presented to synthesis magnesium-cobalt ferrite (MgCoFe2O4) nanocatalyst using an aqueous extract of apple skins as a chelating/combustion agent. The catalyst was assessed by multiple techniques, including FT-IR, XRD, FE-SEM, EDS, elemental mapping, TGA-DTA and VSM. Then, the catalytic potential of the as-prepared MgCoFe2O4 nanocatalyst was examined in the three-component condensation reaction of 1,3-dimethyl barbituric acid, aldehydes and malononitrile for the one-pot synthesis of pyrano[2,3-d]pyrimidinedione and their bis-derivatives. The obtained results indicated the excellent catalytic activity of the MgCoFe2O4 in the three-component reaction. The high catalytic activity of these nanomaterials could be attributed to the synergistic electronic effect between nanoparticles, which showcased the enormous potential of multi-metallic nanomaterials in the catalysis field. More importantly, MgCoFe2O4 showed excellent magnetic properties, and it could be successfully separated and recovered by applying an external magnetic for further reuses. To the best of our knowledge, green synthesis of MgCoFe2O4 mediated by aqueous plant extract was reported here for the first time, and this work, therefore, can open up a new insight in the course of design, green synthesis and application of excellent green nanocatalyst for the sustainable processes. MgCoFe2O4 as a magnetically recyclable heterogeneous catalyst, has been synthesized through plant-mediated procedure using an aqueous extract of apple skins.

A new method has been proposed for the synthesis of pyranopyrimidinone and xanthene derivatives using zinc oxide–starch nanocomposite as catalyst under microwave irradiation. The ZnO–starch nanocomposite was characterized by X-ray diffraction and scanning electron microscopy data, and the size of the ZnO-starch nanocomposite particles was estimated at 70–90 nm. The catalyst was used in the three-component condensation of aromatic aldehydes with barbituric acid and malononitrile and the 1:2 condensation of aromatic aldehydes with naphthalen-2-ol to obtain pyranopyrimidinone and xanthene derivatives, respectively. The catalyst can be reused several times without loss of catalytic activity. The proposed procedure utilizes affordable and inexpensive materials, provides excellent yields in short reaction time, and is eco-friendly, which makes it more economic than conventional methods. The antibacterial activity of the synthesized compounds was evaluated against M. luteus and P. aeruginosa.

A series of novel diphenyl-1,3-thiazole linked barbituric acid hybrids (4) were prepared by two catalyst-free methods from readily available starting materials. The reaction of arylglyoxal, barbituric acid and aryl thioamides in the presence of 3–4 drops of water and liquid assisted grinding (LAG) provides the corresponding trisubstituted thiazoles tethered with a barbituric acid moiety within 30 minutes. Alternatively, a sequential two-step one-pot process involving aryl nitriles, ammonium sulphide, arylglyoxal and barbituric acid in water medium was developed. In this second method, in situ thioamides were prepared at room temperature from the reaction of alkyl/aryl nitriles and ammonium sulphide in aqueous medium. Arylglyoxal and barbituric acid were added to the in situ thioamides after neutralizing the reaction medium to provide trisubstituted thiazoles linked with barbituric acid derivatives. Some of our synthesized molecules showed fluorescent properties with very good quantum yields in DMSO medium. We also observed that fluorescent quantum yields of these thiazole derivatives depend on the type of electron donating/withdrawing character of R1 and R3. R2 has a very small effect on tuning the fluorescent properties. The salient features of this work are catalyst-free reactions, wide substrate scope, green reaction conditions (liquid assisted grinding and room temperature reactions in water medium) as well as the presence of more than one pharmaceutically important heterocyclic moiety with fluorescent properties.

Three N,O-chelate ligands (1a-1c) were synthesized by the reaction of aniline derivatives with 1,3-dimethyl-2,4,6-trioxohexahydropyrimidine-5-carbaldehyde. The corresponding palladacycles complexes (2a-2c) were prepared from treatment of N,O-chelate ligands (1a-1c) with [Pd(μ-OAc)(ppy)]2. The structures of all synthesized compounds were characterized by elemental analyses, ATR-FTIR, 1H- and 13C NMR spectroscopy. Crystal structures of Pd(II) complexes 2a and 2c were determined by single crystal X-ray diffraction. X-ray diffraction studies revealed that the palladium atom in 2a and 2c has distortion of square-planar geometry. Synthesized complexes were tested as catalyst in Suzuki-Miyaura cross-coupling reaction of various aryl bromide with phenyl boronic acid. All complexes behaved as efficient catalyst to produce the biaryls with both high yields and short time under mild reaction conditions.

Zinc terephthalate metal-organic framework catalyzed one-pot, three-component reaction of 3-amino-1H-1,2,4-triazoles, aromatic aldehydes and barbituric acid to prepare some new pyrimido[4,5-d][1,2,4]triazolo[1,5-a]pyrimidinediones. The reactions conducted under ultrasonic irradiation and solvent-free conditions with good to excellent yields of products. The zinc terephthalate metal-organic framework catalyst could be recovered by a simple filtration and applied in consecutive runs with no significant decrease in the yield. The method was demonstrated to be a truly green process with economics and sustainability.

Synthesis of one-dimensional nanofibers with distinct topological (higher-order structural) domains in the same main chain is one of the challenging topics in modern supramolecular polymer chemistry. Non-uniform structural transformation of supramolecular polymer chains by external stimuli may enable preparation of such nanofibers. To demonstrate feasibility of this post-polymerization strategy, we prepared a photoresponsive helically folded supramolecular polymers from a barbiturate monomer containing an azobenzene-embedded rigid p -conjugated scaffold. In contrast to previous helically folded supramolecular polymers composed of a more flexible azobenzene monomer, UV-light induced unfolding of the newly prepared helically folded supramolecular polymers occurred nonuniformly, affording topologically blocky copolymers consisting of folded and unfolded domains. The formation of such blocky copolymers indicates that the photoinduced unfolding of the helically folded structures initiates from relatively flexible parts such as termini or defects. Spontaneous refolding of the unfolded domains was observed after visible-light irradiation followed by aging to restore fully folded structures. .

Ordered molecular self-assembly of glycoamphiphiles has been regarded as an attractive, practical and bottom-up approach to obtain stable, structurally well-defined, and functional mimics of natural polysaccharides. This study describes a versatile and rational design of carbohydrate-based hydrogelators through N,N'-substituted barbituric acid-mediated Knoevenagel condensation onto unprotected carbohydrates in water. Amphiphilic N-substituted β-C-maltosylbarbiturates self-assembled into pH- and calcium-triggered alginate-like supramolecular hydrogel fibers with a multistimuli responsiveness to temperature, pH and competitive metal chelating agent. In addition, amphiphilic N,N'-disubstituted β-C-maltosylbarbiturates formed vesicle gels in pure water that were scarcely observed for glyco-hydrogelators. Finally, barbituric acid worked as a multitasking group allowing chemoselective ligation onto reducing-end carbohydrates, structural diversity, stimuli-sensitiveness, and supramolecular interactions by hydrogen bonding.

Since 2019, the infection of SARS‐CoV‐2 has been spreading worldwide and caused potentially lethal health problems. In view of this, the present study explores the most commodious and environmentally benign synthetic protocol for the synthesis of tetrahydrobenzo[b]pyran and pyrano[2,3‐d]pyrimidinones as SARS‐CoV‐2 inhibitors via three‐component cycloaddition of aromatic aldehyde, malononitrile, and dimedone/barbituric acid in water. Lemon peel from juice factory waste, namely, lemon ( Citrus limon ), sweet lemon ( C. limetta ), and Kaffir lime or Citron ( C. hystrix ), effectually utilized to obtain WELPSA, WESLPSA, and WEKLPSA, respectively, for the synthesis of title compounds. The catalyst was characterized by scanning electron microscope (SEM) and energy‐dispersive x‐ray spectroscopy (EDX). The concentration of sodium, potassium, calcium, and magnesium in the catalyst (WELPSA) was determined using atomic absorption spectrometry (AAS). The current approach manifests numerous notable advantages that include ease of preparation, handling and benignity of the catalyst, low cost, green reaction conditions, facile workup, excellent yields (93%–97%) with extreme purity, and recyclability of the catalyst. Compounds were docked on the crystal structure of SARS‐CoV‐2 (PDB: 6M3M). The consensus score obtained in the range 2.47–4.63 suggests that docking study was optimistic indicating the summary of all forces of interaction between ligands and the protein., Since 2019, the infection of SARS‐CoV‐2 has been spreading worldwide and caused potentially lethal health problems. In view of this, the present study explores the most commodious and environmentally benign synthetic protocol for the synthesis of tetrahydrobenzo[b]pyran and pyrano[2,3‐d]pyrimidinones as SARS‐CoV‐2 inhibitors via three‐component cycloaddition of aromatic aldehyde, malononitrile, and dimedone/barbituric acid in water. The use of green catalyst WELPSA obtained from the agricultural wastes is the major addition to this protocol.

Ultrasound-assisted, mild and highly efficient route for the one-pot multicomponent reaction of ethyl acetoacetate, hydrazine hydrate, aromatic aldehydes and barbituric acid has been developed for the construction of bioactive heterocyclic moieties in a single molecular framework. The synthesis of tri-heterocyclic fused pyrazolopyranopyrimidines promoted by β-Cyclodextrin as a biomimetic catalyst and water as an eco-friendly reaction medium. This environmentally beningn protocol offers selective synthesis of pyrazolopyranopyrimidine derivatives without any side product with excellent yield in shorter duration. The reusability and recyclability of catalyst is carried out in simple way. Also, this method provides various advantages such as metal free synthesis, cost-effective catalyst, no column chromatography and offers easy isolation of products with gram scale synthesis.

The Michael addition reaction of barbituric acid with chalcones incorporating the indole scaffold was achieved by using a highly efficient bimetallic Iron–palladium catalyst in the presence of acetylacetone (acac). This catalytic approach produced the desired products in a simple operation and low catalyst loading with acceptable yield of the new hybrids. All tested compounds were subjected for biological activity on α‐glucosidase and α‐amylase. The results revealed that all synthesized compounds exhibited very good activity against both enzymes when compared to positive control (acarbose). Moreover, compound 5o showed the best activity whereas its IC50 (μM) are 13.02+0.01 and 21.71+0.82 for α‐glucosidase and α‐amylase respectively. Both compounds 5o and 5l exhibited high similarity in binding mode and pose with amylase protein (4UAC). The obtained data may be used for developing potential hypoglycemic agents.

In this study, a novel, simple and efficient procedure to confine Bronsted acid ionic liquids (TEDA/IMIZ-BAIL) in the cages of UiO-66 metal-organic frameworks was introduced. The catalytic activity of TEDA/IMIZ-BAIL@UiO-66 was evaluated for the synthesis of pyrazolopyranopyrimidine derivatives via the reaction of four-components including barbituric acid derivatives, hydrazine hydrate, ethyl acetoacetate and aromatic aldehydes under reflux conditions. Moreover, the catalyst was fully characterized by FT-IR, XRD, SEM, EDX, TGA and BET spectral techniques. The proposed approach associates several advantages including high yield, short reaction time, lower catalyst loadings and facile catalyst separation.

Nano-Fe3O4@SiO2-3,4-dihydroxybenzaldehyde/barbituric acid/phthalhydrazide-FeCl3 (nano-Fe3O4@SiO2-HBP-FeCl3) was prepared and authenticated by usual analytical and spectroscopic techniques. The prepared nano-Fe3O4@SiO2-HBP-FeCl3 was applied to acridinedione and spiroquinazolin-4(3H)-one derivatives under green conditions. In addition, this research offers several advantages such as very easy reaction conditions, simple work-up, excellent yields, high purity of the desired product, short reaction time and one-pot reaction to synthesize Fe3O4@SiO2-HBP-FeCl3. The recycling studies revealed that catalyst could be easily recovered using an external magnet and reused five times without significant loss of its catalytic activity.

An economical and proficient approach has been developed for the synthesis of chromenopyrimidines via three-component reaction of thiobarbituric acid/barbituric acid, methylarenes and dimedone/1,3-cyclohexanedione by using lemon juice as a natural, biodegradable catalyst and TBHP as an oxidant. This transformation involves metal-free C-C bond formation via C-H activation of methylarenes under mild reaction conditions.

An expedient synthesis of spiro-fused heterocycles from multi-component reaction of urea, aryl aldehydes and Meldrum’s or barbituric acid by using polymer gel-entrapped catalyst under aerobic conditions at ambient temperature is reported. The developed protocol is simple, green, atom-economical and includes mild reaction conditions, does not involve tedious workup or purification procedure, avoids hazardous reagents/by-products and results in near-quantitative yields. The polymer gel-entrapped catalyst could be reused seven times without significant change in the catalytic activity.

In this research, a new heterogeneous organometallic catalyst was prepared through Cu(II) Immobilization on l -Histidine Functionalized multi-walled carbon nanotubes (MWCNTs@L-His/Cu(II)). Catalyst was prepared using a simple method and characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), thermal analysis (TGA), inductively coupled plasma optical emission spectrometry (ICP-OES) and Brunauer Emmett Teller (BET) techniques. A clean, rapid and efficient synthesis of pyrido[2,3-d:5,6-d′]dipyrimidine derivatives was accomplished in high to excellent yields and short reaction times via one-pot three-component condensation reaction of barbituric acid or 1,3-dimethylbarbituric acid, 6-aminouracil and aromatic aldehydes in the presence of MWCNTs@L-His/Cu(II) under reflux conditions. This new catalyst can be easily separated from the reaction mixture and recovered several times without a significant loss of activity.

A simple, straightforward, and highly efficient multicomponent one-pot synthesis of a series of pharmaceutically interesting functionalized chromeno[3′,4′:5,6]pyrano[2,3-d]pyrimidines has been developed based on a low-cost and environmentally benign trisodium citrate dihydrate catalyst via ultrasound-assisted tandem reactions of 4-hydroxycoumarin, aromatic aldehydes, and barbituric acid/thiobarbituric acid in aqueous ethanol at ambient conditions. Metal-free synthesis, high atom-economy, good to excellent yields, short reaction time, operational simplicity, eco-friendliness, and mild reaction conditions are some of the important features of his protocol.

Curcumin (bis-α,β-unsaturatedβ-diketone) is a low molecular weight hydrophobic polyphenol isolated from Curcuma longa. Curcumin has attracted significant recent consideration due to its medicinal and pharmacological properties. In this research pyrano[2,3-d]pyrimidine-2,4(3H)-dione derivatives were prepared in excellent yields and short reaction times by a one-pot multi-component cyclocondensation of curcumin, substituted aromatic aldehydes and barbituric acid in the presence of CoFe2O4@OCMC@Cu(BDC) nanostructure as an effective and robust catalyst. The CoFe2O4functionalized OCMC@Cu(BDC) is introduced as a new, strong and efficient catalyst for the synthesis of a variety of heterocyclic compounds. The catalyst was perfectly characterized by various spectroscopy methods such as Fourier-transform infrared spectroscopy (FT-IR), Energy-dispersive X-ray (EDX), Scanning electron microscope (SEM), X-ray diffraction (XRD) and N2 adsorption-desorption isotherm (BET). Furthermore, the heterocyclic compounds were fully characterized by different spectral techniques including FT-IR, 1HNMR, 13CNMR. The magnetic catalyst could be easily recycled and reused for seven runs with a slightly decrease in its activity.

In this work, photoactivated oxidase mimetics was prepared by copolymerizing dicyandiamide with barbituric acid (BA) and characterized by X-ray diffraction pattern, Fourier transformed infrared spectrum, X-ray photoelectron spectroscopy, transmission electron microscopy, photoluminescence spectrum, diffuse reflectance spectrum. Experimental results and density functional theory calculation indicated that the substitution of nitrogen atoms by carbon atoms in tri-s-triazine structure due to the copolymerization of BA enhanced visible light absorption and weakened the barrier of photocarrier transfer. In the presence of visible light and oxygen, 3, 3′, 5, 5′-tetramethylbenzidine was oxidized under the catalysis of photoactivated oxidase mimetics to produce a green colored product, which could be reduced by glutathione (GSH). Therefore, a facile method based on the photoactivated oxidase mimetic has been developed for colorimetric detection of GSH. The linear range for GSH was ranged from 2.0 to 50.0 μmol L−1 (R2 = 0.998) with the detection limit of 1.4 μmol L−1. The proposed method was applied to detect the cellular GSH with satisfactory results.

We report synthesis of triphenyl(propyl-3-hydrogen sulfate)phosphonium bromide ([TPPHSP]Br) as a reusable green Bronsted-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.

A green, convenient, and efficient one-pot synthesis of a new class of spiro[indolinepyranopyrimidine] derivatives was achieved in good yields by the multi-component reaction of N-alkyl-1-(methylthio)-2-nitroethenamine derived from the addition of various amines to nitroketene dithioacetal with isatin and barbituric acid derivatives in water at reflux conditions. Notably, the present method offers desirable advantages including good yields, use of water as green solvent, absence of catalyst, simple workup procedure, and easy purification process with no chromatographic technique.

In the present study, we have developed an efficient and green method for the synthesis of pyrano[2,3-d]pyrimidine-2,4,7-triones employing β-cyclodextrin as a catalyst in aqueous media from substituted aldehydes, barbituric acid and meldrum acid. The reactions were performed under mild conditions to afford biologically active target molecules in excellent yields. All the synthesized compounds are evaluated for their in vitro anticancer activity against HePG-2 (Human liver cancer cell line) and MCF-7 (Human breast cancer cell line). Among them 4c, 4j, 4k, 4l and 4m were active and potent anticancer agents.

A new piperazine-based dicationic Bronsted acidic ionic salt named as piperazine-1,4-diium dihydrogen phosphate was prepared. After characterization by FT-IR, Mass and NMR spectroscopy, it was used as an efficient and reusable catalyst for the synthesis of 5-arylidenepyrimidine-2,4,6(1H,3H,5H)-trione and pyrano[2,3-d]pyrimidinone (thione) derivatives. Some of the advantages of this method are utilization of low amount of the catalyst, ease of work-up, short reaction times, excellent yields and acceptable reusability of the catalyst.

The C(sp3)–H peroxidation of 2-oxindole and barbituric acid derivatives using aliphatic peroxides under continuous flow and their antimalarial evaluation in vitro have been explored using magnetic iron oxide nanoparticles. This transformation uses less toxic, low cost, and eco-friendly ethyl acetate as a solvent. To show the robustness, supported catalysis integrated with continuous-flow was employed as a process development tool for the expeditious synthesis of quaternary peroxide derivatives with a residence time of 7.9 minutes. Additionally, the explosive hazards of TBHP (tert-butyl hydroperoxide) were also minimized during peroxidation in a continuous-flow process by controlled addition.

A new versatile strategy involving a sequential four-component reaction of the nitroketene dithioacetals, alkylamine/benzylamine, isatin and various enolizable active methylene structures (pyrazolone, barbituric acid, 1,3-indandione and 2-hydroxy-1,4-naphthoquinone) as precursors under mild and catalyst-free conditions results in the synthesis of new functionalized spirooxindole pyrans named spiro[indoline-3,4′-pyrano[2,3-c]pyrazol], spiro[indoline-3,5′-pyrano[2,3-d]pyrimidine], spiro[indeno[1,2-b]pyran-4,3′-indoline] and spiro[benzo[g]chromene-4,3′-indoline] in moderate to good yields. The use of various active methylene compounds affords a range of skeletally distinct spirooxindole-based heterocycles with potential biological properties. The present strategy has many advantages, such as convenient one-pot operation, simple workup procedures and straightforward isolation without using tedious purification steps such as column chromatography, progress under catalyst-free condition and high molecular diversity.

In this study, a novel magnetically recoverable Fe3O4@SiO2-BenzIm-Fc[Cl]/ZnCl2 nano-particle was synthesized using a simple chemical coprecipitation approach. In the FT-IR spectroscopy of nano-particles, related absorption peaks appeared which confirmed the successful synthesis of nano-catalyst. In the EDX spectrum of the nano-catalyst, the expected elements on their regions appeared. The XRD diffusion patterns of nano-catalysts showed the crystalline dispersions of Fe3O4 magnetic nano-particles. According to the FE-SEM and TEM images, the nano-particles have relative mono-dispersity and the average size of nano-particles is around 35 nm. The catalytic activities of the novel magnetic nano-particle were evaluated in the one-pot three-component synthesis of a wide variety of pyran annulated bis-heterocyclic derivatives (38 compounds) under ultrasonic irradiation. A simple, facial and highly efficient ultrasound-assisted method has been introduced for the synthesis of fused bis-heterocyclic pyran derivatives by one-pot, three-component reactions at room temperature. A series of pyrano[3,2-c]chromene derivatives were synthesized using a novel nano-catalyst via the condensation reaction of different aldehydes, malononitrile and 4-hydroxycoumarin. Kojic acid was also used in the three-component reaction for the synthesis of pyrano[3,2-b]pyran derivatives. The method was successful in the synthesis of various pyrano[2,3-d]pyrimidine derivatives. Additionally, new ultrasound-assisted synthesis protocol was used for the synthesis of novel chromeno[2,3-d]pyrimidine derivatives via three-component condensation of aromatic aldehydes, orcinol and barbituric acid. The new catalytic method exhibits some notable advantages such as short reaction times, operational simplicity, green reaction conditions, high yields and easy work-up and purification steps. In addition, the novel magnetic nano-particle could be easily separated by an external magnet and reused for six times without significant loss of its catalytic activity in the reaction.

Verjuice (unripe grape juice), a natural mixture of organic acids, which is identified by pH-metric and TGA analysis, is efficiently used for the promotion of the synthesis of 5-arylmethylenepyrimidine-2,4,6-triones, via Knovenagel condensation reaction between barbituric or thiobarbituric acid and aldehydes. Verjuice is also employed for the effective synthesis of pyrano[2,3-d]pyrimidinone derivatives via a three-component reaction of barbituric acid or its thio analogue, aldehydes and malononitrile. In the same way, pyrimido[4,5-d]pyrimidinone derivatives are simply produced via the reaction of barbituric acid, aldehydes and urea or thiourea in the presence of verjuice. This green methodology rewards notable advantages including simple procedures, acceptable reaction times, easy work-up, high yields, circumventing the use of any expensive starting materials, volatile and hazardous organic solvents during the reaction and work-up process, and use of a natural, low-cost, reusable, and bio-degradable catalyst.

A clean and efficient, multi-component strategy for the synthesis of biologically important trisubstituted thiazole via the reaction of readily available barbituric acid, acetophenone, and aryl thioamides is reported in the presence of FeCl3.6H2O / O2(Air) in DMF solvent. The advantages of the present methodology include a one-pot reaction, environment-friendly approach, cost-effectiveness, broad substrate scope, operational simplicity, short reaction time, easy workup procedure, and high yields.

Liquid phase tandem Knoevenagel-Michael condensation of various aromatic and heteroaromatic aldehydes with barbituric acid or 2-thiobarbituric acid and malononitrile was studied in a one-pot three-component reaction. For the first time, TMDP was employed as a safe and efficient solvent and/or catalyst in the liquid and aqueous ethanol medium, respectively, for the practical and eco-friendly Knoevenagel-Michael condensation. The reactions were carried out by using greener procedures, including a) the use of TMDP as an N-heterocycle organocatalyst in a green medium including water and ethanol (1:1 v/v) at reflux temperature, and b) the use of TMDP as a dual solvent-catalyst at 65 °C in the absence of any solvent. High to excellent yields of the desired pyrano[2,3- d ]pyrimidinones were obtained under the two earlier mentioned conditions. The current methodologies have advantages, including (a) avoiding hazardous, toxic, volatile, and flammable materials and solvents, (b) avoiding tedious processes, harsh conditions, and multiple steps for the preparation of catalysts, (c) using a less toxic and noncorrosive catalyst, (d) minimizing hazardous waste generation and simple workup process, and (e) high recyclability of TMDP. Another important result of this work is that the TMDP can be a promising alternative for toxic, volatile, and flammable base reagents such as piperidine and triethylamine in liquid phase organic syntheses owing to its unique properties such as being less toxic, nonflammable, and nonvolatile, and having a low melting point, broad liquid range temperature, high thermal stability, and safe handling and storage.

A variety of bis-heterocycles such as bis(pyrimido[4,5-b]quinolone), bis(chromeno[3′,4':5,6]pyrido[2,3-d]pyrimidine), bis(pyrido[2,3-d:6,5-d']dipyrimidine), and bis(benzo[g]pyrimido[4,5-b]quinolone) derivatives were synthesized via one-pot, multi-component reaction of various 6-aminouracils or 6-aminothiouracils, terephthalaldehyde, and CH-acids such as 4-hydroxycoumarin, dimedone, 2-hydroxy-1,4-naphthoquinone, barbituric acid, and thiobarbituric acid in EtOH as a solvent at reflux. The mild conditions, fast rate of reaction, absence of catalyst, different functional group compatibility, simple operation and work-up involving no chromatographic process, are worth mentioning., Organic chemistry, Multi-component reaction, Bis pyridopyrimidine, Pyrimidoquinolone, Aminothiouracils.

Herein we report iodine-mediated multicomponent reactions for the synthesis of naphthoquinone-fused pyrroles tethered with a pyrimidine moiety. The reaction of aryl methyl ketones (3) or terminal aryl alkynes (5) in the presence of molecular iodine in DMSO medium followed by sequential addition of barbituric acids (2) and 2-amino-1,4-naphthoquinone (1) provides the corresponding three-component hybrid molecules 4 having naphthoquinone-fused pyrroles tethered with a barbituric acid moiety. This three-component reaction proceeds via metal-free C-H oxidation followed by multi-component cyclization forming three new bonds (2 C-C, 1 C-N) in one pot. Alternatively, the same molecules can also be prepared from the reaction of arylglyoxals, 2-aminonaphthoquinone, and barbituric acids in the presence of a catalytic amount of iodine in methanol medium under reflux conditions. The salient features of these methodologies are: one-pot metal-free method, good yields, wide substrate scope, easy purification of products, and the presence of medicinally important naphthoquinone, pyrrole and pyrimidine moieties in the products.

A well-defined and stable "AB" binary system in the presence of "C" a crystalline synthon ground in a ball mill undergoes selective transformation in the solid state according to the equation AB+C→AC+B. When the amount of C is increased two times then the equation AB+2C→AC+BC is valid. The other variants are more complex. The pathway BC+A is allowed and leads to the AC and B products. The pathway AC+B is not preferred, and no transformation is observed. These non-obvious correlations were observed for cocrystal of barbituric acid (BA):thiobarbituric acid (TBA) recently reported by Shemchuk et al. (Chem. Commun. 2016, 52, 11815-11818) in the presence of 1-hydroxy-4,5-dimethyl-imidazole 3-oxide (HIMO). This synthon shows high affinity for the BA0.5 TBA0.5 cocrystal as well for its individual components, BA and TBA. Single-quantum, double-quantum (SQ-DQ) 2D 1 H very fast MAS NMR with a spinning rate of 60 kHz was employed as a basic and most diagnostic tool for the study of cocrystals transformations. Analysis of the experimental data was supported by theoretical calculations, including computation of the stabilization energy, Estab , defined as the energy difference between the energy of a co-crystal and the sum of the energies of particular components in the respective stoichiometric ratios. Two mechanisms of synthon replacement have been proposed. Pathway 1 assumes a concerted mechanism of substitution. In this approach, synthon attack is synchronized in time with the departure of one of the components of the binary system. Pathway 2 implies a non-concerted process, with an intermediate stage in which three separate components are present. Evidence suggesting a preference for Pathway 2 is shown.