One-pot solvent-free synthesis of 2,3-dihydro-2-substituted-1H-naphtho[1,2-e][1,3]oxazine derivatives using Fe3O4@nano-cellulose/TiCl as a bio-based and recyclable magnetic nano-catalyst

1,3-Naphthoxazine derivatives: Synthesis, in silico pharmacokinetic studies, antioxidant and photoprotective properties

Investigation into the interactions between photoprotective agents and skin can offer a precise understanding of their biological behaviors in vitro and in vivo, providing crucial insights for generating new substances. For this purpose, we designed and synthesized a series of naphthoxazine derivatives and examined their photoprotective properties. 1,3-naphthoxazine derivatives were synthesized through the multi-component reaction of 2-naphthol, arylamines and aromatic aldehydes in the presence of copper(II) trifluoromethanesulfonate (Cu(OTf)2) and (±)-Camphor-10-sulfonic acid ((±)-CSA) catalyst system under sonication. The potential of these synthesized 1,3-naphthoxazine derivatives as antioxidants and viable organic structural-based sunscreen ingredients has been investigated. Sun protection factor (SPF) assay results showed that especially compounds 4i, 4c, 4k, 4d, 4r, and 4h had remarkably high activity (23.65, 23.57, 23.04, 21.94, 20.80, and 20.26, respectively at 900 µg/mL concentration). Additionally, antioxidant activity of the synthesized compounds was evaluated and compounds 4h, 4e, 4b, and 4j exhibited the highest activities in DPPH scavenging activity assay (86.46 %, 82.83 %, 80.78 %, and 80.65 % respectively at 400 µg/mL concentration). The synthesized compounds exhibit promising characteristics for effective UV radiation absorption, suggesting their suitability for inclusion in sunscreen formulations. Cytotoxic activity of compound 4k against normal human fibroblast cell line (MRC-5) was determined by CVDK-8 method. The results revealed that the compound provided remarkable viability (87.55 %) of MRC-5 cells at concentration of 100 µM. The study explores their efficacy in providing broad-spectrum protection against UVA and UVB rays, degradation and photostability, ADMET profile, and other pharmacokinetic properties.

Efficient synthesis of some [1,3]-oxazine derivatives in the presence of solid acid nano catalyst based on ferrierite and study on their activity against breast cancer through molecular docking calculation

In this research, the magnetic solid acid nanocatalyst based on ferrierite has been prepared and used as catalyst for the green synthesis of some [1,3]-oxazine derivatives in water at room temperature. The synthesized compounds were obtained in high to excellent yields after short reaction times and the structure of synthesized products were investigated by spectroscopic methods such as: FT-IR, 1H NMR and 13C NMR. The prepared magnetic solid acid catalyst was characterized using XRD, FT-IR, FE-SEM, EDX, elemental mapping, TGA and VSM analysis methods. Magnetic catalyst has easy separation ability, which leads to better and easier recycling. The preparation and synthesis of [1,3]-oxazine derivatives were carried out at room temperature in the presence of M-FER/TEPA/SO3H. Easy workup, green solvent (water) and also short reaction times with high to excellent yield of products, are some of advantageous of presented method. Docking calculations on the structure of the synthesized compounds proved their medicinal properties against breast cancer cells.

Efficient Suzuki coupling over novel magnetic nanoparticle: Fe3O4/L-(+)-tartaric acid/Pd(0)

A new eco-friendly catalytic system is devised for C-C bond formation through Suzuki coupling, using an impressive nanocatalyst (Fe₃O₄/L-(+)-tartaric acid/Pd-NPs). It contains immobilized palladium (0) onto magnetite nanoparticles, stabilized by tartaric acid, and is characterized by FT-IR, XRD, EDS, SEM, TEM, TGA, and VSM. The catalyst is used in an efficient synthesis of biaryls in EtOH/H₂O (1:1), in the presence of K₂CO₃. Our Fe₃O₄/tartaric acid/Pd-NPs exhibit magnetic recoverability and reusability for five cycles without measurable loss of its activity.

Efficient synthesis of 1,3-naphtoxazine derivatives using reusable magnetic catalyst (GO-Fe3O4-Ti(IV)): anticonvulsant evaluation and computational studies

A series of 2-aryl/alkyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazines (S₁-S₁₁) were synthesized with an eco-friendly and recoverable nanocatalyst (GO-Fe₃O₄-Ti^(IV)) as an efficient magnetic composite. The new nanocatalyst was characterized by FT-IR, XRD and, EDS analysis. A conformable procedure, easy to work up and having a short reaction time with high yields are some advantages of this method. The new catalyst is also thermal-stable, reusable and, environment-friendly. The chemical structures of the synthesized 1,3-oxazine compounds were confirmed by comparing their melting points with those reported in literature. Then, the anticonvulsant activity of these compounds was assessed by the intraperitoneal pentylenetetrazole test (ipPTZ). Compounds S₁₀ and S₁₁ displayed considerable activity against chemically-induced seizure tests. The molecular simulation was also done to achieve their binding affinities as γ-aminobutyric acid A (GABA-A) receptor agonists as an assumptive mechanism of their anticonvulsant action. The result of molecular studies represented strongly matched with biological activity. Molecular docking simulation of the potent compound (S₁₀) and diazepam as the positive control was performed and some critical residues like Thr262, Asn265, Met286, Phe289, and Val290 were identified. Based on the anticonvulsant results and also in silico ADME predictions, S₁₁ can be to become a potential drug candidate as an anticonvulsant agent.

A facile green synthesis of MgCoFe2O4 nanomaterials with robust catalytic performance in the synthesis of pyrano[2,3-d]pyrimidinedione and their bis-derivatives

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.

Biosynthesis of Cu/KF/Clinoptilolite@MWCNTs nanocomposite and its application as a recyclable nanocatalyst for the synthesis of new Schiff base of benzoxazine derivatives and reduction of organic pollutants

In this work, we synthesized new Schiff base of benzoxazine derivatives in excellent yields using multicomponent reactions of phthalaldehyde or its derivatives, primary amines, isothiocyanate, 2,4-dihydroxyacetophenone, isopropenylacetylene and methyl or ethyl amine in the presence of catalytic amount of Cu/KF/CP@MWCNTs NCs in water at room temperature. Also, the catalytic activity of the green synthesized Cu/KF/CP@MWCNTs NCs was evaluated in the reduction in organic pollutants such as 4-nitrophenol (4-NP) in water at mild conditions. The results indicated that the biosynthesized NCs have very high and effective catalytic activity for organic pollutants within few seconds. As well the antioxidant activity of some synthesized benzoxazine was studied using trapping of radical by DPPH and ferric reduction activity potential (FRAP) experiment. The short time of reaction, high yields of product, easy separation of catalyst and products are some benefits of this procedure.

Gum arabic-OPO3H2 as a new natural-based green catalyst for the one-pot pseudo-four-component synthesis of naphtho[1,2-e][1,3]oxazines

Gum arabic-OPO3H2 (GA-OPO3H2) as a unique natural-based green catalyst was synthesized by the reaction of phosphorus pentoxide with gum arabic. The structure and properties of the catalyst were studied via several analysis methods such as FT-IR, MAPPING, EDS, SEM, XRD, and TGA. The efficiency of the above-mentioned catalyst was investigated for the synthesis of naphtho-1,3-oxazines via a pseudo-four-component reaction of primary amines, formaldehyde, and 2-naphthol under the solvent-free grinding condition at room temperature using an electrical mortar-heater. The obtained results indicated that GA-OPO3H2 is a highly efficient green catalyst for the synthesis of naphtho[1,2-e][1,3]oxazines with high yields, simple workup, and benign reaction condition.

Nano-Fe3O4@walnut shell/Cu(ii) as a highly effective environmentally friendly catalyst for the one-pot pseudo three-component synthesis of 1,3-oxazine derivatives under solvent-free conditions

Fe3O4@walnut shell/Cu(ii) as an eco-friendly bio-based magnetic nano-catalyst was prepared by adding CuCl2 to Fe3O4@walnut shell in alkaline medium. A series of 2-aryl/alkyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazines were synthesized by the one-pot pseudo three-component reaction of β-naphthol, formaldehyde and various amines using nano-Fe3O4@walnut shell/Cu(ii) at 60 °C under solvent-free conditions. The catalyst was removed from the reaction mixture by an external magnet and was reusable several times without any considerable loss of its activity. This protocol has several advantages such as excellent yields, short reaction times, clean and convenient procedure, easy work-up and use of an eco-friendly catalyst.

Recent development in the synthesis of heterocycles by 2-naphthol-based multicomponent reactions

2-Naphthol or β-naphthol is an important starting material that has drawn great attention in various organic transformations because of its attributes, such as low cost, easy to handle and eco-friendliness. The electron-rich aromatic framework of 2-naphthol with multiple reactive sites allows it to be utilized in several kinds of organic reactions eventuated to several organic molecules with potent biological properties. Multicomponent reaction approach has been tremendously utilized to explore the synthetic utility of 2-naphthol for the construction of diverse N/O-containing heterocyclic framework. In this review, we summarize recent data pertaining to multicomponent reactions, wherein heterocyclic compounds are synthesized utilizing 2-naphthol as one of the starting materials. It is anticipated that this review will stimulate the researchers to design new multicomponent strategies complying with the Green Chemistry principles for the further exploitation of 2-naphthol for the rapid synthesis of versatile biologically relevant heterocycles. This review provides a concise overview of the different 2-naphthol based multicomponent reactions utilized for the construction of diverse bioactive heterocyclic scaffold.

Nano-kaolin/Ti4+/Fe3O4: a magnetic reusable nano-catalyst for the synthesis of pyrimido[2,1-b]benzothiazoles

Herein, nano-kaolin/Ti⁴⁺/Fe₃O₄ as a new magnetic nano-catalyst was synthesized, and its structural properties were characterized using various techniques such as Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), a vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA) and energy-dispersive X-ray spectroscopy (EDX). This catalyst was used for the synthesis of pyrimido[2,1-b]benzothiazoles via the one-pot condensation of 2-aminobenzothiazole, an aldehyde and β-keto ester under solvent-free conditions at 100 °C. This simple protocol has many advantages such as easy workup, high product yields, short reaction times and reusability of the catalyst.

Herein, nano-kaolin/Ti⁴⁺/Fe₃O₄ as a new magnetic nano-catalyst was synthesized, and its structural properties were characterized using various techniques such as FTIR spectroscopy, FE-SEM, TEM, XRD, VSM, TGA and EDX.