Cu(II)‐supported graphene quantum dots modified NiFe 2 O 4 : A green and efficient catalyst for the synthesis of 4H‐pyrimido[2,1‐b]benzothiazoles in water

Bentonite/Ti(IV) as a natural based nano-catalyst for synthesis of pyrimido[2,1-b]benzothiazole under grinding condition

A new natural-based catalyst named Bentonite/Ti(IV) was prepared and characterized by FT-IR, FESEM, TEM, TGA, EDS-MAP, XRD, BET, XRF, XPS and ICP- MS. An efficient and simple one-pot three-component synthesis of pyrimido[2,1-b]benzothiazole derivatives was carried out by the reaction of aldehyde, 2-aminobenzothiazole, and ethyl acetoacetate. In this research, Bentonite/Ti(IV) was used for the synthesis of PBT derivatives in 80 °C under solvent-free conditions by electrical mortar-heater. Solvent-free conditions, simplicity of operation, easy work-up and use of an eco-friendly catalyst are some of advantages of this protocol.

Research on transition metals for the multicomponent synthesis of benzo-fused γ-lactams

Benzo-fused γ-lactams are fundamental in medicinal chemistry, acting as essential elements for various therapeutic agents due to their structural adaptability and capability to enhance biological activity. In their synthesis, transition metals play a pivotal role as catalysts, offering more efficient alternatives to traditional methods by facilitating C-N bond formation through mechanisms like intramolecular coupling. Recent advances have especially spotlighted transition-metal-catalyzed C-H amination reactions for directly converting C(sp2)-H to C(sp2)-N bonds, streamlining the creation of these compounds. Furthermore, biocatalytic approaches have emerged, providing asymmetric synthesis of lactams with high yield and enantioselectivity. This review examined the transition metal-catalyzed synthesis techniques for producing benzo-fused γ-lactams, marking a significant leap in organic synthesis by proposing more effective, selective, and greener production methods. It serves as a valuable resource for researchers in the fields of transition metal catalysts and those engaged in synthesizing these lactams.

Preparation and application of FNAOSiPPEA/Cu(II) as a novel magnetite almondshell based Lewis acid-Bronsted base nano-catalyst for the synthesis of pyrimidobenzothiazoles

Background

The magnetic nano-catalysts improve the contact between substrates and catalyst considerably and simple isolation of catalyst from reaction mixture. In this study, Fe₃O₄@nano-almondshell@OSi(CH₂)₃/2-(1-piperazinyl)ethylamine/Cu(II) abbreviated (FNAOSiPPEA/Cu(II)), was prepared, characterized and applied for the synthesis of 4H-pyrimido[2,1-b]benzothiazole.

Results

FNAOSiPPEA/Cu(II) as a bio-based nano-catalyst was prepared from the complexation of copper on 2-(1-piperazinyl)ethylamine, which was immobilized on Fe₃O₄@nano-almondshell@OSi(CH₂)₃ section. This new heterogeneous bifunctional Lewis acid/Bronsted base catalyst (FNAOSiPPEA/Cu(II)) was characterized by various techniques such as FT-IR, FESEM, TGA, EDS-MAP, XRD, VSM, BET, TEM, and XPS. So, the catalytic performance of this recyclable nano-catalyst was determined to promote the synthesis of 4H-pyrimido[2,1-b]benzothiazole derivatives at 100 °C under solvent-free conditions.

Conclusions

Magnetite nano-catalyst of (FNAOSiPPEA/Cu(II)) is easily separated by an external magnet and successfully reused up at least 3 times with a slight loss of yield of the desired product.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13065-022-00838-6.

Magnetic nanocatalysts utilized in the synthesis of aromatic pharmaceutical ingredients

This review covers recent developments in nanoscale magnetic catalytic systems and their applications in facilitating organic synthetic reactions of aromatic pharmaceutical ingredients.