Nanocrystalline TiO2 , via green combustion synthesis, as an efficient and reusable catalyst for the preparation of 1,8-dioxooctahydroxanthenes and 1,8-dioxodecahydroacridines

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.

Urease: a highly efficient biocatalyst for synthesis of polyhydroquinolines and polyhydroacridines from the ammonia formed in situ

Urease, a nickel-dependent enzyme, has a powerful catalytic activity to decompose urea into ammonia via hydrolysis reaction under mild condition. In the present work, urease was employed for the synthesis of two series of polyhydroquinoline and polyhydroacridine derivatives via one-pot condensation of the ammonia generated in situ from urea, aryl aldehydes, and dimedone or ethyl acetoacetate (i.e., Hantzsch-type reaction) in water under mild green condition. The valuable features of this enzymatic method are mild reaction conditions, short reaction times, wide substrate toleration, and high yield of products. The present work provides a novel enzymatic catalysis to synthesize polyhydroquinolines and polyhydroacridines and expands the application of urease in organic synthesis.

Synthesis of 1,8-Dioxo-decahydroacridine Derivatives via Ru-Catalyzed Acceptorless Dehydrogenative Multicomponent Reaction

A Ru-catalyzed acceptorless dehydrogenative multicomponent reaction has been developed. This reaction offers a cost-effective and simple operational strategy to synthesize biologically active 1,8-dioxodecahydroacridine derivatives. The protocol provides a wide range of substrate scope and various functional groups are also well tolerated under the reaction condition. To shed light on the mechanistic and kinetic study, some controlled experiments and deuterium labeling experiments were executed. A time-dependent product distribution experiment is also presented and the reaction scale-up is performed to highlight the practical utility of this strategy.

Facile route to synthesize Fe3O4@acacia-SO3H nanocomposite as a heterogeneous magnetic system for catalytic applications

In this work, a novel catalytic system for facilitating the organic multicomponent synthesis of 9-phenyl hexahydroacridine pharmaceutical derivatives is reported. Concisely, this catalyst was constructed from acacia gum (gum arabic) as a natural polymeric base, iron oxide magnetic nanoparticles (Fe3O4 NPs), and sulfone functional groups on the surface as the main active catalytic sites. Herein, a convenient preparation method for this nanoscale composite is introduced. Then, essential characterization methods such as various spectroscopic analyses and electron microscopy (EM) were performed on the fabricated nano-powder. The thermal stability and magnetic properties were also precisely monitored via thermogravimetric analysis (TGA) and vibrating-sample magnetometry (VSM) methods. Then, the performance of the presented catalytic system (Fe3O4@acacia-SO3H) was further investigated in the referred organic reaction by using various derivatives of the components involved in the reaction. Optimization, mechanistic studies, and reusability screening were carried out for this efficient catalyst as well. Overall, remarkable reaction yields (94%) were obtained for the various produced derivatives of 9-phenyl hexahydroacridine in the indicated optimal conditions.

Selective and highly efficient synthesis of xanthenedione or tetraketone derivatives catalyzed by ZnO nanorod-decorated graphene oxide

A new and efficient method for the pseudo three-component synthesis of diverse tetraketone or xanthenedione derivatives has been described in the presence of ZnO nanorods decorated graphene oxide.