A greener synthesis of 1,8-dioxo-octahydroxanthene derivatives under ultrasound

Flexible Approach for the Synthesis of Annulated 4H-Pyrans Based on a Cu(I)-Catalyzed C-Allylation/O-Vinylation Reaction of Cyclic 1-Bromoallyl Tosylates with Cyclic and Acyclic 1,3-Dicarbonyls

The Cu(I)-catalyzed reaction between five-, six-, seven-, and eight-membered cyclic 1-bromoallyl tosylates and five- and six-membered cyclic 1,3-dicarbonyls in DMF at 80 °C using Cs₂CO₃ as a base and 2-picolinic acid as an additive selectively delivers a wide array of bisannulated 4H-pyrans in a single step with yields up to 92%. The transformations are considered to proceed as intermolecular C-allylations/intramolecular O-vinylations. With six-membered cyclic 1-bromoallyl tosylates and acyclic β-ketoesters as substrates, the corresponding 5,6,7,8-tetrahydro-4H-chromene-3-carboxylates are obtained with yields up to 59%.

Co-Sn-Cu oxides/graphene nanocomposites as green catalysts for preparing 1,8-dioxo-octahydroxanthenes and apoptosis-inducing agents in MCF-7 human breast cancer cells

In this work, Co-Sn-Cu oxides/graphene nanocomposite, 30-40 ± 0.5 nm in size, was synthesized by solid-state microwave irradiation. This method presents several advantages such as operational simplicity, fast, low cost, safe and energy efficient, and suitability for production of high purity of nanoparticles. Other advantages of this method are there is no need for the use of solvent, fuel, and surfactant. Co-Sn-Cu oxides/graphene nanocomposites have been characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, energy-dispersive X-ray spectroscopy, and UV-Vis spectroscopy. The synthesized nanocomposites were used as novel highly efficient catalysts for the synthesis of 1,8-dioxo-octahydroxanthenes at room temperature. The catalysts are recoverable and can be reused for six runs without loss of their activity. Also, the obtained nanocomposites exhibited significant anticancer activity against breast cancer cells and they could induce apoptosis in cancer cells.

Application of cyclohexane-1,3-diones for six-membered oxygen-containing heterocycles synthesis

Cyclohexan-1,3-dione derivatives are versatile scaffolds for the synthesis of a variety of value-added organic molecules including heterocycles and natural products. Six-membered oxygen heterocycles prepared from cyclohexan-1,3-diones are of much importance as they are intermediate for the synthesis of a number of natural products and several other valuable bioactive molecules which shows anti-viral, anti-bacterial, analgesic, antimalarial, anti-inflammatory, anti-allergic, anti-tumor and anti-cancer activities. These advantages have inspired us to write a detailed survey on the newly developed methods which are very essential in the construction of six-membered oxygen heterocycles. Further, the versatility in the chemistry of cyclohexan-1,3-dione and its derivatives is due to the presence of highly active methylene moiety and its active di-carbonyl groups. Recently, reactions of cyclohexane-1,3-dione and its derivatives with other substrates for instance aldehydes, malononitriles, NMSM, chalcones, isatin etc. have been established for the construction of a variety of six-membered oxygen heterocycles. The studies reported in this review article involved the synthesis of six-membered oxygen-containing heterocycles which includes 4H-chromen-5(6H)-one, 2H-xanthen-1(9H)-one, 2H-xanthen-1,8(5H,9H)-dione, 6H-chromen-2,5-dione derivatives and natural products having six-membered oxygen heterocycles from cyclohexane-1,3-dione and its derivatives as one of the substrate.

Catalytic Applications of Saccharin and its Derivatives in Organic Synthesis

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Saccharin (1,2-benzisothiazol-3(2H)-one-1,1-dioxide) is a very mild, cheap, commercially available, water soluble, environmentally benign and edible Brønsted acidic substance. Recently, with other utilities, saccharin and its derivatives were employed as catalysts for various organic transformations. In this review, catalytic applicability of saccharin and its derivatives under various reaction conditions is summarized.

Solvent-Free Preparation of 1,8-Dioxo-Octahydroxanthenes Employing Iron Oxide Nanomaterials

In this study, 1,8-dioxo-octahydroxanthenes were prepared employing a simple, effective and environmentally sound approach utilizing an iron oxide nanocatalyst under solventless conditions. The proposed iron oxide nanomaterial exhibited high product yields, short reaction times and a facile work-up procedure. The synthesized catalyst was also found to be highly stable and reusable under the investigated conditions (up to twelve consecutive cycles) without any significant loss in its catalytic activity.

Eggshell/Fe3O4 nanocomposite: novel magnetic nanoparticles coated on porous ceramic eggshell waste as an efficient catalyst in the synthesis of 1,8-dioxo-octahydroxanthene

An eggshell/Fe₃O₄ nanocomposite was synthesized via an economic and novel method, using recycled eggshell biowaste as a starting material and an aqueous solution of FeSO₄ as a coating agent without any additional alkali or a protective atmosphere.

1,2,3-Triazoles derived from olanzapine: their synthesis via an ultrasound assisted CuAAC method and evaluation as inhibitors of PDE4B

An ultrasound assisted CuAAC method afforded novel 1,2,3-triazoles derived from olanzapine as inhibitors of PDE4B.