Synthesis of novel 2-aryl-3-benzoyl-1H-benzo[f]indole-4,9-diones using a domino reaction

Synthesis, in vitro Α-Glucosidase, and acetylcholinesterase inhibitory activities of novel Indol-Fused Pyrano[2,3-D]Pyrimidine compounds

In this study, new indol-fused pyrano[2,3-d]pyrimidines were designed and synthesized. These products were obtained in moderate to good yields and their structures were assigned by NMR, MS, and IR analysis. Afterwards, the biological important of the products was highlighted by evaluating in vitro for α-glucosidase inhibitory activity as well as acetylcholinesterase (AChE) inhibitory activity. Eleven products revealed substantial inhibitory activity against α-glucosidase enzyme, among which, two most potent products 11d,e were approximately 93-fold more potent than acarbose as a standard antidiabetic drug. Besides that, product 11k exhibited good AChE inhibition. The substituents on the 5-phenyl ring, attached to the pyran ring, played a critical role in inhibitory activities. The biological potencies have provided an opportunity to further investigations of indol-fused pyrano[2,3-d]pyrimidines as potential anti-diabetic agents.

Microwave-Assisted Three-Component Synthesis of Novel N-Arylated-Dihydrobenzo[g]quinoline-5,10-Diones and Their Potential Cytotoxic Activity

A convenient three-component synthetic approach was developed en route to new and significative N-arylated-dihydrobenzo[g]quinoline-5,10-diones using 2-hydroxy-1,4-naphthoquinone, a variety of aromatic aldehydes, and 4-(arylamino)furan-2(5H)-ones. A sequence of steps including Knoevenagel condensation, Michael addition, [1,3]-hydrogen shift, intramolecular cyclization and dehydration led to the formation of products. All the products were structurally characterized by spectroscopic techniques and assessed in terms of their cytotoxicity profile against four cancer cell lines (KB, HepG2, A549, and MCF7), and human embryonic kidney (Hek-293) cell lines.

Synthesis and biological evaluation of novel benzo[a]pyridazino[3,4-c]phenazine derivatives

A convenient microwave-assisted one-pot four-component synthetic approach was developed en route to novel functionalized benzo[a]pyridazino[3,4-c]phenazine derivatives starting from 2-hydroxy-1,4-naphthoquinone, aromatic aldehydes, methyl hydrazine and o-phenylenediamine. Nine new derivatives were successfully synthesized and subsequently evaluated in terms of their biological profiles. The results revealed good cytotoxic activities of compounds 6a, 6h against KB, HepG2, Lu1 and MCF7 human cancer cell lines. Besides that, compound 6d exhibited promising antimicrobial activities toward Staphylococcuc aureus and Bacillus subtilis bacterial strains with IC₅₀ < 6 μM.

One-pot synthesis of pyrimidine linked naphthoquinone-fused pyrroles by iodine-mediated multicomponent reactions

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.

Divergent Conversion of 4-Naphthoquinone-substituted 4H-Isoxazolones to Different Benzo-fused Indole Derivatives

4,4-Disubstituted 4H-isoxazol-5-ones bearing a 1,4-naphthoquinone moiety undergo transformation into different types of benzoindolyl products depending on the different reaction conditions. A decarboxylative ring opening/ring closure promoted by catalytic [Ru(p-cymene)₂Cl₂]₂ yields benzo[f]indole-4,9-diones. Alternatively, hydrogenation reactions provide the conversion of 4-(1,4-naphthoquinone)-substituted isoxazol-5-ones to benzo[g]indole compounds, with the level of reduction depending on the substituents present on the ring. Starting materials have been easily prepared by the functionalization of isoxazolinones with naphthoquinone under mild conditions.

Access to 2,3-Fused Pyrroles via Visible Light Driven Coupling of α-Azidochalcones with 1/2-Naphthols, or 2-Hydroxy-1,4-Naphthoquinone

α-Azidochalcones were coupled with 1/2-naphthols or 2-hydroxy-1,4-naphthoquinone using Ru(bpy)₃(PF₆)₂ as a photocatalyst under blue LED light irradiation to yield 2,3-fused pyrroles in high yields (68-84%). The overall transformation involves photosensitized decomposition of α-azidochalcones into highly reactive 2 H-azirines which are trapped by 1/2-naphthols or 2-hydroxy-1,4-naphthoquinone, leading to the construction of two new C-N and one new C-C bonds.