49 research outputs found
Rh-Catalyzed Reactions of 1,4-Benzoquinones with Electrophiles:C-H Iodination, Bromination, and Phenylselenation
Under Rh-catalyzed conditions, typically electrophilic 1,4-benzoquinones exhibit nucleophilic reactivity, such that exposure to appropriate electrophiles generates products of C-H iodination, bromination, and phenylselenation. This provides a mild and general method for direct halofunctionalization, and the first method that can achieve direct C-H phenylselenation of this compound class. The scope and limitations of the new protocols are outlined, and representative derivatizations are highlighted.</p
The Synthesis and Reactivity of Naphthoquinonynes
AbstractThe first systematic exploration of the synthesis and reactivity of naphthoquinonynes is described. Routes to two regioisomeric Kobayashi‐type naphthoquinonyne precursors have been developed, and the reactivity of the ensuing 6,7‐ and 5,6‐aryne intermediates has been investigated. Remarkably, these studies have revealed that a broad range of cycloadditions, nucleophile additions and difunctionalizations can be achieved while maintaining the integrity of the highly sensitive quinone unit. The methodologies offer a powerful diversity oriented approach to C6 and C7 functionalized naphthoquinones, which are typically challenging to access. From a reactivity viewpoint, the study is significant because it demonstrates that aryne‐based functionalizations can be utilized strategically in the presence of highly reactive and directly competing functionality.</jats:p
Antimicrobial evaluation of quinones and heterocyclic compounds against mycobacterium marinum, M. kansasii and M. abscessus
The resistance to antimicrobials and biocides observed in mycobacteria which do not cause tuberculosis (MNT) determines the necessity to develop drugs. The present study evaluated the activity of naphthoquinones and heterocyclic derivatives obtained from lapachol against Mycobacterium kansasii, M. marinum, and M. abscessus, through the REMA method. It was observed that lapachol was inactive against the three mycobateria species, while β-lapachone and nor-β-lapachone showed activity only against M. marinum. The most active substances for M. kansasii were the derivates 2, 3, 7, and 11, in which compound 2 (CMI = 0.96 μM) was the most active. For M. marinum, 2, 11, and 14 were the most active, while against M. abcessus the compound 3 was the only active. The results showed a wide and diversified resistance spectrum among the species studied, which could be related to the molecular structure and position of the substituting groups, indicating the potentiality of these molecules as antimicrobial prototypes.Colegio de Farmacéuticos de la Provincia de Buenos Aire
2-(4-Methylphenyl)-1H-anthraceno[1,2-d]imidazole-6,11-dione: a fluorescent chemosensor
In the title compound, C22H14N2O2, the five rings of the molecule are not coplanar. There is a significant twist between the four fused rings, which have a slightly arched conformation, and the pendant aromatic ring, as seen in the dihedral angle of 13.16 (8)° between the anthraquinonic ring system and the pendant aromatic ring plane
Synthesis of Selenium-Quinone Hybrid Compounds with Potential Antitumor Activity via Rh-Catalyzed C-H Bond Activation and Click Reactions
In continuation of our quest for new redox-modulating catalytic antitumor molecules, selenium-containing quinone-based 1,2,3-triazoles were synthesized using rhodium-catalyzed C-H bond activation and click reactions. All compounds were evaluated against five types of cancer cell lines: HL-60 (human promyelocytic leukemia cells), HCT-116 (human colon carcinoma cells), SF295 (human glioblastoma cells), NCIH-460 (human lung cells) and PC3 (human prostate cancer cells). Some compounds showed good activity with IC50 values below 1 µM. The cytotoxic potential of the naphthoquinoidal derivatives was also evaluated in non-tumor cells, exemplified by L929 cells. Overall, these compounds represent promising new lead derivatives and stand for a new class of chalcogenium-containing derivatives with potential antitumor activity
Rhodium-catalyzed C-H bond activation for the synthesis of quinonoid compounds: Significant Anti-Trypanosoma cruzi activities and electrochemical studies of functionalized quinones
It Takes Two to Tango, Part II : Synthesis of A-Ring Functionalised Quinones Containing Two Redox-Active Centres with Antitumour Activities
In 2021, our research group published the prominent anticancer activity achieved through
the successful combination of two redox centres (ortho-quinone/para-quinone or quinone/seleniumcontaining triazole) through a copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The
combination of two naphthoquinoidal substrates towards a synergetic product was indicated, but
not fully explored. Herein, we report the synthesis of 15 new quinone-based derivatives prepared
from click chemistry reactions and their subsequent evaluation against nine cancer cell lines and
the murine fibroblast line L929. Our strategy was based on the modification of the A-ring of paranaphthoquinones and subsequent conjugation with different ortho-quinoidal moieties. As anticipated,
our study identified several compounds with IC50 values below 0.5 µM in tumour cell lines. Some
of the compounds described here also exhibited an excellent selectivity index and low cytotoxicity
on L929, the control cell line. The antitumour evaluation of the compounds separately and in their
conjugated form proved that the activity is strongly enhanced in the derivatives containing two
redox centres. Thus, our study confirms the efficiency of using A-ring functionalized para-quinones
coupled with ortho-quinones to obtain a diverse range of two redox centre compounds with potential
applications against cancer cell lines. Here as well, it literally takes two for an efficient tango
Indirect consequences of exciplex states on the phosphorescence lifetime of phenazine-based 1,2,3-triazole luminescent probes
Cytotoxic, trypanocidal activities and physicochemical parameters of nor-²-lapachone-based 1,2,3-triazoles
Introduction to celebrating Latin American talent in chemistry
In celebration of the excellence and breadth of Latin American research achievements across the chemical sciences, we are delighted to present an introduction to the themed collection, Celebrating Latin American talent in chemistry. [Image: see text