Bioinspired Pyrano[2,3-f]chromen-8-ones: Ring C-Opened Analogues of Calanolide A: Synthesis and Anti-HIV-1 Evaluation

We have designed and synthesized a series of bioinspired pyrano[2,3-f]coumarin-based Calanolide A analogs with anti-HIV activity. The design of these new calanolide analogs involved incorporating nitrogen heterocycles or aromatic groups in lieu of ring C, effectively mimicking and preserving their bioactive properties. Three directions for the synthesis were explored: reaction of 5-hydroxy-2,2-dimethyl-10-propyl-2H,8H-pyrano[2,3-f]chromen-8-one with (i) 1,2,4-triazines, (ii) sulfonylation followed by Suzuki cross-coupling with (het)aryl boronic acids, and (iii) aminomethylation by Mannich reaction. Antiviral assay of the synthesized compounds showed that compound 4 has moderate activity against HIV-1 on enzymes and poor activity on the cell model. A molecular docking study demonstrates a good correlation between in silico and in vitro HIV-1 reverse transcriptase (RT) activity of the compounds when docked to the nonnucleoside RT inhibitor binding site, and alternative binding modes of the considered analogs of Calanolide A were established.

Thioisomünchnones versus Acrylamides via Copper-Catalyzed Reaction of Thioamides with Diazocarbonyl Compounds

A novel carbenoid-mediated approach to thioisomünchnones was developed by intermolecular copper-catalyzed reactions of diazoacetamides with aromatic and heteroaromatic thioamides bearing a pyrrolidine moiety. The direction of the reaction can be switched toward 2-amino-2-heteroarylacrylamides by replacing the pyrrolidine with an aniline group or by the use of 2-cyano-2-diazoacetamides. The proposed mechanism and DFT calculations allowed us to rationalize the effect of substituents on the reaction direction. Effective methods were found for the synthesis of previously unknown both 2-heteroarylthioisomünchones and 2-heteroarylacrylamides, based on a wide scope of available reagents with a similar structure. Some of the synthesized thioisomünchnones exhibited multicolor fluorescence in the solid state and solutions.

Synthesis of Coumarins Linked With 1,2,3-Triazoles under Microwave Irradiation and Evaluation of their Antimicrobial and Antioxidant Activity

A series of coumarin derivatives linked with 1,2,3-triazoles has been synthesized by utilizing the copper catalyzed azide-alkyne cycloaddition reaction and were screened for their antimicrobial and antioxidant properties. Some of the compounds displayed promising antibacterial activities (MIC ranging from 5-150 µg/mL) and moderate antifungal activities as compared to the respective standards. The compounds 4k and 4g displayed good antibacterial activity when compared with the standard, Ciprofloxacin, and 4n exhibited better antifungal activity when compared to other synthesized compounds. The in silico docking studies of the active compounds were carried out against the gyrase enzyme and from those studies, it was acknowledged that 4k possessed significant hydrogen bonding and hydrophobic interactions which could be the plausible reason for its superior activity as compared to the other synthesized compounds. The compounds 4h and 4q showed promising antioxidant activity when compared with the standard, BHT, which could be attributed to the presence of electron donating substituents.                                                Resumen. Una serie de derivados de cumarina enlazados con 1,2,3-triazoles fue sintetizada empleando la reacción de cicloadición azida-alquino catalizada con cobre y fue evaluada en sus propiedades antimicrobianas y antioxidantes. Algunos de los compuestos exhibieron actividad antimicrobiana promisoria (intervalo MIC de 5-150 µg/mL) y actividad antifúngica moderada con respecto a los estándares respectivos. Los compuestos 4g y 4k mostraron buena actividad antibacterial con relación al estándar. Fluconazole y 4n exhibieron mejor actividad antifúngica en comparación con el resto de los compuestos. Se llevaron a cabo estudios in silico de modelado molecular e interacción de los compuestos activos con la enzima girasa ADN. De estos estudios se observó que 4k posee enlaces puentes de hidrógeno e interacciones hidrofóbicas significativos, los cuales podrían ser una causa plausible de su actividad mayor a aquélla mostrada por los otros compuestos sintetizados. Los compuestos 4h y 4q mostraron una importante actividad antioxidante comparada con el estándar (BHT), lo cual podría atribuirse a la presencia de sustituyentes electro-donadores