Regioselective quadruple domino aldolization/aldol condensation/Michael/SNAr-cyclization: construction of hexacyclic indeno-fused C-nor-D-homo-steroid frameworks

A Palladium-Catalyzed 4CzIPN-Mediated Decarboxylative Acylation Reaction of O-Methyl Ketoximes with α-Keto Acids under Visible Light

This work presents a palladium-catalyzed oxime ether-directed ortho-selective benzoylation using benzoylformic acid as the acyl source with a palladium catalyst and 4CzIPN as the co-catalyst under light. Various non-symmetric benzophenone derivatives were obtained in moderate to good yields. A preliminary mechanism study revealed that the reaction proceeds through a free radical pathway.

Effective synthesis of a hexacyclic-steroid derivative from 4-hydroxyestrone

Several studies have been reported for the preparation of hexacyclic-steroid derivatives; however, some reagents are expensive and require special conditions for handling. In this way, the objective of this study was to synthesize a hexacyclic-steroid derivative from 4-hydroxyestrone. The chemical structure was evaluated through both ¹H NMR and ¹³C NMR spectroscopic analysis. The results showed good performance of the hexacyclic-steroid derivative. In conclusion in this study, an easy method for the preparation of the hexacyclic-steroid derivative is reported.

C-2 phenyl replacements to obtain potent quinoline-based Staphylococcus aureus NorA inhibitors

NorA is the most studied efflux pump of Staphylococcus aureus and is responsible for high level resistance towards fluoroquinolone drugs. Although along the years many NorA efflux pump inhibitors (EPIs) have been reported, poor information is available about structure-activity relationship (SAR) around their nuclei and reliability of data supported by robust assays proving NorA inhibition. In this regard, we focussed efforts on the 2-phenylquinoline as a promising chemotype to develop potent NorA EPIs. Herein, we report SAR studies about the introduction of different aryl moieties on the quinoline C-2 position. The new derivative 37a showed an improved EPI activity (16-fold) with respect to the starting hit 1. Moreover, compound 37a exhibited a high potential in time-kill curves when combined with ciprofloxacin against SA-1199B (norA+). Also, 37a exhibited poor non-specific effect on bacterial membrane polarisation and showed an improvement in terms of “selectivity index” in comparison to 1.

Efficient construction of biologically important functionalized polycyclic spiro-fused carbocyclicoxindoles via an asymmetric organocatalytic quadruple-cascade reaction

A cascade organocatalysis has been developed for the asymmetric synthesis of a highly functionalized polycyclic spiro-fused carbocyclicoxindoles containing five contiguous stereogenic centers with good diastereoselectivity and high enantioselectivity.

Developments toward the synthesis and application of 3-hydroxyindanones

3-Hydroxyindanone is an important scaffold in many natural products, biologically active compounds, and functional materials. This review provides a comprehensive overview of the construction of 3-hydroxyindanone derivatives and their applications towards pharmaceutically promising drug candidates.

CuSO4–d-glucose, an inexpensive and eco-efficient catalytic system: direct access to diverse quinolines through modified Friedländer approach involving SNAr/reduction/annulation cascade in one pot

A one-pot, efficient approach to quinoline synthesis, directly from 2-bromoaromatic aldehydes/ketones in a H₂O–EtOH mixture involving a sequence of S_NAr/reduction/annulation cascade using CuSO₄-d-glucose, is devised.

Lewis acid promoted construction of chromen-4-one and isoflavone scaffolds via regio- and chemoselective domino Friedel-Crafts acylation/Allan-Robinson reaction

A facile and efficient synthesis of chromen-4-one and isoflavone frameworks is achieved by the domino C-acylation/O-acylation/aldolization sequence. This operationally simple one-pot elegant strategy provides structurally unique chromen-4-ones and isoflavones directly from phenols via concomitant formation of multiple C-C and C-O bonds in a single operation. The outcomes of the buttressing effect, substituent dependence, and catalyst and solvent specificity during the course of the Friedel-Crafts acylation reactions are demonstrated and supported by fitting experiments.