CuF2/DMAP-Catalyzed N-Vinylation: Scope and Mechanistic Study

HFIP-Promoted Regioselective Hydrofunctionalization of Enamides and N-Vinyl Azoles

An efficient and regioselective method for the intermolecular hydrofunctionalization of enamides and N-vinyl azoles has been developed, enabling the formation of diverse C-S, C-O, C-N, and C-C bonds. This transition-metal-free, additive-free, and Brønsted acid-free protocol employs hexafluoroisopropanol (HFIP) as the sole reagent, which plays a dual role: formation of iminium carbocation intermediate and facilitating nucleophile generation through its hydrogen-bonding network. The reaction demonstrates exceptional substrate versatility, accommodating thiophenols, alcohols, heterocyclic amines, as well as NH-free indoles, pyrroles, and carbazoles as nucleophiles, proceeding via a Markovnikov-selective hydrofunctionalization pathway. The protocol is general and simple with broad substrate compatibility.

CuF2/DTBP-Catalyzed Chan-Lam Coupling of Oxazolidinones with Arylboronic Acid Pinacol Ester: Scope and Application

A new combination of CuF2/DTBP-catalyzed N-arylation of oxazolidinones, amides, amines, and azoles has been explored with arylboronic acid pinacol esters (arylBpin). This methodology has also been applied to the synthesis of oxazolidinone-based marketed drugs, including Rivaroxaban, Linezolid, Sutezolid, and Toloxatone. Mechanistic investigations using various spectroscopic techniques and DFT studies revealed the role of DTBP/MeOH in the catalytic process.

Ex Situ Generation of D2 for Reductive Deuteration: Scope and Application to Late-Stage Functionalization

An efficient deuteration method through the ex situ generation of D2 for the reductive deuteration of biologically significant α-substituted acrylic acids and enamide derivatives is reported. This method was successfully applied to the synthesis of deuterated analogs of marketed NSAIDs such as ibuprofen, flurbiprofen, and naproxen. Additionally, it facilitates late-stage deuteration of enamides and N-vinylated drugs. Moreover, the method was extended to N-viny azoles, cinnamic acid derivatives, and other unsaturated substrates toward deuteration reaction. This technique utilizes D2O as a safe and economical deuterium source. Notably, the reaction is performed in a standard fume hood setup, ensuring ease of handling and enhanced practicality.

One-pot synthesis of functionalized dihydropyridin-2-ones via carbene-catalyzed base-controlled [3+3] annulation reaction

Herein, we have described a novel organocatalytic approach to access biologically important dihydropyridin-2-ones in a one-pot way with generally high yields (up to 99%) and excellent enantioselectivities (up to 99% ee). This reaction proceeded via a new dual activation mode, including in situ-generated α,β-unsaturated acylazoliums and 4-dimethylaminopyridinium salts that underwent a Michael addition/1,4-H migration/lactamization sequence. The base-triggered 4-dimethylaminopyridinium ylide formation pathway over the competing substitution reaction pathway of vicinal haloamines is noteworthy.

Development of di-arylated 1,2,4-triazole-based derivatives as therapeutic agents against breast cancer: synthesis and biological evaluation

The synthesis, anticancer activity, and metabolic stability of di-arylated 1,2,4-triazole molecules have been reported. Utilizing an efficient programmed arylation technique which starts from commercially available 3-bromo-1H-1,2,4-triazole, a series of therapeutic agents have been synthesized and screened against three human breast cancer cell lines, MDA-MB-231, MCF-7, and ZR-75-1, via an in vitro growth inhibition assay. At 10 μM concentration, 4k, 4m, 4q, and 4t have displayed good anticancer potency in the MCF-7 cell line, among which 4q has shown the best efficacy (IC50 = 4.8 μM). Mechanistic investigations of 4q have indicated the elevation of the pro-apoptotic BAX protein in the malignant cells along with mitochondrial outer membrane permeabilization which are hallmarks of apoptosis. Further metabolic stability studies in diverse liver microsomes have provided insights into the favorable pharmacokinetic properties of 4q in humans, establishing it as a promising lead compound of this series that deserves further investigation.

Ullmann-Type N-, S-, and O-Arylation Using a Well-Defined 7-Azaindole-N-oxide (7-AINO)-Based Copper(II) Catalyst: Scope and Application to Drug Synthesis

An air-stable, robust, and well-defined copper(II)-7-azaindole-N-oxide-based catalyst [Cu2II(7-AINO)4] (abbreviated as Cu(II)-7-AINO) has been demonstrated as an efficient catalyst for various Ullmann-type coupling reactions. This easily prepared and cost-effective catalyst facilitates the arylation and heteroarylation of diverse N-, S-, and O-nucleophiles, including azoles, aminoazoles, (hetero)arylthiols, and phenols. Notably, they also exhibit substantial compatibility with a wide range of functional groups. Furthermore, the catalyst demonstrates significant selectivity for -NH sites of aminoazoles and -SH sites of aminothiophenols over -NH2 sites in both cases, enhancing its versatility. Exploiting the catalyst's chemo- and regioselective properties, we have successfully demonstrated the applicability of our methodology in synthesizing various drug molecules. Specifically, Epirizole analogue, Nilotinib, and Vortioxetine were successfully synthesized using our protocol.

CuI/DMAP-Catalyzed Oxidative Alkynylation of 7-Azaindoles: Synthetic Scope and Mechanistic Studies

An efficient and practical method for the N-alkynylation of 7-azaindoles has been established by using CuI/DMAP catalytic system at room temperature and in open air. This simple protocol has been successfully employed in the synthesis of a wide range of N-alkynylated 7-azaindoles with good yields. Also, this approach is well-suited for large-scale N-alkynylation reactions. The designed N-alkynylated 7-azaindoles were further subjected to Cu-/Ir-catalyzed alkyne-azide cycloaddition (CuAAC/IrAAC) or "click" reaction for the rapid synthesis of 1,4-/1,5 disubstituted 1,2,3-triazole decorated 7-azaindoles. A mechanistic study based on density functional theory (DFT) calculations and ultraviolet-visible (UV) spectroscopic studies revealed that the CuI and DMAP combination formed a [CuII (DMAP)2 I2 ] species, which acts as an active catalyst. The DFT method was used to assess the energetic viability of an organometallic in the C-N bond formation pathway originating from the [CuII (DMAP)2 I2 ] complex. We expect that the newly designed Cu/DMAP/alkyne system will offer valuable insights into the field of Cu-catalyzed transformations.