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A series of Pd(0)-catalyzed hydrostannation of E- and Z-enynols variously substituted is examined in order to determine how the nature of the substituents on the alkene bond affects the regiochemical course of these reactions. It is shown that [alpha]-vinyl stannanes are obtained from Z-enynols having different substituents on the double bond regardless of their electronic, steric or chelating natures.

The palladium-catalyzed hydrostannation of terminal arylalkynes are explored to understand the ortho substituent in alkyne substrates that promotes the regioselective addition of [Bu.sub.3]SnH to the triple bond. The results provided new reaction pathways for the Stille coupling of various aryl halides with [alpha]-styrylstannanes bearing either an electron-donating or an electron-withdrawing substituent at the ortho position of the aromatic ring.

In the context of our SAR study concerning 6BrCaQ analogues as C-terminal Hsp90 inhibitors, we designed and synthesized a novel series of 3-(heteroaryl)quinolin-2(1H), of types 3, 4, and 5, as a novel class of analogues. A Pd-catalyzed Liebeskind–Srogl cross-coupling was developed as a convenient approach for easy access to complex purine architectures. This series of analogues showed a promising biological effect against MDA-MB231 and PC-3 cancer cell lines. This study led to the identification of the best compounds, 3b (IC50 = 28 µM) and 4e, which induce a significant decrease of CDK-1 client protein and stabilize the levels of Hsp90 and Hsp70 without triggering the HSR response. [ABSTRACT FROM AUTHOR]

This review concerns the synthesis and biological activities of pyrazino[1,2-a]indoles and pyrazino[1,2-a]indol-1-ones reported since 1997 and the discovery of biological activity of pyrazinoindole derivatives. In the first part, we first presented the synthetic routes that have been reported from a methodological point of view to access the pyrazinoindole unit according to cyclization reactions using or not using metal catalysts. Then, syntheses and neuropsychiatric, auto-immune, anti-infectious and anti-cancer properties of pyrazinoindoles were detailed. In the second part, we first reported the main accesses to pyrazinoindol-1-one substrates according to Michael reactions, metal-catalyzed and metal-free cyclization reactions. The syntheses and anti-cancer, anti-infectious, anti-allergenic and neuropsychiatric properties of pyrazinoindolones were next described and discussed. [ABSTRACT FROM AUTHOR]

This study introduces a straightforward synthetic approach for generating 7,8-dihydrobenzo[ a ]phenanthridine analogs through visible-light-induced cyclization, showing promise as antitumor agents. Unexpectedly, the incorporation of 1,1'-diarylethylene as an additive significantly boosts yield. Through mechanistic investigations, we uncover its crucial role as a trap for the methyl radical formed after the N-O bond cleavage of O- acetyl oxime, promoting intramolecular cyclization of a nitrogen-centered imine radical. These insights into the mechanism pave the way for transformative advancements in this synthesis strategy.

Functionalized 4-aryl-4 H -benzo[ d ][1,3]oxazines are synthesized under transition-metal-free conditions using ortho -amide- N -tosylhydrazones. This synthetic method uses readily available N -tosylhydrazones as the diazo compound precursors and involves an intramolecular ring closure reaction mediated by a protic polar additive ( i PrOH). A wide range of functionalized oxazines are obtained by this straightforward method in good to excellent yields. Furthermore, the viability of our strategy is illustrated by the gram-scale elaboration of a bromo-substituted 4 H -benzo[ d ][1,3]oxazine and its post-functionalization by palladium-catalyzed cross-couplings.

A series of 2,4-di-arylated tropane derivatives was synthesized through a site-selective palladium-catalyzed β-C(sp 3 )-H di-arylation process. This type of structure has been scarcely reported in literature. They nevertheless represent an interesting class of biologically relevant molecules as illustrated by the observed activity at the micromolecular level of eight derivatives toward human colorectal cancer cell line HCT116.

A new strategy for the construction of 3-phenyl-1 H -pyrrolo-imidazo[1,2- a ]pyridine backbone is described. The reaction starts from the coupling between N -tosylhydrazones and 2-chloro-3-nitroimidazo[1,2- a ]pyridines leading to the formation of 3-nitro-2-(arylvinyl)imidazo[1,2- a ]pyridine derivatives. Optimization of Cadogan-reductive conditions allowed the conversion of the obtained nitro derivative to a new scaffold of the type 3-aryl-1 H -pyrrolo-imidazo[1,2- a ]pyridine. This method provides rapid access to new libraries in the context of diversity-oriented synthesis, which intends to generate small molecules with a large structure diversity in an efficient manner. Screening of the biological activity of the newly generated compounds leads to the identification of a new promising compound 5cc , which exhibits good antiproliferative activity in the submicromolar range against a human colon cancer cell line.