Organobismuth compounds are organometallic reagents that contain a C–Bi bond. These species, which are easily accessed from inexpensive and low-toxicity inorganic bismuth salts, are highly attractive in synthesis due to their unique properties and reactivity. A wide diversity of geometries have been found for organobismuth compounds, depending on the oxidation state of the bismuth, its charge, and the number of coordinated elements. Compounds where the bismuth bears a –1 charge (organobismuthate), a +1 (bismuthonium cation) and a +2 charge (bismuthonium dication) have been reported. Due to the presence of a lone pair, trivalent organobismuthines can act as Lewis bases in transition-metal complexes. In addition, organobismuth compounds can act as Lewis acids by forming hypervalent interactions with ligands and metals. Organobismuth compounds have been used as catalysts and reagents in a plethora of reactions. In this review, the synthesis and properties of organobismuth reagents and their use in organic reactions are reviewed. 1 Introduction 2 Synthesis of Trivalent Organobismuthines 3 Synthesis of Pentavalent Organobismuth Compounds 4 Structure, Hypervalency and Chirality 5 C-, N-, O- and S-Arylation Reactions 6 Palladium-Catalyzed Reactions 7 Other Reactions Involving Organobismuth Reagents 8 Conclusion
16 July 2013 in European Journal of Organic Chemistry
The N-arylation of indoles, indazoles, pyrroles, and pyrazoles using highly functionalized trivalent arylbismuth reagents is reported. The reaction is promoted by a substoichiometric amount of copper acetate, and it tolerates a wide diversity of functional groups on the azole and the organobismuth reagent. The method is also applied to the N-arylation of tryptophan derivatives.
DNA-methyltransferases (DNMTs) are a class of epigenetic enzymes that catalyze the transfer of a methyl moiety from the methyl donor S-adenosyl-L-methionine onto the C5 position of cytosine in DNA. This process is dysregulated in cancers and leads to the hypermethylation and silencing of tumor suppressor genes. The development of potent and selective inhibitors of DNMTs is of utmost importance for the discovery of new therapies for the treatment of cancer. We report herein the synthesis and DNMT inhibitory activity of 29 analogues derived from NSC 319745. The effect of selected compounds on the methylation level in the MDA-MB-231 human breast cancer cell line was evaluated using a luminometric methylation assay. Molecular docking studies have been conducted to propose a binding mode for this series.