Spiro sugar-isoxazolidine scaffold as useful polyfunctional building block for peptidomimetics design

Synthesis of anti-proliferative [3.3.0]furofuranone derivatives by lactonization and functionalization of C-glycosyl compounds

The [3.3.0]furofuranone structure is found in numerous families of biologically active natural products. We took advantage of the stereodiversity afforded by carbohydrate derivatives to prepare several compounds structurally similar to goniofufurone and crassalactones which are natural cytotoxic agents. We designed and synthesized several stereoisomers of these natural compounds via lactonization of C-glycosyl compounds bearing an hydroxyl on position 4 and a methyl ester on the pseudo-anomeric positionThe reactivity of this bicyclic moiety was explored through etherification of hydroxyls in position 5 and 7 and various substituants (halogen, phenyl, benzyl, cynanmoyl) were introduced. The anti-proliferative properties of these mimics were then evaluated on various cancer cell lines and two compounds 24 and 35 demonstrated IC₅₀ value of 1.34 µM (U251) and 7.60 µM (U87) respectively.

Isoxazolidine: A Privileged Scaffold for Organic and Medicinal Chemistry

The isoxazolidine ring represents one of the privileged structures in medicinal chemistry, and there have been an increasing number of studies on isoxazolidine and isoxazolidine-containing compounds. Optimization of the 1,3-dipolar cycloaddition (1,3-DC), original methods including electrophilic or palladium-mediated cyclization of unsaturated hydroxylamine, has been developed to obtain isoxazolidines. Novel reactions involving the isoxazolidine ring have been highlighted to accomplish total synthesis or to obtain bioactive compounds, one of the most significant examples being probably the thermic ring contraction applied to the total synthesis of (±)-Gelsemoxonine. The unique isoxazolidine scaffold also exhibits an impressive potential as a mimic of nucleosides, carbohydrates, PNA, amino acids, and steroid analogs. This review aims to be a comprehensive and general summary of the different isoxazolidine syntheses, their use as starting building blocks for the preparation of natural compounds, and their main biological activities.