Short malonyl dehydro peptides as potential scaffolds for peptidomimetics by an efficient Knoevenagel reaction.

Non-symmetric disubstituted malonamides rAA-mGly-AA', obtained from Meldrum's acid, were considered as methylene active compounds and a Knoevenagel condensation methodology was developed involving piperidine and activated 4 A molecular sieves as catalysts. The reaction is efficient, broad in scope, and easy to perform and allows access to E/Z mixtures of short malonyl dehydro peptides (MDHPs) rAA-m Delta(2)AA''-AA', partially modified retro peptides characterized by an interesting combination of retro and dehydro modifications in the same structure.

Solution-phase synthesis of 2-cyano and 2-amido aziridinyl peptides.

Starting from a library of 2-l-α-amino acyl ()-acrylonitriles, different short 2-cyano and 2-amido aziridinyl peptides, potential protease inhibitors, were obtained under parallel solution-phase conditions. The transformations include careful selection of conditions for aziridine deprotection and cyano group partial hydrolysis.

Parallel solution-phase synthesis of acrylonitrile scaffolds carrying L-alpha-amino acidic or D-glycosyl residues.

A practical and straightforward protocol for the preparation of a solution-phase library of acrylonitrile scaffolds is reported. Target compounds were obtained in high yield, stereoselectivity, and purity by two simple and practical steps from cyanoacetic acid. Moreover, our study proposes a synthetic approach starting from the constructed library to obtain three-membered heterocycles.

Functionalised enones as starting materials for the construction of aziridine scaffolds.

alpha-Substituted beta-keto esters have been transformed by means of a straightforward procedure into aziridine-1,2-dicarboxylates, which have been efficiently converted into alkenyl aziridine-1,2-dicarboxylates through Wittig olefination reaction. The possibility of aziridine ring elaborations and the presence of an olefin function make these new molecules suitable scaffolds for further derivatisation into potential bioactive targets.

One-pot synthesis of polyfunctionalized cyclic urea derivatives.

[reaction: see text] Unexpectedly, imidazolidin-2-ones are easily obtained from beta-keto esters upon treatment with tert-butyl nosyloxycarbamate and calcium oxide under mild conditions. The structure of the product was established by X-ray crystallography.

Diastereoselective aziridination of chiral alpha-carbonyl enoates.

Nosyloxycarbamates very efficiently aziridinate optically active alpha-carbonyl enoates with high levels of diastereoselectivity under mild conditions and in a straightforward process.