Ernesto Nicolás

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The multifunctional character of tryptophan has made it a target for the development of new molecules with therapeutic applications. In this sense the design of alternative solid phase routes would allow the widening of synthetic possibilities to access these molecules through conventional or combinatorial strategies. The present work describes a new(More)
The use of a triazene function to anchor phenylalanine to a polymeric support through its side chain is reported. To prove the usefulness of this strategy in solid-phase peptide synthesis, several bioactive peptides have been prepared including cyclic, C-modified, and protected peptides. The triazene linkage is formed by coupling the diazonium salt of(More)
Brain copper imbalance plays an important role in amyloid-β aggregation, tau hyperphosphorylation, and neurotoxicity observed in Alzheimer's disease (AD). Therefore, the administration of biocompatible metal-binding agents may offer a potential therapeutic solution to target mislocalized copper ions and restore metallostasis. Histidine-containing peptides(More)
An optimized solid-phase strategy for the preparation of the cyclic lipononadepsipeptide [N-Mst(L-Ser1), D-Ser4, L-Thr6, L-Asp8, L-Thr9]syringotoxin is reported. The strategy is based on the use of a mild orthogonal protection scheme and the incorporation of the nonproteinogenic amino acid (Z)-Dhb into the peptide chain as the dipeptide(More)
One of the goals of computational chemists is to automate the de novo design of bioactive molecules. Despite significant advances in computational approaches to ligand design and binding energy evaluation, novel procedures for ligand design are required. Evolutionary computation provides a new approach to this design endeavor. We propose an evolutionary(More)
Cys-disulfide bonds contribute to the stabilization of peptide and protein structures. The synthesis of these molecules requires a proper protection of Cys residues, which is crucial to prevent side-reactions and also to achieve the correct Cys connectivity. Here we undertook a mechanistic study of a set of well-known acid-labile Cys protecting groups, as(More)
A lead discovery library and a follow-up focused library of alpha-acylaminoketones were designed based on known dibenzoylhydrazine ecdysone agonists, including GS(TM)-E. The compounds were assayed in mammalian cells expressing the ecdysone receptor from Bombyx mori for their ability to cause expression of a reporter gene downstream of an ecdysone response(More)
Tetrahydropyranyl (Thp) is recognized as a useful protecting group for alcohols in organic synthesis. It has several advantages, including low cost, ease of introduction, general stability to most non-acidic reagents, it confers good solubility, and the ease with which it can be removed if the functional group it protects requires manipulation. However,(More)
Here the aromatic formylation mediated by TiCl4 and dichloromethyl methyl ether previously described by our group has been explored for a wide range of aromatic rings, including phenols, methoxy- and methylbenzenes, as an excellent way to produce aromatic aldehydes. Here we determine that the regioselectivity of this process is highly promoted by the(More)
A five-step solid-phase synthesis of sulfahydantoins from alpha-amino acids and aldehydes was developed. The synthetic method allows the use of hindered amino acids, including Val, Phg, and Aib, and use of aromatic aldehydes substituted with electron-withdrawing and -donating groups. Some limitations were encountered with amino acids with reactive side(More)