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Daniel G Rivera

Publications and source records attributed to Daniel G Rivera.

4 recordsLinked to original sources

Synthesis of steroid-biaryl ether hybrid macrocycles with high skeletal and side chain variability by multiple multicomponent macrocyclization including bifunctional building blocks.

Utilizing the multiple multicomponent macrocyclization including bifunctional building blocks (MiB) strategy, a library of nonracemic, nonrepetitive peptoid-containing steroid-biaryl ether hybrid macrocycles was built. Up to 16 new bonds, including those of the macrocyclization, can be formed in one pot simultaneously while introducing varied elements of diversity. Functional diversity is generated primarily by choosing Ugi-reactive functional building blocks, bearing the respective recognition or catalytic motifs. These appear attached to the peptoid backbone of the macrocyclic cavity, similar to side chains of amino acids found in enzyme active sites. Likewise, skeletal diversity is based on the variation of defined bifunctional building blocks which allow the parallel formation of macrocyclic cavities that are highly diverse in shape and size and thus perspectively in function. This straightforward approach is suitable to generate multifunctional macrocycles for applications in catalysis, supramolecular, or biological chemistry.

Binding Sites↗

Supramolecular compounds from multiple ugi multicomponent macrocyclizations: peptoid-based cryptands, cages, and cryptophanes.

The first 3-fold multicomponent macrocyclizations of trifunctional building blocks were developed to produce, in one pot, cryptands, cages, and cryptophanes with peptoid tethers carrying additional recognition motifs. The straightforward, efficient, and diversity-oriented fashion by which these complex macromulticycles are obtained is suitable for building combinatorial libraries of synthetic receptors with potential applicability in catalysis and supramolecular and coordination chemistry. The strategy also easily allows creation of asymmetric macromulticyclic cavities, with up to 20 new bonds formed in one pot.

Amino Acids↗

Novel 5beta-hydroxyspirostan-6-ones ecdysteroid antagonists: synthesis and biological testing.

Eight new 5beta-hydroxy-spirostan-6-ones bearing hydroxy and amino functions in the A ring, i.e., 3beta-OH, 3alpha-OH, 2beta,3beta-OH, 2alpha,3beta-OH, 3beta-NH2, 2alpha-NH2-3beta-OH, 2beta-NH2-3beta-OH, and 2beta-OH-3beta-NH2, were efficiently synthesized, and their antiecdysteroid activities were evaluated on the metamorphosis bioassay of mosquito Aedes aegypti. To our knowledge, these new steroids represent the first 5beta-hydroxy-spirostanes which have been tested for antiecdysteroid activity in mosquitoes. The higher antagonistic effect was found for compounds bearing the 3beta-hydroxy and 2beta,3beta-dihydroxy functionality, which show promise as environmental friendly insecticides.

Aedes↗