The semisynthetic process initially described for the synthesis of 1 (ET-743) has been extended to the preparation of other natural ecteinascidins. For the synthesis of 2 (ET-729) a demethylation of a N-Me intermediate was carried out by a selective oxidation with MCPBA. Other natural ecteinascidins (ET-745, ET-759B, ET-736, ET-637, ET-594) were accessible from key intermediate 25. The described methodologies allow for the preparation of a wide variety of ecteinascidins by procedures that can be easily scaled up.

The marine environment is a rich source of metabolites with potential therapeutic properties and applications for humans. Here we describe the first isolation, solid-phase total synthesis, and full structural assignment of a new class of cyclodepsipeptides from the Madagascan sponge Ecionemia acervus that shows in vitro cytotoxic activities at submicromolar concentrations. Seven structures belonging to a new family of compounds, given the general name stellatolides, were characterized. The sequence and stereochemistry of all the amino acids in these molecules were established by a combination of spectroscopic analysis, chemical degradation, and derivatization studies. Furthermore, the complete structure of stellatolide A was confirmed by an efficient solid-phase method for the first total synthesis and the full structural assignment of this molecule, including the asymmetric synthesis of the unique β-hydroxy acid moiety (Z)-3-hydroxy-6,8-dimethylnon-4-enoic acid.

New azaquinolizinium-type cations have been obtained from isochromane. The synthesis was completed over seven steps and included as the key feature an intramolecular Westphal condensation. This first example of the intramolecular process allowed the preparation of benzo[f]pyrido[2,1-a]phthalazinium and benzo[f]quino[2,1-a]phthalazinium salts, which were evaluated as DNA intercalators, DNA topoisomerase I inhibitors, and antiproliferative compounds. Both cationic systems behave as DNA intercalators and exhibit antiproliferative activity. The pentacyclic benzo[f]quino[2,1-a]phthalazinium cations also have an inhibitory effect on the catalytic activity of DNA topoisomerase I, without trapping of cleavage complexes. Structural characterization using density functional theory indicates that the fused ring systems are slightly nonplanar, and additional molecular modeling studies suggest a preferred orientation for the intercalating chromophores within a typical CpG or TpG intercalation site.

Verónica Crespo-Pereira es licenciada en publicidad y relaciones públicas por la Universidad de Vigo y máster en producción y gestión audiovisual por la Universidad de A Coruña. Su actividad profesional se ha desarrollado en el sector audiovisual en los departamentos de producción y dirección para series de ficción y programas. Trabaja como investigadora en la Universidad de Vigo donde lleva a cabo su tesis doctoral.

No abstract

The level of contribution of the hotel industry depends on different factors of production that they use in the provision of their services The way they use these factors of production will allow them to act efficiently, in order to improve profitability and market position. Ecuador, in recent years, has directed public policies betting on the development of this industry. In this sense, this research seeks to measure the efficiency and productivity of the Ecuadorian hotel industry. For this purpose, a significant sample has been selected; it consists of 147 businesses that provided hotel services during the period 2013-2017. These businesses are classified according to their quality and geographic location. This information has been useful to make a balanced panel data with one output (Revenue) and three inputs (Total_personnel, the non-current assets, and Consumption) by using the Data Envelopment Analysis (DEA). The results, which proved to be solid and accurate, indicate that the most efficient businesses are the ones in the third class, whereas those hotels located in zones with tourist attractions and activities have a better optimization of those resources. This situation has an effect on the significant improvement of their productivity.

Entre sus líneas de investigación están el estudio de los medios digitales e impresos, el análisis del impacto de la tecnología en la comunicación mediada, el análisis del funcionamiento de las industrias culturales, y la estrategia combinada de productos impresos y online en la sociedad del conocimiento.

No abstract