Synthesis of Bioactive Speciosins G and P from Hexagonia speciosa

The first total synthesis of speciosins P and G, previously isolated from Hexagonia speciosa, is reported. These compounds have been synthesized by Sonogashira coupling from readily available starting materials. Siccayne was also synthesized from the same starting material in two steps along with a number of other derivatives. The compounds were tested in the wheat coleoptile bioassay. The most active compound was the intermediate 18, followed by 29 and 17. The structural requirements for activity in these compounds are the presence of methoxy groups in the aromatic ring and a formyl or hydroxy group in the side chain

Synthesis, antibacterial and antifungal activities of naphthoquinone derivatives: a structure–activity relationship study

The synthesis of 1,4-naphthoquinone derivatives is of great interest since these compounds exhibit strong activity as antimalarial, antibacterial, antifungal and anticancer agents. A series of 50 naphthoquinone derivatives was synthesized and evaluated for antibacterial and antifungal activity against Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, Candida krusei, Candida parapsilosis and Cryptococcus neoformans using the broth microdilution method. The Candida species were the most susceptible microorganisms. Halogen derivatives of 1,4-naphthoquinone presented strong activity, e.g., 2-bromo-5-hydroxy-1,4-naphthoquinone, which exhibited inhibition at an MIC of 16 lg/ mL in S. aureus, and 2-chloro-5,8-dihydroxy-1,4-naphthoquinone, with an MIC of 2 lg/mL in C. krusei. These compounds showed higher activity against fungi, but the antibacterial activities were very low. The study of structure–activity relationships is very important in the search for new antimicrobial drugs due to the limited therapeutic arsenal

Information & Technology Magazine. Volume 1 No. 1 April 1998

Hace apenas algunos años muchos de nosotros soñábamos con un año 2000 parecido al descrito en algunas de nuestras novelas preferidas de ciencia ficción, naves espaciales encima de los cielos Colombianos, acceso público a viajes espaciales, marcianos inundando nuestros sanandresitos y demás aspectos relacionados especialmente con cambios sustanciales en las formas de transporte y uso del espacio, debido a que para esta época eran nuestra mayor preocupación.RESEÑA HISTORICA FACULTAD INGENIERIA DE SISTEMAS GESTION DE LA INFORMACION INGENIERIA CIENCIA EDUCACION EN INGENIERIA FACULTAD INFORME ESPECIALJust a few years ago many of us dreamed of a year 2000 similar to the one described in some of our favorite science fiction novels, spaceships above the Colombian skies, public access to travel space, Martians flooding our sanandresitos and other aspects related especially to substantial changes in the forms of transportation and use of space, because at this time they were our greatest concern.Modalidad Presencia

A VNS-Based Matheuristic to Solve the Districting Problem in Bicycle-Sharing Systems

A matheuristic approach that combines a reduced variable neighbourhood search (rVNS) algorithm and a mathematical programming (MP) solver to solve a novel model for the districting problem in a public bicycle-sharing system is presented. The problem is modelled as an integer programming problem. While the rVNS algorithm aims to find a high-quality set of centres for the repositioning zones, the MP solver computes the optimal allocation network of the stations to the centres of the repositioning zones. We use a predefined grid to reduce the search space the rVNS needs to explore. The proposed approach obtains promising results for small and medium-sized instances, and is also able to handle large-sized models

A VNS-Based Matheuristic to Solve the Districting Problem in Bicycle-Sharing Systems

A matheuristic approach that combines a reduced variable neighbourhood search (rVNS) algorithm and a mathematical programming (MP) solver to solve a novel model for the districting problem in a public bicycle-sharing system is presented. The problem is modelled as an integer programming problem. While the rVNS algorithm aims to find a high-quality set of centres for the repositioning zones, the MP solver computes the optimal allocation network of the stations to the centres of the repositioning zones. We use a predefined grid to reduce the search space the rVNS needs to explore. The proposed approach obtains promising results for small and medium-sized instances, and is also able to handle large-sized models

Synthesis and Antitumor Activity Evaluation of Compounds Based on Toluquinol

Encouraged by the promising antitumoral, antiangiogenic, and antilymphangiogenic properties of toluquinol, a set of analogues of this natural product of marine origin was synthesized to explore and evaluate the effects of structural modifications on their cytotoxic activity. We decided to investigate the effects of the substitution of the methyl group by other groups, the introduction of a second substituent, the relative position of the substituents, and the oxidation state. A set of analogues of 2-substituted, 2,3-disubstituted, and 2,6-disubstituted derived from hydroquinone were synthesized. The results revealed that the cytotoxic activity of this family of compounds could rely on the hydroquinone/benzoquinone part of the molecule, whereas the substituents might modulate the interaction of the molecule with their targets, changing either its activity or its selectivity. The methyl group is relevant for the cytotoxicity of toluquinol, since its replacement by other groups resulted in a significant loss of activity, and in general the introduction of a second substituent, preferentially in the para position with respect to the methyl group, was well tolerated. These findings provide guidance for the design of new toluquinol analogues with potentially better pharmacological properties

Synthesis and Antitumor Activity Evaluation of Compounds Based on Toluquinol.

Encouraged by the promising antitumoral, antiangiogenic, and antilymphangiogenic properties of toluquinol, a set of analogues of this natural product of marine origin was synthesized to explore and evaluate the effects of structural modifications on their cytotoxic activity. We decided to investigate the effects of the substitution of the methyl group by other groups, the introduction of a second substituent, the relative position of the substituents, and the oxidation state. A set of analogues of 2-substituted, 2,3-disubstituted, and 2,6-disubstituted derived from hydroquinone were synthesized. The results revealed that the cytotoxic activity of this family of compounds could rely on the hydroquinone/benzoquinone part of the molecule, whereas the substituents might modulate the interaction of the molecule with their targets, changing either its activity or its selectivity. The methyl group is relevant for the cytotoxicity of toluquinol, since its replacement by other groups resulted in a significant loss of activity, and in general the introduction of a second substituent, preferentially in the para position with respect to the methyl group, was well tolerated. These findings provide guidance for the design of new toluquinol analogues with potentially better pharmacological properties

Cien días vistos por CINEP (no. 58 ene-may 2006)

Edición No 58 de la revista Cien días vistos por CINEP en la que se analiza la coyuntura colombiana en materia de derechos humanos, luchas sociales, conflicto armado y política.I. Editorial La linterna de Diógenes II. Política. La reelección de Uribe ¿Más guerra o menos paz? El embrollo de la política. Lo regional y lo nacional en la contienda electoral. III. Movilización paz Protesta en las regiones contra la violencia y la inseguridad. Fortaleza de una debilidad. IV. Región Apatía y el proceso electoral en Chocó y la circunscripción especial de comunidades negras. Pacto de vida y mandato verde frente a los Cerros Orientales de Bogotá V. Movimientos sociales Luchas sociales de la memoria y la incertidumbre. Octubre 2005 - marzo 2006 VI. Derechos humanos La implacable lógica del conflicto armad