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Contreras-Celedon C.A.,Institute Investigaciones Quimico Biologicas | Mendoza-Rayo D.,Institute Investigaciones Quimico Biologicas | Rincon-Medina J.A.,Institute Investigaciones Quimico Biologicas | Chacon-Garcia L.,Institute Investigaciones Quimico Biologicas
Beilstein Journal of Organic Chemistry | Year: 2014

A simple and efficient catalytic system based on a Pd complex of 4-aminoantipyrine, 4-AAP-Pd(II), was found to be highly active for Suzuki-Miyaura cross-coupling of aryl iodides and bromides with phenylboronic acids under mild reaction conditions. Good to excellent product yields from the cross-coupling reaction can be achieved when the reaction is carried out in ethanol, in the open air, using low loading of 4-AAP-Pd(II) as a precatalyst, and in the presence of aqueous K2CO3 as the base. A variety of functional groups are tolerated. © 2014 Contreras-Celedón et al.


Guzman-Deara J.,Institute Investigaciones Quimico Biologicas | Reyes-De la Cruz H.,Institute Investigaciones Quimico Biologicas | Beltran-Pena E.M.,Institute Investigaciones Quimico Biologicas | Castro-Mercado E.,Institute Investigaciones Quimico Biologicas | Garcia-Pineda E.,Institute Investigaciones Quimico Biologicas
Protoplasma | Year: 2013

Superoxide dismutase (SOD) activities of the oomycete Phytophthora cinnamomi were examined. Five polypeptides with manganese superoxide dismutase (MnSOD) activity were found in mycelium growing in liquid culture with relative molecular weights ranging from approximately 25 to 100 kDa. Comparison with characterized avocado SODs showed no evidence for the presence of either iron or copper/zinc SODs in P. cinnamomi. The level of activity of the MnSOD polypeptides decreased in the presence of avocado root or cell wall components. Growth of P. cinnamomi, measured as dry weight, increased when the mycelium was grown in the presence of superoxide anion (O2 -), which was added exogenously. Our results suggest that the metabolism of O2 - has an important role in the development of P. cinnamomi. © 2012 Springer-Verlag Wien.


Bedolla-Medrano M.,Institute Investigaciones Quimico Biologicas | Chacon-Garcia L.,Institute Investigaciones Quimico Biologicas | Contreras-Celedon C.A.,Institute Investigaciones Quimico Biologicas | Campos-Garcia J.,Institute Investigaciones Quimico Biologicas
Tetrahedron Letters | Year: 2011

We describe the first synthesis of the novel meso-pentaspirocyclohexyl calix[5]pyrrole 2b. Anion-guest properties of the new compound were evaluated with respect to fluoride, chloride, and bromide tetrabutylammonium salts by 1H NMR titration techniques in deuterated dichloromethane at 22 °C by following the induced shifts in the NH resonances upon complexation. © 2010 Elsevier Ltd. All rights reserved.


Contreras-Celedon C.A.,Institute Investigaciones Quimico Biologicas | Rincon-Medina J.A.,Institute Investigaciones Quimico Biologicas | Mendoza-Rayo D.,Institute Investigaciones Quimico Biologicas | Chacon-Garcia L.,Institute Investigaciones Quimico Biologicas
Applied Organometallic Chemistry | Year: 2015

A one-step synthesis of symmetric biaryls is reported under very mild conditions via the homocoupling reaction of substituted arylboronic acids using an air- and moisture-stable 4-aminoantipyrine-Pd(II) complex as catalyst. The reaction is conducted at a low catalyst loading of 0.1 mol% at room temperature in methanol in the presence of K2CO3 as the base and KMnO4 as the oxidant. The catalytic methodology is shown to be compatible with diverse functional groups and affords the desired biphenyls in good to excellent yields. Copyright © 2015 John Wiley & Sons, Ltd.


PubMed | Institute Investigaciones Quimico Biologicas
Type: Journal Article | Journal: FEMS yeast research | Year: 2013

Ethanol accumulation during fermentation contributes to the toxic effects in Saccharomyces cerevisiae, impairing its viability and fermentative capabilities. The iron-sulfur (Fe-S) cluster biogenesis is encoded by the ISC genes. Reactive oxygen species (ROS) generation is associated with iron release from Fe-S-containing enzymes. We evaluated ethanol toxicity, ROS generation, antioxidant response and mitochondrial integrity in S. cerevisiae ISC mutants. These mutants showed an impaired tolerance to ethanol. ROS generation increased substantially when ethanol accumulated at toxic concentrations under the fermentation process. At the cellular and mitochondrial levels, ROS were increased in yeast treated with ethanol and increased to a higher level in the ssq1, isa1, iba57 and grx5 mutants - hydrogen peroxide and superoxide were the main molecules detected. Additionally, ethanol treatment decreased GSH/GSSG ratio and increased catalase activity in the ISC mutants. Examination of cytochrome c integrity indicated that mitochondrial apoptosis was triggered following ethanol treatment. The findings indicate that the mechanism of ethanol toxicity occurs via ROS generation dependent on ISC assembly system functionality. In addition, mutations in the ISC genes in S. cerevisiae contribute to the increase in ROS concentration at the mitochondrial and cellular level, leading to depletion of the antioxidant responses and finally to mitochondrial apoptosis.


PubMed | Institute Investigaciones Quimico Biologicas
Type: Journal Article | Journal: Protoplasma | Year: 2013

Superoxide dismutase (SOD) activities of the oomycete Phytophthora cinnamomi were examined. Five polypeptides with manganese superoxide dismutase (MnSOD) activity were found in mycelium growing in liquid culture with relative molecular weights ranging from approximately 25 to 100 kDa. Comparison with characterized avocado SODs showed no evidence for the presence of either iron or copper/zinc SODs in P. cinnamomi. The level of activity of the MnSOD polypeptides decreased in the presence of avocado root or cell wall components. Growth of P. cinnamomi, measured as dry weight, increased when the mycelium was grown in the presence of superoxide anion (O(2) (-)), which was added exogenously. Our results suggest that the metabolism of O(2) (-) has an important role in the development of P. cinnamomi.

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