Teorethical studies of the stability of 8a-alkyll-1,2,3,4,6,8a- hexahydronaphtalen-1-ones using semiempirical methods

The Birch alkylation products are very unstable. We are showing, in this communication, the results of a theoretical study that compares different decomposition reaction mechanisms. The conclusions are in agreement with our experimental results.Facultad de Ciencias Exacta

Teorethical studies of the stability of 8a-alkyll-1,2,3,4,6,8a- hexahydronaphtalen-1-ones using semiempirical methods

The Birch alkylation products are very unstable. We are showing, in this communication, the results of a theoretical study that compares different decomposition reaction mechanisms. The conclusions are in agreement with our experimental results.Facultad de Ciencias Exacta

Ação inseticida do extrato de Derris amazonica Killip para Cerotoma arcuatus Olivier (Coleoptera: Chrysomelidae

A abundância e o potencial inseticida de Derris amazonica e a necessidade de controle de Cerotoma arcuatus Olivier (Coleoptera: Chrysomelidae) na cultura do feijão-caupi (Vigna unguiculata L. Walp) estimularam a realização desta pesquisa, que objetivou avaliar a ação inseticida do extrato de D. amazonica a adultos de C. arcuatus em condições de laboratório. Os bioensaios testaram as vias de intoxicação por ingestão de folhas contaminadas, contato com superfície contaminada e aplicação tópica, com delineamento experimental inteiramente casualizado, com quatro repetições. Os valores de mortalidade e consumo foliar dos insetos foram submetidos à análise de regressão, sendo utilizada a análise de Probit para determinação das CL50, da DL50 e dos TL50. O extrato de D. amazonica, contendo 3,7% de rotenona, foi tóxico para adultos de C. arcuatus via ingestão de folhas contaminadas (CL50=15,14 µL do extrato.mL-1 de água), superfície contaminada (CL50=0,45 µL do extrato.cm-2) e aplicação tópica (DL50=1,44 µL do extrato.g-1 do inseto). Mortalidades de adultos de C. arcuatus superiores a 80% e os menores tempos letais médios foram obtidos na concentração de 5% (v v-1) do extrato em todos os bioensaios. O consumo foliar de adultos de C. arcuatus foi inversamente proporcional a concentração do extrato quando expostos por via de ingestão foliar ou aplicação tópica, sendo inclusive observada inibição da alimentação dos indivíduos. O extrato de D. amazonica é tóxico para C. arcuatus e inibe a alimentação dos insetos a partir da concentração de 1% (v v-1).The abundance and insecticidal potential of Derris amazonica in addition to need of controlling Cerotoma arcuatus for bean crop stimulated this research. The objective of this work was to evaluate insecticide action of the extract of D. amazonica to adults of C. arcuatus in laboratory conditions. The bioassays were carried out using three distend methodologies: leaf intake, contact in treated surface (filter paper) and topical application. A completed randomized experimental design was used with four replications. Mortality values and leaf consumption of the insects were subjected to regression analyses, being the Probit analyses used to determine of the i.e., LC50, LT50 and LD50. The extract of D. amazonica containing 3.7% of rotenone was toxic to adults C. arcuatus when exposed to treated leaves (LC50 = 15.14 µl.mL-1), treated surface (LC50 = 0.45 µl.cm-2) and subjected to topical exposure (LD50 = 1.44 µl.g-1). In all bioassays the adults mortality was higher than 80% with lower median lethal times obtained with 5% (v.v-1) concentrations of the extract. Leaf consumption by adults C. arcuatus was inversely proportional to the concentration of the extract when exposed by leaf intake or topical application, also being observed inhibition of feeding individuals. The extract of D. amazonica is toxic to C. arcuatus and inhibits the feeding of insects from the concentration of 1% (v v-1)

A synthetic approach to PW2‐Like compounds

The 9H‐xanthene derivatives, like PW2, displayed a wide spectrum of bioactivities. Herein, we reported a rapid and simple synthetic route for compounds containing the xanthenic moiety in their structure and amides. The efficient preparation of novel 1,8‐dioxo‐2,3,4,5,6,7,8,9‐octahydro‐1‐xanthen‐9‐yl‐ acetic acid alkyl esters by multicomponent tandem Michael‐cyclization reactions starting from cyclohexanediones and alkynes is described. Iodine and cerium (IV) ammonium nitrate were used for the oxidative aromatization step proving a series of 1,8‐mono and dialkoxy‐alkyl‐xanthenyl‐9‐yl acetic acid esters in good yields. The proposed mechanism for the oxidative aromatization involves several organic transformations. The final step was the incorporation of an amide to mimic the PW2 structure that was prepared by hydrolysis of the esters, followed by the amide formation using N,N ‐dimethyl‐1,3‐ propandiamine, and benzylamine.Fil: Forastieri, Pamela S. Universidad Nacional del Rosario. Facultad de Ciencias Bioquímicas y Farmaceúticas. Instituto de Química Rosario (IQUIR-CONICET); Argentina.Fil: Luna, Liliana E. Universidad Nacional del Rosario. Facultad de Ciencias Bioquímicas y Farmaceúticas. Instituto de Química Rosario (IQUIR-CONICET); Argentina.Fil: Cravero, Raquel M. Universidad Nacional del Rosario. Facultad de Ciencias Bioquímicas y Farmaceúticas. Instituto de Química Rosario (IQUIR-CONICET); Argentina.Fil: Labadie, Guillermo Roberto. Universidad Nacional del Rosario. Facultad de Ciencias Bioquímicas y Farmaceúticas. Instituto de Química Rosario (IQUIR-CONICET); Argentina

A Short Synthesis of the Main Lactone Ketal Backbone Present in Saudin

We are describing a brief stereospecific synthesis of a model compound related to Saudin, with a lactone ketal backbone present in the natural product starting from a tricyclic epoxiketal

A Short Synthesis of the Main Lactone Ketal Backbone Present in Saudin

Abstract: We are describing a brief stereospecific synthesis of a model compound related to Saudin, with a lactone ketal backbone present in the natural product starting from a tricyclic epoxiketal

Teorethical Studies of the Stability of 8a-Alkyll-1,2,3,4,6,8ahexahydronaphtalen-1-ones Using Semiempirical Methods

The Birch alkylation products are very unstable. We are showing, in this communication, the results of a theoretical study that compares different decomposition reaction mechanisms. The conclusions are in agreement with our experimental results