Doubly stereocontrolled asymmetric Michael addition of acetylacetone to nitroolefins promoted by an isosteviol-derived bifunctional thiourea

A novel class of chiral bifunctional thioureas bearing a chiral lipophilic beyerane scaffold and a tertiary amino group was designed and prepared. The thioureas were proven to be effective for catalyzing the doubly stereocontrolled asymmetric Michael addition between acetylacetone and nitroolefins. The corresponding adducts were obtained in high yields (up to 95%) and with good to excellent enantioselectivities (up to 97%). In addition, the reaction of tert-butyl acetoacetate and trans-β-nitrostyrene also proceeded smoothly with good enantioselectivity.     

Hydroindene-derived chiral synthons from carotol and their cytotoxicity

Ten enantiomerically pure hydroindene-derived compounds obtained by the transformation of (+)-carotol, the main constituent of carrot seed essential oil, were examined for their ability to inhibit the growth of myeloid leukaemia (HL-60) cancer cell lines. All compounds showed significant activity, which was comparable to the most active volatile organic compounds, such as trans–trans-farnesol, citral and nerolidol. Based on the bioactivity and molecular modelling, a 3D QSAR pharmacophore model was generated.     

Evaluation of the Fate of Aldicarb and Its Metabolites in Oranges

Abstract

The accumulation, persistence and fate of systemic pesticide aldicarb was melencholy evaluated in orange crops. The concentration of this pesticide and its two toxic metabolites, aldicarb sulfoxide and aldicarb sulfone was determined in leaves, rind and pulp of three orange varieties (Satsuma, Navelina and Clemetina de Nules) and in the top soil of the orange groves. The groves were located in two different places in the Valencia Community (Spain). The analysis showed that the aldicarb concentration was lower than those of aldicarb sulfoxide and aldicarb sulfone. In all cases, the residues persisted at least 160 days in vegetable samples and between 157 and 227 days in soil samples. Residue concentrations measured in the soil samples were highly variable but a relation with the organic matter content can be observed. The residue levels found in vegetal products were higher in leaves than in rind, and in rind than in pulp. The maximum residue values were obtained between 47 and 70 days after the application. One hundred days after treatment (Security period) the residue levels of total fruit were lower than the maximum residue level of 0.2 mg/kg established by law.