Carmen M. Rodríguez

Diterpenes from the flowers of Salvia canariensis

Abstract The new diterpenes, 11,12-dimethoxy-abieta-6,8,11,13-tetraen-20-oic acid methyl ester, rosmanoyl carnosate, 7-oxocarnosic acid, 6-oxo-7β-hydroxycarnosic acid and 6-oxo-7α-hydroxycarnosic acid, together with the already known rosmanol, galdosol, isorol, carnosol and carnosic acid were isolated from the flowers of Salvia canariensis .

Use of asymmetric propargyl dicobalt hexacarbonyl complexes in organic synthesis: Access to enantiomerically pure α-hydroxy acid derivatives

Abstract The trapping under different conditions of the carbocation generated by acid treatment of chiral Co 2 (CO) 6 -complexed propargylic secondary alcohols permitted access to either diastereoisomer at the propargylic center. Further chemical manipulations provided either enantiomer of enantiomerically pure 1,2-difunctionalized molecules such as 1,2-diols, α-hydroxy-aldehydes or α-hydroxy-acids.

A new approach to functionalized cyclobutanes: Stereoselective synthesis of the enantiomers of grandisol and fraganol

Abstract Enantiomerically enriched (+)-grandisol and (+)-fraganol were synthesized using as the key step a new stereoselective synthesis of cyclobutanes fused to γ-lactones by a stereochemically-controlled intramolecular alkylation of α-benzenesulfonyl-γ-lactones. This method provides a way to synthesize the enantiomers in a straightforward manner.

Simple and efficient oxidation of sulfides to sulfones using catalytic ruthenium tetroxide

Abstract A procedure for the oxidation of sulfides to sulfones using ruthenium tetroxide as catalyst and periodic acid as stoichiometric oxidant in a biphasic system (CCl 4 , CH 3 CN, H 2 O) is reported.

Soil chemical characteristics in relation to Fusarium wilts in banana crops of Gran Canaria Island (Spain)

Abstract Several soil characteristics have been studied in relation to Fusarium wilts in field plots of banana plantations of Gran Canaria Island (Spain). Principal component analysis has been applied to soil chemical parameters, the aim being to determine the possible relationships between the apparition and development of the Fusarium wilts and soil characteristics. The results seem to indicate that there is a relationship between the disease incidence and the values of some parameters like pH, cation exchange capacity (CEC), sodium (Na) in solution, and iron (Fe); pH, CEC, and Na values were significantly smaller in areas affected by the disease. However, the values of Fe extracted with DTPA and Fe associated with fulvic acids were significantly higher in disease affected areas; the same tendency was observed in the values of total carbon (C) and nitrogen (N) in the different areas. Other parameters studied, like exchangeable cations, Fe‐oxalate, etc., have not showed either differences or general tend...

An approach to the stereocontrolled synthesis of polysubstituted chiral butenolides and γ-lactones

Abstract The enantioselective synthesis of polysubstituted butenolides and γ-lactones by an intramolecular Michael addition of chiral thiophenylacetates of γ-hydroxy-α,β-unsaturated esters is described.

γ-Lactones α,β- and β,γ-fused to carbocycles as novel antiproliferative drugs

A set of gamma-lactones alpha,beta-fused and beta,gamma-fused to carbocycles have been synthesized and evaluated for their in vitro antiproliferative activities using the human cancer cell lines SW1573 (lung), T-47D (breast) and WiDr (colon). The compounds are obtained by intramolecular ring closing metathesis of the corresponding dienes. Active compounds exhibited GI(50) values in the range 8-18 microM. A structure-activity relationship is also discussed.

An example of a chiral non-racemic carbanion as versatile synthon in the asymmetric synthesis of polysubstituted γ-lactones

Abstract The application of a chiral non-racemic carbanion generated from enantiomerically enriched α-sulfonyl-γ-lactones to the asymmetric synthesis of highly substituted and fused γ-lactones is described.

Soil Potassium Indices and Clay‐Sized Particles affecting Banana‐Wilt Expression Caused by Soil Fungus in Banana Plantation Development on Transported Volcanic Soils

Abstract Relations among the expression of banana disease symptoms caused by the soil fungus Fusarium oxysporum f. sp. cubense, soil potassium (K)–sodium (Na) properties [soluble K‐Na ratios (SK/SS), potential buffering capacity for K (KBC), potassium adsorption ratio (KAR)], and clay‐sized particles were evaluated in Sorribas plots from the Canary Islands. Soils were sampled in areas of Sorribas where banana plants show positive or negative wilting symptoms characteristic of Panama disease. The Bartoli method was used for soil dispersion (Na resin). This method was able to show a clear separation between diseased and disease‐free areas by the amount of clay‐sized particles. Results also show that the greatest SK/SS ratios and clay‐sized particles in soils from diseased areas could explain the increase of water‐stable aggregate mass in these soils and the release of available iron (Fe) to soil solution in diseased areas, at least in Sorribas cultivated soils under the arid climate conditions of the Canary Islands.