RESUMEN
The total synthesis of (+)-crocacin D has been achieved in 15 steps (9 isolated intermediates) and 14% overall yield from commercially available starting materials and using (+)-crocacin C as a key intermediate. A number of simplified analogues and their biological activities are also reported.
Asunto(s)
Amidas/síntesis química , Amidas/química , Amidas/farmacología , Animales , Antifúngicos/farmacología , Áfidos/efectos de los fármacos , Herbicidas/farmacología , Insecticidas/farmacologíaRESUMEN
The enantioselective synthesis of the oxa-pinnaic acid framework has been achieved through internal asymmetric induction. The synthetic strategy pursued illustrates the adaptability of the Achmatowicz oxidative rearrangement for the synthesis of complex spirocyclic pyrans starting from tertiary alcohols.
Asunto(s)
Alcaloides/química , Piranos/química , Piranos/síntesis química , Compuestos de Espiro/química , Compuestos de Espiro/síntesis química , Estructura Molecular , Piranos/farmacología , Compuestos de Espiro/farmacologíaRESUMEN
Enamides, dienamides, and enynamides are important building blocks in synthetic, biological, and medicinal chemistry as well as materials science. Despite the extensive breath of their potential utility in synthetic chemistry, there is a lack of simple, high-yielding methods to deliver them efficiently and as single isomers. In this paper, we present a novel, protecting group free, efficient, and stereoselective approach to the generation of ß-halo-enamides. The methodology presented provides a robust synthetic platform from which E- or Z-enamides can be generated in good yields and with complete stereocontrol.
Asunto(s)
Amidas/síntesis química , Amidas/química , Cristalografía por Rayos X , Modelos Moleculares , Estructura Molecular , EstereoisomerismoRESUMEN
The step-economic total synthesis of (+)-crocacin C has been achieved in 20% yield from commercially available starting materials. This approach requires the isolation of only 8 intermediates and can provide a reliable supply of (+)-crocacin C for the development of new antifungal and crop protection agents.
Asunto(s)
Alquenos/síntesis química , Amidas/síntesis química , Antifúngicos/síntesis química , Compuestos de Boro/química , Espectroscopía de Resonancia Magnética , Estructura Molecular , EstereoisomerismoRESUMEN
Iodinated contrast media (ICM) are persistent and ubiquitous water pollutants. Because of their high water solubility and biochemical stability, their phase-separation and recovery from the aquatic environment is very difficult. Here, borate was chosen as a complexing agent of the two diagnostic aids iomeprol and iopamidol in order to provide them with a negative charge and to fix the resulting adducts on Dowex 1X4 ion exchangers. A systematic characterization study of the complex by means of capillary zone electrophoresis and 11B NMR revealed that iomeprol and iopamidol interact with borate anions in aqueous solutions giving a 1:1 single-charged adduct and that the association constant at 25 °C for both contrast agents is highest at pH 10.5. These findings allowed the proper calibration of experimental parameters for further batch adsorption-desorption trials, where the two ICM were shown to be almost completely removed from the water phase and released from the solid sorbents in mild conditions, enabling the recovery of functional resin.