Person: Herrera Fernández, Antonio
Universidad Complutense de Madrid
Faculty / Institute
Now showing 1 - 4 of 4
- PublicationAutomatic 1H-NMR Screening of Fatty Acid Composition in Edible Oils(MDPI, 2016-02-26) Castejón Ferrer, David; Fricke, Pascal; Cambero Rodríguez, María Isabel; Herrera Fernández, AntonioIn this work, we introduce an NMR-based screening method for the fatty acid composition analysis of edible oils. We describe the evaluation and optimization needed for the automated analysis of vegetable oils by low-field NMR to obtain the fatty acid composition (FAC). To achieve this, two scripts, which automatically analyze and interpret the spectral data, were developed. The objective of this work was to drive forward the automated analysis of the FAC by NMR. Due to the fact that this protocol can be carried out at low field and that the complete process from sample preparation to printing the report only takes about 3 min, this approach is promising to become a fundamental technique for high-throughput screening. To demonstrate the applicability of this method, the fatty acid composition of extra virgin olive oils from various Spanish olive varieties (arbequina, cornicabra, hojiblanca, manzanilla, and picual) was determined by 1H-NMR spectroscopy according to this protocol.
- PublicationPhotochemical Oxidation of Thioketones by Singlet Molecular Oxygen Revisited: Insights into Photoproducts, Kinetics, and Reaction Mechanism(ACS, 2015-09-30) Sánchez Arroyo, Antonio José; Pardo Botero, Zulay D.; Moreno Jiménez, Florencio; Herrera Fernández, Antonio; Martín, Nazario; García Fresnadillo, DavidPhotosensitized oxidation of trimethyl[2.2.1]-bicycloheptane thioketones by 1 O2 can yield more photoproducts than exclusively ketones and sulfines. Moreover, the ketone/sulfine ratio can be reversed when protic conditions and high thioketone concentrations are used, conversely to earlier results reporting ketones as the main photoproducts. A new mechanistic proposal for sulfine formation is suggested following intermolecular oxygen transfer from a peroxythiocarbonyl intermediate to a second thioketone molecule. Reaction quantum yields (10−5−10−2) depend on the reaction conditions and time. Sulfine production reaches a maximum at short irradiation times, whereas decomposition to the corresponding ketone is observed at long reaction times. When the thioketone substrate has a hydrogen atom at the α position a peroxyvinylsulfenic acid intermediate can be formed by proton transfer. Reaction of this intermediate with another thioketone molecule can yield more sulfine and its tautomeric vinylsulfenic acid, which dimerizes in situ to the thiosulfinate. The hydroperoxyl group of the peroxyvinylsulfenic acid can also rearrange to the α position, and by reaction with the starting thioketone, α-hydroxy thioketone and additional sulfine can be formed, while dehydration yields the α-oxo thioketone. In situ [2 + 2] and [4 + 2] self-cycloaddition of the α-oxo thioketone yields significant amounts of the corresponding adducts at prolonged irradiation times.
- PublicationNew procedures for the synthesis of heterocyclic substituted and 2,4-difunctionalized pyrimidines(Elsevier, 1996-06-03) García Martínez, Antonio; Herrera Fernández, Antonio; Moreno Jiménez, Florencio; Muñoz Martínez, Pablo J.; Alonso Martín, Cristina; Subramanian, Laksminarayanapuran R.N-Tosyl-2- and -3-acetylpyrrols 1 or N-tosyl-2-pyrrolidone 5 were condensed with cyano compounds in the presence of triflic anhydride (Tf2O) to yield heteroarylpyrimidines. 2,4 Difunctionalized pyrimidines were obtained by reaction of the corresponding 2,4-bis(methylsulfonyl)pyrimidines with nucleophiles.