A simple protocol for the preparation of β-enamino ketones catalyzed by NbOPO4 under solvent free conditions

A novel application of the highly stable niobium oxide phosphate (NbOPO₄) as an efficient catalyst for the synthesis of β-enamino ketones under solvent-free conditions is described. This protocol, exhibits attractive yields, short reaction periods, lower loading of catalyst and high chemoselectivity.     

Thermal behavior of furosemide

Data from theoretical, thermal, and spectroscopic methods were compared in order to map a possible mechanism for the thermal decomposition of furosemide, a diuretic compound, in solid state. TG/DTG curves suggested a two-stage decomposition process. The first product of decomposition is water (m/z = 18), released due to a dimerization resulting in the formation of an amide. Then carbon dioxide (m/z = 44), nitroxide (m/z = 30), and 2-methyl-furanyl ion (m/z = 81) are released in the second stage. The chlorine substituted benzene ring, due to the double bond conjugated system, being the last fraction to decompose. Theoretical calculations presented are in agreement with experimental results.     

Microextraction by packed sorbent liquid chromatography with time‐of‐flight mass spectrometry of triazines employing a molecularly imprinted polymer†

Molecularly imprinted polymers for the determination of triazines were synthesized by precipitation using atrazine as template, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinker, and 2,2′‐azobisisobutrynitrile as initiator. The polymers were characterized by infrared spectroscopy and scanning electron microscopy and packed in a device for microextraction by packed sorbent aiming for the preconcentration/cleanup of herbicides, such as atrazine, simazine, simetryn, ametryn, and terbutryn in corn samples. Liquid chromatography coupled with time‐of‐flight mass spectrometry was used for the separation and determination of the herbicides. The selectivity coefficient of molecularly imprinted polymers was compared with that of nonimprinted polymer for the binary mixtures of atrazine/propanil and atrazine/picloram, and the values obtained were 15.6 and 2.96, respectively. The analytical curve ranged from 10 to 80 μg/kg (r = 0.989) and the limits of detection and quantification in the corn matrices were 3.3 and 10 μg/kg, respectively. Intra‐ and interday precisions were < 14.8% and accuracy was better than 90.9% for all herbicides. Polymer synthesis was successfully applied to the cleanup and preconcentration of triazines from fortified corn samples with 91.1–109.1% of recovery.     

Electrodes based on zeolites modified with cobalt and/or molybdenum for pesticide degradation: part II—2,4,6-trichlorophenol degradation

Journal of Solid State Electrochemistry - 2,4,6-trichlorophenol (TCP) is a persistent pollutant introduced in water by industrial processes and pesticides. We have studied the electrooxidation of...     

UHPLC-DAD Characterization of Origanum vulgare L. from Atacama Desert Andean Region and Antioxidant,Antibacterial and Enzyme Inhibition Activities

The Lamiaceae family is an important source of species among medicinal plants highly valued for their biological properties and numerous uses in folk medicine. Origanum is one of the main genera that belong to this family. The purpose of the study was to determine the phenolic composition of the Origanum vulgare extract and evaluate the antimicrobial, antioxidant, and inhibitory activities of this species that grows in the Andean region of the Atacama Desert. High-performance liquid chromatography was performed to determine the main phenols. Rosmarinic acid was identified as the predominant phenolic compound in this species (76.01 mg/100 g DW), followed by protocatechuic acid, which to our knowledge, no previous study reported similar concentrations in O. vulgare. The oregano extract exhibited a content of total phenolic (3948 mg GAE/100 g DW) and total flavonoid (593 mg QE/100 g DW) with a higher DPPH antioxidant activity (IC₅₀ = 40.58 µg/mL), compared to the same species grown under other conditions. Furthermore, it was found to inhibit α-glucosidase activity with an IC₅₀ value (7.11 mg/mL) lower than acarbose (129.32 mg/mL). Pseudomonas syringae and Pantoea agglomerans (both MIC 0.313 mg/mL and MBC 1.25 mg/mL) were the bacteria most susceptible to oregano extract with the lowest concentration necessary to inhibit bacterial growth. These results open the door for the potential use of this plant to manage chronic diseases, and they expand the knowledge of the species cultivated in arid environmental conditions.