Armando Aríza-Castolo

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The effects of persistent organic pollutants (POPs) on humans and biodiversity are multiple and varied. Nowadays environmentally-friendly pesticides are strongly preferred to POPs. It is noteworthy that the crop protection role of pesticides and other techniques, i.e. biopesticides, plant extracts, prevention methods, organic methods, evaluation of plant(More)
Two new eunicellin-based diterpenes, seco-briarellinone (1) and briarellin S (2), and a known seco-asbestinin (3) have been isolated from the methanolic extract of the common octocoral Briareum asbestinum collected in Bocas del Toro, Caribbean of Panama. The structures and relative stereochemistry of the compounds were defined using extensive spectroscopic(More)
HPLC-UV, (1)H NMR, (13)C NMR, and (1)H-(1)H COSY analyses revealed that exogenous capsaicin was specifically converted into 5,5'-dicapsaicin by both cell suspension cultures of Capsicum annuum var. annuum (chili Jalapeño chigol) and their soluble and NaCl-extracted cell wall protein fractions under oxidative conditions. In cell suspension cultures(More)
This paper reports the synthesis of a series of piperidones 1-8 by the Mannich reaction and analysis of their structures and conformations in solution by NMR and mass spectrometry. The six-membered rings in 2,4,6,8-tetraphenyl-3,7-diazabicyclo[3.3.1]nonan-9-ones, compounds 1 and 2, adopt a chair-boat conformation, while those in(More)
An NMR titration method has been used to simultaneously measure the acid dissociation constant (pKa) and the intramolecular NHO prototropic constant ΔKNHO on a set of Schiff bases. The model compounds were synthesized from benzylamine and substituted ortho-hydroxyaldehydes, appropriately substituted with electron-donating and electron-withdrawing groups to(More)
Expression systems based on plant cells, tissue, and organ cultures have been investigated as an alternative for production of human therapeutic proteins in bioreactors. In this work, hairy root cultures of Brassica oleracea var. italica (broccoli) were established in an airlift with mesh bioreactor to produce isoform 1 of the human growth hormone (hGH1) as(More)
The relative acidities of the cis and trans isomers of a series of 1,5-oxazaspiro[5.5]undecane derivatives were determined by measuring DeltapK in acid-base titrations followed by (1)H NMR. Relative structural stabilities were determined by measuring substituent chemical shift and gamma-gauche effects in (13)C, (15)N, and (17)O NMR. Crystallographic(More)
A structural and conformational analysis of 1-oxaspiro[2.5]octane and 1-oxa-2-azaspiro[2.5]octane derivatives was performed using (1) H, (13)  C, and (15)  N NMR spectroscopy. The relative configuration and preferred conformations were determined by analyzing the homonuclear coupling constants and chemical shifts of the protons and carbon atoms in the(More)
The relative configuration of 11 1,4-diazaspiro[4.5]decanes (1a-1j and 1m), 15 1,4-oxazaspiro[4.5]decanes (2a-2o) and 10 1,4-dioxaspiro[4.5]decanes (3a-3n) substituted at the 2-, 6-, 7- or 8-position by a methyl group or using the tert-butyl group as a model for the ananchomeric structure is reported. The relative stereochemistry was analyzed by 1H, 13C,(More)
The (1)H, (13)C, and (15)N NMR spectra of 5 exocyclic alkenes and 15 different ketimines obtained from cyclohexanone and derivatives using benzyl bromide and primary amines-are analyzed. Relative stereochemical and preferential conformations are determined by analyzing both the homonuclear coupling and the chemical shifts of the protons and carbon atoms in(More)