Browsing by Author "Abonia, Rodrigo"
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Item A facile synthesis of stable β-amino-N-/O-hemiacetals through a catalyst-free three-component Mannich-type reaction(Elsevier Ltd, 2017-03-02) Abonia, Rodrigo; Castillo, Juan C.; Garay, Alexander; Insuasty, Braulio; Quiroga, Jairo; Nogueras, Manuel; Cobo, Justo; D'Vries, Richard F.A practical, straightforward and one-step procedure for the synthesis of novel and stable b-amino-N-/Ohemiacetals (i.e. c-aminoalcohols) is provided. The title compounds were obtained in good to excellent yields through an uncatalyzed three-component reaction by treatment of secondary amines with polyformaldehyde and electron-rich alkenes in acetonitrile as solvent at ambient temperature. The reactions proceeded with the formation of iminium ions, through a Mannich-type reaction, as the key intermediates for the generation of the target products. Single crystal X-ray analysis of derivative 4l confirmed unequivocally the structure and stability of the obtained compounds.Item A facile synthesis of stable β-amino-N-/O-hemiacetals through a catalyst-free three-component Mannich-type reaction(Tetrahedron Letters, 2017) Abonia, Rodrigo; Castillo, Juan C.; Garay, Alexander; Insuasty, Braulio; Quiroga, Jairo; Nogueras, Manuel; Cobo, Justo; D’Vries, Richard F.A practical, straightforward and one-step procedure for the synthesis of novel and stable β-amino-N-/O-hemiacetals (i.e γ-aminoalcohols) is provided. The title compounds were obtained in good to excellent yields through an uncatalyzed three-component reaction by treatment of secondary amines with polyformaldehyde and electron-rich alkenes in acetonitrile as solvent at ambient temperature. The reactions proceeded with the formation of iminium ions, through a Mannich-type reaction, as the key intermediates for the generation of the target products. Single crystal X-ray analysis of derivative 4l confirmed unequivocally the structure and stability of the obtained compounds.Item Synthesis of novel quinoline–based 4,5–dihydro–1H–pyrazoles as potential anticancer, antifungal, antibacterial and antiprotozoal agents(Elsevier Masson SAS, 2017-03-16) Ramírez Prada, Jonathan; Robledo, Sara M.; Velez, Ivan D.; Crespo, María del Pilar; Quiroga, Jairo; Abonia, Rodrigo; Montoya, Alba; Svetaz, Laura; Zacchino, Susana; Insuasty, BraulioA new series of Nesubstituted 2epyrazolines 9aef, 10aef, 11aef, 12aef and 13aef were obtained from the cyclocondensation reaction of [(7echloroquinoline4eyl)amino]chalcones 8aef with hydrazine hydrate and its derivatives. Fourteen of the synthesized compounds including the starting chalcones were selected by US National Cancer Institute (NCI) for testing their anticancer activity against 60 different human cancer cell lines, with the most important GI50 values ranging from 0.28 to 11.7 mM (0.13e6.05 mg/ mL) and LC50 values ranging from 2.6 to > 100 mM (1.2 to > 51.7 mg/mL), for chalcones 8a,d and pyrazolines 10c,d. All compounds were assessed for antibacterial activity against wild type and multidrug resistant gram negative and gram positive bacteria, with MIC values ranging from 31.25 to 500 mg/mL. Additionally, the novel compounds were tested for antifungal and antiparasitic properties. Although these compounds showed mild activity against Candida albicans, chalcones 8a and 8e showed high activity against Cryptococcus neoformans with MIC50 ¼ 7.8 mg/mL. For antiePlasmodium falciparum activity the 2epyrazoline 11b was the most active with EC50 ¼ 5.54 mg/mL. Regarding the activity against Trypanosoma cruzi, compound 10a was highly active with EC50 ¼ 0.70 mg/mL. Chalcone 8a had good activity against Leishmania panamensis amastigotes with EC50 ¼ 0.79 mg/mL.Item Synthesis, structural characterization and theoretical studies of a new Schiff base 4-(((3-(tert-Butyl)-(1-phenyl)pyrazol-5-yl) imino)methyl)phenol(Elsevier B.V., 2017-09) Cuenú, Fernando; Londono Salazar, Jennifer; Torres, John Eduard; Abonia, Rodrigo; D'Vries, Richard F.4-(((3-(tert-Butyl)-(1-phenyl)pyrazol-5-yl)imino)methyl)phenol (4-OHFPz) was synthesized and characterized by FT-IR, MS, NMR, and single-crystal X-ray diffraction. Optimization of molecular geometry, vibrational frequencies, and chemical shifts were calculated by using the methods of density functional theory (DFT) with B3LYP and B3PW91 as functionals and Hartree-Fock with 6-311G++(d,p) as basis set using the GAUSSIAN 09 program package. With the VEDA 4 software, the vibrational frequencies were assigned in terms of the potential energy distribution (PED). The equilibrium geometries calculated by all methods were compared with X-ray diffraction results, indicating that the theoretical results matches well with the experimental ones. The data obtained from the vibrational analysis and the calculated NMR are consistent with the experimental spectra.