32 documents found, page 1 of 4
Molecular and crystal structure, spectroscopy, and photochemistry of a dispiro ...
Amado, Patrícia; Lopes, Susy; Brás, Elisa M.; Paixão, José A.; Takano, Ma‐aya; Abe, Manabu; Fausto, Rui; Cristiano, Maria De LurdesThe molecular structure and photochemistry of dispiro[cyclohexane-1,3′-[1,2,4,5]tetraoxane-6′,2′′-tricyclo[3.3.1.13,7]decan]-4-one (TX), an antiparasitic 1,2,4,5-tetraoxane was investigated using matrix isolation IR and EPR spectroscopies, together with quantum chemical calculations undertaken at the DFT(B3LYP)/6-311++G(3df,3pd) level of theory, with and without Grimme's dispersion correction. Photolysis of the...
Synthesis and Structural and Magnetic Properties of Polycrystalline GaMo4Se8
Malta, José F.; Henriques, Marta S. C.; Paixão, José A.; Gonçalves, António P.GaMo4Se8, is a lacunar spinel where skyrmions have been recently reported. This compound belongs to the GaM4X8 family, where M is a transition metal (V or Mo) and X is a chalcogenide (S or Se). In this work, we have obtained pure GaMo4Se8 in polycrystalline form through an innovative two-step synthetic route. Phase purity and chemical composition were confirmed through the Rietveld refinement of the powder XRD ...
Ethyl 7-Acetyl-8a-methyl-3-(1-phenyl-1H-tetrazol-5-yl)-1,4,4a,5,6,8a-hexahydro-...
Lopes, Susana M. M.; Lemos, Americo; Paixão, José A.; Pinho e Melo, Teresa M. V. D.The Diels–Alder reaction of ethyl 3-(1-phenyl-1<i>H</i>-tetrazol-5-yl-1,2-diaza-1,3-butadiene-1-carboxylate with 2-acetyl-6-methyl-2,3-dihydro-4<i>H</i>-pyran (methyl vinyl ketone dimer) regioselectively afforded the corresponding 3-(tetrazol-5-yl)-hexahydro-7<i>H</i>-pyrano[2,3-<i>c</i>]pyridazine in quantitative yield. An X-ray crystal structure of this cycloadduct is reported.
Synthesis, structure and antileishmanial evaluation of endoperoxide–pyrazole hy...
Amado, Patrícia S. M.; Costa, Inês C. C.; Paixão, José A.; Mendes, Ricardo F.; Cortes, Sofia; Cristiano, Maria L.Leishmaniases are among the most impacting neglected tropical diseases. In attempts to repurpose antimalarial drugs or candidates, it was found that selected 1,2,4-trioxanes, 1,2,4,5-tetraoxanes, and pyrazole-containing chemotypes demonstrated activity against <i>Leishmania</i> parasites. This study reports the synthesis and structure of trioxolane–pyrazole (<b>OZ1</b>, <b>OZ2</b>) and tetraoxane–pyrazole (<b>T...
Unravelling the structure of peroxides with antiparasitic activity: the relativ...
Amado, Patrícia; Jesus, A. J. Lopes; Paixão, José A.; Fausto, Rui; Cristiano, Maria De LurdesPlasmodium falciparum artemisinin-resistance boosted the quest for novel plasmodial "fast killers," uncovering antimalarial candidates OZ439 and E209, whose peroxide precursors are 1,2,4-trioxolane (1) and 1,2,4,5-tetraoxane (2), differing solely in the pharmacophore (trioxolane or tetraoxane). Combining X-ray crystallography and vibrational spectroscopy, along with Hirsh-feld surface analysis and calculations ...
Ethyl 7-Acetyl-8a-methyl-3-(1-phenyl-1H-tetrazol-5-yl)-1,4,4a,5,6,8a-hexahydro-...
Lopes, Susana M. M.; Lemos, Américo; Paixão, José A.; Melo, Teresa M. V. D. Pinho eThe Diels–Alder reaction of ethyl 3-(1-phenyl-1H-tetrazol-5-yl-1,2-diaza-1,3-butadiene- 1-carboxylate with 2-acetyl-6-methyl-2,3-dihydro-4H-pyran (methyl vinyl ketone dimer) regios- electively afforded the corresponding 3-(tetrazol-5-yl)-hexahydro-7H-pyrano[2,3-c]pyridazine in quantitative yield. An X-ray crystal structure of this cycloadduct is reported.
Color Polymorphs of ROY-ol
Nogueira, Bernardo A.; Lopes, Susana M. M.; Milani, Alberto; André, Vânia; Paixão, José A.; Eusébio, M. Ermelinda S.; Melo, Teresa M. V. D. Pinho eColor polymorphism is a fascinating property exhibited by compounds that have polymorphs of different colors. The most famous family of substances forming molecular organic color polymorphs is the ROY family of compounds. ROY, which states for the red, orange, and yellow colors of the polymorphs of 5-methyl-2-((2-nitrophenyl)amino)thiophene-3-carbonitrile, is currently the compound exhibiting the largest number...
Insightful vibrational imaging study on the hydration mechanism of carbamazepine
Fateixa, Sara; Nogueira, Helena I. S.; Paixão, José A.; Fausto, Rui; Trindade, TitoAnhydrous carbamazepine (CBZ) is an anti-convulsant drug commonly used to treat epilepsy and relieve trigeminal neuralgia. The presence of the dihydrate form in commercial CBZ tablets can change the dissolution rate of the active pharmaceutical ingredient (API), thus decreasing its activity. The hydration transformation can occur during wet granulation or storage, within a few weeks, depending on the ambient co...
On the development of selective chelators for Cadmium: Synthesis, structure and...
Leal, Joana F.; Guerreiro, Bruno; Amado, Patrícia; Fernandes, André L.; Barreira, Luísa; Paixão, José A.; Lurdes S. Cristiano, M.Aquatic contamination by heavy metals is a major concern for the serious negative consequences it has for plants, animals, and humans. Among the most toxic metals, Cd(II) stands out since selective and truly efficient methodologies for its removal are not known. We report a novel multidentate chelating agent comprising the heterocycles thiadiazole and benzisothiazole. 3-((5-(trifluoromethyl)-1,3,4-thiadiazol-2-...
Thiabendazole and Thiabendazole-Formic Acid Solvate: A Computational, Crystallo...
Tabanez, Andreia M. M.; Nogueira, Bernardo A.; Milani, Alberto; Eusébio, Maria Ermelinda da Silva; Paixão, José A.; Nur Kabuk, Hayrunnisa; Jajuga, MariaThiabendazole (TBZ) is a substance which has been receiving multiple important applications in several domains, from medicine and pharmaceutical sciences, to agriculture and food industry. Here, a comprehensive multi-technique investigation on the molecular and crystal properties of TBZ is reported. In addition, a new solvate of the compound is described and characterized structurally, vibrationally and thermoc...