134 documents found, page 1 of 14
A correlation-based approach for predicting humic substance bioactivity from di...
Silva, Ana Catarina; Bento, M. Fátima; Rocha, José Pedro Pereira Rebelo; Geraldo, Dulce; Proença, M. Fernanda R. P.; Antelo, Juan; Fiol, SarahThe efficient characterization of compost quality is essential for optimizing its application in agriculture and soil improvement. In this study, a correlation-based approach was employed to evaluate relationships between physicochemical properties, structural features, and reactivity indicators of compost extracts—fulvic acid-like (FA-L), humic acid-like (HA-L), and dissolved organic matter (DOM)—and their res...
A simple protocol for the synthesis of perylene bisimides from perylene tetraca...
Marinho, Elina Margarida Ribeiro; Figueiredo, Pedro Miguel Reis; Araújo, Rui Filipe; Proença, M. Fernanda R. P.Perylene bisimides are highly attractive polycyclic aromatic hydrocarbons due to their photostability associated to unique and characteristic photochemical properties. They have been widely used for analytical purposes, despite the hydrophobicity of most of these compounds. The ring substitution pattern plays an important role in fine-tuning the physicochemical properties that govern solubility and aggregation....
Discovery of 2,9-diaryl-6-carbamoylpurines as a novel class of antitubercular a...
Correia, Carla; Leite, Ana Claúdia; Fraga, Alexandra G.; Proença, M. Fernanda R. P.; Pedrosa, Jorge; Carvalho, M. AliceA series of novel 9-alkyl/aryl-2-aryl-6-carbamoylpurines were synthesized, and their activity against $\text{Mycobacterium tuberculosis}$ strain $\text{H}37\text{Rv}$ was assessed. The $\text{SAR}$ analysis on the first set of derivatives, with an alkyl or aryl unit at $\text{N}$-$9$ and a phenolic unit at $\text{C}$-$2$, showed that the activity depends on the purine ring substituents at $\text{N}$-$9$ and $\t...
2-Aryladenine derivatives as a potent scaffold for adenosine receptor antagonis...
Areias, Filipe; Correia, Carla; Rocha, Ashly; Teixeira, Sofia; Castro, Marián; Brea, Jose; Hu, Huabin; Carlsson, Jens; Loza, Maria I.A set of 2-aryl-9-H or methyl-6-morpholinopurine derivatives were synthesized and assayed through radioligand binding tests at human A<inf>1</inf>, A<inf>2A</inf>, A<inf>2B</inf>, and A<inf>3</inf> adenosine receptor subtypes. Eleven purines showed potent antagonism at A<inf>1</inf>, A<inf>3</inf>, dual A<inf>1</inf>/A<inf>2A</inf>, A<inf>1</inf>/A<inf>2B</inf>, or A<inf>1</inf>/A<inf>3</inf> adenosine receptor...
Regioselective synthesis of 2-Aryl-5-cyano-1-(2-hydroxyaryl)-1H-imidazole-4-car...
Pedroso de Lima, Fabio; Lence, Emilio; Suarez de Cepeda, Pilar; Correia, Carla; Carvalho, M. Alice; Gonzalez-Bello, ConcepcionThe reactivity of the diaminomaleonitrile-based imines containing hydroxyphenyl substituents with diverse aromatic aldehydes has been explored for the synthesis of novel highly substituted nitrogen heterocycles, which are considered privileged scaffolds in drug discovery. We report here a simple and efficient method for the regiocontrolled synthesis of a variety of 2-aryl-5cyano-1-(2-hydroxyaryl)-1H-imidazole-4...
Poly(lactic acid) composites with few layer graphene produced by noncovalent ch...
Peixoto, Tânia; Nunes, Joana; Lopes, Maria A.; Marinho, Elina Margarida Ribeiro; Proença, M. Fernanda R. P.; Lopes, Paulo Estevão CaldeiraIn recent years, significant attention has been given to “green” product innovation and related manufacturing processes. This work reports the preparation of few-layer graphene (FLG) and respective PLA-based composites by an ecofriendly, efficient, and cost-effective approach. FLG was produced in a scaledup process, based on the noncovalent functionalization of a micronized graphite with a pyrene derivate (PY),...
Selective cytotoxicity of Portuguese propolis ethyl acetate fraction towards re...
Freitas, Ana Sofia; Costa, Marta Sílvia Freitas; Pontes, Olívia; Seidel, Veronique; Proença, M. Fernanda R. P.; Cardoso, Susana M.Renal cell carcinoma is the most lethal cancer of the urological system due to late diagnosis and treatment resistance. Propolis, a beehive product, is a valuable natural source of compounds with bioactivities and may be a beneficial addition to current anticancer treatments. A Portuguese propolis sample, its fractions (<i>n</i>-hexane, ethyl acetate, <i>n</i>-butanol and water) and three subfractions (<b>P1</b...
Unravelling the anticancer potential of functionalized chromeno[2,3-b ] pyridin...
Oliveira-Pinto, Sofia; Pontes, Olivia; Lopes, Diogo; Marques, Maria Belém Sousa Sampaio; Costa, Marta D.; Carvalho, Luisa; Goncalves, Celine S.A selection of new chromeno[2,3-b]pyridines was prepared from chromenylacrylonitriles and N-substituted piperazines, using a novel and efficient synthetic procedure. The compounds were tested for their anticancer activity using breast cancer cell lines MCF-7, Hs578t and MDA-MB-231 and the non-neoplastic cell line MCF-10A for toxicity evaluation. In general, compounds showed higher activity towards the luminal b...
Synthesis of 2-(aminophenyl)adenine derivatives: a simple protocol using the cl...
Rocha, A.; Proença, M. Fernanda R. P.; Carvalho, M. Alice2-(Nitrophenyl)adenine derivatives were isolated from the reaction of 5-amino-4-amidino-imidazoles with nitro-benzaldehydes. The conversion of the nitro derivatives to 2-(aminophenyl)adenine derivatives was performed using iron/acetic acid as reducing agent, in 70% aqueous ethanol. The products were isolated in good yield and the isolation protocol involves simple filtration and extraction procedures. This meth...
A convenient one-pot synthesis of Chromenyl Acrylates and Acrylonitriles
Lopes, Diogo; Costa, Marta; Louçano, João; Proença, M. Fernanda R. P.2H-Oxo-chromenyl acrylates and 2H-imino-chromenyl acrylonitriles have been prepared from a salicylaldehyde and ethyl cyanoacetate or 2-amino-1,1,3-tricyanopropene, respectively. The reaction occurs in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) and the products were isolated in good to quantitative yields. Despite the simplicity of the synthesis, this is the first time that these substituted chromenes...