412 research outputs found
Synthesis of diarylamines in the benzo[b]thiophene series bearing electron donating or withdrawing groups
The synthesis of diarylamines has attracted a great deal of interest due to their
importance in diverse fields as natural biological active products and analogues,
photography and materials science.
Herein we report the synthesis of diarylamines 1 bearing electron donating or
withdrawing groups by palladium catalyzed amination, in good yields (50%-quantitative
yield) using two different bases and choosing the right components
Synthesis of 6-(2’ or 4’- nitrophenyl)benzo[b]thiophenes by Palladium-catalyzed cross-coupling
The palladium-catalyzed cross-coupling reactions of organoboron compounds are very useful for carbon-carbon bond formation.
Compounds 1 were synthesized by a palladium-catalyzed cross-coupling of bromo or
iodonitrobenzenes with boronic esters 2, which were prepared from methylated 6-
bromobenzo[b]thiophenes2 by halogen-metal exchange and transmetalation. The intermediates esters 2 were not isolated but directly, after evaporation of the ether, coupled in acetone/water using palladium acetate in the presence of sodium hydrogencarbonate. Yields of isolated compounds 1 were about 40%
QSAR model for predicting radical scavenging activity of di(hetero)arylamines derivatives of benzo[b]thiophenes
A QSAR study was developed in order to model the antioxidant activity, specifically the radical scavenger
activity (RSA), of 26 di(hetero)arylamines’ derivatives of benzo[b]thiophenes. The QSAR model was
constructed, using the partial least squares projection of latent structures (PLS) method, and its
robustness and predictability were verified by internal and external cross-validation methods. A total of 4
molecular descriptors, belonging to RDF (Radial Distribution Function) descriptors (RDF020e and
RDF045e) and 2D-autocorrelation descriptors (GATS8p and MATS5e) were selected to build the QSAR
model. RDF descriptors seem to relate the presence of electronegative atoms at the inner atmosphere of
the compounds to increase RSA. 2D-Autocorrelation descriptors associate the presence of polarizable and
electronegative pairs of atoms, at specific topological distance, with the RSA of the compounds. Finally
this QSAR model proved to be a useful tool in the prediction of radical scavenger activity of congeneric
compounds and will be used to guide the synthesis of new diarylamines in our laboratory
QSAR studies on di(hetero)arylamines derivatives of benzo[b]thiophenes as free radical scavengers
Synthetic antioxidants are widely used in food industry y, but because of
toxic and carcinogenic effects revealed by some compounds such as
BHA and BHT, their use is being restricted. The pursuit for novel
compounds with antioxidant properties gained higher significance,
since these compounds may contribute for the prevention of diseases in
which free radicals are implicated
O bolo eterno : memória efêmera na Arte alimentar
Trabalho de Conclusão de Curso (graduação)—Universidade de BrasÃlia, Instituto de Artes, Departamento de Artes Visuais, 2017
Biodegradation of textile azo dyes by Phanerochaete chrysosporium
Instituto de Biotecnologia e QuÃmica Fina / Universidade do Minho (IBQF/UM) - Praxis XXI, Praxis XXI 2/2.1/QUI/44/94, Praxis XXI/BD/9120/96
Palladium-catalyzed amination of electron-rich or poor benzo[b]thienyl bromides
Recently we have applied the palladium-catalyzed amination to the synthesis of ortho-bromodiarylamincs in the benzo[blthiophene series . Here we describe the application of this methodology to the amination of electron-rich or poor 3-bromobenzo[b}thiophcnes, using the same conditions for both cases
Efeito da razão c/n e do inóculo na remoção de nitrogênio do efluente da indústria da pesca pela cianobactéria aphanothece microscopica nägeli
O presente trabalho teve por objetivo avaliar a utilização da cianobactéria Aphanothece microscopica Nägeli como pós-tratamento do efluente oriundo do processamento de pescado. As condições experimentais foram temperatura de 30 ºC, ausência de luminosidade e razões C/N de 20 e 60. Os inóculos utilizados nos experimentos foram obtidos a partir de culturas na fase logarÃtmica desenvolvidas em meio BGN e em meio BGN modificado pela substituição do nitrato de sódio por cloreto de amônio em concentração equivalente em nitrogênio contido no meio padrão (Braun- Grunow Medium – BGN). Utilizou-se um reator de mistura completa com capacidade de 3 l provido de sistema de aeração. Os modelos de remoção de nitrogênio apresentaram coeficientes de correlação significativos para todas as condições analisadas. Os experimentos com inóculos gerados em meio BGN foram considerados as melhores
condições avaliadas, apresentando uma redução significativa do
parâmetro NTK em menos de 24 h de cultivo e atingindo neste perÃodo concentrações inferiores aos limites estabelecidos pela legislação. Os resultados indicam que tanto a razão C/N como o inóculo apresentaram efeito significativo na remoção de nitrogênio do efluente do processamento de pescado pela cianobactéria Aphanothece microscopica Nägeli.
Palavras-chave: cianobactéria, Aphanothece microscopica Nägeli, efluente pescado, pós-tratamento
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