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Search Results: 1 - 10 of 724189 matches for " Célia R. A. Maltha "
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Metals Complexes Formed with Oleanolic Acid  [PDF]
Nilton C. Ribeiro, Antonio J. Demuner, Marcelo H. dos Santos, Célia R. A. Maltha, Elson A. de Alvarenga, Slavko Komarnytsky
International Journal of Organic Chemistry (IJOC) , 2018, DOI: 10.4236/ijoc.2018.81011
Abstract: The oleanolic acid possesses diverse pharmacological properties, it is considered as a good starting material for creating new compounds. The oleanolic acid isolated of Plumeria obtusa leaves was used as raw material to obtained calcium, magnesium, zinc, nickel and copper complexes. The structures of complexes were confirmed by HRMS, 1H NMR, and 13C NMR. Five new compounds were synthesized to promote increased biological activity of oleanolic acid and PCR assays for the different type of cancer.
Constituintes químicos de Melaleuca alternifolia (Myrtaceae)
Vieira Tatiana R.,Barbosa Luiz C. A.,Maltha Célia R. A.,Paula Vanderlúcia F.
Química Nova , 2004,
Abstract: The first chemical study of non-volatile constituents from the bark and stem of Melaleuca alternifolia (Myrtaceae) led to the isolation and identification of 3,3'-O-dimethylellagic acid (1) and five pentacyclic triterpenes: 2alpha,3beta,23-trihydroxyolean-12-en-28-oic acid (arjunolic acid, 2), 3beta-hydroxylup-20(29)-en-27,28-dioic acid (melaleucic acid, 3), betulinic acid (4), betuline (5), 3beta-O-acetylurs-12-en-28-oic acid (6), a mixture of fatty acids and esters, and several hydrocarbons. For 2alpha,3beta,23-trihydroxyolean-12-en-28-oic acid (2) and 3beta-O-acetylurs-12-en-28-oic acid (6) a first detailed assignment of 1H NMR is presented.
Determina??o da rela??o siringila/guaiacila da lignina em madeiras de eucalipto por pirólise acoplada à cromatografia gasosa e espectrometria de massas (PI CG/EM)
Barbosa, Luiz C. A.;Maltha, Célia R. A.;Silva, Vanessa Lopes;Colodette, Jorge Luiz;
Química Nova , 2008, DOI: 10.1590/S0100-40422008000800023
Abstract: the use of analytical pyrolysis combined with gas chromatography/mass spectrometry (py-gc/ms) to determine the syringyl/guaiacyl ratio (s/g) in lignins from eucalyptus spp woods was investigated. sample of e. grandis and "e. urograndis" wood, with and without extractives, were subjected to pyrolysis from 300 oc to 600 oc. the products that results from pyrolysis were identified by mass spectrometry and the s/g ratio was determined based on the areas of the peaks corresponding to the guaiacyl and syringyl derivatives. the best s/g estimation is achieved when pyrolysis is carried out at 550 oc. extractives and carbohydrate present in the woods do not interfere with the results.
Caracteriza o química do "pitch" em indústria de celulose e papel de Eucalyptus
Cruz Mariluze P.,Barbosa Luiz C. A.,Maltha Célia R. A.,Gomide José L.
Química Nova , 2006,
Abstract: The chemical analysis of the acetone, chloroform, toluene and methanol extracts of a pitch sample was carried out by IR and GC-MS, leading to the identification of sixty nine compounds, including fatty acids, alcohols and hydrocarbons. Analysis of the acetone extractive of a eucalyptus wood used in Brazil for pulp production was also carried out, resulting in identification of fifty nine compounds, including mainly fatty acids, phenolic compounds, beta-sitosterol and other steroids. This analysis showed that pitch formation had a contribution from wood extractives and other sources of contamination. The results obtained and the methodology applied can be used by the pulp industry to develop new methods of pitch control.
Constituintes químicos de Melaleuca alternifolia (Myrtaceae)
Vieira, Tatiana R.;Barbosa, Luiz C. A.;Maltha, Célia R. A.;Paula, Vanderlúcia F.;Nascimento, Evandro A.;
Química Nova , 2004, DOI: 10.1590/S0100-40422004000400004
Abstract: the first chemical study of non-volatile constituents from the bark and stem of melaleuca alternifolia (myrtaceae) led to the isolation and identification of 3,3'-o-dimethylellagic acid (1) and five pentacyclic triterpenes: 2a,3b,23-trihydroxyolean-12-en-28-oic acid (arjunolic acid, 2), 3b-hydroxylup-20(29)-en-27,28-dioic acid (melaleucic acid, 3), betulinic acid (4), betuline (5), 3b-o-acetylurs-12-en-28-oic acid (6), a mixture of fatty acids and esters, and several hydrocarbons. for 2a,3b,23-trihydroxyolean-12-en-28-oic acid (2) and 3b-o-acetylurs-12-en-28-oic acid (6) a first detailed assignment of 1h nmr is presented.
Caracteriza??o química do "pitch" em indústria de celulose e papel de Eucalyptus
Cruz, Mariluze P.;Barbosa, Luiz C. A.;Maltha, Célia R. A.;Gomide, José L.;Milanez, Augusto F.;
Química Nova , 2006, DOI: 10.1590/S0100-40422006000300011
Abstract: the chemical analysis of the acetone, chloroform, toluene and methanol extracts of a pitch sample was carried out by ir and gc-ms, leading to the identification of sixty nine compounds, including fatty acids, alcohols and hydrocarbons. analysis of the acetone extractive of a eucalyptus wood used in brazil for pulp production was also carried out, resulting in identification of fifty nine compounds, including mainly fatty acids, phenolic compounds, b-sitosterol and other steroids. this analysis showed that pitch formation had a contribution from wood extractives and other sources of contamination. the results obtained and the methodology applied can be used by the pulp industry to develop new methods of pitch control.
Toxicidade de amidas análogas à piperina a larvas de Ascia monuste orseis Godart (Lepidoptera: Pieridae) e Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)
Estrela, Joelma L.V.;Guedes, Raul N.C.;Maltha, Célia R.A.;Fazolin, Murilo;
Neotropical Entomology , 2003, DOI: 10.1590/S1519-566X2003000200022
Abstract: the objective of this study was to evaluate the toxicity piperine amide analogs to 3rd-instar larvae of ascia monuste orseis godart and spodoptera frugiperda (j.e. smith). the bioassays were based on the topical application of 0.5 μl of the following amides: n-isopenthyl-(3,4-metilenodioxiphenyl)-amide, n-isopropyl-(3,4-metilenodioxiphenyl)-amide, n-hexyl-3-(3,4-etilenodioxiphenyl)-amide and piperonyl butoxide. the dl50 (mg a.i./ mg larva) values of the amides n-isopropyl e n-hexyl to a. monuste orseis were 0,278 and 0,004, respectively, and to s. frugiperda were 1.359 and 0.613, respectively. the steeper slopes of the dose-response curves for both species were obtained with n-isopropyl, indicating the higher homogeneity of response of the pest species studied to this compound. n-isopropyl was also the most promising piperine synthetic analog as insecticide agent among the compounds studied because it was the most toxic amide to both insect-pest species.
Síntese de novas fitotoxinas derivadas do 8-oxabiciclo[3.2.1]oct-6-en-3-ona
Barbosa, Luiz C. A.;Maltha, Célia R. A.;Demuner, Ant?nio J.;Ganen, Flávia R.;Silva, Ant?nio A. da;
Química Nova , 2005, DOI: 10.1590/S0100-40422005000300015
Abstract: the [4+3] cycloaddition was utilized in order to prepare 8-oxabicyclo[3.2.1]oct-6-en-3-one (1) derivatives. the correspondent acetonide 6 was converted into several alcohols (11-16). addition of aryllithium reagents to 6 resulted in 3-(2-fluorophenyl)-6,7-exo-isopropylidenedioxy -8-oxabicyclo[3.2.1]octan-3a-ol (11, 72%) and 3-(2,4-dimethoxyphenyl)-6,7-exo-isopropylidenedioxy-8-oxabicyclo[3.2.1]octan -3a-ol (16, 20%). the 3-butyl-6,7-exo-isopropylidenedioxy-8-oxabicyclo[3.2.1]octan-3 a-ol (15, 56%) was obtained through a grignard reaction. reduction of 6 resulted in 6,7-exo-isopropylidenedioxy-8-oxabicyclo[3.2.1]octan-3 b-ol (7, 62%) and 6,7-exo-isopropylidenedioxy-8-oxabicyclo[3.2.1]octan-3 a-ol (8, 20%). the alcohols were treated with thionyl chloride in pyridine, and the corresponding alkenes were obtained with 31-80% yield. the effect of these compounds on the development of radicle and aerial parts of sorghum bicolor was evaluated.
Síntese e avalia??o da atividade antimicrobiana de furanonas halogenadas e de compostos análogos aos nostoclídeos
Barbosa, Luiz C. A.;Maltha, Célia R. A.;Demuner, Ant?nio J.;Pinheiro, Patrícia F.;Varej?o, Jodieh O. S.;Montanari, Ricardo M.;Andrade, Nélio J.;
Química Nova , 2010, DOI: 10.1590/S0100-40422010001000003
Abstract: considering the broad spectrum of biological activity of gamma-butyrolactone derivatives, we presented the synthesis of 3,4-dihalo-5-arylidenefuran-2(5h)-ones (17-21) and analogues (24-28) of the natural product nostoclide (7,8). furanones 17-21 were synthesized from the condensation of aromatic aldehydes with lactones 14 and 15, that were obtained from mucobromic and mucochloric acids. lactone 15 was converted into the intermediate 23 in 36% overall yield. compound 23 was then transformed into the nostoclide analogues 24-28. some of the compounds prepared showed antimicrobial activities against escherichia coli, staphylococcus aureus and bacillus cereus comparable to commercial antibiotics.
Synthesis and Cytotoxic Activity of Some 3-Benzyl-5-Arylidenefuran-2(5H)-ones
Róbson Ricardo Teixeira,Luiz Cláudio Barbosa,Célia Regina Alvares Maltha,Marcelo E?a Rocha,Daniel Pereira Bezerra,Letícia Veras Costa-Lotuf,Cláudia Pessoa,Manoel Odorico Moraes
Molecules , 2007, DOI: 10.3390/12051101
Abstract: 3-Benzyl-furan-2(5H)-one (2a) and 3-(4-bromobenzyl)-furan-2(5H)-one (2b) were treated with TBDMSOTf and converted into the corresponding tert-butyldimethyl-silylfuran ethers. These furans were further condensed with several aromatic aldehydes affording compounds 5-14 with general 3-benzyl-5-arylidene-furan-2(5H)-one structures in 31% to 98% yields. Such compounds are analogues of the naturally occurring nostoclide lactones, reported to present moderate cytotoxic activity. Compounds 5-14 were submitted to an in vitro bioassay against the HL-60, HCT-8, SF295 and MDA-MB-435 cancer cell lines using the MTT cytotoxicity assay.
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