Luiz Everson da Silva | Universidade Federal do Paraná (original) (raw)
Papers by Luiz Everson da Silva
The present paper reports the synthesis and antiprotozoal activity of N-quinolin-8-yl-arylsulfona... more The present paper reports the synthesis and antiprotozoal activity of N-quinolin-8-yl-arylsulfonamides and their copper and zinc complexes. Sulfonamides 2-5 were synthesized by reacting 8-aminoquinoline with several commercial arylsulfonyl chlorides. The corresponding complexes 6-13 were obtained using copper (II) acetate or zinc chloride in methanol. In vitro activity was carried out against promastigote forms of Leishmania braziliensis and L. chagasi, and epimastigote forms of Trypanosoma cruzi. Selected compounds were tested against axenic amastigote forms of L. braziliensis. The new 2,5-dichlorobenzenesulfonamide ligand was found to be inactive under the selected bioassays, however its copper complex 8 was active with the highest selective indexes (SI) against L. braziliensis promastigote and amastigote forms, with IC 50 values of 2.59 and 0.35 μM, respectively. Difluorinated copper 10 and zinc 11 complexes were most active against L. braziliensis, with IC 50 of 1.11 μM and 1.25 μM, respectively. However, the SI values were about 12 for both compounds. In general, the complexation of sulfonamides increases the antiprotozoal activity, as well as the cytotoxicity on Vero cells. These results confirm the antiprotozoal potential of sulfonamides and metal-based sulfonamides.
Acta Crystallographica Section E-structure Reports Online, 2006
Single-crystal X-ray study T = 299 K Mean (C-C) = 0.004 Å R factor = 0.043 wR factor = 0.116 Data... more Single-crystal X-ray study T = 299 K Mean (C-C) = 0.004 Å R factor = 0.043 wR factor = 0.116 Data-to-parameter ratio = 14.7
Tetrahedron, 2002
The thermocyclisation of phenylenediamine-bis(methylene Meldrum's acid) derivatives has been inve... more The thermocyclisation of phenylenediamine-bis(methylene Meldrum's acid) derivatives has been investigated. Those of o-phenylenediamines give 1,10-phenanthroline derivatives, while those of m-and p-phenylenediamines lead to the preferential formation of angular diazatricycles. Thus, for example, the di-Meldrum's acid derivative of 2,5-dichloro-1,4-phenylenediamine gives, via ipsosubstitution, the unexpected angular product 19. q
![Research paper thumbnail of 5-[(8-Hydroxyquinolin-2-ylamino)methylene]-2,2-dimethyl-1,3-dioxane-4,6-dione](https://attachments.academia-assets.com/49663206/thumbnails/1.jpg)
](Acta Crystallographica Section E-structure Reports Online, 2007
Key indicators: single-crystal X-ray study; T = 299 K; mean (C-C) = 0.002 Å; R factor = 0.046; wR... more Key indicators: single-crystal X-ray study; T = 299 K; mean (C-C) = 0.002 Å; R factor = 0.046; wR factor = 0.119; data-to-parameter ratio = 11.6.
Cheminform, 2008
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Acta Crystallographica Section E-structure Reports Online, 2006
Bioorganic & Medicinal Chemistry, 2008
Reexamination of the NMR data indicates that the authors did not prepare compounds 7b, 12b, and 1... more Reexamination of the NMR data indicates that the authors did not prepare compounds 7b, 12b, and 13b. The actual products were 7a, 12a, and 13a, respectively, as shown by a diaxial coupling constant in the H-2 multiplets. Therefore, all references to 7b, 12b, and 13b should be corrected to 7a, 12a, and 13a, respectively. However, the 1 H NMR data for azides 28a and 28b (direct precursors of 7a and 7b, respectively) confirm the original structure assignments and suggest that epimerization occurred at C-2 during the Staudinger reaction (see Scheme 2, steps e and f). Compound 28a: 1 H NMR (CDCl 3 ) d 1.12 (s, 3H), 1.47 (s, 3H), 1.52-1.80 (m, 4H), 2.05-2.23 (m, 4H), 2.34 (ddd, J = 3.5, 7.4, 13.7 Hz, 1H), 2.59 (dd, J = 5.1, 13.2 Hz, 1H), 2.71 (dd, J = 3.5, 13.4 Hz, 1H), 3.73 (s, 3H), 3.92 (dd, J = 7.3, 12.8 Hz, 1H), 5.56 (dd, J = 5.1, 11.7 Hz, 1H), 6.38-6.39 (m, 1H), 7.40-7.43 (m, 2H). Compound 28b: 1 H NMR (CDCl 3 ) d 1.10 (s, 3H), 1.43 (s, 3H), 1.55-1.76 (m, 4H), 2.01-2.18 (m, 3H), 2.38 (ddd, J = 4.2, 13.2, 15.0 Hz, 1H), 2.56 (dd, J = 5.6, 13.3 Hz, 1H), 2.61 (s, 1H), 2.87 (dd, J = 3.3, 13.2 Hz, 1H), 3.71 (s, 3H), 3.96 (dd, J = 2.4, 3.9 Hz, 1H), 5.55 (dd, J = 5.4, 11.4 Hz, 1H), 6.40 (br s, 1H), 7.40-7.43 (m, 2H). 0960-894X/$ -see front matter Ó
Synthetic Communications, 2007
An efficient synthesis of 1,8-naphthyridine-4(1H)-one sulfonamide derivatives by thermolysis of 2... more An efficient synthesis of 1,8-naphthyridine-4(1H)-one sulfonamide derivatives by thermolysis of 2-pyridylaminomethylene (Meldrum's acid derivative) starting from 4,6-dimethyl-2-aminopyridine (1) is described.
Quimica Nova, 2008
Sulfonamides obtained by reaction of 8-aminoquinoline with 4-nitrobenzenesulfonylchloride and 2,4... more Sulfonamides obtained by reaction of 8-aminoquinoline with 4-nitrobenzenesulfonylchloride and 2,4,6-triisopropylbenzenesulfonyl chloride were used to synthesize coordination compounds with CuII and ZnII with a ML2 composition. Determination of the crystal structures of the resulting zinc and copper complexes by X-ray diffraction show a distorted tetrahedral environment for the [Cu(qnbsa)2], [Cu(qibsa)2] and [Zn(qibsa)2] complexes in which the sulfonamide group acts as a bidentate ligand through the nitrogen atoms from the sulfonamidate and quinoline groups. The complex [Zn(qnbsa)2] crystallizes with a water molecule from the solvent and the Zn is five-coordinated and shows a bipyramidal-trigonal geometry. The electrochemical and electronic spectroscopy properties of the copper complexes are also discussed.
Acta Crystallographica Section E-structure Reports Online, 2007
ABSTRACT In the title compound, C17H16BrN3O3S, the C—N—S—C torsion angle between the pyrazole uni... more ABSTRACT In the title compound, C17H16BrN3O3S, the C—N—S—C torsion angle between the pyrazole unit and the bromobenzene ring is −117.3 (3)°. The phenyl ring and the pyrazole residue are twisted with respect to each other by an angle of 70.8 (2)°. One intermolecular N—H...O and two non-classical intermolecular C—H...O hydrogen bonds are observed in the crystal structure.
Acta Crystallographica Section E-structure Reports Online, 2006
The phytochemical investigation of the methanol crude extract obtained from Acosmium dasycarpum (... more The phytochemical investigation of the methanol crude extract obtained from Acosmium dasycarpum (Vog.) Yakovlev root bark led to the isolation of the quinolizidine alkaloids lupanine, acosmine, acosminine and lupanacosmine, as well as the diaza-adamantane alkaloids panacosmine and dasycarpumine. Lupanacosmine (4) and dasycarpumine (6) have been described for the first time herein.The phytochemical investigation of the methanol crude extract obtained from Acosmium dasycarpum (Vog.) Yakovlev root bark led to the isolation of the quinolizidine alkaloids lupanine, acosmine, acosminine, and lupanacosmine, as well as the diaza-adamantane alkaloids panacosmine, and dasycarpumine. Lupanacosmine (4) and dasycarpumine (6) have been described for the first time herein.
Allelopathy can offer new substances with herbicidal properties less harmful to the environment a... more Allelopathy can offer new substances with herbicidal properties less harmful to the environment and humans than the synthetic compounds traditionally used in agriculture. The aim of this work was to evaluate the effect of extracts of Annona crassiflora on germination and growth of Brachiaria brizantha, Euphorbia heterophylla and Ipomoea grandifolia, as well as to determine the effect of the most promising extract fraction on soybean (Glycine max). Thus, hydroalcoholic extracts from seeds, leaves and stems of A. crassiflora were prepared and evaluated in germination tests as well as root and hypocotyl development of the weeds. The extract of the most promising part of the plant was fractioned using solvents with increasing polarity order. The hydroalcoholic extract, prepared from A. crassiflora seeds was found to have the greatest effect on the weeds. Also, the germination of B. brizantha and E. heterophylla was completely inhibited by the extract. In general, the species were more sensitive to the ethyl acetate fraction, although this extract did not interfere in the soybean development. The results obtained allowed to conclude that A. crassiflora presents a good potential for the management of B. brizantha, E. heterophylla and I. grandifolia, in soybean post-emergence.
This paper describes the study of two alkaloids extracted from Pilocarpus Microphyllus (Rutaceae)... more This paper describes the study of two alkaloids extracted from Pilocarpus Microphyllus (Rutaceae): pilosine and epiisopilosine. These substances have potential application in the treatment of several diseases. In this work FT-Raman and the FT-IR spectra of pilosine and epiisopilosine were investigated at 300 K. Vibrational wavenumber and wave vector have been predicted using density functional theory (B3LYP) calculations with the 6-31 G(d,p) basis set. A comparison with experiment, allowed us to assign most of the normal modes of the crystals.
Leishmaniasis is one of the neglected diseases. High cost, systemic toxicity, and diminished effi... more Leishmaniasis is one of the neglected diseases. High cost, systemic toxicity, and diminished efficacy due to development of resistance by the parasites has a negative impact on the current treatment options. Thus, the search for a new, effective and safer anti-leishmanial drug becomes of paramount importance. Compounds derived from natural products may be a better and cheaper source in this regard. This study evaluated the in vitro anti-leishmanial activity of Spiranthera odoratíssima (Rutaceae) fractions and isolated compounds, using promastigote and amastigote forms of different Leishmania species. J774 A.1 macrophage was used as the parasite host cell for the in vitro assays. Evaluations of cytoxicity, nitric oxide (NO), interleukin-10 and in silico analysis were carried out. In vitro experiments showed that the fruit hexanic fraction (Fhf) and its alkaloid skimmianine (Skm) have a significant (P<0·001) effect against L. braziliensis. This anti-L. braziliensis activity of Fhf and Skm was due to increased production of NO and attenuation of IL-10 production in the macrophages at concentrations ranging from 1·6 to 40·0 μg/ml. The in silico assay demonstrated significant interaction between Skm and amino acid residues of NOS2. Skm is thus a promising drug candidate for L. braziliensis due to its potent immunomodulatory activity.(Received April 14 2011)(Revised May 31 2011)(Revised June 15 2011)(Accepted June 16 2011)(Online publication August 03 2011)
In the present study, the natural product 3-Methoxyquercetin, a flavonoid with potential antivira... more In the present study, the natural product 3-Methoxyquercetin, a flavonoid with potential antiviral activity, was characterized through infrared and Raman spectroscopies combined with Density Functional Theory calculation. The flavonoid was extracted from Strychnos pseudoquina St. Hil (Loganiaceae) by chromatographic techniques. The optimized molecular structure and calculated vibrational spectra were performed by B3LYP/6-31G (d,p) basis set. The optimized structure was compared with X-ray diffraction data of other flavonoids compounds, and the theoretical data are in good agreement with experimental ones. Fourier transform–Raman and –infrared spectra, as well as the assignment of the normal modes are also presented.► Synthesis of flavonoid. ► Physical characterization of a substance. ► Density Functional Theory, Raman and infra red studies.
The Schiff base 4-{[(1E)-(2-Hydroxyphenyl)methylidene]amino}-1,5-dimethyl-2-phenyl-1,2-dihydro-3H... more The Schiff base 4-{[(1E)-(2-Hydroxyphenyl)methylidene]amino}-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (C18H17N3O2) is a synthetic compound with a variety of scientific and technological applications, such as clinic, analytic and pharmacologic. In this work FT-Raman spectrum and FT-infrared spectrum of C18H17N3O2 were investigated at 300 K. Vibrational wavenumber and wave vector have been predicted using Density Functional Theory (B3LYP) calculations with the 6-31 G(d,p) basis set. The description of the normal modes was performed by means of the potential energy distribution. A comparison with experiment allowed us to assign most of the normal modes of the crystal.► Synthesis of a Schiff base with potential use as drug for tropical diseases. ► Physical characterization of a substance. ► Density Functional Theory, Raman and infra red studies of a potential drug.
Two 1,8–naphthyridines were synthesized and found to be fluorescent in solution. These compounds ... more Two 1,8–naphthyridines were synthesized and found to be fluorescent in solution. These compounds were studied in the presence of Cu+ and Cu2+ ions and it was verified that the metal causes the quenching of their fluorescence emission, due to the formation of complexes between the naphthyridine and the metal. A displacement assay was carried out in a DMSO–water mixture with the addition of various anions to the solutions of the complexes, and it was observed that these systems have a high capacity to selectively detect cyanide.
The present paper reports the synthesis and antiprotozoal activity of N-quinolin-8-yl-arylsulfona... more The present paper reports the synthesis and antiprotozoal activity of N-quinolin-8-yl-arylsulfonamides and their copper and zinc complexes. Sulfonamides 2-5 were synthesized by reacting 8-aminoquinoline with several commercial arylsulfonyl chlorides. The corresponding complexes 6-13 were obtained using copper (II) acetate or zinc chloride in methanol. In vitro activity was carried out against promastigote forms of Leishmania braziliensis and L. chagasi, and epimastigote forms of Trypanosoma cruzi. Selected compounds were tested against axenic amastigote forms of L. braziliensis. The new 2,5-dichlorobenzenesulfonamide ligand was found to be inactive under the selected bioassays, however its copper complex 8 was active with the highest selective indexes (SI) against L. braziliensis promastigote and amastigote forms, with IC 50 values of 2.59 and 0.35 μM, respectively. Difluorinated copper 10 and zinc 11 complexes were most active against L. braziliensis, with IC 50 of 1.11 μM and 1.25 μM, respectively. However, the SI values were about 12 for both compounds. In general, the complexation of sulfonamides increases the antiprotozoal activity, as well as the cytotoxicity on Vero cells. These results confirm the antiprotozoal potential of sulfonamides and metal-based sulfonamides.
Acta Crystallographica Section E-structure Reports Online, 2006
Single-crystal X-ray study T = 299 K Mean (C-C) = 0.004 Å R factor = 0.043 wR factor = 0.116 Data... more Single-crystal X-ray study T = 299 K Mean (C-C) = 0.004 Å R factor = 0.043 wR factor = 0.116 Data-to-parameter ratio = 14.7
Tetrahedron, 2002
The thermocyclisation of phenylenediamine-bis(methylene Meldrum's acid) derivatives has been inve... more The thermocyclisation of phenylenediamine-bis(methylene Meldrum's acid) derivatives has been investigated. Those of o-phenylenediamines give 1,10-phenanthroline derivatives, while those of m-and p-phenylenediamines lead to the preferential formation of angular diazatricycles. Thus, for example, the di-Meldrum's acid derivative of 2,5-dichloro-1,4-phenylenediamine gives, via ipsosubstitution, the unexpected angular product 19. q
Acta Crystallographica Section E-structure Reports Online, 2007
Key indicators: single-crystal X-ray study; T = 299 K; mean (C-C) = 0.002 Å; R factor = 0.046; wR... more Key indicators: single-crystal X-ray study; T = 299 K; mean (C-C) = 0.002 Å; R factor = 0.046; wR factor = 0.119; data-to-parameter ratio = 11.6.
Cheminform, 2008
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Acta Crystallographica Section E-structure Reports Online, 2006
Bioorganic & Medicinal Chemistry, 2008
Reexamination of the NMR data indicates that the authors did not prepare compounds 7b, 12b, and 1... more Reexamination of the NMR data indicates that the authors did not prepare compounds 7b, 12b, and 13b. The actual products were 7a, 12a, and 13a, respectively, as shown by a diaxial coupling constant in the H-2 multiplets. Therefore, all references to 7b, 12b, and 13b should be corrected to 7a, 12a, and 13a, respectively. However, the 1 H NMR data for azides 28a and 28b (direct precursors of 7a and 7b, respectively) confirm the original structure assignments and suggest that epimerization occurred at C-2 during the Staudinger reaction (see Scheme 2, steps e and f). Compound 28a: 1 H NMR (CDCl 3 ) d 1.12 (s, 3H), 1.47 (s, 3H), 1.52-1.80 (m, 4H), 2.05-2.23 (m, 4H), 2.34 (ddd, J = 3.5, 7.4, 13.7 Hz, 1H), 2.59 (dd, J = 5.1, 13.2 Hz, 1H), 2.71 (dd, J = 3.5, 13.4 Hz, 1H), 3.73 (s, 3H), 3.92 (dd, J = 7.3, 12.8 Hz, 1H), 5.56 (dd, J = 5.1, 11.7 Hz, 1H), 6.38-6.39 (m, 1H), 7.40-7.43 (m, 2H). Compound 28b: 1 H NMR (CDCl 3 ) d 1.10 (s, 3H), 1.43 (s, 3H), 1.55-1.76 (m, 4H), 2.01-2.18 (m, 3H), 2.38 (ddd, J = 4.2, 13.2, 15.0 Hz, 1H), 2.56 (dd, J = 5.6, 13.3 Hz, 1H), 2.61 (s, 1H), 2.87 (dd, J = 3.3, 13.2 Hz, 1H), 3.71 (s, 3H), 3.96 (dd, J = 2.4, 3.9 Hz, 1H), 5.55 (dd, J = 5.4, 11.4 Hz, 1H), 6.40 (br s, 1H), 7.40-7.43 (m, 2H). 0960-894X/$ -see front matter Ó
Synthetic Communications, 2007
An efficient synthesis of 1,8-naphthyridine-4(1H)-one sulfonamide derivatives by thermolysis of 2... more An efficient synthesis of 1,8-naphthyridine-4(1H)-one sulfonamide derivatives by thermolysis of 2-pyridylaminomethylene (Meldrum's acid derivative) starting from 4,6-dimethyl-2-aminopyridine (1) is described.
Quimica Nova, 2008
Sulfonamides obtained by reaction of 8-aminoquinoline with 4-nitrobenzenesulfonylchloride and 2,4... more Sulfonamides obtained by reaction of 8-aminoquinoline with 4-nitrobenzenesulfonylchloride and 2,4,6-triisopropylbenzenesulfonyl chloride were used to synthesize coordination compounds with CuII and ZnII with a ML2 composition. Determination of the crystal structures of the resulting zinc and copper complexes by X-ray diffraction show a distorted tetrahedral environment for the [Cu(qnbsa)2], [Cu(qibsa)2] and [Zn(qibsa)2] complexes in which the sulfonamide group acts as a bidentate ligand through the nitrogen atoms from the sulfonamidate and quinoline groups. The complex [Zn(qnbsa)2] crystallizes with a water molecule from the solvent and the Zn is five-coordinated and shows a bipyramidal-trigonal geometry. The electrochemical and electronic spectroscopy properties of the copper complexes are also discussed.
Acta Crystallographica Section E-structure Reports Online, 2007
ABSTRACT In the title compound, C17H16BrN3O3S, the C—N—S—C torsion angle between the pyrazole uni... more ABSTRACT In the title compound, C17H16BrN3O3S, the C—N—S—C torsion angle between the pyrazole unit and the bromobenzene ring is −117.3 (3)°. The phenyl ring and the pyrazole residue are twisted with respect to each other by an angle of 70.8 (2)°. One intermolecular N—H...O and two non-classical intermolecular C—H...O hydrogen bonds are observed in the crystal structure.
Acta Crystallographica Section E-structure Reports Online, 2006
The phytochemical investigation of the methanol crude extract obtained from Acosmium dasycarpum (... more The phytochemical investigation of the methanol crude extract obtained from Acosmium dasycarpum (Vog.) Yakovlev root bark led to the isolation of the quinolizidine alkaloids lupanine, acosmine, acosminine and lupanacosmine, as well as the diaza-adamantane alkaloids panacosmine and dasycarpumine. Lupanacosmine (4) and dasycarpumine (6) have been described for the first time herein.The phytochemical investigation of the methanol crude extract obtained from Acosmium dasycarpum (Vog.) Yakovlev root bark led to the isolation of the quinolizidine alkaloids lupanine, acosmine, acosminine, and lupanacosmine, as well as the diaza-adamantane alkaloids panacosmine, and dasycarpumine. Lupanacosmine (4) and dasycarpumine (6) have been described for the first time herein.
Allelopathy can offer new substances with herbicidal properties less harmful to the environment a... more Allelopathy can offer new substances with herbicidal properties less harmful to the environment and humans than the synthetic compounds traditionally used in agriculture. The aim of this work was to evaluate the effect of extracts of Annona crassiflora on germination and growth of Brachiaria brizantha, Euphorbia heterophylla and Ipomoea grandifolia, as well as to determine the effect of the most promising extract fraction on soybean (Glycine max). Thus, hydroalcoholic extracts from seeds, leaves and stems of A. crassiflora were prepared and evaluated in germination tests as well as root and hypocotyl development of the weeds. The extract of the most promising part of the plant was fractioned using solvents with increasing polarity order. The hydroalcoholic extract, prepared from A. crassiflora seeds was found to have the greatest effect on the weeds. Also, the germination of B. brizantha and E. heterophylla was completely inhibited by the extract. In general, the species were more sensitive to the ethyl acetate fraction, although this extract did not interfere in the soybean development. The results obtained allowed to conclude that A. crassiflora presents a good potential for the management of B. brizantha, E. heterophylla and I. grandifolia, in soybean post-emergence.
This paper describes the study of two alkaloids extracted from Pilocarpus Microphyllus (Rutaceae)... more This paper describes the study of two alkaloids extracted from Pilocarpus Microphyllus (Rutaceae): pilosine and epiisopilosine. These substances have potential application in the treatment of several diseases. In this work FT-Raman and the FT-IR spectra of pilosine and epiisopilosine were investigated at 300 K. Vibrational wavenumber and wave vector have been predicted using density functional theory (B3LYP) calculations with the 6-31 G(d,p) basis set. A comparison with experiment, allowed us to assign most of the normal modes of the crystals.
Leishmaniasis is one of the neglected diseases. High cost, systemic toxicity, and diminished effi... more Leishmaniasis is one of the neglected diseases. High cost, systemic toxicity, and diminished efficacy due to development of resistance by the parasites has a negative impact on the current treatment options. Thus, the search for a new, effective and safer anti-leishmanial drug becomes of paramount importance. Compounds derived from natural products may be a better and cheaper source in this regard. This study evaluated the in vitro anti-leishmanial activity of Spiranthera odoratíssima (Rutaceae) fractions and isolated compounds, using promastigote and amastigote forms of different Leishmania species. J774 A.1 macrophage was used as the parasite host cell for the in vitro assays. Evaluations of cytoxicity, nitric oxide (NO), interleukin-10 and in silico analysis were carried out. In vitro experiments showed that the fruit hexanic fraction (Fhf) and its alkaloid skimmianine (Skm) have a significant (P<0·001) effect against L. braziliensis. This anti-L. braziliensis activity of Fhf and Skm was due to increased production of NO and attenuation of IL-10 production in the macrophages at concentrations ranging from 1·6 to 40·0 μg/ml. The in silico assay demonstrated significant interaction between Skm and amino acid residues of NOS2. Skm is thus a promising drug candidate for L. braziliensis due to its potent immunomodulatory activity.(Received April 14 2011)(Revised May 31 2011)(Revised June 15 2011)(Accepted June 16 2011)(Online publication August 03 2011)
In the present study, the natural product 3-Methoxyquercetin, a flavonoid with potential antivira... more In the present study, the natural product 3-Methoxyquercetin, a flavonoid with potential antiviral activity, was characterized through infrared and Raman spectroscopies combined with Density Functional Theory calculation. The flavonoid was extracted from Strychnos pseudoquina St. Hil (Loganiaceae) by chromatographic techniques. The optimized molecular structure and calculated vibrational spectra were performed by B3LYP/6-31G (d,p) basis set. The optimized structure was compared with X-ray diffraction data of other flavonoids compounds, and the theoretical data are in good agreement with experimental ones. Fourier transform–Raman and –infrared spectra, as well as the assignment of the normal modes are also presented.► Synthesis of flavonoid. ► Physical characterization of a substance. ► Density Functional Theory, Raman and infra red studies.
The Schiff base 4-{[(1E)-(2-Hydroxyphenyl)methylidene]amino}-1,5-dimethyl-2-phenyl-1,2-dihydro-3H... more The Schiff base 4-{[(1E)-(2-Hydroxyphenyl)methylidene]amino}-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (C18H17N3O2) is a synthetic compound with a variety of scientific and technological applications, such as clinic, analytic and pharmacologic. In this work FT-Raman spectrum and FT-infrared spectrum of C18H17N3O2 were investigated at 300 K. Vibrational wavenumber and wave vector have been predicted using Density Functional Theory (B3LYP) calculations with the 6-31 G(d,p) basis set. The description of the normal modes was performed by means of the potential energy distribution. A comparison with experiment allowed us to assign most of the normal modes of the crystal.► Synthesis of a Schiff base with potential use as drug for tropical diseases. ► Physical characterization of a substance. ► Density Functional Theory, Raman and infra red studies of a potential drug.
Two 1,8–naphthyridines were synthesized and found to be fluorescent in solution. These compounds ... more Two 1,8–naphthyridines were synthesized and found to be fluorescent in solution. These compounds were studied in the presence of Cu+ and Cu2+ ions and it was verified that the metal causes the quenching of their fluorescence emission, due to the formation of complexes between the naphthyridine and the metal. A displacement assay was carried out in a DMSO–water mixture with the addition of various anions to the solutions of the complexes, and it was observed that these systems have a high capacity to selectively detect cyanide.