Constituintes químicos dos frutos de Copaifera langsdorffii Desf.

Phytochemical investigation of the hexane extract of fruit shells of Copaifera langsdorffii Desf. (Caesalpinioideae) afforded ent-kaur-16-en-19-oic acid, polyalthic acid, nivenolide and the mixture of caryophyllene oxide and ent-kaur-16-en-19-oic acid. The chloroform extract of unripe seeds led to the isolation of coumarin and the GC/MS analysis of the extract allowed the identification of 81.8% of the fatty acid composition after hydrolysis followed by methylation. The main fatty acid identified was oleic acid (33.1%). The isolation of all secondary metabolites was accomplished by modern chromatographic methods and the structure determination was accomplished by spectrometric methods (IR, MS, NMR ¹H and 13C).

Estudos termoanalíticos de sais de sódio e potássio de ditiocarbamatos em atmosfera oxidante

Thermoanalytical behavior of sodium and potassium salts of pyrrolidinedithiocarbamate (pyr), piperidineditiocarbamate (pip), morpholinedithiocarbamate (mor), hexametileneiminedithiocarbamate (hex), were investigated. In a first step the salts were synthesized and characterized by infrared spectroscopy (FTIR), ¹H and 13C nuclear magnetic resonance (NMR) and elementar analysis. Finally, thermal analytical (TG/DTG and DSC) studies were performed in order to evaluate the thermal stability, as well as the pathways of the thermal decomposition based in the intermediate and final decomposition products.

Salicilatos isolados de folhas e talos de Salix martiana Leyb. (Salicaceae)

Salix martiana Leyb. is an endemic species from the Amazon river floodplain areas (varzeas), of the State of Amazonas. Stems and leaves were extracted with dichloromethane, methanol and hydro-alcohol and these extracts were fractionated by using conventional chromatographic techniques. The major substances isolated, salicin and trichocarposide (6-0-p-coumaroyl salicin), were determined through analyses of NMR 1D (¹H and 13C) and NMR 2D (gHSQC and gHMBC). These compounds were isolated for the first time in Salix martiana Leyb. (Salicaceae). The percentage of these compounds in S. martiana is very high. The extracts were analyzed for their DPPH antioxidant capacity and the methanolic from the leaves and the hydro-alcoholic from the stems were the more active.

Estudo espectroscópico em elucidação estrutural de flavonoides de Solanum jabrense Agra & Nee e S. paludosum Moric

The NMR (RMN¹H, 13C, COSY, HMQC, HMBC, NOE-DIFF, NOESY) and mass spectra data analysis of sixteen flavonoids, including nine natural, 7-O-methylkanferol (ramnocitrin), 3,7-di-O-methylkanferol (kumatakenin), 3-O-methylquercetin, 3,7,3',4'-tetra-O-methylquercetin (retusin), 3,7,8,4'-tetra-O-methylgossipetin, 3,7,8,3',4'-penta-O-methylgossipetin, 7-O-methylapigenin (genkwanin), 3,7,8-tri-O-methylherbacetin, 7,4'- di-O-methylquercetin (ombuine), isolated from Solanum paludosum and S. jabrense, and seven prepared methyl and acetyl derivatives, are discussed according the substitution on the rings A, B and C.

Alcaloides iboga de Peschiera affinis (Apocynaceae) - Atribuição inequívoca dos deslocamentos químicos dos átomos de hidrogênio e carbono: atividade antioxidante

Six known alkaloids iboga type and the triterpen α- and β-amyrin acetate were isolated from the roots and stems of Peschiera affinis. Their structures were characterized on the basis of spectral data mainly NMR and mass spectra. 1D and 2D NMR spectra were also used to unequivocal ¹H and 13C chemical shift assignments of alkaloids. The ethanolic extract of roots, alkaloidic and no-alkaloidic fractions and iso-voacristine hydroxyindolenine and voacangine were evaluated for their antioxidative properties using an autographic assay based on β-carotene bleaching on TLC plates, and also spectrophotometric detection by reduction of the stable DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical.

Characterization of the major nutritional components of Caryocar brasiliense fruit pulp by nmr spectroscopy

Pequi (Caryocar brasiliense Camb.), a typical fruit of Brazilian Cerrado, is well known in regional cookery and used in folk medicine to treat various illnesses. Mass spectrometry and chromatographic methods have identified the organic composition of pequi fruit pulp; however, NMR spectroscopy is used for the first time to characterize the nutritional components of organic and aqueous-ethanolic extracts. This spectroscopic technique determined the triacylglycerols in the pequi organic fraction, which is constituted mainly by oleate and palmitate esters, and detected the carbohydrate mixtures as the major components of aqueous and ethanolic fractions, respectively. In this study, presence of phenolic compounds was only evidenced in the ethanolic fraction.

Alcaloides indólicos de cascas de Aspidosperma vargasii e A. desmanthum

Fractionation of extracts resulted in isolation and identification of indole alkaloids ellipticine and N-methyltetrahydroellipticine from A. vargasii and aspidocarpine from A. desmanthum. Identification of these compounds was achieved based on IR, MS, ¹H, 13C and 2-D NMR data and comparison to data in the literature.

Síntese e caracterização de complexos de platina(IV) com derivados N-benzilados da 1,3-propanodiamina

The present work describes the synthesis of a series of platinum(IV) complexes with N-benzyl 1,3-propanediamine derivatives. Since substitution of the axial ligands in the platinum(IV) complexes may alter their pharmacological properties, we have prepared complexes with different groups, such as hydroxide, chloride and acetate using a sequence of substitution reactions. The resulting complexes were fully characterized by IR, ¹H, 13C and 195Pt NMR spectroscopies, and elemental analysis.

Preparation of association compound between rhodium(II) citrate and β-cyclodextrin

Inclusion compound of rhodium(II) citrate with β-cyclodextrin in a 1:1 molar ratio was prepared using freeze-drying method. X-ray diffactometry, thermal analysis (TG/DTG/DSC), infrared and ¹H-NMR with ¹H spin lattice relaxation (¹H T1) measurements and 13C techniques were used to characterize the system prepared. The results indicated the formation of inclusion or association compounds between rhodium(II) citrate and β-cyclodextrin.

Flavonoids and a neolignan glucoside from Guarea macrophylla (Meliaceae)

This work describes the phytochemical study of the methanol extract obtained from leaves of Guarea macrophylla, leading to the isolation and identification of three flavonoid glycosides (quercetin 3-O-β-D-glucopyranoside, quercetin 3-O-b-D-galactopyranoside, kaempferol 7-O-β-D-glucopyranoside) and a neolignan glucoside, dehydrodiconiferyl alcohol-4-β-D-glucoside. All compounds were identified by a combination of spectroscopic methods (¹H, 1D, 2D NMR, 13C and UV), ESI-MS and comparison with the literature data. This is the first report of flavonoids in the genus Guarea and of a neolignan glucoside in the Meliaceae family.

Self-condensation of n-(N-propyl)butanimine: NMR and mass spectral analyses and investigation by theoretical calculation

The stability of N-propylbutanimine (1) was investigated under different experimental conditions. The acid-catalyzed self-condensation that produced the E-enimine (4) and Z-inimine (5) was studied by experimental analyses and theoretical calculations. Since the calculations for the energy of 5 indicated that it had a lower energy than 4, yet 4 was the principal product, the self-condensation of 1 must be kinetically controlled.

Authenticity study of Phyllanthus species by NMR and FT-IR Techniques coupled with chemometric methods

The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as "quebra-pedras" in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, ¹H HR-MAS NMR and ¹H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques.

Estudo fitoquímico e avaliação da atividade anti-inflamatória de Aeschynomene fluminensis vell. (Fabaceae)

Phytochemical investigation of Aeschynomene fluminensis leaves and branches led to isolation of the flavonoid glycosides kaempferol 3,7-di-O-α-L-rhamnopyranoside, kaempferol 7-O-α-L-rhamnopyranoside, kaempferol 3-O-apiofuranosil-7-O- rhamnopyranoside, quercitin 3-O-α-L-rhamnopyranoside, quercitin 3-O-arabinofuranoside, 8-β-D-glucopyranosyl 4',5,7-trihydroxyflavanone, the isoflavonoid 4',7-di-hydroxy-isoflavone, the dimer epicatechin-(2β→7, 4β→8)- epicatechin, the polyol 3-O-methyl-chiro-inositol and two steroids in sitosterol and stigmasterol mixture. These compounds were identified by NMR ¹H and 13C and compared with literature data. Anti-inflammatory activity of the crude methanolic extract and its fractions was evaluated.

Síntese e controle de qualidade da ureia enriquecida em 13C para diagnóstico da Helicobacterpylori (HP)

The aim of the study was to synthesize the urea (13CO(NH2)2), with 99% 13C atoms, and to perform a quality analysis for the diagnosis (breath test) of Helicobacter pylori. Furthermore, the process was submitted to economic analysis. The reaction was performed in a stainless steel reactor, lined with polytetrafluoroethylene, under low pressure and temperature. The synthesis method was shown to be appropriate (2.35 g; 81.9% yield), evidenced by physico-chemical and microbiological results, according to Brazilian legislation. The production and diagnosis costs were competitive compared with national and international market values, rendering this a valuable tool in clinical medicine.

Optimization and practical implementation of ultrafast 2D NMR experiments

Ultrafast 2D NMR is a powerful methodology that allows recording of a 2D NMR spectrum in a fraction of second. However, due to the numerous non-conventional parameters involved in this methodology its implementation is no trivial task. Here, an optimized experimental protocol is carefully described to ensure efficient implementation of ultrafast NMR. The ultrafast spectra resulting from this implementation are presented based on the example of two widely used 2D NMR experiments, COSY and HSQC, obtained in 0.2 s and 41 s, respectively.