Much is said and written regarding alchemy all across the world, in what could be called a renaissance of alchemical studies. However, relatively little is done in terms of actual alchemical laboratory work. The aim of the project described herein was to show how crucial the development of technical alchemical practice was along the centuries, in the discovery of an immense number of substances, processes and operations, which were of paramount importance in the establishment of modern chemistry. Alchemy is often derided in many circles. On the contrary, for two thousand years it constituted the basis of humankind’s understanding of the material world and the changes undergone by compounds and materials. Here we present an experimental reconstitution of several alchemical discoveries of great importance, using old descriptions followed by modern characterizations. The results were often startling and demonstrated how ancient wisdom bore fruit in different ways, even in the absence of our present-day means of analysis.
ABSTRACT The triterpene lupeol (1) and some of its esters are secondary metabolites produced by species of Celastraceae family, which have being associated with cytotoxic activity. We report herein the isolation of 1, the semi-synthesis of eight lupeol esters and the evaluation of their in vitro activity against nine strains of cancer cells. The reaction of carboxylic acids with 1 and DIC/DMAP was used to obtain lupeol stearate (2), lupeol palmitate (3) lupeol miristate (4), and the new esters lupeol laurate (5), lupeol caprate (6), lupeol caprilate (7), lupeol caproate (8) and lupeol 3’,4’-dimethoxybenzoate (9), with high yields. Compounds 1-9 were identified using FT-IR, 1H, 13C-NMR, CHN analysis and XRD data and were tested in vitro for proliferation of human cancer cell activity. In these assays, lupeol was inactive (GI50> 250µg/mL) while lupeol esters 2 -4 and 7 - 9 showed a cytostatic effect. The XRD method was a suitable tool to determine the structure of lupeol and its esters in solid state. Compound 3 showed a selective growth inhibition effect on erythromyeloblastoid leukemia (K-562) cells in a concentration-dependent way. Lupeol esters 4 and 9 showed a selective cytostatic effect with low GI50 values representing promising prototypes for the development of new anticancer drugs.
Dois novos friedelanos, 1 e 2, e cinco triterpenos pentacíclicos conhecidos foram isolados dos galhos de Maytenus robusta. Suas estruturas químicas foram identificadas como 3,16-dioxo-29-hidroxifriedelano (1), 3-oxo-16b,29-di-hidroxifriedelano (2), 3-oxofriedelano (3), 3b-friedelinol (4), 3,16-dioxofriedelano (5), 3-oxo-29-hidroxifriedelano (6) e 3,16-dioxo-12a-hidroxifriedelano (7). A estrutura e estereoquímica dos triterpenos 1 e 2 foram estabelecidas por infravermelho (IR), ressonância magnética nuclear (NMR) 1D/2D, espectrometria de massas de alta resolução com ionização química à pressão atmosférica (HR-APCIMS) e difração de raios X de pó. A atividade citotóxica in vitro dos triterpenos 1 a 6 foi avaliada frente a células de câncer de mama murino. Os triterpenos 1 e 2 apresentaram atividade citotóxica contra células 4T1 em baixa concentração.
Two new friedelane-type compounds 1 and 2 and five known pentacyclic triterpenes were isolated from branches of Maytenus robusta. Their structures were identified as 3,16-dioxo-29-hydroxyfriedelane (1), 3-oxo-16b,29-dihydroxyfriedelane (2), 3-oxofriedelane (3), 3b-friedelinol (4), 3,16-dioxofriedelane (5), 3-oxo-29-hydroxyfriedelane (6), and 3,16-dioxo-12a-hydroxyfriedelane (7). The structures and the stereochemistry of triterpenes 1 and 2 were established through infrared (IR), 1D/2D nuclear magnetic resonance (NMR), high-resolution atmospheric pressure chemical ionization mass spectrometry (HR-APCIMS) spectral data and powder X-ray diffraction. The in vitro cytotoxic property of triterpenes 1 to 6 on 4T1 murine breast cancer cells was evaluated. The triterpenes 1 and 2 showed cytotoxic activity against 4T1 cells at a lower concentration.
Three samples of hydrotalcite-like materials (HTC) were synthesized and their structural characteristics were compared with two HTCs obtained commercially. Thermal analyses, FT-IR, PXRD and textural analyses were used to investigate the structural differences between commercial and synthetic samples. Particularly, the memory effect was observed at temperature higher than 600 ºC. The Rietveld refinements were obtained with expressive accuracy and the statistical parameters of goodness of fit are quite satisfactory. In conclusion, the procedures adopted in synthesis of HTC produced crystalline materials with high surface area materials.
Friedelin molecular conformers were obtained by Density Functional Theory (DFT) and by ab initio structure determination from powder X-ray diffraction. Their conformers with the five rings in chair-chair-chair-boat-boat, and with all rings in chair, are energy degenerated in gas-phase according to DFT results. The powder diffraction data reveals that rings A, B and C of friedelin are in chair, and rings D and E in boat-boat, conformation. The high correlation values among powder diffraction data, DFT and reported single-crystal data indicate that the use of conventional X-ray diffractometer can be applied in routine laboratory analysis in the absence of a single-crystal diffractometer.
Thermogravimetry (TG) and differential scanning calorimetry (DSC) are used in pharmaceutical studies for drugs characterization, purity, formulations compatibility, polymorphism identification, stability evaluation, and thermal decomposition of drugs and pharmaceutical formulations. Simvastatin showed fusion at 138.5 ºC and thermal stability up to 248 ºC. Simvastatin was incompatible with preservative excipient butylhydroxyanisole (BHA) performing a process of crystal amorphization. The drug showed morphological polymorphism, where it has the same unit cell but with different crystal habits according to the recrystallization solvent.
O beneficiamento industrial do caulim envolve a remoção de óxidos e hidróxidos de ferro e outras impurezas, que conferem coloração indesejável ao produto final e depreciam seu valor comercial, particularmente se destinado à indústria de papel. A lixiviação química, na linha de processamento industrial, pode ser feita com tratamentos com hipossulfito de sódio, zinco metálico e ácidos sulfúrico e fosfórico, para redução, solubilização e remoção de compostos ferruginosos. A fim de minimizar o impacto ambiental, o efluente ácido, procedente da etapa de lixiviação, deve ser inicialmente neutralizado, usualmente por óxido de cálcio. O resíduo sólido resultante contém fósforo, zinco e cálcio, entre outros nutrientes, o que sugere seu uso como fonte de macro e micronutrientes. O principal objetivo do presente estudo foi avaliar o uso do resíduo sólido como fertilizante agrícola, em experimentos de incubação em casa de vegetação, em amostras de dois solos: um de textura média e outro argiloso. A pequena alteração do pH do solo, em função da aplicação do resíduo, não constitui fator limitante à sua aplicação na agricultura. A evolução das concentrações de cálcio trocável, e fósforo e zinco extraíveis por Mehlich-1, em função do tempo de incubação, confirmam a potencialidade de uso do resíduo industrial como fertilizante agrícola.
The industrial refining of kaolin involves the removal of iron oxides and hydroxides along with other impurities that cause discoloration of the final product and depreciate its commercial value, particularly undesirable if destined to the paper industry. The chemical leaching in the industrial processing requires treatments with sodium hyposulfite, metallic zinc, or sulfuric and phosphoric acids, in order to reduce, dissolve and remove ferruginous compounds. To mitigate the environmental impact, the acidic effluent from the leaching process must be neutralized, usually with calcium oxide. The resulting solid residue contains phosphorous, zinc, and calcium, among other essential nutrients for plant growth, suggesting its use as a macro and micronutrient source. Samples of such a solid industrial residue were used here to evaluate their potential as soil fertilizer in an incubation greenhouse experiment with two soil samples (clayey and medium-textured). The small pH shift generated by applying the residue to the soil was not a limiting factor for its use in agriculture. The evolution of the concentrations of exchangeable calcium, and phosphorous and zinc extractability by Mehlich-1 extractant during the incubation period confirms the potential use of this industrial residue as agricultural fertilizer.
Nickel- and cobalt-doped magnetites were prepared by a co-precipitation method and studied in some detail, in an effort to identify some effects of the doping cations on the magnetic, crystallographic and morphological properties of the resulting spinel. The synthetic samples were characterized by conventional chemical analysis, powder X-ray diffractometry, Mössbauer spectroscopy, saturation magnetization and scanning electron microscopy. From chemical analysis, the continuous increase of Ni2+ or Co2+ is accompanied by a simultaneous decrease of the Fe2+ contents, in the spinel structure. The magnetization values also decrease continuously with increasing doping cation contents. Mössbauer parameters are characteristic of substituted magnetites and indicate the presence of a single phase only. Based on the inverted intensities of the lines 1 (leftmost, on the negative Doppler velocity scale) and 2 of Mössbauer spectra of doped samples, relatively to the pure magnetite, it was assumed that the isomorphical substitution occurs preferentially on octahedral coordination sites of the spinel structure. The coercive field of these ferrites decrease steadily with Ni2+ but increases with Co2+ contents, reaching a maximum at x = 0.38, in the general formula Co xFe3-xO4 .