Optimización de la síntesis de aldehído canfolénico a partir del epóxido de α-pineno con Cu/MCM-41 / Optimization of the synthesis of campholenic aldehyde from α-pinene epoxide with Cu/MCM-41 / Optimização da síntese de aldeído camfolênico desde epóxido de α-pineno com Cu/MCM-41

Resumen Se sintetizó el catalizador Cu/MCM-41 mediante impregnación húmeda incipiente y se caracterizó por DRX, XPS, TPD-NH3 y adsorción-desorción de N2. Se evaluó el efecto de diferentes condiciones de reacción (temperatura, tiempo, tipo de solvente y cantidad de catalizador) en la isomerización del epóxido de α-pineno para la obtención de aldehído canfolénico con el catalizador Cu/MCM-41, que no había sido reportado previamente para este tipo de reacción. Se partió de un diseño experimental central compuesto mediante análisis de superficie de respuesta. Se encontró que la mejor selectividad fue de 85% (5 mg de catalizador; 70 °C; 0,5 h y el uso de acetato de etilo como solvente). Adicionalmente, se determinaron los principales factores y sus combinaciones que tenían mayor significancia en la síntesis del aldehído ajustado a un modelo polinomial de segundo grado. Se encontró que los factores que tienen mayor influencia en la conversión son la cantidad de catalizador, tiempo de reacción, el tipo de solvente y el factor combinado entre la cantidad de catalizador y el tipo de solvente. En el caso de la selectividad hacia el producto deseado no se encontró ningún factor significativo.

Abstract The Cu/MCM-41 catalyst was synthesized by incipient wet impregnation and characterized by XRD, XPS, TPD-NH3, and N2 adsorption-desorption. The effect of different reaction conditions (temperature, time, type of solvent, and amount of catalyst) on the isomerization reaction of α-pinene epoxide was evaluated to obtain camphoric aldehyde with the Cu/MCM-41 catalyst, which had not been previously reported for this kind of reaction. The experiment was based on a central composite experimental design composed by response surface analysis. The best campholenic aldehyde selectivity was found to be 85% (5 mg of catalyst, 70 °C, 0.5 h and the use of ethyl acetate as a solvent). Furthermore, the main factors and their combinations that had the greatest significance in the synthesis were adjusted to a polynomial second order model. The factors with the main influence on conversion were the catalyst amount, reaction time, solvent type, and the combined factor between catalyst amount and the solvent type. In the case of campholenic aldehyde selectivity no significant factor was found.

Resumo O catalisador Cu/MCM-41, sintetizado pelo método de impregnação a umidade incipiente, foi caracterizado por DRX, XPS, TPD-NH3 e adsorção-dessorção de N2 e testado na reação de isomerização do epóxido de α-pineno. Diferentes condições de reação foram exploradas a partir de um desenho experimental central composto. A melhor seletividade de aldeído camfolênico encontrada foi de 85% (5 mg de catalisador; 70 °C; 0,5 h e acetato de etilo como solvente). Além disso, os principais fatores e as combinações entre eles que tiveram influência na síntese do aldeído camfolênico foram ajustados a um modelo polinomial de segunda ordem. Verificou-se que os fatores com a principal influência na conversão foram a quantidade de catalisador, o tempo de reação e o tipo de solvente e o fator combinado entre a quantidade de catalisador e o tipo de solvente. No caso da seletividade do aldeído camfolênico, não foi encontrado um fator significativo.

A Study on the Synthesis of Veratraldehyde / 昆明医科大学学报

Objective Veratraldehyde is an important pharmaceutical intermediate and chemical raw material. Taking common synthetic methods of Veratraldehyde into consideration, the study is aimed to further investigate a more efficient synthetic route in order to provide a solid foundation for the application of Veratraldehyde.Methods This article introduces an alternative method based on the Triton－B catalyzed olefin isomerization of methyl Eugenol followed by ozonation/reduction reaction.Results In the experiment,the optimal conditions was selected by investigating the influence of reaction time, reaction temperature and catalyst dosage on the yield of Veratraldehyde. The total yield of this 2－step reactions was 64% . Conclusion The above－mentioned synthesis method only requires raw materials that are easily acquired and its relative reaction conditions are mild, thus it will provide values in the industrial applications.

Obtainment, quantification and use of lactulose as a functional food - a review

Abstract Whey (milk serum) is produced by the dairy industry during the manufacture of cheese. In addition to being a valuable source of functional and nutritional proteins, whey also presents almost all the lactose from the original whole milk. However, many industries still consider the whey as an effluent, which can cause serious environmental problems when not properly treated. Therefore, it is important to develop alternatives for the adequate use of whey. The lactose obtained from whey permeate can be converted into lactulose, a prebiotic which may be metabolized in the intestine by probiotic bacteria, such as Lactobacillus sp. and Bifidobacterium sp., through enzymatic isomerization or by using alkaline catalysts, with minimal secondary reactions and high yield. This manuscript provides information about various techniques used to produce lactulose, its purification and analysis, as well as its mechanisms of action and alternative applications in food products and medicines.

Study on isomerization law of aescins A, B, C, and D / 中草药

Objective: To investigate the isomerization law of aescins A, B, C, and D under different conditions and optimize the isomerization process. Methods: Using the conversion of aescin C and D, and the content of impurity as index, single factor experiment was applied to evaluate the effect trends of isomerization from three parameters including pH value, reaction temperature and time. Then, central composite design-response surface method was used to estimate the relationship between the dependent and independent variables and to validate the optimal conditions. Results: According to the single factor experiment, the effect trends of three parameters on conversion of aescins C and D were analogous, and the isomerization happened under the conditions as follows: pH value of 5.0-10.0, reaction temperature of 45-85℃, and reaction time of 0.25-8 h. Based on the central composite design, the optimal conditions were predicted as follows: pH value was 6.9, reaction temperature was 54℃ and reaction time was 7.4 h. Under such conditions, the experimental values showed on significant difference from the predicted values. Conclusion: The isomerization of aescins A, B, C, and D could show a certain law under different conditions, and the optimal isomerization process is stable and available, which could provide a scientific basis of regulating the proportion of aescins A, B, C, and D during industrial production.

Photochemical and electrochemical studies on lanthanide complexes of 6-(hydroxymethyl) pyridine-2-carboxaldehyde[2-methyl-pyrimidine-4,6-diyl]bis-hydrazone / Estudios fotoquímicos y electroquímicos de complejos lantánidos de 6-(hidroximetil)piridin-2-carboxaldehído[2-metilpirimidina-4,6-diil]bishidrazona / Estuduios fotoquímicos e eletroquímicos do complexos lantanídeos do 6-(hidroximetil)piridin-2-carboxaldeído[2-metilpirimidina-4,6-diil]bis-hidrazona

Herein we report the synthesis of the 6-(hydroxymethyl)pyridine-2-carboxaldehyde[2-methyl-pyrimidine-4,6-diyl]bis-hydrazone by a condensation reaction between 6-(hydroxymethyl)picolinaldehyde with 4,6-(bis-hydrazino)-2-methylpyrimidine. This bis-hydrazone can be visualized as a two-arm system which exhibits photochemical induced [E,E]/[E,Z]/[Z,Z’] isomerizations and double coordination to metal centers. Configurational changes, upon UV light irradiation, were followed over time by ¹H NMR, establishing that isomerization, in both arms, is a consecutive reaction that follows first-order kinetics (k1= 4.06 x 10-4 s-1 and k2= 2.80 x 10-4 s-1). Furthermore, the synthesis of bis-hydrazone metal complexes with La and Sm (III) ions was achieved; subsequently, the absorption and emission properties of these complexes were studied, determining the fluorescence quantum yields, ΦLa= 0.2024 and ΦSm= 0.1413. Electrochemical studies of the complexes were conducted by square wave voltammetry, demonstrating that the bis-hydrazone and its complexes are electroactive species between +1.5 and -2.5 V.

Se reporta la síntesis de la 6-(hidroximetil)piridin-2-carboxaldehído[2-metilpirimidina-4,6-diil]bishidrazona mediante la reacción de condensación entre el 6-(hidroximetil)piconaldehído con la 4,6-(bishidracino)-2-metilpirimidina. Esta bishidrazona puede ser visualizada como un sistema de dos brazos los cuales exhiben isomerizaciones [E,E]/[E,Z]/[Z,Z’] fotoquímicamente inducidas y coordinación a centros metálicos. Los cambios configuracionales, después de irradiación UV, fueron seguidos en el tiempo mediante RMN ¹H estableciendo que la isomerización, en ambos brazos del sistema, corresponde a una reacción consecutiva que sigue una cinética de primer orden (k1= 4,06 x 10-4 s-1 and k2= 2,80 x 10-4 s-1). Además se prepararon complejos metálicos de La y Sm(III), seguidamente, las propiedades de absorción y emisión de dichos complejos fueron estudiadas calculando rendimientos cuánticos de fluorescencia de ΦLa= 0,2024 y ΦSm= 0,1413. Estudios electroquímicos de los complejos se llevaron a cabo a través de voltametría de onda cuadrada indicando que los compuestos preparados poseen potenciales redox dentro del rango de trabajo del solvente.

Reporta-se a síntese da 6-(hidroximetil)piridin-2-carboxaldeído[2-metilpirimidina-4,6-diil]bis-hidrazona mediante a reação de condensação entre o 6-(hidroximetil)piconaldeído e a 4,6-(bis-hidrazino)-2-metilpirimidina. Esta bis-hidrazona pode ser visualizada como um sistema de dois braços os quais exibem isomerizações [E,E]/[E,Z]/[Z,Z’] fotoquimicamente induzidas e coordenação com íons metálicos (dupla coordenação a íons metálicos). Após a irradiação UV, as mudanças configuracionais foram monitoradas com o tempo por RMN 1H. Essas medidas estabeleceram que a isomerização em ambos braços do sistema corresponde a uma reação consecutiva apresentando uma cinética de primeira ordem (k1= 4.06 x 10-4 s-1 e k2= 2.80 x 10-4 s-1). Além disso, os complexos metálicos de La e Sm(III) foram preparados e suas propriedades de absorção e de emissão foram estudadas, calculando os rendimentos quânticos de fluorescência de ΦLa= 0.2024 e de ΦSm= 0.1413. Estudos eletroquímicos dos complexos foram feitos através de voltametria de onda quadrada indicando que os compostos preparados possuem potenciais redox dentro da faixa de trabalho do solvente.

Síntese do piperonal a partir do óleo essencial de pimenta longa (Piper hispidinervium C. DC.) / Synthesis of piperonal from essential oil of long-pepper (Piper hispidinervium C. DC.)

O óleo essencial de pimenta longa (Piper hispidinervum C. DC) é rico em safrol, tornando-o suscetível à reação de isomerização para a obtenção de cis, trans-isosafrol. O presente artigo apresenta a etapa de eletroxidação dos isômeros cis, trans-isosafrol advindos da isomerização direta do óleo essencial de pimenta longa, apresentando 99,7 por cento de conversão em isosafrol glicol, o qual é sujeito à oxidação com conversão de 99 por cento em piperonal, este apresentando 84,9 por cento de pureza.

The essential oil of long-pepper (Piper hispidinervum C. DC) is rich in safrole, then susceptible to isomerization reaction to obtain cis, trans-isosafrole. In this paper it is presented the eletroxidation of cis, trans-isosafrole from direct isomerization of essential oil of long-pepper, with 99,7 percent of convertion to isosafrole glicol, that it is react by oxidation to convert 99 percent into piperonal with 84,9 percent purity.

Isomerização do óleo essencial de pimenta-longa (Piper hispidinervium C. DC) para a obtenção de isosafrol / Isomerization of essential oil of (Piper hispidinervium) C. DC to obtain isosafrole

As piperáceas brasileiras apresentam propriedades para serem utilizadas, entre outras aplicações, como inseticidas e antifúngicos. Dentre as piperáceas, pode-se citar a Piper hispidinervum C. DC. De suas folhas e dos talos finos extrai-se um óleo essencial rico em safrol, que é utilizado pela indústria como matéria-prima na manufatura, por exemplo, do piperonal. A sequência natural do processo para a obtenção do piperonal é o de submeter o safrol obtido da concentração do óleo essencial à isomerização para seu correspondente isômero estável chamado isosafrol. Apresenta-se neste artigo, por sua vez, a síntese do isosafrol diretamente do óleo essencial de pimenta-longa (Piper hispidinervium C. DC). Este óleo essencial apresenta o safrol como constituinte majoritário, possibilitando a sua isomerização para a produção de isosafrol, que é empregado nas indústrias farmacêuticas e de fragrâncias. O objetivo deste trabalho é o de apresentar a obtenção do isosafrol sem a necessidade da etapa de separação do safrol do óleo essencial de pimenta-longa. Para tanto, foram realizados ensaios de isomerização do óleo essencial, obtendo-se uma solução contendo 79,4 % da mistura cis, trans-isosafrol. Ressalte-se que o óleo essencial continha 86,4 % de safrol, resultando em alto rendimento na sua conversão a cis, trans-isosafrol de 97,1 %.

The Brazilian peppers present proprieties that can be used in fragrance and pharmaceutical industries, for example. One these pepper is long pepper (Piper hispidinervium C. DC.), who its essential oil is rich in safrole. Safrole is an important compound with application in several industries, such as pharmaceutics, cosmetics. After its chemical conversion, for example, it is possible to obtain heliotropin, a fixative agent for fragrances. The sequence to obtain the heliotropin is by safrole isomerization, that, initially, produce isosafrole. In this work, however, presents the synthesis of isosafrole directly from essential oil of Piper hispidinervium C. DC. In this case, the isomerization of essential oil was done getting 79,4 % of cis, trans-isosafrole mixture. The essential oil presented 86,4 % of safrole, resulting in 97,1 % yield to cis, trans-isosafrole.

Isomerización dll 1-ciclohexiloctano en zeolitas h-zsm-22 y h-y / 1-cyclohexyloctane isomerizationinto h-zsm-22 and h-yzeolites / Isoerizacáo de 11-ciclohexiloctano na zeólitas h-zsm-22 yh-y

En este trabajo se presentan los resultados de la evaluación energética de los intermediarios de la isomerización del 1-ciclohexiloctano en dos etapas. La primera etapa corresponde a la isomerización del 1-ciclohexiloctano en fase gaseosa vía carbocationes clásicos, usando el nivel de teoría DFT/B3LYP y conjunto de funciones base 6-31G. En la segunda etapa se desarrolló la coordenada de reacción de la isomerización del 1-ciclohexiloctano en presencia de zeolitas acidas H-ZSM-22 y H-Y empleando el método ONIOM, usando los niveles de teoría B3LYP/ 6-31G:UFF. Los resultados muestran diferencias significativas entre las reacciones en fase gaseosa y condensada. Estas diferencias ponen de manifiesto la influencia del confinamiento cuántico que sufren las moléculas al interior de los sistemas microporosos del tipo zeolitas.

We studied the isomerization mechanism of 1-cycle-hexyloctane either in gas phase or inside zeolites using quantum models. In the gas phase the reaction was simulated following the classical scheme via carbocations. On the other hand, the isomerization reaction was modeled with 1-cycle-hexyloctane inside HZSM-22 and H-Y acid zeolites (condensed phase). We used the ONIOM(B3LYP/6-31G: UFF) hybrid method to study such behavior in both zeolites. Our results show that the reaction follows different pathways when the simulations are performed either in gas phase or within the zeolites pores. Such differences show the importance of quantum confinement inside microporous materials.

Neste trabalho foram desenvolvidos os mecanismos das reacção de isomerização de 1-ciclo-hexil-octano através de duas etapas. Na primeira etapa, a reação foi realizada como carbocátions clasicos, utilizando-se o método DFT/B3LYP e as funções básicas 6-31G. Na segunda, a reação de isomerização de 1-ciclo-he-xil-octano foi estudou em zeolites ácido H-ZSM-22 e H-Y utilizando-se o método híbrido ONIOM o nível B3LYP e funções básicas 6-31G.

Effect of Phosphorylation on Peptidyl-Prolyl Imide Bond cis/trans Isomerization of Peptides With Xaa-Pro Motif / 生物化学与生物物理进展

The peptidyl-prolyl imide bond cis/trans isomerization of Xaa-Pro motif in the peptide and protein plays an important role to influence their conformation and function. Here, a series of model peptides including phosphorylated and its unphosphorylated counterparts were designed and synthesized. Preliminary 1H NMR experiments and molecular dynamics (MD) simulation were used to analyze the peptidyl-prolyl cis/trans imide bond isomerization. The data indicated that the side-chain O-phosphorylation of the Xaa residues preceding proline affected evidently the isomerization and thereby regulated the peptides conformations. The charges of the phosphate moiety as well as their steric effects might be the driving force for the conformational changes of these phosphopeptides.Moreover, the obtained most stable multiple configurations and their statistic cis/trans concentration distribution in MD simulation were basically consistent with the NMR experiments, which demonstrated that phosphorylation increased the cis conformation of the peptide and the maximum cis ratio is given while the phosphate group has no negative charge.

Proline peptide isomerization and protein folding.

The unfolding-refolding of proteins is a cooperative process and, as judged by equilibrium properties, occurs in one step involving the native, N, and the unfolded U, conformational states. Kinetic studies have shown that the denatured protein exists as a mixture of slow-(US) and fast-(UF) refolding forms produced by proline peptide cis-trans isomerization. Proline residues in UF are in the same configuration as in the native protein while they are in non-native configuration in US. For protein folding to occur quickly US must be converted into UF. The fact that the equilibrium and kinetic properties of US UF are the same as those found for proline cis-trans isomerization taken together with the absence of slow phase in the kinetics of refolding of a protein devoid of proline, support this view. However, the absence of a linear correlation between half-time of reactivation of denatured enzymes and their proline-contents, as well as the dissimilarities in the kinetic properties of US UF in unfolding and refolding experiments are not consistent with the model. Conformational energy calculation and experimental results on refolding of proteins suggest that some proline residues are non-essential. They will not block protein folding even in wrong isomeric form. The native-like folded structure with incorrect proline isomers will serve as intermediate state(s) in which these prolines will more readily isomerize to the correct isomeric form. The picture becomes more complex when one considers the consequence of cis-trans isomerism of non-proline residues on protein folding.