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Alkylation or arylation of selenide or diselenide anions is a well-established method to obtain organoselenium compounds. Nevertheless, detecting inorganic selenium anions using 77Se NMR is still a challenge. In a previous work, alkylation of Na2Se was found sometimes to yield a mixture of organyl selenides/diselenides in variable amounts. In the literature, this mixture is sometimes attributed to the oxidation of an intermediate alkyl selenol during the extraction. To understand this process, a series of experiments using 77Se NMR were performed. It was clear from the 77Se NMR experiments that NaHSe− and S e 2 2 − formation was very dependent on the NaBH4 stoichiometry used. After alkylation, alkyl selenol and dialkyl diselenide were identified, proving they were not formed during the extraction step. As a result, alkyl selenols, dialkyl selenides or dialkyl diselenides with a high purity degree were obtained. To achieve high purity and selectivity of the organoselenium compound, the stoichiometric ratio between Se0/NaBH4 has to be carefully measured.

The field responses of Diabrotica speciosa (Germar) to traps baited with adults were studied as an suggestion of the pheromone production. Firstly, an assay to settle a suitable height placement to capture D. speciosa was carried out in common beans, Phaseolus vulgaris L., field. Traps placed at 0.25-m height captured ca. 3.5 times more beetles than 0.5, 0.75 and 1.0-m traps. The responses to virgin females and males of two ages (younger = 24 to 72h and older = 72 to 120h after adult emergence), mated females and males were assessed in common bean interplanted among coffee, Coffea arabica L., field. Virgin females baited traps captured ca. 22 times (younger) and 13 times (older females) more male beetles than control traps. Captures were ca. 70% more effective using younger females. None of the other treatments improved trap attraction. These results strongly indicated that there is a female-produced sexual pheromone in D. speciosa. As respostas de Diabrotica speciosa (Germar) para armadilhas com adultos foram estudadas como sugestão da produção de feromônio. Inicialmente, um ensaio para estabelecer a altura adequada para colocação de armadilhas para capturar D. speciosa foi conduzido em campo de feijão. Armadilhas colocadas a 0,25 m de altura capturaram cerca de 3,5 vezes mais adultos do que a 0,5; 0,75 e 1,0 m. As respostas para fêmeas e machos virgens de duas idades (mais novos = 24 a 72h e mais velhos = 72 a 120h após emergência de adultos), fêmeas e machos copulados foram avaliadas em campo de feijão consorciado com café, Coffea arabica L. Armadilhas com fêmeas virgens capturaram cerca de 22 (mais jovens) e 13 vezes (mais velhas) mais adultos machos do que as testemunhas (armadilhas sem insetos). Capturas foram cerca de 70% mais efetivas usando fêmeas mais jovens. Nenhum dos outros tratamentos aumentou as capturas nas armadilhas. Os resultados indicam que há um feromônio sexual produzido por fêmeas em D. speciosa.

The stink bugs Euschistus heros and Piezodorus guildinii (Heteroptera: Pentatomidae) are economically important soybean pests in Brazil. An intriguing characteristic of these species is the fact that they use the same chemical compounds as sex pheromone, e.g., methyl 2,6,10-trimethyldodecanoate (1) (minor) and methyl 2,6,10-trimethyltridecanoate (2). In order to investigate the specific biological function of these molecules and to increase the knowledge of the communication system of each species, we have synthesized the minor component 1 and an analogue compound, methyl 2,6,10-trimethyltetradecanoate (3). These compounds will be tested on indoor bioassay, in addition with the previously synthesized major component 2. Os percevejos Euschistus heros e Piezodorus guildinii (Heteroptera: Pentatomidae) são importantes pragas da cultura da soja no Brasil. Uma característica marcante nestas espécies é o fato de que ambas se utilizam das mesmas estruturas químicas como feromônios sexuais, ou seja, os ésteres metílicos 2,6,10-trimetildodecanoato de metila (1) (minoritário) e o 2,6,10-trimetiltridecanoato de metila (2). No intuito de se verificar a exata função biológica destas estruturas e melhor entender o sistema de comunicação de cada espécie, realizou-se a síntese do componente minoritário 1 juntamente com um composto análogo, o 2,6,10-trimetiltetradecanoato de metila (3). Tais compostos serão submetidos a testes em laboratório, juntamente com o componente majoritário 2, já previamente sintetizado.

This article summarizes how chiral 2-oxazolines have been employed as inducers of asymmetry in many kinds of organic reactions, including the more recent examples reported in which chiral bis(oxazolines) have been complexed in situ with transition metals and utilized to induce the stereoselectivity of some reactions.

The success of cancer treatment is directly related to early detection before symptoms emerge, although nowadays few cancers can be detected early. In this sense, 1H nuclear magnetic resonance (1H NMR)-based metabonomics was used to identify metabolic changes in biofluid as a consequence of tumours growing in mice. Through partial least squares discriminant analysis (PLS-DA) analysis of 1H NMR spectra from serum samples it was possible to diagnose Ehrlich ascites and Sarcoma 180 tumours five and ten days after cell inoculation, respectively. Lipids, lipoproteins and lactate were the main biomarkers at onset as well as in the progress of carcinogenic process. Thus, NMR-based metabonomics can be a valuable tool to study the effects of tumour establishment on the chemical composition of biofluids.

Conjugate additions of lower order and higher order cyano cuprates containing the cis -2-tri- n -butylstannylvinyl group to cycloalkenones have been studied. The higher order cuprates were more reactive towards hindered enones such as 4,4- dimethylcyclohexenone and 2,4,4-trimethylcyclohexenone, and produced higher yields with the base-sensitive acetonide of cis -4,5-dihydroxycyclohexenone.

Introduction of a synthon equivalent to a carboxymethyl anion to enones and nitroalkenes, through a 1,4-addition reaction of 2,4,4-trimethyl-2-oxazoline cyanocuprate 3, proved to be an interesting methodology for the synthesis of natural products such as (±)-methyl jasmonate (1) and (±)-baclofen (2). A introdução de um grupamento equivalente ao ânion carboximetil a enonas e nitroalquenos através da reação de adição 1,4 do cianocuprato da 2,4,4-trimetil-2-oxazolina 3, resulta numa metodologia interessante para a síntese de produtos naturais como (±)-metil jasmonato (1) e (±)-baclofen (2).

Five enaminones 4a-e derived from the reaction of 2,4,4-trimethyl-2-oxazoline anion with ethyl acetate, ethyl benzoate, ethyl cyclohexanoate, ethyl hexanoate and ethyl p-methyl benzoate, respectively, were obtained and characterized by 13C-NMR, ¹H-NMR, FTIR, and mass spectral analysis. The enaminones 4a and 4b were also analysed by X-ray diffraction. Enaminone 4a crystallized in the monoclinic P2(1)/n space group with a = 9.1450(20) Å, b = 10.5150(20) Å, c = 9.5670 (20) Å, beta= 106.21(30)°, Z = 4. Enaminone 4b crystallized in the monoclinic P2(1)/c space group with a = 16.0520(30) Å, b = 26.0460(50) Å, c = 12.3520 (20) Å, beta = 111.900(30)°, Z = 4. All five enaminones were found to have an extensive pi electron delocalization and to have the same configuration where the double bond is trapped by an internal hydrogen bond between the NH and the C=O. Cinco enaminonas 4a-e, derivadas da reação do ânion da 2,4,4-trimetil-2-oxazolina com acetato de etila, benzoato de etila, ciclohexanoato de etila, hexanoato de etila e p-metil benzoato de etila, respectivamente, foram preparadas e caracterizadas por RMN¹H, RMN13C, FTIR e EM. As enaminonas 4a e 4b também foram analisadas pela técnica de difração de raios-X. A enaminona 4a cristalizou-se no sistema monoclínico P2(1)/n, grupo espacial com a = 9.1450(20) Å, b = 10.5150(20) Å, c = 9.5670(20) Å, beta = 106.21(30)°, Z = 4. A enaminona 4b cristalizou-se no sistema monoclínico P2(1)/c, grupo espacial com a = 16.0520(30) Å, b= 26.0460(50) Å, c = 12.3520 (20) Å, beta= 111.900(30)°, Z = 4. Todas as cinco enaminonas possuem uma extensa delocalização de elétrons pi e a mesma configuração para a ligação dupla, a qual é fixada por ponte de hidrogênio intramolecular entre os grupamentos NH e C=O.

A stereoselective synthesis of (3E,5Z)-dodecadienyl acetate, the sex pheromone of the leafroller moth Bonagota cranaodes, was efficiently carried out using a methodology based on the coupling of Z-alkenyl cuprate with 4-iodo-3-butyn-1-ol in the key step. O acetato de (3E,5Z)-dodecadienila, feromônio sexual da lagarta enroladeira da maçã, Bonagota cranaodes (Lepidoptera: Tortricidae), foi estereosseletivamente sintetizado empregando-se uma metodologia envolvendo o acoplamento de Z-alquenil cuprato com 4-iodo-3-butin-1-ol, como etapa chave.

As an extension to our work on intramolecular annulations via silyloxycyclopropane derived anions, we have investigated the chemistry of cyclopentyl cyclopropane systems, 6-9, in an effort to prepare stereospecifically functionalized hydrindenones. The intramolecular closures of the cyclopropane-derived anions were less stereoselective and more complicated than the corresponding cyclohexyl systems. Nevertheless, modest yields of isomeric hydrinenones such as 20 and 21 were obtained as well as several products derived from a prototropic shift to form the cyclopentanone enolates. These latter products possessed the 5,5-pentalenone systems, 22 and 23. Como uma extensão de nosso trabalho em anelações intramoleculares via anions derivados de sililoxiciclopropanos, investigamos a química dos sistemas ciclopentilciclopropanos 6-9, em um esforco visando a preparação de hidrindenonas estereoespecificamente funcionalizadas. As ciclizações intramoleculares de anions derivados do ciclopropano foram menos estereosseletivas e mais complicadas do que aquelas com o corresponente sitema cicloexila. Entretanto, rendimentos modestos de hidrindenonas, tais como 20 e 21, foram obtidos, assim como vários produtos derivados a partir de um deslocamento prototrópico que gerou enolatos de ciclopentanona. Estes últimos produtos possuem os sistemas 5,5-pentalenônicos 22 e 23.

In this article we describe the construction of two cooling systems with an immersion probe which will allow one to work at temperatures of either -40ºC or -60ºC. The two systems were constructed with readily available components and have been used daily for the last year in our laboratory to carry out reactions at low temperature or to cool down traps of vacuum pumps, reducing our need of dry-ice or liquid nitrogen.