Fabio Simonelli

A simple methodology for the determination of fatty acid composition in edible oils through 1H NMR spectroscopy

A simple methodology for the determination of the fatty acid composition of edible oils through 1H NMR is proposed. The method is based on the fact that all fatty acid chains are esterified to a common moiety, glycerol, and the quantification is done directly in the 1H NMR spectra through the relationship between the areas of a characteristic signal of each fatty acid and a signal of the glycerol moiety, without the use of mathematical equations. The methodology was successfully applied to determine the fatty acid composition of several edible oils, with equivalent results to those given by the AOAC Official method by gas chromatography. Its main advantages are simplicity and the lack of need for sample pre‐treatment such as derivatization or extraction. Copyright

Alarm pheromone system of stink bug Piezodorus guildinii (Heteroptera: Pentatomidae)

Os compostos utilizados pelo percevejo da soja Piezodorus guildinii como feromonio de alarme foram caracterizados atraves da analise da composicao quimica das secrecoes da glândula metatoracica dos insetos adultos. Alem dos hidrocarbonetos caracteristicos, (E)-2-hexenal e (E)-4-oxo-2-hexenal foram detectados como constituintes majoritarios. Tais compostos ja foram previamente descritos como feromonio de alarme em outras especies de pentatomideos.

Oxidative coupling of 4-substituted 2-methoxy phenols using methyltributylammonium permanganate in dichloromethane

Abstract Dimers of 4-substituted 2-methoxy phenols were prepared using methyltributylammonium permanganate (MTBAP) in dichloromethane. This methodology allows the selective coupling of such compounds preserving other moieties easily oxidized by permanganate anion in aqueous solution.

Oxazoline cuprate addition to nitroalkenes: a new route approaching γ-amino acids

Abstract Current studies of oxazoline cyanocuprates addition to conjugated nitroalkenes, and their improved reactivity when compared to lithium oxazoline anions, has shown to be an efficient method for the synthesis of a variety of γ-nitrooxazolines, an interesting intermediate of γ-amino acids.

Males Are Attracted by Female Traps: A New Perspective for Management of Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae) Using Sexual Pheromone

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.

A new approach to the synthesis of (±)-methyl jasmonate and (±)-baclofen via conjugated addition of oxazoline cyanocuprate to Michael acceptors

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).

Synthesis of enaminones with stationary stereochemistry

Cinco enaminonas 4a-e, derivadas da reacao 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 tambem foram analisadas pela tecnica de difracao de raios-X. A enaminona 4a cristalizou-se no sistema monoclinico P2(1)/n, grupo espacial com a = 9.1450(20) A, b = 10.5150(20) A, c = 9.5670(20) A, b = 106.21(30)°, Z = 4. A enaminona 4b cristalizou-se no sistema monoclinico P2(1)/c, grupo espacial com a = 16.0520(30) A, b= 26.0460(50) A, c = 12.3520 (20) A, b= 111.900(30)°, Z = 4. Todas as cinco enaminonas possuem uma extensa delocalizacao de eletrons p e a mesma configuracao para a ligacao dupla, a qual e fixada por ponte de hidrogenio intramolecular entre os grupamentos NH e C=O.

Grape juice quality control by means of ¹H nmr spectroscopy and chemometric analyses

This work shows the application of 1H NMR spectroscopy and chemometrics for quality control of grape juice. A wide range of quality assurance parameters were assessed by single 1H NMR experiments acquired directly from juice. The investigation revealed that conditions and time of storage should be revised and indicated on all labels. The sterilization process of homemade grape juices was efficient, making it possible to store them for long periods without additives. Furthermore, chemometric analysis classified the best commercial grape juices to be similar to homemade grape juices, indicating that this approach can be used to determine the authenticity after adulteration.

Synthesis of the minor sex pheromone component of two brazilian soybean stink bugs (Het.: Pentatomidae), and an analogue compound

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.

2-oxazolinas quirais: algumas aplicações como indutores de assimetria em reações orgânicas

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.