MaxPHOS is an active and robust P-stereogenic ligand for asymmetric catalysis. The presence of an À NH À bridge between the two phosphine moieties allows the NH/PH tautomerism to take place. The neutral ligand, in which the NH form predominates, is an air-sensitive compound. However, protonation of MaxPHOS leads to the stable PH form of the ligand, in which the overall positive charge is distributed on both P centers. This protonation turns the MaxPHOS·HBF 4 salt 3 into an airstable compound both in the solid state and in solution.The salt 3 is also a convenient precursor for the preparation of rhodium(I) complexes by direct ligand exchange with the complexFinally, the corresponding rhodium(I)-MaxPHOS complex was tested in the asymmetric hydrogenation of a wide range of substrates. The complex proved to be a highly selective and robust system in these reactions.

Aims Cells limit the cell number of dense biofilms by releasing self‐inhibitory molecules. Here, we aim to assess the effectiveness of yeast quorum sensing (QS) molecules and the antifungal agent natamycin against yeast biofilms of strains commonly isolated from fruit juice ultrafiltration membranes. Methods and Results Yeast QS molecules, such as tyrosol, 2‐phenylethanol and farnesol, were detected by solvent extraction and HS‐SPME GC‐MS in Candida tropicalis cultures. The effect of QS molecules on mono‐ and multispecies biofilms formed by Rhodotorula mucilaginosa, C. tropicalis, Candida krusei and Candida kefyr was evaluated by plate count and epifluorescence microscopy. Farnesol caused a decrease in cell number and disrupted mono‐ and multispecies yeast biofilms during adhesion (0·6 mmol l−1). 2‐phenyl ethanol 1·2 mmol l−1 stimulated biofilm density and increased cell number in both mono‐ and multispecies biofilms, while tyrosol did not show effects when tested against C. tropicalis biofilms (0·05–1·2 mmol l−1). Natamycin caused a strong decrease in cell number and disruption of biofilm structure in C. tropicalis biofilms at high concentrations (0·3–1·2 mmol l−1). The combination of farnesol 0·6 mmol l−1 and natamycin at 0·01 mmol l−1, the maximum concentration of natamycin accepted for direct addition into fruit juices, effectively reduced cell counts and disrupted the structure of C. tropicalis biofilms. Conclusion Farnesol 0·6 mmol l−1 significantly increased the inhibition exerted by natamycin 0·01 mmol l−1 (~5 ppm) reducing biofilm development from juice on stainless steel surfaces. Significance and Impact of the Study These results support the use of QS molecules as biofilm inhibitors in beverages and would certainly inspire the design of novel preservative and cleaning products for the food industry based on combinatory approaches.

Visually impaired or blind students require adjustments to the traditional hands-on activities and methodological and didactic strategies employed by the teacher. These adaptations are based on multisensory teaching tools, which reinforce the learning of all students in general. This paper presents simple teaching resources that allow students with visual disabilities to solve problems of Organic Chemistry independently and on an equal footing with their nondisabled peers.

The asymmetric Pauson−Khand reaction catalyzed by [Rh(COD)(MaxPHOS)]BF 4 is described. Several 1,6-enynes have been chosen as model substrates affording moderate yields and selectivities of up to 86% ee. Besides binap-type ligands, we have demonstrated that the Pstereogenic C 1 -symmetry small-bite-angle ligand MaxPHOS is a viable ligand in this process. The formation of [2+2+2] cycloaddition compounds has shown to be a competitive process. A mechanism is proposed to account for the observed results. The intermediate rhodium dicarbonyl complex 6 was synthesized, and its solid-state structure was elucidated by X-ray crystallography. ■ INTRODUCTIONThe Pauson−Khand reaction (PKR) is one of the most efficient methods for the construction of cyclopentanic compounds. 1,2 Both the intra-and the intermolecular version of this process have been utilized in the synthesis of natural products and bioactive molecules. 3,4 A great deal of effort has been devoted to the development of enantioselective versions of the PKR using cobalt, 5 titanium, 6 rhodium, 7 and iridium. 8,9 In 2000 Jeong and co-workers published the first catalyzed enantioselective intermolecular PKR under a CO atmosphere in the presence of a rhodium source and the chiral atropoisomeric ligand BINAP (Scheme 1). 7 Since this early report, mostly C 2 -symmetric 1,1-binaphthyl diphosphines have been used in Rhcatalyzed intermolecular PKR. 7,10−17 Ratovelomanana-Vidal has shown that electronic and steric effects of the diphosphine ligands are crucial to achieve good conversions and high enantioselectivity. 10,11,13 Interestingly, other C 2 -diphosphines such as DIOP, CHIRAPHOS, or Me-DuPHOS have not shown catalytic activity in this reaction. 7 To the best of our knowledge, no examples of electron-rich diphosphines bearing a stereogenic phosphorus atom have been applied in the PKR.Our group has a long-standing experience in the development of asymmetric approaches for the intermolecular PKR using chiral auxiliaries and ligands. 3,4,18−21 We have recently developed novel methodologies for the synthesis of Pstereogenic phosphine ligands. In this field, we have prepared the small-bite-angle MaxPHOS ligand (Scheme 2). 22−24 We have shown that the MaxPHOS-Rh complex 2 is a highly active and efficient catalyst in asymmetric hydrogenation. 25 Due to NH/PH tautomerism, protonation of MaxPHOS leads to the

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Fluoxetine is a selective serotonin reuptake inhibitor, commonly used for the treatment of a variety of psychopathological conditions. As such, fluoxetine may be expected to appear in clinical and forensic cases. Dermestes maculatus De Geer (Coleoptera: Dermestidae) has been recognized as a relevant component of the insect fauna associated with decomposing human and animal remains. Experiments were conducted to study the effect of fluoxetine on developing D. maculatus using twodrug administration models: a non-living animal model (pork muscle) and a living one (Sus scrofa L. pigs). We assessed the duration of immature stages and total life cycle, as well as morphological parameters (body length, cephalic width, and weight). The effect of fluoxetine was studied at an overdose concentration: In the non-living animal model the drug was mixed with macerated pork muscle (2000 mg/kg) and in the living animal model, pigs were given the drug orally (833 mg/kg). A control was used for each model. Daily observations were performed from the beginning to the end of the experiments. GC-MS was used for drug detection and quantification. There were no statistically significant differences in the duration of immature stages, life cycle, larval mortality, morphological parameters, or sex ratio, between treatment and control, regardless of the drug administration model. Given that fluoxetine had no detectable effect on the development of D. maculatus, detection of this drug in forensic situations would not compromise the accuracy of PMI estimations.

A systematic study for esterification procedures to the synthesis of BINOL diesters is described. Reaction conditions with TFAA and 85% H 3 PO 4 were selected as the best procedure to prepare enantiomerically pure (S)-BINOL diesters VIII to XI with almost quantitative yields and very low reaction times.[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s):Full experimental and spectral details.]

Chalcones are a group of compounds that belong to the flavonoid family and have a wide variety of uses, including a high therapeutic potential for multiple diseases, such as, anticancer, antifungal or antibacterial agents. As is well known, chalcones are commonly synthesized by Claisen-Schmidt condensation, aldol condensation involving the appropriate aldehydes and ketones, in presence of acid or base as catalyst followed by dehydration reactions. However, under conventional conditions it is carried out with prolonged reaction times and requires expensive catalysts. For this reason, alternative source of energy, microwave or ultrasound, are employed. On the other hand, in all chemical processes a considerable amount of variables (instrumental parameters, reagents, temperatures, times, etc.) take part so a large number of experiments must be carried out in order to define the optimal conditions. In addition, the experimental design technique -important tool-allows the optimization of conditions leading to better yields in shorter times. Here and in line with previous research, we explore the synthesis, assisted by ultrasound, of (E)-1,3diphenyl-2-propen-1-one like a model reaction. Taguchi Design was the mathematical method employed to determine the best working condition. In conclusion, the desired product is obtained quantitatively, without undesired by-products, and in short reaction times. Additionally, the reaction was used, as an alternative method, to monitor the ultrasound equipment using the control chart methodology (Shewhart chart), which allowed us to study how a process changes over time.