Synergistic effects of the exo- and endocyclic chiral centers of an imidazolidinone-based auxiliary were investigated in the perspective of acetate aldol reactions. The reversal in diastereoselectivity was accomplished by lithium and titanium enolate reactions, which proceed through proposed open and closed transitions states, respectively. The aldol adducts were used in the stereoselective synthesis of fluoxetine.

A polymeric ligand (thiourea‐formaldehyde resin ‐ TUFR) bearing nitrogen and sulfur donor groups was synthesized by the polycondensation of thiourea and formaldehyde in acidic medium and its polychelates were prepared in alcoholic solution of metal ions such as Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The TUFR polymeric ligand and its TUFR‐M(II) polychelates were characterized with micro‐analytical analysis and spectral studies. The FTIR spectra of polychelates indicated that the metal ions were coordinated through the sulfur of the thionyl (CS) groups and formed a covalent bond with the nitrogen of the NH groups. Electronic spectra, electronic spin resonance (ESR) spectra and magnetic moments revealed that the polychelates of Mn(II), Co(II) and Ni(II) were octahedral; however, Cu(II) and Zn(II) polychelates were square‐planar and tetrahedral, respectively. The thermogravimetric analysis data indicated that the polychelates were more stable than the corresponding ligand. The antimicrobial activities of all the compounds against several bacteria and fungi were also investigated by using the agar well diffusion method. Copyright © 2006 Society of Chemical Industry

Flowers are the most vulnerable plant organ to infection by the necrotrophic fungus Botrytis cinerea. Here we show that pre-treatment of chrysanthemum (Chrysanthemum morifolium) flowers with phenylalanine (Phe) significantly reduces their susceptibility to B. cinerea. To comprehend how Phe treatment induces resistance, we monitored the dynamics of metabolites (by GC/LC-MS) and transcriptomes (by RNAseq) in flowers after Phe treatment and B. cinerea infection. Phe treatment resulted in accumulation of 3-phenyllactate and benzaldehyde, and in particular induced the expression of genes related to Ca 2+ signaling and receptor kinases, implicating an induction of the defense response. Interestingly, the main effects of Phe treatment were observed in flowers exposed to B. cinerea infection, stabilizing the global fluctuations in the levels of metabolites and transcripts while reducing susceptibility to the fungus. We suggest that Pheinduced resistance is associated to cell priming, enabling rapid and targeted reprogramming of cellular defense responses to resist disease development. After Phe pre-treatment, the levels of the anti-fungal volatiles phenylacetaldehyde and eugenol were maintained and the level of coniferin, a plausible monolignol precursor in cell wall lignification, was strongly increased. In addition, Phe pre-treatment reduced ROS generation, prevented ethylene emission, and caused changes in the expression of a minor number of genes related to cell wall biogenesis, encoding the RLK THESEUS1, or involved in Ca 2+ and hormonal signaling processes. Our findings point to Phe pre-treatment as a potential orchestrator of a broad-spectrum defense response which may not only provide an ecologically friendly pest control strategy but also offers a promising way of priming plants to induce defense responses against B. cinerea.

A novel greener methodology is reported for the synthesis of titanium dioxide (TiO 2 ) nanoparticles (NPs) using gum Arabic ( Acacia senegal ) and the characterization of the ensuing TiO 2 NPs by various techniques such as X-ray diffraction (XRD), Fourier transform infrared, Raman spectroscopy, scanning electron microscopy–energy dispersive X-ray, transmission electron microscopy (TEM), high resolution-TEM, and UV–visible spectroscopy. The XRD analysis confirmed the formation of TiO 2 NPs in the anatase phase with high crystal purity, while TEM confirmed the size to be 8.9 ± 1.5 nm with a spherical morphology. The electrode for the electrochemical detection of Pb 2+ ions was modified by a carbon paste fabricated using the synthesized TiO 2 NPs. Compared to the bare electrode, the fabricated electrode exhibited improved electro–catalytic activity toward the reduction of Pb 2+ ions. The detection limit, quantification limit, and the sensitivity of the developed electrode were observed by using differential pulse voltammetry to be 506 ppb, 1.68 ppm, and 0.52 ± 0.01 μA μM –1 , respectively. The constructed electrode was tested for the detection of lead content in plastic toys.

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