Synthesis of Selenium Derivatives using Organic Selenocyanates as Masked Selenols: Chemical Reduction with Rongalite as a Simpler Tool to give Nucleophilic Selenides.

The chemical reduction within a family of organic selenocyanates, as masked selenols, using reducing agents, such as Rongalite, sodium dithionite, and sodium thiosulfate is investigated. Using Rongalite, the corresponding diselenides were obtained quantitatively and selectively in very good to excellent yields (51-100 %) starting from alkyl, aryl, and benzyl selenocyanates. The scope of the reaction is unaffected by the electronic nature of the substituents.

A Dual Fluorescence-Spin Label Probe for Visualization and Quantification of Target Molecules in Tissue by Multiplexed FLIM-EPR Spectroscopy.

Simultaneous visualization and concentration quantification of molecules in biological tissue is an important though challenging goal. The advantages of fluorescence lifetime imaging microscopy (FLIM) for visualization, and electron paramagnetic resonance (EPR) spectroscopy for quantification are complementary. Their combination in a multiplexed approach promises a successful but ambitious strategy because of spin label-mediated fluorescence quenching.

Synthesis, Self-Assembly, and Biological Activities of Pyrimidine-Based Cationic Amphiphiles.

Pyrimidine-based cationic amphiphiles (PCAms), i.e., di-trifluoroacetic acid salts of 1-[1'-(1″,3″-diglycinatoxy-propane-2″-yl)-1',2',3'-triazole-4'-yl]methyl-3-alkylpyrimidines have been synthesized utilizing naturally occurring biocompatible precursors, like glycerol, glycine, and uracil/ thymine in good yields.

Riboflavin as Photoredox Catalyst in the Cyclization of Thiobenzanilides: Synthesis of 2-Substituted Benzothiazoles.

Benzothiazoles are synthesized from thiobenzanilides using riboflavin as a photosensitizer and potassium peroxydisulfate as a sacrificial oxidizing agent under visible light irradiation. The methodology accepts a broad range of functional groups and affords the 2-substituted benzothiazoles by transition-metal-free organic photoredox catalysis under very mild conditions.

Combined Experimental and Theoretical Studies on the Radical Nucleophile Addition Reaction for Sulfide- and Selenide-Centered Anions.

The reactivity of sulfur- and selenium-centered nucleophiles toward 1-naphthyl radicals was studied in dimethylsulfoxide. The photostimulated reaction of sulfide anions, SC(NH)CH (1), SC(NH)NH (2), and SC(NH)CH (3), renders, after the addition of MeI, methyl 1-naphthylsulfide as a main product together with bis(1-naphthyl) sulfide and naphthalene under irradiation. Concordantly, the reaction of selenide anions, SeC(NH)CH (4), SeC(NH)NH (5), and SeCN (6), produces methyl 1-naphthyl selenide, bis(1-naphthyl) selenide, and naphthalene in the presence of potassium tert-butoxide anion (entrainment conditions).

Photoinduced One-Electron Oxidation of Aromatic Selenides: Effect of the Structure on the Reversible Dimerization Reaction.

The photochemical one-electron oxidation of alkyl aryl selenides was studied by means of laser flash photolysis (355 nm). Quenching of the sensitizers in their excited state leads to selenide radical cation in the presence of selenium derivatives. The π-type dimer of methyl phenyl selenide radical cation was detected at 630 nm at expenses of the monomeric radical cation (530 nm).

Stereoselective one-pot synthesis of β-alkylsulfide enol esters. Base-triggered rearrangement under mild conditions.

A stereoselective one-pot procedure was developed to prepare S-substituted (Z)-enol esters through a base-triggered rearrangement. This transition metal-free multicomponent approach can be performed under an air atmosphere at room temperature, tolerates a wide set of chemical functionalities and generally affords high isolated yields. The (Z)-selectivity arises from the [1,4]-S- to O-acyl migration.

Sensing chiral drugs by using CdSe/ZnS nanoparticles capped with N-acetyl-L-cysteine methyl ester.

Chiral quantum dots (QDs), differing in their core or shell size and, consequently, in their optical properties, were synthesized by the treatment of commercially available amine-capped quantum dots with methyl ester N-acetyl-L-cysteine (CysP). Interestingly, their colloidal methanol solutions remain stable for several months. Their NMR and IR spectra were in accordance with CysP binding to the QD surface through two anchoring groups; its thiolate (strongly bound) and the carbonyl group of its ester (weaker bound) group, whereas their circular dichroism (CD) spectra showed a new broad redshifted band, suggesting that the attachment to the QD surface modified the conformational equilibrium towards conformer(s) with optical activity in this region.