Synthetic Cathinones: Recent Developments,Enantioselectivity Studies and Enantioseparation Methods

New psychoactive substances represent a public health threat since they are not controlled by international conventions, are easily accessible online and are sold as a legal alternative to illicit drugs. Among them, synthetic cathinones are widely abused due to their stimulant and hallucinogenic effects. To circumvent the law, new derivatives are clandestinely synthesized and, therefore, synthetic cathinones keep emerging on the drug market, with their chemical and toxicological properties still unknown. In this review, a literature assessment about synthetic cathinones is presented focusing on the recent developments, which include more than 50 derivatives since 2014. A summary of their toxicokinetic and toxicodynamic properties are also presented. Furthermore, synthetic cathinones are chiral compounds, meaning that they can exist as two enantiomeric forms which may present different biological and toxicological activities. To analyze the enantiomers, the development of enantiomeric resolution methods for synthetic cathinones is crucial. Many methods have been reported over the years that include mostly chromatographic and electromigration techniques, with liquid chromatography using chiral stationary phases being the technique of choice. This review intended to present an overview of enantioselectivity studies and enantioseparation analysis regarding synthetic cathinones, highlighting the relevance of chirality and current trends.     

Ferroelectric switching behavior of pulsed laser deposited Ba0.8Sr0.2TiO3 thin films

The effect of pulse amplitude on the ferroelectric and switching properties of pulsed laser deposited Ba_0.8Sr_0.2TiO₃ thin films has been studied. The structural and morphological analysis revealed that the films had a well crystallized perovskite phase and grain size of about 30–40 nm. A well saturated P–E hysteresis loop was observed with a remnant polarization (P_r) ≈ 4.8 μC/cm² and a coercive field ≈ 100 kV/cm at a frequency of 1 kHz. The P_r has been found to be decreased only 4.3% after passing 8.0 × 10⁸ cycles. The analysis of switching response with nucleation limited switching model reveals that characteristic switching time (t₀) variance is due to the random distribution of the local electric fields. The peak value of polarization current and t₀ exhibits exponential dependence on reciprocal of pulse amplitude.     

Structure factor of ferrofluids with chain aggregates: Theory and computer simulations

In this paper we present theoretical and simulation results on the structure factor of mono- and bidisperse ferrofluids with chain aggregates, both with and without an applied external magnetic field. Chain distribution is obtained by the density functional theory (DFT). The radial distribution function (RDF) is calculated directly on the basis of the chain distribution and Fourier transformed to calculate the structure factor. An extensive comparison of the theoretical predictions to the results of the molecular dynamics computer simulations is provided. The proposed combined approach allows to elucidate the connection between experimentally observed small angle neutron scattering (SANS) images and the ferrofluid microstructure.     

Dammarane Triterpenes from Gardenia aubryi Vieill.

Three new dammarane triterpenoids, gardaubryones A–C ( 1 – 3 ), were isolated from the gum collected on the aerial parts of Gardenia aubryi Vieill ., together with the known compounds hydroxydammarenone II ( 4 ), ocotillone ( 5 ), cabraleone, and hollongdione. The structures of the novel compounds were established on the basis of mass spectrometry, NMR experiments, and chemical‐correlation reactions.     

The trans-1,4-cyclohexylene group as a structural fragment in liquid crystals

In this review the effect on physico-chemical and electro-optical properties of the introduction of the trans-1,4-cyclohexylene fragment into the molecular core of liquid crystals is discussed, rationalized in terms of existent theories, and compared with the effect of other well-known molecular fragments.     

Synthesis of a Resorcylic Acid Lactone (RAL) Library Using Fluorous‐Mixture Synthesis and Profile of its Selectivity Against a Panel of Kinases

A library of resorcylic acid lactones (RAL) containing a cis‐enone moiety targeting kinases bearing a cysteine residue within the ATP‐binding pocket was prepared using a fluorous‐mixture synthesis and evaluated against a panel of 19 kinases thus providing important structure–activity trends. Two new analogues were then profiled for their selectivity against a panel of 402 kinases providing the broadest evaluation of this pharmacophores’ selectivity.     

A New Nonconjugated Naphthalene Derivative of Meso-tetra-(3-hydroxy)-phenyl-porphyrin as a Potential Sensitizer for Photodynamic Therapy

A new 5,10,15,20-tetra-(phenoxy-3-carbonyl-1-amino-naphthyl)-porphyrin was prepared by an isocyanate condensation reaction and its photophysical properties fully evaluated, both in terms of photostability and singlet oxygen production. It shows considerably enhanced photostability when compared with the parent 5,10,15,20-tetra-(3-hydroxy-phenyl)-porphyrin, with the photodegradation quantum yields for T(NAF)PP and T(OH)PP being 4.65 × 10⁻⁴ and 5.19 × 10⁻³, respectively. Its photodynamic effect in human carcinoma HT-29 cells was evaluated. The new porphyrin showed good properties as a sensitizer in photodynamic therapy with an in vitro cytotoxicity IC₅₀ value of 6.80 μg mL⁻¹ for a 24 h incubation. In addition to the potential of this compound, the synthetic route used provides possibilities of extension to a wide range of new sensitizers.     

A rotating disc electrode study of oxygen reduction at platinised nickel and cobalt coatings

Platinized nickel and cobalt coatings, Pt(Ni) and Pt(Co), have been prepared on glassy carbon, GC, rotating disc electrode substrates by a two-step room temperature procedure that involved the electrodeposition of nickel and cobalt layers and their spontaneous partial replacement by platinum (“transmetalation”) when immersed into a chloroplatinic acid solution. By tuning the quantity of initially deposited nickel and cobalt, Pt(Ni) and Pt(Co) bimetallic coatings having a 26% atom Ni and 30% atom Co composition have been prepared. For both materials typical Pt surface electrochemistry was recorded during fast voltammetry in deaerated acid, pointing to the existence of a continuous Pt skin over a Pt–Ni and Pt–Co core. Oxygen reduction at the Pt(Ni)/GC and Pt(Co)/GC electrodes was studied by means of steady-state voltammetry at a rotating disc electrode and the construction of Tafel plots from corresponding voltammetric data. It was found that, when the initial potential of the voltammetric sweep allowed the formation of a complete Pt oxide monolayer, then oxygen reduction was hindered for low overpotentials at Pt(Ni) and Pt(Co), compared to pure bulk Pt. On the other hand, when the initial potential was less positive (thus leading to the formation of a fraction of surface oxide monolayer) the presence of Ni and Co enhanced the kinetics of oxygen reduction. The former behaviour is attributed to a decrease in oxide reduction ability of Pt in the presence of Ni and Co, while the latter to an increase in dissociative oxygen chemisorption due to Ni and Co.