Research on nitrogen containing heterocyclic compounds. XVI. Synthesis of 1, 3, 4, 14b-tetrahydro-2, 10-dimethyl-2H,10H-pyrazino[2, 1-d]pyrrolo[1, 2-b][1, 2, 5]benzotriazepine (1:1) maleate (10-methyl-10-azaaptazepine)

A synthesis of the potential antidepressant 1, 3, 4, 14b-tetrahydro-2, 10-ditnethyl-2H,10H-pyrazino[2, 1-d]-pyrrolo[1, 2-b][1, 2, 5]benzotriazepine 4 , structurally related to aptazepine, is reported in four steps. The key steps of the synthesis were the formation of the tricyclic compound ethyl 10, 11-dihydro-5-methyl-5H-pyrrolo[1, 2-6-b][1, 2, 5]benzotriazepine-11-carboxylate 6 via a Pictet-Spengler type condensation and the formation of the diketopiperazine 8 by cyclization of the chloroester 7 with methylamine.     

Parametric generation of high-energy 14.5-fs light pulses at 1.5 mum

High-energy light pulses that are tunable from 1.1 to 2.6 mum, with a duration as short as 14.5 fs were generated in a type II phase-matching beta-BaB(2)O(4) traveling-wave parametric converter pumped by 18-fs pulses obtained from a Ti:sapphire laser with chirped-pulse amplification, followed by a hollow-fiber compressor.     

Sub-8-fs pulses from an ultrabroadband optical parametric amplifier in the visible

Pulses with 180-THz bandwidth and 2-microJ energy were generated by a noncollinear optical parametric amplifier in the visible, pumped by the second harmonic of a Ti:sapphire laser. A portion of the amplified pulse spectrum was compressed to 7.2 fs by use of a thin prism sequence.     

Synthesis of 9H-pyrrolo[2,1-b][1,3,6]benzothiadiazocin-10(11H)-one 4,4-dioxide,a potential anti-HIV-1 agent

Starting from 2-(2-aminophenylthio)-1-ethoxycarbonylmethyl-1H-pyrrole a four-step synthesis of 9H-pyrrolo[2,1-b][1,3,6]benzothiadiazocin-10(11H)-one 4,4-dioxide, a new heterocycle related to anti-HIV-1 tricyclic non-nucleoside agents, is described.     

High-performance liquid chromatography and capillary electrophoresis: methodological challenges for the determination of biologically relevant low-aliphatic aldehydes in human saliva

Tobacco smoke is involved in the pathogenesis of cardiovascular and respiratory diseases and also has a local toxic effect in the oral cavity. Low-aliphatic aldehydes, such as formaldehyde, acetaldehyde and acrolein, are among the main components of mainstream cigarette smoke and their local noxious and carcinogenic effects in the oral cavity and upper gastrointestinal tract are well-known. Although various studies have been performed so far to determine their content in cigarette smoke, none has included the direct measurement of these compounds in the saliva of smoking and nonsmoking subjects. Thus, in an attempt to verify whether typical chromatographic (high-performance liquid chromatography, HPLC) and/or electrophoretic (capillary electrophoresis, CE) techniques could be reliable methods for determining the levels of these analytes in human saliva, we submitted specimens obtained from a selected population of heavy, moderate, and nonsmoking subjects to HPLC and CE analyses. Both methods showed good reproducibility in terms of migration times and peak height and/or areas and had comparable linearity. Quantitative analyses performed on the specimens investigated evidenced a 3.5-fold increase of low-aliphatic aldehydes in saliva of nonsmoking subjects after they have smoked a single cigarette and a further 2-fold increase of these compounds in saliva of smokers with a daily consumption of 10 or more cigarettes.     

Simple and efficient synthesis of benzofuran derivatives from tyrosol

A convenient strategy for the preparation of compounds bearing the benzofuran skeleton starting from tyrosol, a phenol largely present in olive oil production waste, with no biological importance, is reported. A bromination/methoxylation sequence, already described for the synthetic transformation of naturally occurring compounds, was exploited. Depending on the solvent used for the methoxylation reaction together with the presence of a 4-phenol moiety respect to the side chain, benzodihydrofurans or a benzofurans derivative can be obtained.     

Random lasing in an organic light‐emitting crystal and its interplay with vertical cavity feedback

The simultaneous vertical‐cavity and random lasing emission properties of a blue‐emitting molecular crystal are investigated. The 1,1,4,4‐tetraphenyl‐1,3‐butadiene samples, grown by physical vapour transport, feature room‐temperature stimulated emission peaked at about 430 nm. Fabry‐Pérot and random resonances are primed by the interfaces of the crystal with external media and by defect scatterers, respectively. The analysis of the resulting lasing spectra evidences the existence of narrow peaks due to both the built‐in vertical Fabry‐Pérot cavity and random lasing in a novel, surface‐emitting configuration and threshold around 500 μJ cm⁻². The anti‐correlation between different modes is also highlighted, due to competition for gain. Molecular crystals with optical gain candidate as promising photonic media inherently supporting multiple lasing mechanisms.     

Efficient synthesis of scutellarein

Scutellarein is a component of Scutellaria, recently known as a potent cytotoxic agent on human leukaemia cells. The aim of this study was the synthesis of scutellarein and its methylated derivative. The new features are the innovating method to afford flavones from flavanones and the A-ring regioselective bromination step that lead to the target molecule by a facile and high-yielding pathway.     

Organic Functional Group on Carbon Nanotube Modulates the Maturation of SH-SY5Y Neuronal Models

Carbon nanotubes (CNT) have proven to be excellent substrates for neuronal cultures, showing high affinity and greatly boosting their synaptic functionality. Therefore, growing cells on CNT offers an opportunity to perform a large variety of neuropathology studies in vitro. To date, the interactions between neurons and chemical functional groups have not been studied extensively. To this end, multiwalled CNT (f-CNT) is functionalized with various functional groups, including sulfonic (–SO₃H), nitro (–NO₂), amino (–NH₂), and oxidized moieties. f-CNTs are spray-coated onto untreated glass substrates and are used as substrates for the incubation of neuroblastoma cells (SH-SY5Y). After 7 d, its effect is evaluated in terms of cell attachment, survival, growth, and spontaneous differentiation. Cell viability assays show quite increased proliferation on various f-CNT substrates (CNTs-NO₂ > ox-CNTs ≈ CNTs-SO₃H > CNTs ≈ CNTs-NH₂). Additionally, SH-SY5Y cells show selectively better differentiation and maturation with –SO₃H substrates, where an increased expression of β-III tubulin is seen. In all cases, intricate cell-CNT networks are observed and the morphology of the cells adopts longer and thinner cellular processes, suggesting that the type of functionalization may have an effect of the length and thickness. Finally, a possible correlation is determined between conductivity of f-CNTs and cell-processes lengths.