Chemical Synthesis

meso‐Indolocarbazolylporphyrins endowed with a different number of indolocarbazole units have been synthesized via condensation of an appropriately substituted monoformylated 5,11‐dihydroindolo[3,2‐b]carbazole precursor and mesityldipyrromethane. Under specific conditions, analogous meso‐indolocarbazolylcorroles could also be prepared. The photophysical features of the novel luminescent free‐base and Zn‐porphyrin derivatives were investigated. The introduction of indolocarbazole substituents results in progressive bathochromic shifts of the porphyrin absorbance and fluorescence bands due to the rising energy of the a2u orbital. The excitation energy is efficiently transferred from the meso‐indolocarbazole units to the porphyrin macrocycle. An increased number of indolocarbazole moieties does not lead to porphyrin fluorescence quenching; on the contrary, a small increase of the fluorescence quantum yield is observed. The main route for excitation energy deactivation of all the studie...

Protonation of an azasugar inhibitor inside the active site of a glycosidase has been studied by solid‐state NMR spectroscopy. By measuring 13C chemical shifts of azafagomine bound to yeast α‐glucosidase, almond β‐glucosidase, andAspergillus niger glucoamylase, and 15N chemical shift ofazafagomine bound to β‐glucosidase, we find evidence for an N1‐protonation of azafagomine inside β‐glucosidase. For α‐glucosidase and glucoamylase the corresponding chemical shifts are similar to those of the non‐protonated inhibitor, which shows that charge stabilization at anomeric position is not occurring in these enzymes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

A simple and stereoselective method for the preparation of (Z)‐2‐substituted 1‐aminocyclopropanecarboxylic acids is described. The common key step for these reaction sequences involves the stereoselective Ti‐mediated coupling of benzyloxy nitrile and homoallylic alcohol. The resulting 2‐hydroxyethyl‐substituted cyclopropylamine can be transformed shortly into various cyclopropane amino acid analogues on the gram scale, in good overall yields. Several syntheses of 2,3‐methanoamino acids, that is, ACCs derived from proteinogenic α‐amino acids or analogues, such as glutamic acid, arginine, homoarginine, and lysine derivatives are presented to exemplify the usefulness of the method. Additionally, starting from cyanoesters, spirocyclopropane γ‐amino acid analogues are available in this way. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Three known alkaloidal compounds; glaucine, oxoglaucine and hemiargyrine; have been isolated from the methanolic extract of Codiaeum variegatum cv. petra leaves and two diterpenoids, identified as ent-trachyloban-3-one and ent-18-OH-trachyloban-3-one, were isolated in addition to α-amyrin and β-sitosterol. The structures of all isolated compounds were established by spectral data. The cytotoxicity of the methanolic extract and the isolated alkalodial compounds were studied against human hepatocellular carcinoma cell line (HepG2), human caucasian breast adenocarcinoma (MCF7), colon cell line (HCT116) and lung carcinoma cell line (A549) and proved to be active.

Platinum and nitrogen co-doped titania films of different surface morphologies obtained via a sol-gel process have been tested for tetracycline hydrochloride photocatalytic decomposition under simulated solar light. Titania crystallization to anatase is shown by XRD for all films. A shift of the bandgap edge toward the visible region in absorption spectra and, consequently, a narrowing of the bandgap is observed for some films doped with nitrogen and/or exposed to UV pretreatment. The surface peculiarities of the samples are presented by an SEM and TEM investigation. The surface saturation by Pt and N with a homogeneous distribution of Pt ions on the surface as well as bulk as established by XPS and EDS data can be achieved with a certain synthesis procedure. The influence of the platinum content and of the pretreatment procedure on the state and atomic surface concentration of incorporated nitrogen and platinum is studied by XPS analysis: substitutional and interstitial nitrogen, n...

Parkinson’s disease (PD) is a neurodegenerative disease characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta, leading to alteration of the integrity of dopaminergic transporters (DATs). In recent years, some radiopharmaceuticals have been used in the clinic to evaluate the integrity of DATs. These include tropane derivatives such as radiolabeled β-CIT and FP-CIT with iodine-123 (123I), and TRODAT-1 with metastable technetium-99 (99mTc). Radiolabeling of β-CIT with radioactive iodine is based on electrophilic radioiodination using oxidizing agents, such as Chloramine T or Iodo-Gen®. For the first time, the present work performed a comparative study of the radiolabeling of β-CIT with iodine-131 (131I), using either Chloramine T or Iodo-Gen® as oxidizing agents, in order to improve the radiolabeling process of β-CIT and to choose the most advantageous oxidizing agent to be used in nuclear medicine. Both radiolabeling methods were similar and resulted ...

Sulfenic acids as small molecules are too unstable to be isolated and their transient nature offers the possibility to involve them in concerted processes that lead to the obtainment of functional groups such as sulfoxides, sulfones and disulfides. All these functions are present in a number of natural and synthetic drugs and can represent structural motives inducing biological relevant properties. In this small review the generation and reactions of sulfenic acid bearing naturally occurring residues are described. Carbohydrate and aminoacid-derived sulfenic acids have been used in concerted addition to triple bonds to obtain alliin derivatives and thiosugars in enantiomerically pure form. Glycoconjugates with sulfinyl, sulfonyl and disulfane functional groups and pyridine-derived disulfides have been obtained from bis and tris-sulfinyl precursors of sulfenic acids. Small families of such compounds have been subjected to preliminary biological tests. Starting from the evidence that ...