Cyclization Reactions for the Synthesis of Phthalans and Isoindolines

Oxygen and nitrogen heterocycles are present in a vast number of natural substrates and biologically active molecules. In particular, phthalan and isoindoline subunits are found in many classes of products such as antibiotics, antioxidants, antimycotics, pigments, and fluorophores. Therefore several procedures dedicated to the construction of these heterocycles have been developed. In this review, a detailed analysis of the literature data regarding the synthesis of these nuclei via cyclization reactions is reported

Sistemi supportati contenenti il legante tris-[(1-benzil-1H-1,2,3-triazol-4-il)metil]ammina (TBTA) per la cicloaddizione 1,3-dipolare di Huisgen catalizzata da rame(I).

Scopo del presente lavoro di Tesi è stato quello di preparare nuovi catalizzatori supportati contenenti il legante tris-[(1-benzil-1H-1,2,3-triazol-4-il)metil]ammina (TBTA) utilizzabili per la reazione di cicloaddizione 1,3-dipolare di Huisgen catalizzata da rame(I) (CuAAC) in batch e, potenzialmente, anche in condizioni di flusso continuo, permettendo così di risolvere i problemi emersi nell’impiego di sistemi analoghi riportati in letteratura. Una prima parte del lavoro è stata dedicata allo sviluppo di alcuni sistemi catalitici a base di rame(I) contenenti il legante TBTA immobilizzato covalentemente su silice; sfortunatamente, in prove esplorative di CuAAC in batch essi hanno evidenziato attività catalitiche molto basse. Nella seconda parte del lavoro sono stati invece preparati sistemi a base di rame(I) contenenti il TBTA ancorato su resine polistireniche macroporose. In particolare, inizialmente essi sono stati preparati in forma di beads, al fine di valutare le loro caratteristiche in prove esplorative di CuAAC in batch; i buoni risultati ottenuti hanno successivamente portato al loro sviluppo in forma di monoliti porosi e alla loro valutazione preliminare come reattori catalitici per la CuAAC in condizioni di flusso continuo

Synthesis of new bis[1-(thiophenyl)propynones] as potential organic dyes for colorless luminescent solar concentrators (LSCs)

New luminophores having different aryl nuclei and propynones moieties have been obtained via Sonogashira reactions. Their optical properties were evaluated and indicated that carbonyl groups are responsible for significant bathochromic effects and high Stokes shifts. The insertion of -OMe groups on the central benzene unit gives to the fluorophore high optical efficiency (7.7%) when homogeneously dispersed in a poly(cyclohexyl methacrylate) (PCMA) film and connected to a PV cell

Supramolecular organization of new chiral π-conjugated oligomers: synthesis and spectroscopic study

π-Conjugated polymers and oligomers are widely used as organic semiconductors in devices such as field-effect transistors (OFET), light-emitting diodes (OLED) and solar cells (OPV)1; in the last years, a very important role in this field has been played by olygothiophenes2. Their optoelectronic properties (structure of the absorption bands, fluorescence efficiency, charge and exciton transport) depend not only on the chemical nature and the conformation assumed, but also on their supramolecular organization in the solid state. In particular, the introduction of chiral groups can be used to drive their self-assembly. We shall summarize our recent results about the supramolecular aggregation of three new chiral π- conjugated oligomers, consisting of an aromatic central ring (1,4-hydroquinone, benzo[1,2-b:4,5-b′]dithiophene- 4,8-diol, 1,4-diketopyrrolo[3,4-c]pyrrole) functionalized with two (S)-3,7-dimethyl-1-octyl groups and connected to two 2,2'-bithienyl units. In particular, we shall discuss: a) the synthetic route developed for the preparation of these new molecules;b) the characterization of their supramolecular aggregates in solution and of their thin films through optical (UV-VIS, fluorescence) and chiroptical (electronic circular dichroism) spectroscopies, in connection with optical microscopy investigation

Infrared irradiation-assisted solvent-free Pd-catalyzed (hetero)aryl-aryl coupling via C-H bond activation

The increasing attention towards environmentally friendly synthetic protocols has boosted studies directed to the development of green and sustainable methods for direct C−H bond arylation of (hetero)arenes. In this context, here the infrared (IR) irradiation-assisted solvent-free Pd-catalyzed direct C−H bond arylation of (hetero)arenes was achieved. Several heteroaryl-aryl coupling reactions were described, also involving heterocycles commonly used as building blocks for the synthesis of organic semiconductors. The reaction tolerated many functional groups on the aromatic nuclei. The IR-irradiation as the energy source compared favorably with thermal heating and, in combination with solvent-free conditions, provided an important contribution to the development of protocols fitting with the principles of green chemistry

Patients' preferences for chronic lymphocytic leukemia treatment: The CHOICE study

Chronic lymphocytic leukemia (CLL) therapies differ in efficacy, side effects, route, frequency, and duration of administration. We assessed patient preferences for treatment attributes and evaluated associations with disease stage, treatment line, and socio-demographic characteristics in a cross sectional, observational study conducted at 16 Italian hematology centers. Study visits occurred between February and July 2020; 401 adult patients with CLL (201 Watch and Wait (W & W), 200 treated) participated in a discrete choice experiment (DCE), composed of 8 choices between pairs of treatment profiles with different levels of 5 attributes of currently available CLL treatments (length of response, route and duration of administration, risk of side effects including diarrhea, infections, or organ damage). Health-related quality of life was assessed with the EQ-5D-5L, EORTC QLQ-C30 and QLQ CLL-16. Previously treated patients had longer disease duration (7 vs. 5 years), higher prevalence of serious comorbidities (45.5% vs. 36.2%) and high-risk molecular markers (unmutated IGHV 55.6% vs. 17.1%; TP53 mutation 15.2% vs. 4.0%). Health-related quality of life scores were similar between groups. In the DCE, W & W patients rated "possible occurrence of infections" highest (relative importance [RI] = 36.2%), followed by "treatment and relevant duration" (RI = 28.0%) and "progression-free survival (PFS)" (RI = 16.9%). Previously treated patients rated "treatment and relevant duration" highest (RI = 33.3%), followed by "possible occurrence of infections" (RI = 28.8%), "possible occurrence of organ damage" (RI = 19.4%), and "PFS" (RI = 9.8%). Concern over infection was rated highest overall; unexpectedly PFS was not among the most important criteria in either group, suggesting that the first COVID-19 pandemic wave may have influenced patient preferences and concerns about CLL therapy options

Lista bibliografica

Questa lista bibliografica contiene il secondo aggiornamento della bibliografia della Lisy e deriva dall’assemblaggio da parte della redazione (M. Serdoz ed E. Panfili) dei contributi parziali stilati dai gruppi regionali

Outstanding chiroptical features in thin films of chiral π-conjugated oligomers: from synthesis to applications

Chirality is gaining large interest in organic optoelectronics: first, it is a valid tool for controlling the supramolecular order of π-conjugated systems constituting the active layer of devices; secondly, it opens the way to innovative technological applications, like detecting or producing circularly polarized (CP) light. A current research goal is to obtain thin films of organic semiconductors with high discrimination of CP-light in absorption (electronic circular dichroism, ECD) or emission (circularly polarized luminescence, CPL). Chiral supramolecular architectures of π-conjugated systems could be the key to achieve this goal. In the present doctoral work, we developed a family of novel chiral π-conjugated oligomers functionalized with inexpensive alkyl chiral groups from natural sources, studying their ECD and CPL features in thin films. Since special care should be taken, in order to avoid the occurrence of false signals, here we provided practical tools for recognizing, quantifying and possible separating the main contributions of experimental ECD and CPL spectra. Although in general we observed a manifold of situations, thus revealing the central role of different local supramolecular structures (whose formation is strictly related to chemical structure, deposition technique and post-deposition operations), in some cases we discovered outstanding chiroptical features. Encouraged by promising results, for some of them we finally explored the application as active layers in circularly polarized organic light-emitting diode (CP-OLED) devices

Acyl Sonogashira Cross-Coupling: State of the Art and Application to the Synthesis of Heterocyclic Compounds

The acyl Sonogashira reaction represents an extension of Sonogashira cross-coupling to acid chlorides which replace aryl or vinyl halides, while terminal acetylenes are used as coupling partners in both reactions. The introduction of a carbonyl functional group on the alkyne backbone determines a radical change in the reactivity of the products. Indeed, α,β-alkynyl ketones can be easily converted into different heterocyclic compounds depending on the experimental conditions employed. Due to its potential, the acyl Sonogashira reaction has been deeply studied with particular attention to the nature of the catalysts and to the structures of both coupling compounds. Considering these two aspects, in this review, a detailed analysis of the literature data regarding the acyl Sonogashira reaction and its role in the synthesis of several heterocyclic derivatives is reported

Synthetic Methods for the Preparation of Conformationally Restricted Analogues of Nicotine

In the context of naturally occurring nitrogen heterocycles, nicotine is a chiral alkaloid present in tobacco plants, which can target and stimulate nicotinic acetylcholine receptors (nAChRs), a class of ligand-gated ion channels commonly located throughout the human brain. Due to its well-known toxicity for humans, there is considerable interest in the development of synthetic analogues; in particular, conformationally restricted analogues of nicotine have emerged as promising drug molecules for selective nAChR-targeting ligands. In the present mini-review, we will describe the synthesis of the conformationally restricted analogues of nicotine involving one or more catalytic processes. In particular, we will follow a systematic approach as a function of the heteroarene structure, considering: (a) 2,3-annulated tricyclic derivatives; (b) 3,4-annulated tricyclic derivatives; (c) tetracyclic derivatives; and (d) other polycyclic derivatives. For each of them we will also consider, when carried out, biological studies on their activity for specific nAChR subunits