Photophysical and anion sensing properties of a triphenylamine-dioxaborinine trimeric compound.

Herein, we report the synthesis and photophysical characterization of the novel tris(4-(2,2-difluoro-6-methyl-2-1λ,3,2λ-dioxaborinin-4-yl)phenyl)amine trimeric probe (A2) the reaction between triphenylamine (1), acetic anhydride, and BF·OEt implying the twelve new bond formation in a one-pot manner. This highly fluorescent compound in solution ( up to 0.91 at 572 nm) and solid state ( = 0.

BF-Mediated Acetylation of Pyrazolo[1,5-]pyrimidines and Other π-Excedent (-Hetero)arenes.

An operably simple microwave-assisted BF-mediated acetylation reaction of pyrazolo[1,5-]pyrimidines and a plausible mechanism based on density functional theory (DFT) theoretical calculations for this transformation are reported. Remarkably, and to the best of our knowledge, this is the first example of the direct acetylation for the functional pyrazolo[1,5-]pyrimidine (PP) core. The synthesis of this essential building block is reported in high yields using mild reaction conditions, inexpensive reagents, and even substrates with electron-deficient or highly hindered groups.

Pyrazolo[1,5-]pyrimidines-based fluorophores: a comprehensive theoretical-experimental study.

Fluorescent molecules are crucial tools for studying the dynamics of intracellular processes, chemosensors, and the progress of organic materials. In this study, a family of pyrazolo[1,5-]pyrimidines (PPs) 4a-g has been identified as strategic compounds for optical applications due to several key characteristics such as their simpler and greener synthetic methodology (RME: 40-53%) as compared to those of BODIPYS (RME: 1.31-17.

Recent progress in chemosensors based on pyrazole derivatives.

Colorimetric and fluorescent probes based on small organic molecules have become important tools in modern biology because they provide dynamic information concerning the localization and quantity of the molecules and ions of interest without the need for genetic engineering of the sample. In the past five years, these probes for ions and molecules have attracted great attention because of their biological, environmental and industrial significance combined with the simplicity and high sensitivity of absorption and fluorescence techniques. Moreover, pyrazole derivatives display a number of remarkable photophysical properties and wide synthetic versatility superior to those of other broadly used scaffolds.

Cyanide chemosensors based on 3-dicyanovinylpyrazolo[1,5-a]pyrimidines: Effects of peripheral 4-anisyl group substitution on the photophysical properties.

Novel dual-mode colorimetric/fluorometric probes based on 3-dicyanovinylpyrazolo[1,5-a]pyrimidines for cyanide (CN) sensing have been developed (DPPa-c). These probes displayed high selectivity and sensitivity toward CN over other interfering anions, with a detection limit (LOD) as low as 610/170 nmol L (absorption/emission) for some of the prepared probes. After a reaction with CN, low-fluorescent DPPa-c showed a significant decrease of the intramolecular charge transfer (ICT) bands at approximately 390 nm (color changes from yellow to colorless) and exhibited up to an 82-fold fluorescence enhancement at approximately 465 nm (strong blue-light emission).

Synthesis of Pyrrolo[2,3-]isoquinolines via the Cycloaddition of Benzyne with Arylideneaminopyrroles: Photophysical and Crystallographic Study.

An efficient and quick access toward a series of ()-2-arylideneaminopyrroles and to their benzyne-promoted aza-Diels-Alder cycloaddition products is provided. These products are three pyrrolo[2,3-]isoquinolines substituted in position 5 with different electron-acceptor (A) or electron-donor (D) aryl groups. Intermediates and products were obtained in good yields (up to 78 and 84%, respectively), and their structures were determined on the basis of NMR measurements and HRMS analysis.

Integrated pyrazolo[1,5-a]pyrimidine-hemicyanine system as a colorimetric and fluorometric chemosensor for cyanide recognition in water.

A new probe for cyanide detection based on the integrated pyrazolo[1,5-a]pyrimidine-hemicyanine (PpHe) system was synthesized in an efficient and straightforward manner using microwave-assisted heating. Photophysical studies in a 100% aqueous solution demonstrated high cyanide selectivity and detection limits as low as 600 and 86 nmol L for UV-vis absorption and fluorescence emission, respectively. Both values are well below 1900 nmol L, which is the maximum concentration permitted for drinking water by the World Health Organization (WHO).

3-Formylpyrazolo[1,5- a]pyrimidines as Key Intermediates for the Preparation of Functional Fluorophores.

A one-pot route for the regioselective synthesis of 3-formylpyrazolo[1,5- a]pyrimidines 4a-k in good yields through a microwave-assisted process is provided. The synthesis proceeds via a cyclocondensation reaction between β-enaminones 1 with NH-3-aminopyrazoles 2, followed by formylation with an iminium salt moiety (Vilsmeyer-Haack reagent). These N-heteroaryl aldehydes 4 were successfully used as strategic intermediates for the preparation of novel functional fluorophores with yields up to 98%.

Synthesis of 1-substituted 3-aryl-5-aryl(hetaryl)-2-pyrazolines and study of their antitumor activity.

Three series of novel 1,3,5-trisubstituted 2-pyrazoline derivatives containing thiophene and benzodioxol moieties as potential antitumor agents were synthesized. The in vitro antitumor activity of the obtained compounds was determined at the National Cancer Institute (NCI). The 5-(benzo[d][1,3]dioxol-5-yl)-3-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazole-1-carbothioamide (9a) is the most prominent of the compounds due to its remarkable activity toward leukemia (RPMI-8226), renal cancer (UO-31) and prostate cancer (DU-145) cell lines with GI(50) values of 1.

Synthesis of novel pyrazolic analogues of chalcones and their 3-aryl-4-(3-aryl-4,5-dihydro-1H-pyrazol-5-yl)-1-phenyl-1H-pyrazole derivatives as potential antitumor agents.

Novel (E)-1-aryl-3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)prop-2-en-1-ones 5/6 (pyrazolic chalcones) were synthesized from a Claisen-Schmidt reaction of 3-aryl-1-phenylpyrazol-4-carboxaldehydes 4 with several acetophenone derivatives 1. Subsequently, the microwave-assisted cyclocondensation reaction of chalcones 5/6 with hydrazine afforded the new racemic 3-aryl-4-(3-aryl-4,5-dihydro-1H-pyrazol-5-yl)-1-phenyl-1H-pyrazoles 7 or their N-acetyl derivatives 8 and 9 when reactions where carried out in DMF or acetic acid, respectively. Several of these compounds were screened by the US National Cancer Institute (NCI) for their ability to inhibit 60 different human tumor cell lines, where 5c and 9g showed remarkable activity mainly against leukemia (K-562 and SR), renal cancer (UO-31) and non-small cell lung cancer (HOP-92) cell lines, with the most important GI50 values ranging from 0.