New tri- and tetra-substituted pyrroles via quinazolinium N1-ylides

New tri-and tetra-substituted N-arylpyrroles were synthesized by one-pot reaction of 3,7-disubstituted quinazolinonium bromides with substituted alkynes having at least one electron-withdrawing substituent in 1,2-epoxybutane acting both as solvent and hydrogen bromide scavenger. Structural characterization of the new compounds was based on IR and NMR spectroscopy as well as on single crystal X-ray analysis

Synthesis and electrochemical characterization of substituted indolizine carboxylates

This work is devoted to the synthesis and characterization of new indolizine derivatives. Particular attention was paid to the electrochemical investigations by cyclic voltammetry and differential pulse voltammetry. The redox processes for each compound were established, analyzed and assessed to the particular functional groups at which they take place. This assessment was based on detailed comparison between the electrochemical behaviour of the compounds, similarities in their structure, as well as substituent effects

Indolizines and pyrrolo[1,2- c ]pyrimidines decorated with a pyrimidine and a pyridine unit respectively

The three possible structural isomers of 4-(pyridyl)pyrimidine were employed for the synthesis of new pyrrolo[1,2-c]pyrimidines and new indolizines, by 1,3-dipolar cycloaddition reaction of their corresponding N-ylides generated in situ from their corresponding cycloimmonium bromides. In the case of 4-(3-pyridyl)pyrimidine and 4-(4-pyridyl)pyrimidine the quaternization reactions occur as expected at the pyridine nitrogen atom leading to pyridinium bromides and consequently to new indolizines via the corresponding pyridinium N-ylides. However, in the case of 4-(2-pyridyl)pyrimidine the steric hindrance directs the reaction to the pyrimidinium N-ylides and, subsequently, to the formation of the pyrrolo[1,2-c]pyrimidines. The new pyrrolo[1,2-c]pyrimidines and the new indolizines were structurally characterized through NMR spectroscopy. The X-ray structures of two of the starting materials, 4-(2-pyridyl)pyrimidine and 4-(4-pyridyl)pyrimidine, are also reported

Synthesis of Pyrrolo[2,1-a]isoquinolines by Multicomponent 1,3-Dipolar Cycloaddition

Pyrrolo[2,1-a]isoquinoline derivatives were synthesized by one-pot three-component reactions starting from isoquinoline, 2-bromoacetophenones and different non-symmetrical acetylenic dipolarophiles using 1,2-epoxypropane as solvent. The structure of the compounds was assigned by IR and NMR spectroscopy

The Influence of Strigolactone Analog and Mimetic on <i>Trametes versicolor</i>

Strigolactones (SLs) are apocarotenoids, belonging to carotenoid-derivative metabolites that include other phytohormones, signaling molecules, and volatile compounds [...

New highlights of the syntheses of pyrrolo[1,2-a]quinoxalin-4-ones

The one-pot three-component reactions of 1-substituted benzimidazoles with ethyl bromoacetate and electron-deficient alkynes, in 1,2-epoxybutane, gave a variety of pyrrolo[1,2-a]quinoxalin-4-ones and pyrrolo[1,2-a]benzimidazoles. The influence of experimental conditions on the course of reaction was investigated. A novel synthetic pathway starting from benzimidazoles unsubstituted at the five membered ring, alkyl bromoacetates and non-symmetrical electron-deficient alkynes in the molar ratio of 1:2:1, in 1,2-epoxybutane at reflux temperature, led directly to pyrrolo[1,2-a]quinoxalin-4-ones in fair yield by an one-pot three-component reaction

Synthesis and Solvent Dependent Fluorescence of Some Piperidine-Substituted Naphthalimide Derivatives and Consequences for Water Sensing

Novel fluorescent strigolactone derivatives that contain the piperidine-substituted 1,8-naphthalimide ring system connected through an ether link to a bioactive 3-methyl-furan-2-one unit were synthesized and their spectroscopic properties investigated. The solvatochromic behavior of these piperidine-naphthalimides was monitored in solvents of different polarity using the electronic absorption and fluorescence spectra. These compounds exhibited a strong positive solvatochromism taking into account the change of solvent polarity, and the response mechanism was analyzed by fluorescence lifetime measurements. According to Catalan and [f(n), f(&epsilon;), &beta;, &alpha;] solvent scales, the dipolarity and polarizability are relevant to describe the solute&ndash;solvent interactions. The emission chemosensing activity was discussed in order to determine the water content in organic environments. The emission intensity of these compounds decreased rapidly in dioxane, increasing water level up to 10%. Measuring of quantum yield indicated that the highest values of quantum efficiency were obtained in nonpolar solvents, while in polar solvents these derivatives revealed the lowest quantum yield. The fluorescence decay can be described by a monoexponential model for low water levels, and for higher water contents a biexponential model was valid