CFL light promoted one-pot synthesis of pyrano[3,2-c]chromen-5(4H)-ones

An eco-friendly synthesis of pyrano[3,2-c]chromen-5(4H)-one derivatives was conducted by the condensation of 4-hydroxycoumarins, aromatic aldehydes, and acetophenones. Clean profile, excellent yield, ambient temperature, and use of visible light intensity instead of catalyst are the attractive features of this method.     

Discrimination between 2AP producing and non‐producing rice rhizobacterial isolates using volatile profiling: a chemometric approach

2‐Acetyl‐1‐pyrroline (2AP) is known as a principal basmati aroma compound. The present study aims at discriminating rhizobacteria isolated from soils cultivated with basmati and non‐basmati rice for long duration. Volatile profiling was used as marker to discriminate the rhizobacterial isolates. Quantification of 2AP and other volatile compounds (VCs) produced by rhizobacteria was undertaken using HS‐SPME coupled with GC‐MS. Chemometrics tools such as hierarchical cluster analysis (HCA), principle component analysis (PCA) and multi dimensional scaling (MDS) were applied for volatile profiling of different isolates. Results showed significant discrimination of all 2AP producing (AP‐P) and non‐producing rhizobacterial isolates (AP‐NP) on the basis of their VC profile. This was validated by bacterial identification data as well. The frequency distribution for 2AP levels indicates that basmati isolates had higher frequency for 2AP production as compared to non‐basmati control. AP‐P and AP‐NP isolates have different VC profiling pattern irrespective of their origin. These isolates were found belonging to different groups when identified using 16S rDNA sequencing data. Chemometric analysis (PCA, HCA and MDS) helped to identify volatiles, which could be used as biomarker in discriminating the AP‐P and AP‐NP isolates. VC pattern of rhizobacteria could be used as volatile markers to distinguish between AP‐P and AP‐NP rhizobacterial isolates. Copyright © 2015 John Wiley & Sons, Ltd.     

Solvent effects on the absorption and fluorescence spectra of coumarins 6 and 7 molecules: determination of ground and excited state dipole moment

Absorption and fluorescence emission spectra of coumarins 6 and 7 were recorded in solvents with different solvent parameters, viz., dielectric constant epsilon and refractive index n. The fluorescence lifetime of these dyes were measured in butanol at higher values of viscosity over temperature. Experimental ground and excited state dipole moments are determined by means of solvatochromic shift method and also the excited state dipole moments are determined in combination with ground state dipole moments. It was determined that dipole moments of the excited state were higher than those of the ground state in both the molecules.     

Solvent Dependence on Structure and Electronic Properties of 7-(Diethylamino) - 2H -1- Benzopyran-2- one (C-466) Laser Dye

In this work, we studied influences on the absorption and fluorescence emission spectra of coumarin-4066 (C-466) with different solvent polarity scale. The spectral shifts reflect the effect of the equilibrium solvents association across the energized solute particle, which adjusts inertially as a result of quick charge realignment upon radiative deactivation to the lowest electronic state. The dipole moments of C-466 are determined by employing the Bakhshiev, Kawski-Chamma-Viallet, Lippert-Mataga and McRae relations. The results from all these methods are, excited state dipole moment of C-466 is higher than the ground state dipole moments and which indicates molecule is less polar in the ground state. Theoretical analysis was also carried out by Density Functional theory (DFT and TD –DFT) employing the BECKE-1998 (exchange)/STO-6G basic set in ethanol solvent and in vacuum medium. The HOMO-LUMO, Solvent Accessible Surfaces (SAS) and Molecular Electrostatic Potential (MEP) were analysed to acquire additional knowledge of the molecular arrangement and electronic properties of C-466. These photophysical properties suggest delineation can be mauled for laying out new luminescent tests for various solvents microenvironment.     

Palladium-Catalyzed Cross-Coupling Reactions of Potassium N-Methyltrifluoroborate Isoindolin-1-one with Aryl and Heteroaryl Chlorides

Potassium N-methyltrifluoroborate isoindolin-1-one was synthesized and used in Suzuki–Miyaura palladium-catalyzed cross-coupling reactions with aryl and heteroaryl chlorides to prepare 29 examples of substituted N-benzyl isoindolin-1-ones. The new approach benefits from mild reaction conditions that tolerate a variety of functional groups. In addition, because of the large number of commercially available aryl and heteroaryl chlorides that can serve as coupling partners, the approach readily provides access to libraries of substituted N-benzyl isoindolin-1-ones.     

Pd-catalyzed 5-endo-trig-type cyclization of β,γ-unsaturated carbonyl compounds: an efficient ring closing reaction to give γ-butenolides and 3-pyrrolin-2-ones

The 5-endo-trig-type cyclization has been performed using a Pd-bis(isoxazoline) catalyst. The present cyclization of β,γ-unsaturated carbonyl compounds gave γ-butenolides and 3-pyrrolin-2-ones in good to excellent yields.     

Biological synthesis and characterization of gold nanoparticles using Verbascum speciosum Schrad. and cytotoxicity properties toward HepG2 cancer cell line

Research on Chemical Intermediates - Gold nanoparticles (AuNPs) are considered as one of the best modes of drug releasing plans for the treatment of various diseases. AuNPs have different...