Aurivillius family of layered perovskites,BiREWO6 (RE = La,Pr, Gd,and Dy): Synthesis,characterization, and photocatalytic studies

The present work deals with the synthesis, characterization, and photocatalytic studies of layered perovskites belonging to Aurivillius family. Layered perovskites of various chemical compositions, BiREWO₆ (RE = La, Pr, Gd, and Dy), were synthesized by an ethylene glycol–assisted sol–gel method. These materials were characterized by X-ray diffraction, scanning electron microscopy–energy dispersive spectroscopy (EDS), Fourier transform infrared, Raman, and ultraviolet–visible diffuse reflectance techniques. The composition of all these materials was obtained from EDS. The unit cell lattice parameters were attained from Rietveld refinement program, Fullprof.2k, by refining the d-lines of BiREWO₆. The band gap energy of these samples was obtained from the Kubelka–Munk plot. The photocatalytic activity of all the samples was evaluated by photodegradation of methylene blue. The mechanistic degradation pathway of methylene blue was studied using radical quenchers.     

New polymorphs of curcumin

Two new crystalline polymorphs and an amorphous phase of the active curcuminoid ingredient in turmeric are reported. Curcumin polymorph 2 has higher dissolution rate and better solubility than the known polymorph 1.     

One-pot synthesis of bis (phenylimino dihydro thiazolyl-2H-chromene) derivatives

A novel series of bis (phenylimino dihydro thiazolyl-2H-chromene) derivatives have been synthesized through an efficient one-pot multicomponent approach involving different substituted of 3-(2-bromoacetyl)-2H-chromen-2-ones, phenyl isothiocyanates and para-phenylenediamine in presence of dimethylformamide solvent. The target compounds were obtained in a shorter reaction time through simple reaction work up with good yields. All the synthesized products were characterized by their spectral and analytical data like IR, ¹H NMR, ¹³C NMR, Roesy, and mass spectral data.     

Triphenylphosphine–Iodine: An Efficient Reagent System for the Synthesis of Nitriles From Aldoximes

A wide range of aldoximes were smoothly converted to the corresponding nitriles with triphenylphosphine–iodine.     

Efficient Synthesis of β‐Amino Alcohols Catalyzed by Niobium Pentachloride: Regioselective Ring Opening of Epoxides with Aromatic Amines

Epoxides undergo a rapid ring‐opening reaction with aromatic amines catalyzed by niobium pentachloride under mild reaction conditions. All the reactions were carried out at room temperature to afford the corresponding β‐amino alcohols in excellent yields and with high regioselectivity.     

Stereoselective synthesis of the phytotoxic nonenolide herbarumin-I from l-ascorbic acid

A stereoselective synthesis of herbarumin-I in 22% overall yield, starting from l-ascorbic acid derived (S)-2,3-O-isopropylidine glyceraldehyde as a chiral template is reported. Stereoselective allylation and vinylation to control the required stereogenic centres and macrolactonisation followed by a ring-closing metathesis (RCM) are the key steps.     

Synthesis of 3-(2-(4,5-Dihydro-3,5-diphenylpyrazol-1-yl)thiazol-4-yl)-2H-chromen-2-one Derivatives via Multicomponent Approach

An efficient synthesis of 3-(2-(4,5-dihydro-3,5-diphenylpyrazol-1-yl)thiazol-4-yl)-2H-chromen-2-one derivatives by a simple, atom-economical, and multicomponent reaction of chalcones, thiosemicarbazide, and 3-(2-bromoacetyl) coumarins in the presence of aqueous sodium hydroxide in refluxing ethanol is reported. The structures of newly prepared compounds have been confirmed by their analytical and spectral (IR, ¹HNMR, ¹³CNMR and mass) data.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Cation‐ and Anion‐Substituted Potassium Manganese Phosphate,KMnP3O9: Luminescence and Photocatalytic Studies

Phosphates as multifunctional materials were of vital importance in the environmental and energy fields. In the present work, a new cyclophosphate, potassium manganese phosphate (KMnP₃O₉) (hereafter KMPO), was prepared by solid state method. Cations (Ag⁺ and Cu²⁺) and anion (N^3?) were substituted into KMPO lattice via ion‐exchange and solid state methods, respectively. The as‐prepared materials were characterized by powder X–ray diffraction, SEM–EDS and UV–visible diffuse reflectance spectra. Rietveld refinement was carried out for parent material. All the prepared materials were found to crystallize in the hexagonal lattice and isomorphous with KCoP₃O₉. The nitrogen content in N^3?‐substituted KMPO was estimated by EDS and O‐N‐H analysis. The bandgap energy of the cation‐ and anion‐substituted samples was lower compared to that of pristine KMPO. Gouy method was employed to determine the magnetic susceptibility of KMPO. The photoluminescence property of Mn²⁺ in all the samples was studied, and the color coordinates were calculated using CIE 1931 chromaticity. The photocatalytic activity of visible light active material, N^3?‐substituted KMPO, was examined against the degradation of methylene blue and methyl violet at ambient conditions.     

Sulfamic acid: an efficient, cost-effective and recyclable solid acid catalyst for the Friedlander quinoline synthesis

o-Aminoaryl ketones undergo smooth condensation with α-methylene ketones in the presence of sulfamic acid (NH₂SO₃H) (SA) under mild reaction conditions to afford the corresponding polysubstituted quinolines in excellent yields. The catalyst can be recovered by simple filtration and can be recycled in subsequent reactions. The method is simple, cost-effective and environmentally benign.