Facile Knoevenagel and Domino Knoevenagel/Michael Reactions Using Gel‐Entrapped Base Catalysts

An efficient method for Knoevenagel condensation of arenecarbaldehydes with active methylene compounds such as barbituric acid and Meldrum's acid in the presence of gel‐entrapped base catalysts is reported. The method has been extended to the one‐pot synthesis of arylmethylene‐bis[3‐hydroxycyclohex‐2‐en‐1‐one] derivatives from dimedone (=5,5‐dimethylcyclohexane‐1,3‐dione) and arenecarbaldehydes by using domino Knoevenagel/Michael reaction sequence.     

Vibrational,Thermal, and Physical Characterizations of Some Zinc Niobo Tellurite Glasses Doped with Rare Earth (Eu,Dy)

Optics and Spectroscopy - In this communication, we report physical and thermal properties along with Raman spectroscopic investigations on Zinc Niobo Tellurite glass systems doped with Eu2O3 and...     

Biogenic synthesis of palladium nanoparticles using Boswellia sarrata and their applications in cross-coupling reactions

A facile and green route for biogenic synthesis of palladium nanoparticles (PdNPs) using aqueous extract of nontoxic and renewable Boswellia sarrata leaves is reported. The as-synthesized PdNPs were systematically characterized by using ultraviolet (UV)–visible spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The PdNPs were crystalline and cubic in nature with average particle size of ~6 nm and successfully employed as heterogeneous catalyst in the Suzuki–Miyaura and Mizoroki–Heck cross-coupling reactions. The PdNPs could be recycled up to five times with modest change in the catalytic activity.     

CO2 and SnII Adducts of N‐Heterocyclic Carbenes as Delayed‐Action Catalysts for Polyurethane Synthesis

Catalytic rivals : Both CO₂‐protected tetrahydropyrimidin‐2‐ylidene‐based N‐heterocyclic carbenes (NHCs) and Sn^II‐1,3‐dimesitylimidazol‐2‐ylidene, as well as Sn^II‐1,3‐dimesitylimidazolin‐2‐ylidene complexes (example displayed), have been identified as truly latent catalysts for polyurethane (PUR) synthesis rivaling all existing systems both in activity and latency.

     

An expeditious synthesis of 2,3-dihydroquinozoline-4(1H)-ones using graphene-supported sulfonic acid

Graphene-supported sulfonic acid (Gr@SO₃H) has been prepared by covalent grafting of (3-mercaptopropyl)trimethoxysilane in the matrix of graphene followed by treatment with sulfuric acid and hydrogen peroxide. Gr@SO₃H has been successfully characterized by Fourier transform infrared (FT-IR) spectroscopy, Fourier transform Raman (FT-Raman) spectroscopy, CP-MAS ¹³C NMR spectroscopy, thermogravimetric analysis (TGA), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, and X-ray diffractometer (XRD) analysis. Gr@SO₃H served as a robust heterogeneous catalyst for the synthesis of bioactive 2,3-dihydroquinazolin-4(1H)-ones from anthranilamide and aryl aldehydes in ethanol. Recyclability experiments were executed successfully for six consecutive runs.     

An alternative model of a nonlinear business cycle

The purpose of this paper is to develop a piecewise linear model to understand complex dynamics that arise out of sophisticated nonlinear macrodynamic models developed by Hicks and Goodwin. This piecewise analogue has several advantages: (i) it is a natural extension of a linear accelerator; (ii) it exhibits all the qualitative results of Goodwin's model; (iii) it enables one to conveniently derive newer bounds on output; and (iv) students find its representation appealing and understandable. The use of computer software is advocated for complex economic models that are described by systems of differential equations. To this end, the usefulness of STELLA (a Macintosh-based software) in verifying the qualitative predictions of the analysis, is illustrated.     

SYNTHESIS AND APPLICATION OF 2-(ARYLAZO)-8-NITRONAPHTHO[1,2-d] THIAZOLE DISPERSE DYES

Abstract

The paper describes the synthesis of 2-amino-8-nitronaphtho[1,2d]thiazole and its utilization to prepare a range of heterocyclic azo disperse dyes. These arylazo dyes were studied with respect to their color and constitution relationship. These dyes were applied on polyester fibre and their fastness properties were evaluated.