New Fluorescent Hybrid Materials Based on Eu-Complexes in Oxyfluoride Glass and Glass-Ceramic Matrix

Hybrid materials were synthesized using a high temperature reaction. We used 80PbF2–20B2O3 glass as an inorganic matrix and various phenanthroline complexes europium(III) – as organic phosphors. The photoluminescence spectra of hybrid materials were measured just after synthesis and after heat treatment. We suggested that an exchange reaction between a Eu-complex and a glass matrix had occurred

N-Methylimidazole Promotes The Reaction Of Homophthalic Anhydride With Imines

The addition of N-methylimidazole (NMI) to the reaction of homophthalic anhydride with imines such as pyridine-3-carboxaldehyde-N-trifluoroethylimine (9) reduces the amount of elimination byproduct and improves the yield of the formal cycloadduct, tetrahydroisoquinolonic carboxylate 10. Carboxanilides of such compounds are of interest as potential antimalarial agents. A mechanism that rationalizes the role of NMI is proposed, and a gram-scale procedure for the synthesis and resolution of 10 is also described

Direct electrophilic acylation of n-substituted pyrazoles by anhydrides of carboxylic acids

A simple, convenient and scalable approach to 1-substituted 4-acylpyrazoles through direct acylation of pyrazoles by anhydrides of aliphatic, aromatic and fluorinated carboxylic acids in the presence of concentrated sulfuric acid as a catalyst is described. Target ketones were obtained in 41-86% isolated yields in high purity without laborious purification. The scope and limitations of the method are discussed. © 2013 Georg Thieme Verlag Stuttgart New York

Direct electrophilic acylation of n-substituted pyrazoles by anhydrides of carboxylic acids

A simple, convenient and scalable approach to 1-substituted 4-acylpyrazoles through direct acylation of pyrazoles by anhydrides of aliphatic, aromatic and fluorinated carboxylic acids in the presence of concentrated sulfuric acid as a catalyst is described. Target ketones were obtained in 41-86% isolated yields in high purity without laborious purification. The scope and limitations of the method are discussed. © 2013 Georg Thieme Verlag Stuttgart New York

An efficient synthesis of isomeric 1-(1-Alkyl-1H-pyrazolyl) ethanones

A simple and versatile general method for the preparation of N-substituted 3-, 4-, or 5-acetylpyrazoles from corresponding acids via hydrolysis and decarboxylation of substituted diethyl [(1-alkyl-1H-pyrazolyl)carbonyl]malonates was developed. Title compounds were prepared in three steps without isolation of intermediates in 48-82% overall yield. © 2012 HeteroCorporation

Direct bromination of ethyl 5-alkylthiophene-2-carboxylates

Approaches to brominated thiophene-2-carboxylic acids by electrophilic bromination of the corresponding acids and esters were compared and investigated. A synthetic route was developed involving direct bromination of ethyl 5-alkylthiophene-2-carboxylates followed by saponification of the resulting ethyl 5-alkyl-4-bromothiophene-2-carboxylates. The key bromination step is selective in dichloromethane solution at 0-5 °C and furnishes the corresponding ethyl 5-alkyl-4-bromothiophene-2-carboxylates in excellent yields. No migration or isomerization of the alkyl substituents was observed. © Georg Thieme Verlag Stuttgart New York