Carbonyl and thiocarbonyl compounds. XI. Synthesis of halogenated benzodioxoles by the action of tetrahalo-o-benzoquinones on benzophenone hydrazones and their cleavage by nucleophilic reagents

p,p′-Dichloro-, p,p′-dimethyl- and p,p′-dimethoxybenzophenone hydrazones react with tetrachloro- and tetrabromo-o-benzoquinone to give directly the halogenated benzodioxoles (IIIa-IIIf), respectively, together with the corresponding tetrahalocatechol. Cleavage of the dioxole ring by nucleophilic reagents depends markedly on the nature of the substituents. The dimethoxyderivatives (IIIc) and (IIIf) proved to be unusually reactive toward cleavage by dilute mineral acids, lithium aluminum hydride, hydrazines and malonitrile, whereas the dichloro analog behaves normally and is not cleaved under the same conditions.     

Oxazolidinone polycyclitols. Stereospecific synthesis of novel aminocarbasugars with oxazolidinone ring

Two new oxazolidinone polycyclitols, 4,5,7,8,9-pentahydroxy-3-tosyldecahydronaphtho [2,1-d]oxazol-2(9bH)-one and 4,5,6,7,8-pentahydroxy-3-tosyldecahydronaphtho [2,1-d]oxazol-2(9bH)-one were synthesized starting from p-benzoquinone. An endo selective Diels–Alder cycloaddition between p-benzoquinone and 1-acetoxybutadiene followed by stereoselective reduction with NaBH₄–CeCl₃·7H₂O led to the formation of an allylic cis-diol. The obtained diols were protected with p-TsNCO to yield bis-carbamates and then a palladium-catalyzed ionization/cyclization reaction produced two oxazolidinone derivatives. Oxidation of the two double bonds in either oxazolidinones with OsO₄ followed by acetylation produced oxazolidinone-pentaacetates whose exact configurations were determined by X-ray diffraction analysis. Controlled removal of the acetate groups furnished the desired two new oxazolidinone polycyclitols.     

12-Tungstophosphoric acid niched in Zr-based metal-organic framework: a stable and efficient catalyst for Friedel-Crafts acylation

Heteropoly acids(HPA) are well known for their versatile solid acid catalysis in diverse chemical reactions, however they suffer from low surface area(10 m~2/g) and leaching into the reactions media, which reduce their prospects as industrial catalyst.Herein, a novel hybrid material HPW@Zr-BTC,composed of 12-tungstophoric acid(HPW) and Zr~(Ⅳ)-benzene tri-carboxylate(Zr-BTC) metal-organic framework(MOF), was prepared via one-pot solvothermal method. Excellent HPW loading up to 32.3 wt% was achieved, and HPW@Zr-BTC composite proved to be highly stable, besides the crystalline morphology of Zr-BTC was intact. The catalytic activity of the hybrid composite was explored via Friedel-Crafts acylation of anisole with benzoyl chloride.The 28.2 wt% HPW@Zr-BTC showed excellent catalytic performance, with 99.4% anisole conversion and 97.6% yield(pmethoxybenzophenone) under solvent free conditions. Excellent retention of catalytic activity was achieved after at least five consecutive runs due to non-observable HPW leaching. The promising activity and stability of the catalyst forecasted its potential industrial applications.     

Reactions of 2-Cyano-2-nitrosomethylbenzthiazole: One-Pot Synthesis of New Polyfunctional Pyrazine Derivatives

2-Cyano-2-nitrosomethylbenzthiazole reacts with some active methylene and nucleophile derivatives to yield new fused and isolated polyfunctional pyrazine, -[1,2,4]triazine, -[1,4,5]benzoxadiazepin, -[1,4,5]benzothiadiazepine, [1,4,5]benzotriazepine, -triazole and -triazolo[3,2-c]triazine derivatives in one-pot reaction. The structures were based on IR, MS, and 1 H NMR spectra and elemental data.     

An Efficient and Facile Synthesis of Novel Benzimid-(Thi) Azole Dicarboxaldehydes as a Versatile Precursors for new Ox-, Thi-and Diazepine Derivatives

Abstract

Novel 2-cyanomethylbenzimid-(thi)-azole-2,2-dicarboxaldehydes were prepared in quantitative yields and reacted easily with o-aminophenol derivatives to yield new multi-functionallized ox-, thi- and diazepine derivatives in one-pot reaction.     

2‐[N‐(X‐Chlorophenyl)carbamoyl]benzenesulfonamide (with X = 2 and 4)

The structures of 2‐[N‐(2‐chlorophenyl)carbamoyl]benzenesulfonamide and 2‐[N‐(4‐chlorophenyl)carbamoyl]benzenesulfonamide, both C₁₃H₁₁ClN₂O₃S, are stabilized by extensive intra‐ and intermolecular hydrogen bonds. In both structures, sulfonamide groups are hydrogen bonded via the N and O atoms and form chains of molecules. The carbamoyl groups are also hydrogen bonded, involving the O and N atoms, further strengthening the polymeric chains running along the c and a axes in the 2‐ and 4‐chloro derivatives, respectively. Carbamoylsulfonamide derivatives are novel compounds with a great potential for medicinal applications.     

Molecular imprinted membrane biosensor for pesticide detection: Perspectives and challenges

Polymers are crucial component for modern sensor devices. However, comprehensive research on polymer sensor technology is still going strong. Molecular imprinted membrane (MIM) is a great design that demonstrates acceptable recognition ability when integrated with a sensing transducer. Generally, the detection technique that has been widely and sparingly used for pesticide is mass spectrometry merged with gas and/or liquid chromatography. Nevertheless, this review focuses not on these common methods but on the specific methodology of MIM biosensor for the analysis of pesticides. Finally, the transduction schemes of the MIM sensor are reviewed. The interest of this article is sketched to the trends and challenges present in this field of study.