Synthesis of new (pyrazol-1-yl)(7-nitro-1h-indol-2-yl)ketone derivatives

The condensation of 7-nitroindole-2-carbohydrazide derivatives with acetylacetone lead to (pyrazol-1-yl)(7-nitroindol-2-yl)ketones.     

Recent Advances in Electrochemical Sensors Based on Molecularly Imprinted Polymers and Nanomaterials

This review focuses on the recent achievement during period of 2013–2018 related to the electrochemical sensors based on molecularly imprinted polymers (MIPs) combined with nanomaterials for various kinds of applications. MIPs based electrochemical sensors have found a great interest due to their high stability, short time required for electropolymerization, and high specificity towards the target analyte. The sensitivity is considered as one of the important parameter in electrochemical sensing strategies that should be improved by the combination of highly conductive nanomaterials with selective MIPs. In general, the most employed nanomaterials are magnetic nanoparticles, gold nanoparticles (AuNPs), carbon nanotubes and graphene. This review discusses the main current achievement as well as the current challenges regarding the development of biomimetic sensors in electroanalysis.     

Symmetric multi-box splines for higher degree

We consider the space S _n =S _n (v ₀,…,v _n+r ) of compactly supported C ^n?1 piecewise polynomials on a mesh M of lines through ?² in directions v ₀,…,v _n+r . A sequence ψ=(ψ ₁,…,ψ _r ) of elements of S _n is called a multi-box spline if every element of S _n is a finite linear combination of shifts of (the components of) ψ. For the case n=2, 3 we give some examples for multi-box splines and show that they are not always stable. It is further shown that any C ^n?1 piecewise polynomial of degree n≥2 on M, is possibly a symmetric multi-box spline.     

Théorèmes de trace de type Szegö dans le cas singulier

Let f be a function eiθ→f(eiθ)=|1−eiθ|^2αf₁(eiθ) with f₁ a regular strictly positive function and a real number α in ]−1/2,1/2[?{0}. In a previous paper for such a number α we have obtained the asymptotic behaviour of the entries of the inverse of the Toeplitz matrix TN,f when N goes to infinity. These results allow us to give trace formulas, which extend a classical expression of Szegö's limits theorems.     

Studies with enaminonitriles: Synthesis and chemical reactivity of 2‐phenyl‐3‐piperidin‐1‐yl acrylonitrile under microwave heating

Benzyl cyanide reacts with triethylorthoformate and piperidine in DMF solution to yield the title compound 2 . This reacted with aromatic amines to yield either aminoacrylonitriles or quinoline depending on reaction conditions and substitution pattern on the aromatic amine. The reaction of compound 2 with hydrazine hydrate could only be effected in the microwave oven and resulted in the formation of aminopyrazole 7 . Diazotization of 7 and coupling with an active methylene reagent afforded pyrazolo[5,1‐c]‐[1,2,4]triazine derivatives.     

Selective Monoesterification of Unprotected Mono and Disaccharides

Abstract

Under mild conditions, treatment of unprotected methyl-α-D-glucopyranoside, N-acetylglucosamine and maltose with triphenylphosphine, diethylazodicarboxylate and equimolar amount of various carboxylic acids allowed regioselective 6-O-esterifications (6′-O for maltose) of the carbohydrate without esterification of other hydroxyl groups. This reaction found an application in the synthesis of liposoluble, labelled sugars and hydrosoluble polymers.