An unexpected tetragonal unit cell for N‐(L‐2‐aminobutyryl)‐L‐serine

The title dipeptide {systematic name: (S)‐2‐[(S)‐2‐azaniumylbutanamido]‐3‐hydroxypropanoate}, C₇H₁₄N₂O₄, was synthesized in the anticipation that it would form nanoporous crystals with hexagonal symmetry. Single‐crystal X‐ray diffraction analysis showed that it had instead adopted a unit cell in the space group I4, similar to L‐alanyl‐L‐alanine [Fletterick, Tsai & Hughes (1970). J. Phys. Chem. 75 , 918–922]. The resulting packing arrangement has a high density for a peptide (1.462 Mg m⁻³), which is rendered possible by extensive disorder over two positions for the ethyl side chain of the 2‐aminobutyric acid fragment and over three positions for the serine side chain.<!?tpb=17.5pt>     

Chromatography-Based Determination of Anabolic Steroids in Biological Fluids: Future Prospects Using Electrochemistry and Miniaturized Microchip Device

Anabolic steroids form one of the important classes of doping agents and their consumption has been found to give benefits to the athletes. Inspite of the fact that they also produce adverse effects and damage several organs and systems, their consumption is continuously increasing in competitive games. The World Anti-Doping Agency and International Olympic Committee have banned the use of anabolic steroids and several other compounds. This article focuses an over view of various chromatographic techniques commonly used for detecting anabolic steroids and their metabolites during last 3 years in human biological fluids to establish the cases of doping. The possibility of electrochemistry- and microchip-based techniques have been considered as possible techniques for future to achieve simple and fast analysis at the site of competitive games as the first tool to detect the cases of doping.     

Solvent-Free Conversion of N,N-Dimethylhydrazones to Nitriles Under Microwave Irradiation

A variety of aldehyde N,N-dimethylhydrazones are rapidly converted into the corresponding nitriles using oxone supported on wet Al₂O₃ under microwave irradiation in dry media.     

Synthesis of (R)‐Japonilure and (4R,9Z)‐9‐Octadecen‐4‐olide,Pheromones of the Japanese Beetle and Currant Stem Girdler

Asymmetric total synthesis of the sex pheromones of Japanese beetle and currant stem girdler, (R)‐japonilure (1) and (4R,9Z)‐9‐octadecen‐4‐olide (2), has been achieved.     

A Mild and Versatile Method for the Tetrahydropyranylation of Alcohols and Their Detetrahydropyranylation

An efficient and mild method for tetrahydropyranylation of alcohols and their detetrahydropranylation using NH₄Cl is described. This protocol provides a useful alternative tetrahydropyranylation of alcohols and their deprotection at different pH.

     

CeCl3·7H2O-Catalyzed Synthesis of 1-Oxo-hexahydroxanthene Derivatives in Aqueous Media

Cerium(III) chloride heptahydrate (CeCl₃·7H₂O) catalyzes the reaction of substituted salicylaldehydes with 1,3-cyclohexane dione or dimedone in aqueous medium at reflux temperature to afford the corresponding 1-oxo-1,2,3,4,9,10-hexahydroxanthene derivatives4 0 in high yields.     

Regioselective Photocyclization Reactions of 3‐Allyloxy‐6‐chloro‐2‐(thiophen‐3‐yl)‐4H‐chromen‐4‐one: Solvent Effect

The photo‐irradiation of thienylchromenone resulted in the regioselective cyclization which is exclusively controlled by the nature of solvent used as reaction medium. Compared to nonpolar medium, polar solvent furnished a diverse array of novel angular tetracyclic photoproducts with gem‐dihydro functionality and exocyclic double bonds on the fused pyran ring, which is unprecedented to best of our knowledge.     

Heteropoly Acids as Heterogeneous and Reusable Catalyst for α-Thiocyanation of Ketones

Simple, efficient, and mild method for α-thiocyanation of ketones in presence of heteropolyacid has been developed. This methodology offered α-oxothiocyanates in good to excellent yields at room temperature in a highly selective manner. The catalyst could be efficiently recovered from the reaction and reused.