1. INTRODUCTION Nitrogen-rich compounds are unique very reactive substances which have high heats of formation. Pyridine is one of the most well known aromatic cycles where a CH is replaced by a nitrogen atom, but the pyridine ring is only one member of the azine heterocycles, in which one or more CH group of benzene is replaced by π-accepting and σ-donating nitrogen atoms, proceeding from diaz...

Diboron compounds with a B−B bond, discovered B2Cl4 century ago, have been developed only since the turn of this for catalyzed borylation reactions, mostly well-know reagent bis(binacolato)diboron, (B2pin2). On other hand, chemistry tetrahydroxydiboron (THDB), also named bis-boric acid, is relatively underdeveloped. In review, properties THDB as borylation, reductant (including transfer hydroge...

This communication describes the first proof of concept for an asymmetric α-cyanation of β-ketoesters using a hypervalent iodine-based electrophilic cyanide-transfer reagent. A series of different organocatalysts has been investigated and it was found that the use of naturally occurring Cinchona alkaloids allows obtaining the target products in good yields and with moderate enantioselectivities...

MOTIVATION Fixed nitrogen is an essential requirement for the biosynthesis of cellular nitrogenous compounds. Some cyanobacteria can fix nitrogen, contributing significantly to the nitrogen cycle, agriculture and biogeochemical history of Earth. The rate and position on the species phylogeny of gains and losses of this ability, as well as of the underlying nif genes, are controversial. RESULT...

Structural characterisation and reactivity of new tetrahedral intermediates based on a highly modular barbituric acid scaffold, formed via chemoselective electron transfer using the SmI2–H2O reagent, are reported. Lewis acid promoted cleavage of bicyclic a-amino alcohols affords vinylogous N-acyliminium ions, which undergo selective (>95 :5, 1,4 over 1,2) capture with a suite of diverse nucleop...

The first one-pot deoxycyanamidation of alcohols has been developed using N-cyano-N-phenyl-p-methylbenzenesulfonamide (NCTS) as both a sulfonyl transfer reagent and a cyanamide source, accessing a diverse range of tertiary cyanamides in excellent isolated yields. This approach exploits the underdeveloped desulfonylative (N-S bond cleavage) reactivity pathway of NCTS, which is more commonly empl...

Transition-metal-free radical α-perfluoroalkylation with the accompanying vicinal β-alkenylation of unactivated alkenes is presented. These radical cascades proceed by means of 1,4- or 1,5-alkenyl migration by electron catalysis on readily accessed allylic alcohols. The reactions comprise a regioselective perfluoroalkyl radical addition with subsequent alkenyl migration and concomitant deproton...

An air- and moisture-stable fluoroiodane in the presence of AgBF4 is suitable for selective geminal difluorination of styrenes under mild reaction conditions. One of the CF bonds is formed by transfer of electrophilic fluorine from the hypervalent iodine reagent, while the other one arises from the tetrafluoroborate counterion of silver. Deuterium-isotope-labelling experiments and rearrangemen...

We propose a routine method for the mechanized measurement of aspartate aminotransferase with the CentrifiChem Analyzer, which is based on the recommendations of both the International Federation of Clinical Chemistry and the Société Française de Biologie Clinique. A modification of the CentrifiChem pipettor permits simultaneous pipetting of two reagents, thus achieving automatic preincubation ...

A mutant of Escherichia coli that lacks leucyl-, phenylalanyl-transfer ribonucleic acid-protein transferase had diminished activities of L-phenylalanyl-transfer ribonucleic acid synthetase and tryptophanase, grew faster than its parent with aspartic acid as the sole nitrogen source, accumulated higher levels of enterochelin in the medium during iron limitation, and exhibited an abnormal morphol...