Search

The article explains various mechanisms that are involved in the catalysis and inhibition of nicotinamidase/pyrazinamidase (PncA) from Mycobacterium tuberculosis. Pyrazinecarbonitrile is shown to be one compound that acts as an irreversible inactivator of PcnA.

A convenient synthesis of [beta]-hydroxynitriles from enantiomerically enriched 3-unsubstituted 2-isoxazolines is described by using a base-catalyzed ring-opening reaction taking place without loss of enantiopurity. The ring-opening along with organocatalytic enantioselective synthesis of 3-unsubstituted 2-isoxazolines has enabled a short 2-step synthesis of [beta]-hydroxynitriles from [alpha],[beta]-unsaturated aldehydes in high enantiomeric purity.

The ruthenium bis(dihydrogen) complex Ru[H.sub.2][([H.sub.2]).sub.2][(P[Cyp.sub.3]).sub.2], incorporating two tricyclopentylphosphines is used as catalyst to perform hydrogenation of benzonitrile into benzylamine under very mild conditions. The reaction mechanism involves N-coordination through the nitrile function or first hydrogenation with benzylimine formation, followed by C-H activation, coordination at ruthenium as an orthometalated ligand.

A novel series of thermally stable yellow light emitting fluoranthenes with an amine donor and a nitrile acceptor is prepared from a ketene-S,S-acetal under mild conditions without using an organometal catalyst. The organic light emitting device of yellow fluoranthene has displayed low turn-on voltage and maximum brightness with luminance efficiency of 2.0 Cd/A without using any dopant.

The cobalt catalyzed hydroaldoximation and hycrocyanooximation of unactivated alkenes is described. Secondary and tertiary aldoximes and oximonitriles are prepared and the reactions have expanded the arsenal of reductive carbon-carbon bond forming reactions as well as regioselective functionalizations of unactivated double bonds.

The addition of allyl cyanides across alkynes in the presence of a nickel/P[(4-C[F.sub.3]-[C.sub.6][H.sub.4]).sub.3] catalyst to yield polysubstituted 2,5-hexadienenitriles with defined stereo- and regiochemistry is reported. The carbocyanation reaction could also be applied for the stereoselective construction of the trisubstituted double bond of plaunotol, an antibacterial natural product active against Helicobacter pylori.

An efficient and selective Re[H.sub.7][(P[Ph.sub.3]).sub.2]-catalyzed addition of carbonyl compounds to the carbon-nitrogen bond of nitriles to yield the corresponding (Z)-enamines as important synthetic intermediates is described. The key step in the reaction includes the chemoselective [alpha]-C-H activation of carbonyl compounds induced by the [alpha]-heteroatom effect in the presence of nitriles.

A highly stereoselective Rh(II)-catalyzed formation of nitrile-substituted cyclopropanes is presented and [alpha]-cyano diazoacetamide reagents have reacted with a variety of mono- and disubstituted olefins. This method has featured the unprecedented use of an achiral hydrogen-bond donor additive to increase the selectivity and has exploited the powerful trans-directing ability of amides solving the diastereocontrol issue of the formation of substituted 1-cyanocyclopropane-1-carboxy derivatives.

The reaction of chloroformate esters, trimethylsilyl cyanide, and 1,2-dienes in the presence of a nickel/dppp catalyst to yield cyanoesterification products is reported. The obtained cyanoesterification products have a structure of allylic cyanide undergo further allyl cyanation reaction across alkynes with the aid of a nickel/P[(4-C[F.sub.3]-[C.sub.6][H.sub.4]).sub.3] catalyst to afford highly substituted acrylonitrile derivatives.

The intramolecular arylcyanation of alkenes is shown to be a versatile protocol to prepare a range of synthetically interesting nitriles having a benzylic quaternary carbon. The characterization of important intermediates in the catalytic cycle and synthetic applications including enantioselective versions of the reaction is achieved.

Several studies are conducted to explain the principles underlying the encapsulation of the reaction taking place between carboxylic acids and isonitriles in small spaces. The analysis has also led to the identification of an elusive intermediate along the reaction pathway.

A one-pot stereoselective synthesis of oxazolines based on metal triflate catalyzed haloamidation reaction of alkenes with NBS, a nitrile, and water is described. The reaction used Lewis acids, Cu[(OTf).sub.2] and Zn[(OTf).sub.2] and chalcones as catalyst for synthetic transformation.

A Rhodococcus erythropolis AJ270, the nitrile hydratase and amidase-containing microbial whole cell catalyst, under very mild conditions were used to study the biotransformations of a number of racemic [beta]-hydroxy and [beta]-amino nitrile derivatives. The study provided an efficient and powerful approach to highly enantiopure [beta]-hydroxy and [beta]-amino acids and their amide derivatives that are valuable chiral intermediates in organic synthesis.

The new chemistry of carboxylic acids and isonitriles is described. The isonitrile-initiated chemistry has gone beyond the synthesis of secondary amides, providing access to tertiary amides bearing N-methyl groups.