Effect Of Nitriles Research Articles

Impact of Nitriles on Bacterial Communities

Nitriles are organic molecules with −C≡N as functional group and often toxic for living organisms. Detoxification can occur via nitrilases that degrade nitriles directly to carboxylic acids and ammonia, or with nitrile hydratases and amidases that convert nitriles to amides and subsequently to carboxylic acids and ammonia. Despite the knowledge of enzymatic degradation pathways, the influence of these compounds on the composition of bacterial communities is unknown. The tolerances of four phylogenetically different bacterial strains without known nitrile detoxification systems (Agrobacterium tumefaciens, Bacillus subtilis, Corynebacterium glutamicum, and Escherichia coli) to the toxic effects of nine nitriles and the corresponding carboxylic acids were determined. Based on these results, the effect of nitriles on diversity and composition of compost-derived bacterial communities was monitored over time by 16S rRNA gene amplicon-based and metagenome analyses. Acetone cyanohydrin, 2-phenylpropionitrile, and pyruvonitrile exhibited a lethal, phenylacetonitrile, 4-hydroxybenzonitrile, and cyclohexanecarbonitrile a growth-suppressing and succinonitrile, acetonitrile, and crotononitrile a growth-promoting effect on the studied communities. Furthermore, each nitrile had a specific community-shaping effect, e.g. communities showing growth-suppression exhibited high relative abundance of Paenibacillus. In general, analysis of all data indicated a higher resistance of Gram-positive than Gram-negative bacterial community members and test organisms to growth-suppressing nitriles. More than 70 putative nitrilase-encoding and over 20 potential nitrile hydratase-encoding genes were identified during analysis of metagenomes derived from nitrile-enrichments, underlining the high yet often unexplored abundance of nitrile-degrading enzymes.

Back Cover: Diastereoselective Synthesis of β‐Ether Derivatives of Artemisinin, an Antimalarial Drug: The Effect of Nitrile on Stereoselectivity (Asian J. Org. Chem. 2/2016)

Back Cover: Diastereoselective Synthesis of β‐Ether Derivatives of Artemisinin, an Antimalarial Drug: The Effect of Nitrile on Stereoselectivity (Asian J. Org. Chem. 2/2016)

Diastereoselective Synthesis of β‐Ether Derivatives of Artemisinin, an Antimalarial Drug: The Effect of Nitrile on Stereoselectivity

AbstractMalaria is a life‐threatening disease affecting a major portion of the world's population with considerable loss of human life. Artemisinin, isolated from Artemisia annua, its oil‐ and water‐soluble derivatives, and other known antimalarials are recommended for artemisinin combination therapy by the World Health Organization. We have established a method for the stereoselective synthesis of β‐ether derivatives of dihydroartemisinin in high yield and high diastereoselectivity. The reaction either in acetonitrile or dichloromethane/trichloroacetonitrile (6:1) mixtures at 0 °C or room temperature, respectively, furnished the antimalarial drugs artemether 3 or arteether 4 in high yield with a high diastereomeric ratio. The effect the nitrile has on the yield and stereoselectivity is mechanistically explained.

Solvent Effect on Reaction Rate of Ruthenium–Fulvalene Complexes Intramolecularly Bridged by Alkyl Disulfides and the Effect of Chalcogen

Abstract The reaction rate of [(PPh3)(MeCN)Ru(µ2-η5:η5-C10H8)(µ-MeSSMe)Ru(MeCN)(PPh3)](BF4)2 (2A), the intermediate of oxidative addition of disulfide to produce bis(thiolato)-bridged complex [(PPh3)Ru(µ2-η5:η5-C10H8)(µ2-SMe)2Ru(PPh3)](BF4)2 (2), changed depending on the solvent (CDCl3, CD2Cl2, CD3COCD3, and CD3NO2). The dependency is well explained by the stabilization energy of solvation of eliminated nitrile during the reaction. The corresponding PhCN complexes [(PhCN)2(PPh3)Ru(µ2-η5:η5-C10H8)Ru(PPh3)(PhCN)2](BF4)2 (1C) and [(PPh3)(PhCN)Ru(µ2-η5:η5-C10H8)(µ-MeSSMe)Ru(PhCN)(PPh3)](BF4)2 (2C) were newly synthesized to know the effect of nitrile. The intermediate of oxidative addition of diselenide [(PPh3)(MeCN)Ru(µ2-η5:η5-C10H8)(µ-MeSeSeMe)Ru(MeCN)(PPh3)](BF4)2 (3A) and the corresponding end product [(PPh3)Ru(µ2-η5:η5-C10H8)(µ2-SeMe)2Ru(PPh3)](BF4)2 (3) were also isolated, and the structures were determined by single-crystal X-ray structural analysis.

Role of CYP2E1-mediated metabolism in the acute and vestibular toxicities of nineteen nitriles in the mouse

Allylnitrile, cis-crotononitrile, and 3,3′-iminodipropionitrile are known to cause vestibular toxicity in rodents, and evidence is available indicating that cis-2-pentenenitrile shares this effect. We evaluated nineteen nitriles for vestibular toxicity in wild type (129S1) and CYP2E1-null mice, including all the above, several neurotoxic nitriles, and structurally similar nitriles. A new acute toxicity test protocol was developed to facilitate evaluation of the vestibular toxicity by a specific behavioral test battery at doses up to sub-lethal levels while using a limited number of animals. A mean number of 8.5 ± 0.3 animals per nitrile, strain and sex was necessary to obtain evidence of vestibular toxicity and optionally an estimation of the lethal dose. For several but not all nitriles, lethal doses significantly increased in CYP2E1-null mice. The protocol revealed the vestibular toxicity of five nitriles, including previously identified ototoxic compounds and one nitrile ( trans-crotononitrile) known to have a different profile of neurotoxic effects in the rat. In all five cases, both sexes were affected and no decrease in susceptibility was apparent in CYP2E1-null mice respect to 129S1 mice. Fourteen nitriles caused no vestibular toxicity, including six nitriles tested in CYP2E1-null mice at doses significantly larger than the maximal doses that can be tested in wild type animals. We conclude that only a subset of low molecular weight nitriles is toxic to the vestibular system, that species-dependent differences exist in this vestibular toxicity, and that CYP2E1-mediated metabolism is not involved in this effect of nitriles although it has a role in the acute lethality of some of these compounds.

Synthesis of the O-linked pentasaccharide in glycoproteins of Trypanosoma cruzi and selective sialylation by recombinant trans-sialidase

The mucin-like glycoproteins of Trypanosoma cruzi have novel O-linked oligosaccharides that are acceptors of sialic acid in the trans-sialidase (TcTS) reaction. The transference of sialic acid from host glycoconjugates to the mucins is involved in infection and pathogenesis. The synthesis of the pentasaccharide, β- d-Gal p-(1→2)-[β- d-Gal p-(1→3)]-β- d-Gal p-(1→6)-[β- d-Gal f-(1→4)]- d-Glc pNAc and the corresponding alditol, previously isolated by reductive β-elimination of the mucins, is described. The key step was the 6-O-glycosylation of a easily accessible derivative of β- d-Gal f-(1→4)- d-Glc pNAc with a β- d-Gal p-(1→2)-[β- d-Gal p-(1→3)]- d-Gal p donor using the trichloroacetimidate method. The β-linkage was diastereoselectively obtained by the nitrile effect. The pentasaccharide is the major oligosaccharide in the mucins of T. cruzi, G strain and presents two terminal β- d-Gal p residues for possible sialylation by TcTS. A preparative sialylation reaction was performed with its benzyl glycoside and the sialylated product was isolated and characterized. NMR spectroscopic analysis showed that selective monosialylation occurred at the terminal (1→3) linked galactopyranose.

Effects of nitriles and amides on the growth and the nitrile hydratase activity of the Rhodococcus sp. strain gt1

Effects of some nitriles and amides, as well as glucose and ammonium, on the growth and the nitrile hydratase (EC 4.2.1.84) activity of the Rhodococcus sp. strain gt1 isolated from soil were studied. The activity of nitrile hydratase mainly depended on carbon and nitrogen supply to cells. The activity of nitrile hydratase was high in the presence of glucose and ammonium at medium concentrations and decreased at concentrations of glucose more than 0.3%. Saturated unsubstituted aliphatic nitriles and amides were found to be a good source of nitrogen and carbon. However, the presence of nitriles and amides in the medium was not absolutely necessary for the expression of the activity of nitrile hydratase isolated from the Rhodococcus sp. strain gt1.

Glycosyl Imidates, 65. Efficient synthesis of the Lewis antigen X (Lex) family

Abstracttert‐Butyldimethylsilyl 2‐azido‐4,6‐O‐benzylideneglucopyranoside 5 proved to be a versatile starting material for the synthesis of the Lex antigen family. 3‐O‐Fucosylation of 5, ensuing reductive benzylidene ring cleavage, and then 4‐O‐galactosylation afforded Lex trisaccharide building block 12 which was readily converted into trisaccharide donor 14α,β and into trisaccharide 3c‐O‐acceptor 16. Their reaction in acetonitrile as solvent at low temperatures (nitrile effect) afforded exclusively the β‐connected hexasaccharide 17, which was transformed via the same steps into hexasaccharide donor 20α,β and acceptor 22. The use of these building blocks and known lactose derivative 23b, and 3‐O‐benzoylprotected azidosphingosine 32 as acceptors led to ready formation of the target molecules. Thus, from 20α, β and 23b octasaccharide 24b was obtained which was converted via 25b and 26b into O‐unprotected octasaccharide 27; the derived O‐acyl‐protected donor 29bα was linked to 32, thus providing by application of the “azidosphingosine glycosylation procedure” dimeric Lex 1B. From 20α, β and 16 nonasaccharide 35a was obtained; its transformation via 36a and 37a into donor 38aα,β gave by reaction with 23b undecasaccharide 39a; the derived donor 43aα furnished by treatment with 32 trimeric Lex 1C. Similarly, from 20α, β and 22 dodecasaccharide 35b was generated which gave via 36b, 37b, and donor 38bα, β by reaction with 23b as acceptor tetradecasaccharide 39b; 39b, after transformation into the corresponding donor 43bα, β gave by treatment with 32 as acceptor tetrameric Lex 1D. Additionally, octasaccharide donor 29bα, β was attached to spacer 30, thus yielding spacer‐connected dimeric Lex antigen 2. magnified image

Synthesis of β-O-glycosides using enol ether and imidate derived leaving groups. Emphasis on the use of nitriles as a solvent

Two new methods of β-glycoside synthesis using donors 2 and 3 that contain leaving groups derived from enol ether and imidates have been developed. Effect of nitriles as a solvent in directing mainly β-glycosidations has been compared with various methods reported in the literature. Effectiveness of leaving group at low temperatures and participation of nitriles in the formation of nitrilium—nitrile conjugate has been emphasized.

Cuprous hydrometallurgy: Part I. Electrorefining copper via acidic solutions of cuprous sulphate containing organic nitriles

Cuprous sulphate is stable in acid solutions containing organic nitriles. Such solutions may be used as electrolytes in the electrorefining of copper much like the aqueous cupric sulphate electrolytes. High quality fine-grained copper is deposited from cuprous sulphate electrolytes in a one-electron process offering savings in energy or time compared with the conventional two-electron process. The effect of nitriles on the cell voltage, optimum current density and role of additives is considered and optimum electrolyte compositions and cell arrangements are proposed.

Vinyl polymerization by metal complexes, 17. Effect of nitriles on the vinyl polymerization initiated by imidazole‐copper (II) complex

AbstractPolymerization of vinyl monomers initiated by the imidazole‐copper(II) complex was studied in dimethyl sulfoxide solution. Different from the case of acrylonitrile, the polymerization of styrene and methyl methacrylate did not proceed, even in the presence of various sort of nitriles. From these findings and the copolymerization behaviour of acrylonitrile with styrene and methyl methacrylate, together with the spectroscopic data, the presence of acrylonitrile monomer is essential for generating active species to initiate the polymerization.

Effect of nitriles on the polarization of iron in 1·0N HCl

The polarization of iron in the presence of nine nitriles was studied at absolute concentrations of 1·0 × 10 −4M and 1·0 × 10 −3M for nitriles of eight carbons or less and at reduced concentrations of 0·2, 0·4, 0·75 and 1·0 for all nine nitriles. At the same reduced concentration, it was found that normal aliphatic nitriles from C 4 to C 15, phenylacetonitrile and 1,6-dicyanohexane gave about the same inhibition. Cycloheptylcyanide at reduced concentrations less than 1·0 resulted in a lower inhibition than the others. All nine nitriles were of a mixed type, affecting both the anodic and cathodic polarization curves.