Reaction Of Nitriles Research Articles

Simultaneous determination of cyanide and thiocyanate in plasma by chemical ionization gas chromatography mass-spectrometry (CI-GC-MS)

An analytical method utilizing chemical ionization gas chromatography-mass spectrometry was developed for the simultaneous determination of cyanide and thiocyanate in plasma. Sample preparation for this analysis required essentially one-step by combining the reaction of cyanide and thiocyanate with pentafluorobenzyl bromide and simultaneous extraction of the product into ethyl acetate facilitated by a phase-transfer catalyst, tetrabutylammonium sulfate. The limits of detection for cyanide and thiocyanate were 1 μM and 50 nM, respectively. The linear dynamic range was from 10 μM to 20 mM for cyanide and from 500 nM to 200 μM for thiocyanate with correlation coefficients higher than 0.999 for both cyanide and thiocyanate. The precision, as measured by %RSD, was below 9 %, and the accuracy was within 15 % of the nominal concentration for all quality control standards analyzed. The gross recoveries of cyanide and thiocyanate from plasma were over 90 %. Using this method, the toxicokinetic behavior of cyanide and thiocyanate in swine plasma was assessed following cyanide exposure.

Cyanide Detoxifying Enzyme: Rhodanese

Rhodanese is an ubiquitous enzyme active in all living organisms from bacteria to man. It is multifunctional enzyme but plays central role in cyanide detoxification. This enzyme is also widely distributed in plants. It functions through double displacement (ping pong) mechanism. The activity of rhodanese in a particular tissue reflect the ability of that tissue to detoxify cyanide. The level of rhodanese in different tissues of animals is correlated with the level of exposure to cyanide. Mitochondrial bovine rhodanese is the best characterized rhodanese which is 293 amino acids long consisting of inactive N-terminal and catalytic C-terminal domain. It comprises of single polypeptide chain of 32,900 Da folded into two domains of about equal size. Active site of rhodanese has essential sulfhydryl and aromatic groups in close proximity. In addition to this, competitive inhibition of rhodanese by aromatic ions suggests the presence of tryptophanyl residue at the active center. Sequence analysis of rhodanese-like proteins highlights their heterogeneity to form rhodanese superfamily presenting variably arranged rhodanese domains as single or tandem domains, or combined with other protein domains. Many methods for rhodanese assay have been reported but the most common one is colorimetric estimation of thiocyanate formed from the reaction of cyanide with thiosulphate catalyzed by rhodanese. Keywords: Rhodanese, ubiquitous, cyanide, detoxification, domain, thiosulphate, thiocyanate, mitochondrial enzyme, double displacement mechanism, toluene, ageing, colonic epithelium, Rhodanese activity, rhodanese-selenium.

Perfectly Green Organocatalysis: Quaternary Ammonium Base Triggered Cyanosilylation of Aldehydes

AbstractQuaternary ammonium bases, such as aqueous (CH3)4NOH, were found to be an extraordinarily efficient catalyst for cyanosilylation of aldehydes. The addition reaction of trimethylsilyl cyanide (TMSCN) to equivalent aldehydes could proceed smoothly with turnover frequency (TOF) up to 3000000 h−1 and in near 100% yield under solvent‐free conditions. These organic catalysts also tolerated various aldehydes including aromatic, aliphatic and α,β‐unsaturated aldehydes. This process perfectly conforms to the features of green chemistry: no waste regarding side‐products and unconverted reactants, solvent‐free, excellent catalytic activity, and no requirement for separation.

A Comparison Between Catalyst‐Free and ZrOCl2⋅8H2O‐Catalyzed Strecker Reactions for the Rapid and Solvent‐Free One‐Pot Synthesis of Racemic α‐Aminonitrile Derivatives

AbstractA rapid, straightforward, and efficient method for the synthesis of racemic α‐aminonitriles has been developed. This one‐pot, three‐component Strecker reaction of carbonyl compounds, amines and trimethylsilyl cyanide (TMSCN) proceeds in excellent yields in the presence of a catalytic amount of zirconium oxychloride octahydrate (ZrOCl2⋅8 H2O) under solvent‐free conditions at room temperature. The protocol is particularly convenient for both aliphatic and aromatic aldehydes, as well as cyclic ketones, in combination with primary and secondary amines. This method is also highly chemoselective. Mild reaction conditions, excellent yields, high chemoselectivity, operational simplicity, the absence of tedious separation procedures, clean reaction profiles, high atom‐economy, as well as the inexpensive and environmentally benign catalyst are the key advantages of this protocol. This Strecker reaction has also been studied in the absence of any catalyst and proceeds with good yields. The overall outcomes of these reactions in the presence and absence of catalyst are compared in the present study.

Stereoselective nitrile hydratase

Nitrile hydratase, catalyzing the hydration reaction of nitrile to amides, is an important enzyme which has been used in the industrial production. Various studies on nitrile hydratase revealed its crystal structure and also proposed some hypothesis of its catalytic mechanism. Recent reports suggested the stereoselectivity of nitrile hydratase, which is regarded as a potential character to enrich its application. However, the isolated organisms are limited as only few genera identified contain this special stereoselective enzyme. This review described the corresponding strain for producing the enzyme, the structure and catalytic mechanism for stereoselectivity of the enzyme. Key words: Stereoselectivity, nitrile hydratase, substrate specificity, asymmetric synthesis.

ChemInform Abstract: CeO2‐Catalyzed One‐Pot Selective Synthesis of Esters from Nitriles and Alcohols.

AbstractCeric oxide is a reusable catalyst for the preparation of esters (III) by solvent‐free reaction of nitriles (I) with alcohols (II).

ChemInform Abstract: Solvent‐Free Tandem Synthesis of 2‐Thiazolines and 2‐Oxazolines Catalyzed by a Copper Catalyst.

Tandem reactions of nitriles with 2-aminoethanethiol hydrochloride or amino alcohols in the presence of a catalytic amount of cupric methacrylate (CuII2L4, L = methacrylate) were employed to prepare 2-thiazolines and 2-oxazolines under mild reaction conditions. The synthetic procedure showed high selectivity for the synthesis of mono- and bis-thiazolines and oxazolines, and a variety of 2-thiazolines and 2-oxazolines was obtained in good to excellent yields.

A convenient synthesis of 3-aryl-1,2,4-oxadiazoles from ethyl acetoacetate and amidoximes under solvent-free conditions

1,2,4-Oxadiazole containing compounds have attracted great attention due to their applications in material chemistry and therapeutics. Herein we report a convenient synthesis of 3-aril-[1,2,4-oxadiazol-5yl] propan-2-one ( 3a-d) by heating of b -ceto esters and an amidoximes without any solvent and in the absence of base. The arylamidoximes ( 1a-f ) was synthesized in moderate and excellent yields (31- 89%) by reaction of nitrile with hydroxylamine hydrochloride in water at 25oC. In the general synthetic strategy employed in our study is illustrated in scheme 1. The 3-aril-[1,2,4-oxadiazol-5yl] propan-2-one ( 3a-f ) were synthesized by treatment of arylamidoxime ( 1a-f with b -ceto esters for 4 hour without any solvent and in the absence of base . The reaction was monitored by TLC (thin layer chromatography). The heterocycles ( 3a-f) were obtained in moderate and good yields (60-88%). The products were identified using both analytical and spectral data (IR, 1 H and 13 C NMR) and all compounds are in full agreement with the proposed structure.

Boric Acid Catalysed Synthesis of α-Aminonitriles by a Three-Component Reaction at Room Temperature

A simple, efficient, and cost-effective method has been developed for the one-pot, three-component condensation reaction of trimethylsilyl cyanide, aldehydes and aromatic amines using boric acid as a heterogeneous solid acid catalyst, under solvent-free conditions. α-Aminonitriles were synthesised relatively quickly in good yields at room temperature.

Synthesis of Benzoxazoles by the Copper Triflate Catalysed Reaction of Nitriles and O-Aminophenols

An efficient procedure for the synthesis of benzoxazoles by the heteroannulation of nitriles and o-aminophenols in the presence of a catalytic amount of copper(II) trifluoromethanesulfonate, has been developed. This method represents a practical and attractive alternative for the synthesis of both 2-arylbenzoxazoles and 2-alkylbenzoxazoles.

Utility of Enaminonitriles in Heterocyclic Synthesis: Synthesis and Antimicrobial Activity of Some New Azole and Azine Derivatives

Reactions of 6-amino-3-methyl-1,4-diphenyl-1,4-dihydropyrano(2,3-c)pyrazole-5-carbonitrile (1) with a va- riety of reagents leads to the synthesis of pyrano(2,3-c)pyrazole derivatives has been investigated with the aim to explore the use of this exceptionally reactive nitrile in heterocyclic synthesis. Keywords Dihydropyrano(2,3-c)pyrazole, Enaminonitriles, Azoles, Pyrimidines, Pyridines

ChemInform Abstract: Tandem One‐Pot Synthesis of Polysubstituted Pyridines Using the Blaise Reaction Intermediate and 1,3‐Enynes.

AbstractSequential reaction of nitriles, Reformatsky reagents and 1,3‐enynes proceeds with complete regio‐ and chemoselectivity to provide the polysubstituted pyridines.

One-pot three-component reaction: Synthesis of substituted β-cyanocarbonyls in aqueous media

An environmentally friendly and simple method for the synthesis of alkyl nitriles or β-cyanocarbonyls via a one-pot three-component reaction of Meldrum's acid, aldehydes and sodium cyanide in water, without using any catalyst or activation at room temperature is reported.

An efficient, solvent-free microwave-assisted synthesis and antimicrobial screening of 1,6-dihydropyrimidine analogues

A series of compounds 4-(4-(4-aminophenyl)-6-(aryl)-1,6-dihydropyrimidin-2-ylthio)butanenitriles 5a–l were synthesised by the reaction of allyl cyanide 4 with 3a–l. Compounds 3a–l were prepared from reaction between various chalcones 1a–l and thiourea in presence of catalytic amount of potassium hydroxide. Compounds 3a–l, and 5a–l were prepared by classical as well as MWI methods. Structures of the compounds were characterized by IR, 1H NMR, 13C NMR and mass spectral data. The newly synthesized compounds 5a–l were screened for their antimicrobial activity against different strains of bacteria and fungi using serial broth dilution method. Compounds 5e, 5g and 5k were found to be most active with MIC of 25 μg/mL against selected bacterial strains, while compound 5d, 5f, 5j and 5k were found to be most active with MIC 50 μg/mL against selected fungal strains.

Solvent‐Free Tandem Synthesis of 2‐Thiazolines and 2‐Oxazolines Catalyzed by a Copper Catalyst

AbstractTandem reactions of nitriles with 2‐aminoethanethiol hydrochloride or amino alcohols in the presence of a catalytic amount of cupric methacrylate (CuII2L4, L = methacrylate) were employed to prepare 2‐thiazolines and 2‐oxazolines under mild reaction conditions. The synthetic procedure showed high selectivity for the synthesis of mono‐ and bis‐thiazolines and oxazolines, and a variety of 2‐thiazolines and 2‐oxazolines was obtained in good to excellent yields.

Amberlyst-15 as a recyclable heterogeneous catalyst for synthesis of N-tert-butylamides via Ritter-type reaction

Abstract Highly efficient method for the preparation of N - tert -butylamides by reaction of nitriles with tert -butylacetate is described using Amberlyst-15 as a recyclable heterogeneous catalyst. Selective amidation of benzonitrile in the presence of acetonitrile was also achieved.

Ultrasound-assisted catalytic synthesis of acyclic imides in the presence of p-toluenesulfonic acid under solvent free conditions

A rapid and convenient preparation of acyclic imides by the reaction of aliphatic and aromatic nitriles with acyclic carboxylic anhydride in the presence of catalytic amounts of p-toluenesulfonic acid under thermal or ultrasonic conditions is reported. The advantages of this procedure are moderate reaction times, good to excellent yields, use of inexpensive and ecofriendly catalyst. The reaction of nitriles with aliphatic anhydrides proceeds in thermal conditions, while by the use of ultrasound irradiations these reactions get accelerated.

Facile synthesis of novel poly(α-aminonitrile) networks through one-pot Strecker reactions

Organic polymeric networks (OPNWs) containing the repeated structural units of α-aminonitriles were successfully prepared for the first time in high yields (88–93%) via one-pot Strecker reactions of dialdehydes, di/tri-amines, and trimethylsilyl cyanide under catalyst-free conditions. The OPNWs possessing two functional groups (cyano- and secondary amino-groups) were very stable and insoluble in water and many common organic solvents, and also had high thermal stabilities.

Cross-linkable nitrile functionalized graphene oxide/poly(arylene ether nitrile) nanocomposite films with high mechanical strength and thermal stability

To develop high performance graphene-based nanocomposites, precise interface control and dispersal of graphene in the polymer hosts are challenging due to its strong interlayer cohesive energy and surface inertia. Here, we firstly report an efficient and novel method to functionalize graphene oxide with 4-aminophenoxyphthalonitrile and successfully compound them with poly(arylene ether nitrile)(PEN) to prepare nanocomposite films. Fourier transforms infrared spectra (FTIR), Raman spectra, and atomic force microscopy (AFM) were employed to examine the surface functionalization of the graphene oxide. The resulting PEN nanocomposite, with 0.75 wt% nitrile functionalized graphene oxide (G-CN), revealed an approximate 27% and 68% increase in tensile strength and Young's modulus, respectively, compared to that of neat PEN. The onset thermal degradation temperature (Td5) and the maximum decomposition temperature (Td,max) of the composite with 0.75 wt % of G-CN were increased by 21 and 25 °C compared to those of neat PEN. More importantly, the mechanical and thermal properties of the PEN composite films were further enhanced by the chemical cross-linking reaction of nitriles, which opens a new route to optimize the interface structures and improve the comprehensive performances of graphene–polymer nanocomposites.

Cu(OTf)2-catalysed Ritter reaction: efficient synthesis of amides from nitriles and halohydrocarbons in water

An efficient and green protocol for the synthesis of amides through the Ritter reaction of nitriles and halohydrocarbons was developed. Cu(OTf)2 economically efficiently catalysed the Ritter reaction in water. A range of halohydrocarbons (benzyl, tert-butyl, sec-alkyl and primary alkyl halohydrocarbons) were coupled with nitriles, providing the corresponding amides.