Cyanoethyl Group Research Articles

Synthesis and Crystal Structures of Bromo(1,10-phenanthroline-N,N′)tris(2-cyanoethyl)phosphinocopper(I) and Bromo(2,2′-bipyridine-N,N′)tris(2-cyanoethyl)phosphinocopper(I)

The two new complexes bromo(1,10-phenanthroline-N,N′)tris(2-cyanoethyl)phosphinocopper(I) and bromo(2,2′-bipyridine-N,N′)tris(2-cyanoethyl)phosphinocopper(I) were synthesized and their X-ray crystal structures were determined. The first complex crystallizes in the triclinic space group P-1 with the crystal cell parameters a = 7.7596(7) A, b = 11.470(1) A, c = 12.803(1) A, α = 78.884(1)°, β = 79.759(1)°, γ = 86.867(1)°, V = 1100.0(2) A3 and Z = 2. The second complex crystallizes in the orthorhombic space group Pbca with the crystal cell parameters a = 10.614(1) A, b = 12.345(1) A, c = 31.903(3) A, V = 4180.3(7) A3 and Z = 8. In both compounds, the copper(I) ion is four-coordinate with a distorted tetrahedral geometry. In the 1,10-phenanthroline complex, an intermolecular dipole–dipole interaction between two cyano groups stabilizes an unfavorable synclinal conformation of one cyanoethyl group of the phosphine ligand.

Preparation of New Nitrogen-Bridged Heterocycles. 59. Syntheses and Intramolecular Interactions of 3-(Acylmethylthio)- and 3-[(3-Ethoxycarbonyl-2-propenyl)thio]thieno[3,4-<i>b</i>]indolizine Derivatives

Various thieno[3,4-b]indolizine derivatives having an acylmethylthio or (3-ethoxycarbonyl-2-propenyl)thio group at the 3-position which could not be obtained by a conventional method were prepared by a new procedure using cyanoethyl group as a protecting group and their intramolecular arene-pi interactions were investigated. In the (1)H-NMR spectra of these thieno[3,4-b]indolizines, the low-field shifts (delta 0.10-0.33 ppm) for the 5-protons were observed in comparison with those of 3-(methylthio)thieno[3,4-b]indolizines as a standard. The UV spectra also exhibited a characteristic absorption band at 425-445 nm attributable to the arene-pi interaction but their intensities were generally lower than those of 3-(arylmethylthio)thieno[3,4-b]indolizines. In their X-ray analyses, the anti conformation for 3-(acylmethylthio)thieno[3,4-b]indolizines and the gauche one for the 3-(3-ethoxycarbonyl-2-propenyl)thio derivatives were exhibited.

Synthesis and properties of novel conducting polyaniline copolymers

AbstractA novel copolymer based on aniline and N‐β‐cyanoethylaniline was chemically prepared and characterized by a number of techniques including UV–vis, FTIR, ESR, XRD, and TGA. According to the systematic studies on the physical properties, it was found that the copolymers had excellent solubility in common organic solvents especially in DMF and pyridine, while the conductivity and yield decreased as the content of cyanoethyl group increased in the system. Moreover, an increase in the feed ratio of N‐β‐cyanoethylaniline induced a blue‐shift of the absorption bands in the UV–vis and IR region and significant line broadening of ESR signals together with a reduction in spin density. The XRD patterns of the copolymers lost the characteristic diffraction peaks of emeraldine salt as the ratio of cyanoethyl group increased. The thermal stability of the copolymer was increased with increasing the feed molar ratio of N‐β‐cyanoethylaniline. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 140–147, 2007

Cyanoethylation of pyrazoles under conditions of phase-transfer catalysis and hydrogenation of the cyanoethylation products

Cyanoethylation of pyrazoles with acrylonitrile was studied under conditions of phase-transfer catalysis. The ease of the process depends on the acidity of pyrazoles. Cyanoethylpyrazoles can be converted into the corresponding aminopropylpyrazoles via reduction of the cyano group. The reduction with lithium tetrahydridoaluminate is accompanied by β-elimination of the cyanoethyl group.

Solvent-induced partial cyanoethylation and hydroxylation of cyanoethyl group

An investigation has been made on the cyanoethylation of cotton fabric using aqueous sodium hydroxide with acrylonitrile in presence of solvents acetone and ethanol at different concentrations. The hydrolysis of β-cyanoethyl ether of cyanoethylated fabric in presence of solvents is studied. The rate of hydrolysis is enhanced by acetone and ethanol concentration. The formation of various products during hydrolysis is analyzed by infrared spectroscopy method while scanning electron microscopy follows the variations in surface morphology. Some of the physical and chemical properties are also studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 183–191, 2006

A General Method for the Synthesis of 2‘-O-Cyanoethylated Oligoribonucleotides Having Promising Hybridization Affinity for DNA and RNA and Enhanced Nuclease Resistance

[reaction: see text] An effective method for the synthesis of 2'-O-cyanoethylated oligoribonucleotides as a new class of 2'-O-modified RNAs was developed. The reaction of appropriately protected ribonucleoside derivatives with acrylonitrile in t-BuOH in the presence of Cs2CO3 gave 2'-O-cyanoethylated ribonucleoside derivatives in excellent yields, which were converted by a successive selective deprotection/protection strategy to 2'-O-cyanoethylated 5'-O-dimethoxytritylribonucleoside 3'-phosphoramidite derivatives in high yields. Fully 2'-O-cyanoethylated oligoribonucleotides, (Uce)12 and (GceAceCceUce)3, were successfully synthesized in the phosphoramidite approach by use of the phosphoramidite building blocks. It was also found that oligoribonucleotides having a 2'-O-cyanoethylated ribonucleoside (Uce, Cce, Ace, or Gce) could be obtained by the selective removal of the TBDMS group from fully protected oligoribonucleotide intermediates without loss of the cyanoethyl group by use of NEt3 x 3HF as a desilylating reagent. The detailed T(m) experiments revealed that oligoribonucleotides containing 2'-O-cyanoethylated ribonucleosides have higher hybridization affinity for both DNA and RNA than the corresponding unmodified and 2'-O-methylated oligoribonucleotides. In addition, introduction of a cyanoethyl group into the 2'-position of RNA resulted in significant increase of nuclease resistance toward snake venom and bovine spleen phosphodiesterases compared with that of the methyl group.

A new method for RNA synthesis by use of the cyanoethyl group as the 2′-hydroxyl protecting group

A new method for the synthesis of natural RNAs was developed via 2'-O-cyanoethylated RNA derivatives as available precursors. It was found that the cyanoethyl groups of 2'-O-cyanoethylated RNAs could be removed by use of the reverse reaction of the Michael addition of alcohols with acrylonitrile to afford 2'-unprotected RNAs. In addition, new ribonucleoside 3'-phosphoramidite building blocks having the cyanoethyl group as the 2'-hydroxyl protecting group have sterically less hindered circumstance around the 3' reaction site than the commercially available phosphoramidite building blocks.

Synthesis of 9‐Substituted Tetrahydrodiazepinopurines: Studies Toward the Total Synthesis of Asmarines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of 9-Substituted Tetrahydrodiazepinopurines: Studies toward the Total Synthesis of Asmarines

A methodology for the preparation of asmarine analogues has been developed. The asmarines are cytotoxic marine alkaloids with a unique tetrahydro[1,4]diazepino[1,2,3-g,h]purine (THDAP) structure. Three cyclization methods were applied for the preparation of the 9,9-disubstituted 10-hydroxy-THDAP system, namely, aminomercurization, iodocyclization, and acid-catalyzed cyclization. The DMPM group of the NOH functionality and cyanoethyl group of the N-9 atom were found to be the most suitable protecting groups. The structures of all compounds were mainly determined from NMR measurements including (15)N chemical shifts obtained from (15)NH HMBC spectra. The end products are at least about 1 order of magnitude less active than the natural product asmarine B.

Preparation and structural characterisation of O-aminopropyl starch and amylose

O-Aminopropyl starch was prepared by Michael addition of acrylonitrile and subsequent reduction with freshly prepared cobalt boride and sodium borohydride. In a second approach, the aminopropyl group was introduced via Williamson etherification with N-phthalyl-protected 3-bromo-1-propylamine. The protecting group was removed by borohydride reduction and subsequent hydrolysis in acetic acid. The DS of all samples and the degree of reduction of the cyanoethyl groups were estimated from the 1H NMR spectra. Total monomer composition was determined after methanolysis or hydrolysis and trimethylsilylation by GLC and GCMS. While the regioselectivity in the thermodynamically controlled reaction was O -6>O-2>O-3 (50:37:13), the kinetically controlled process showed strongly preferred O-2-etherification (up to 94%) followed by O-6- and O-3-substitution. It could be influenced by choice of solvent (water, Me 2SO) and base (NaOH, Li-dimsyl).

Toward an Ideal Synthesis of Oligonucleotides: Development of a Novel Phosphoramidite Method with High Capability

Abstract Several novel methods for reliably carrying out the oligonucleotide synthesis via the phosphoramidite strategy have been developed. The first is the method using allyloxycarbonyl and allyl groups for the protection of nucleoside bases and internucleotide linkages, respectively. These protectors can be cleanly removed under almost neutral conditions with a mixture of an organic Pd(0) complex such as Pd[P(C6H5)3]4 or Pd2[(C6H5CH=CH)2CO]3·CHCl3, and P(C6H5)3 in the presence of a nucleophile such as butylammonium formate, diethylammonium hydrogencarbonate, diethylammonium carbonate, or dimedone. A method for the facile oxidation of nucleoside phosphites to phosphates has been developed; this is performed under non-aqueous and non-basic conditions using 2-butanone peroxide in dichloromethane, t-butyl hydroperoxide in toluene, or bis(trimethylsilyl) peroxide in dichloromethane. The combined use of the N-allyloxycarbonyl/P–O-allyl-protected method and anhydrous/non-basic oxidation is extremely useful for the synthesis of nucleotide derivatives sensitive to moisture and/or bases, producing them in higher yield and at a greater level of purity than the existing methods using acyl or aroyl and cyanoethyl groups for the protection of nucleoside bases and internucleotide linkages, respectively, and iodine in aqueous pyridine for the oxidation. Further, acid/azole complexes serving as highly useful activators of phosphoramidites have been invented. The reagents include imidazolium triflate, N-(phenyl)imidazolium triflate, benzimidazolium triflate, and N-(methyl)benzimidazolium triflate, which allow higher-yield synthesis of oligonucleotides than conventionally employed 1H-tetrazole and related reagents. For example, synthesis of oligoribonucleotides via the allyloxycarbonyl/allyl-protected strategy has been carried out more efficiently using N-(phenyl)imidazolium triflate as a promoter than 5-(ethylthio)-1H-tetrazole, which has been found to be the most effective promoter among those currently available for oligoribonucleotide synthesis. Further, imidazolium triflate has opened the door to the extremely convenient and efficient synthesis of oligodeoxyribonucleotides without nucleoside-base protection. This method is obviously advantageous over N-protected methods because it eliminates tedious operations and the use of superfluous reagents required for the introduction and removal of the N-protecting group; risks of decomposition and loss of product by protection and deprotection are also avoided. Facile liquid-phase preparation of short oligomers has also been developed; this is successfully accomplished using stoichiometric amounts of building blocks by the aid of an equimolar amount of azolium reagent or a catalytic amount of 5-(p-nitrophenyl)-1H-tetrazole. These two methods are beneficial from an economical point of view, particularly in large-scale synthesis.

Improvement of functional properties of jute‐based composite by acrylonitrile pretreatment

Cyanoethylation of jute fiber in the form of nonwoven fabric was successfully achieved using an acrylonitrile monomer which is said to react with the hydroxyl groups of fiber constituents. The degrees of cyanoethylation to different extents were undertaken by varying the reaction time. An IR study showed that extent of cyanoethylation increases with increase of the reaction time. Cyanoethylated fibers thus obtained were further treated with unsaturated polyester resin to obtain modified fiber composites. These composites have been found to be tolerant against cold and boiling water where water absorption and thickness swelling are much reduced compared to those of unmodified fiber composite. It is also observed that the moisture content of the modified fiber composites is remarkably reduced. Cyclic tests reveal that use of cyanoethylated fiber leads to improvement of the dimensional stability of the fiber composites. The mechanical properties of the modified fiber composites improved remarkably due to better bonding at the fiber–matrix interface and this effect is more pronounced with a higher degree of cyanoethylation. A scanning electron micrograph of the fractured surfaces of cyanoethylated jute composite showed excellent retention of resin on broken fiber ends, whereas the unmodified composite showed uncoated fibers and holes in the matrix. DSC data demonstrated that the moisture content of the composites reduces with increase of the cyanoethylation. Both TG and DSC thermograms showed an additional peak due to decomposition of cyanoethyl group which is shifted to a higher value with the extent of cyanoethylation. However, the cellulose degradation temperature remained almost the same. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 495–506, 2000

Tris(2-cyanoethyl)amine.

In the title compound, N(CH(2)CH(2)CN)(3), (I), the three cyanoethyl groups adopt a conformation with the CN groups oriented in the same direction, suggesting the compound may behave as a potential tripodal ligand.

Improvement of functional properties of jute-based composite by acrylonitrile pretreatment

Cyanoethylation of jute fiber in the form of nonwoven fabric was successfully achieved using an acrylonitrile monomer which is said to react with the hydroxyl groups of fiber constituents. The degrees of cyanoethylation to different extents were undertaken by varying the reaction time. An IR study showed that extent of cyanoethylation increases with increase of the reaction time. Cyanoethylated fibers thus obtained were further treated with unsaturated polyester resin to obtain modified fiber composites. These composites have been found to be tolerant against cold and boiling water where water absorption and thickness swelling are much reduced compared to those of unmodified fiber composite. It is also observed that the moisture content of the modified fiber composites is remarkably reduced. Cyclic tests reveal that use of cyanoethylated fiber leads to improvement of the dimensional stability of the fiber composites. The mechanical properties of the modified fiber composites improved remarkably due to better bonding at the fiber–matrix interface and this effect is more pronounced with a higher degree of cyanoethylation. A scanning electron micrograph of the fractured surfaces of cyanoethylated jute composite showed excellent retention of resin on broken fiber ends, whereas the unmodified composite showed uncoated fibers and holes in the matrix. DSC data demonstrated that the moisture content of the composites reduces with increase of the cyanoethylation. Both TG and DSC thermograms showed an additional peak due to decomposition of cyanoethyl group which is shifted to a higher value with the extent of cyanoethylation. However, the cellulose degradation temperature remained almost the same. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 495–506, 2000

Scanning electron microscopy study of chemically modified coir fibers

Chemical-surface modification of coir fibers was done by dewaxing, using an alkali treatment (5% and 10% NaOH), vinyl grafting with methyl methacrylate (MMA) and cyanoethylation. The chemically modified fibers were characterized by Fourier transform infrared (FTIR) spectroscopy. In addition, the surface features of untreated, dewaxed, alkali-treated, grafted, and cyanoethylated coir fibers were studied using scanning electron microscopy (SEM). Progressive changes in surface morphology were observed. SEM observations showed the removal of tyloses from the surface of coir as a result of alkali treatment (5%), resulting in a rough fiber surface with regularly spaced pits. At a lower percentage of grafting (PMMA), the surfaces became more or less uniform, while the surfaces of the coir fibers with a higher percentage of grafting were increasingly covered with grafted materials, resulting in canal-like cavities between the overgrowths of the grafted materials on the unit cells. Cyanoethylated coir-fiber surfaces showed an insufficient deposit of cyanoethyl groups. SEM analysis of the samples was corroborated by measurements of a mechanical property (maximum stress at break). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1169–1177, 2001

A new method for introducing amidate linkages in oligonucleotides using phosphoramidite chemistry

Cyanoethyl-protected phosphotriester links in oligonucleotides made with standard phosphoramidite chemistry were converted to phosphoramidate linkages during oligonucleotide synthesis on solid support. The cyanoethyl group was removed with piperidine, and the resulting phosphodiester was activated with p-tosyl chloride. An amine nucleophile displaced the tosyl to yield a phosphoramidate linkage.

Ethyl 1-(2-cyanoethyl)-3,5-dimethyl-1H-indole-2-carboxylate

The title compound, C16H18N2O2, is an important precursor in the synthesis of 1,2,3,4-tetrahydropyrazinoindoles, which show excellent antihistamine, antihypertensive and central nervous system depressant properties. The carbethoxy group attached to C2 and the planar cyanoethyl group attached to N1 make dihedral angles of 11.0(4) and 75.0(3)degrees, respectively, with the mean plane of the indole ring, The C-C=N chain is linear with a bond angle of 179.3 (4)degrees.

Facile preparation of TTP series donors by using cyanoethyl groups

TTP (tctralhiapcntalcnc) scries donors have been prepared by two steps of phosphite-mediated cross-couplings. By using cyanoethyl groups instead of acctoxybenzyl as a protecting group, we have succeeded in improving the yields. The applicability of this method will be discussed.

First synthesis of alternating SATE-phosphotriester/ phosphodiester prooligonucleotides on solid support

Prooligonucleotides with alternating S-Acyl-ThioEthyl (SATE) phosphotriester and phosphodiester linkages or a gap were synthesized by elimination of cyanoethyl group with non-nucleophilic base DBU. Their half-lives in the presence of Pig Liver Esterases (PLE) and in total cell extract were determined.

Ionic association in gel electrolytes of varied polarity as studied by FT Raman spectroscopy

Ion solvation and ion association in liquid oligo (ethylene glycol) dimethylether ((EG) nDME) lithium triflate solution and in gel type polymer electrolytes of varied polarity have been investigated. The gel electrolytes were prepared by photoinitiated crosslinking homopolymerization of oligo (ethylene glycol) dimethacrylate ((EG) nDMA, n=23) and its copolymerization with acrylonitrile (AN), cyclocarbonatopropylmethacrylate (CPMA) and cyanomethylmethacrylate (CyMA), respectively, in the presence of (EG) 11DME as plasticizer and LiCF 3SO 3. The symmetric stretching mode of the SO 3 group and the lithium–oxygen mode of LiCF 3SO 3 in these systems were studied as a function of ether oxygen atoms to lithium ratio and temperature by means of Raman spectroscopy. The substitution of the nonpolar methyl end groups of the oligo (ether) by cyanoacetate or cyanoethyl groups causes an increase of the content of free anions in the solution. The contents of free anions observed for (EG) 23DMA gel networks is lower compared with that of (EG) 11DME - LiCF 3SO 3 solutions. The insertion of the polar comonomers AN, CPMA and CyMA into (EG) 23DMA based networks has been found to enhance the content of free anions.