- Cu-catalyzed cyanomethylation of imines and α,β-alkenes with acetonitrile and its derivatives
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We describe copper-catalyzed cyanomethylation of imines and α,β-alkenes with a methylnitrile source and provide an efficient route to synthesize arylacrylonitriles and β,γ-unsaturated nitriles. This method tolerates aliphatic and aromatic alkenes substituted with a variety of functional groups such as F, Cl, Br, Me, OMe,tert-Bu, NO2, NH2and CO2H with good to excellent yields (69-98%). These systems consist of inexpensive, simple copper catalyst and acetonitrile with its derivatives (α-bromo/α-iodo-acetonitrile) and are highly applicable in the industrial production of acrylonitriles.
- Ahmad, Muhammad Siddique,Ahmad, Atique
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p. 5427 - 5431
(2021/02/12)
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- Reactions of 3-arylpropenenitriles with arenes under superelectrophilic activation conditions: Hydroarylation of the carbon-carbon double bond followed by cyclization into 3-arylindanones
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Reactions of 3-arylpropenenitriles [ArCH[dbnd]CHCN] with arenes [Ar'H] under the superelectrophilic activation conditions with Br?nsted superacid TfOH (CF3SO3H) or strong Lewis acid AlBr3 result, first, in the formation of products of hydroarylation of the carbon-carbon double bond, 3,3-diarylpropanenitriles [Ar(Ar’)CHCH2CN]. Reactions may go further in TfOH leading to 3-arylindanones, as products of intramolecular aromatic acylation by the electrophilically activated nitrile group. Intermediate cationic species, derived at the protonation of the starting 3-arylpropenenitriles onto the carbon of C[dbnd]C bond and the nitrile nitrogen, have been studied by DFT calculation. A plausible reaction mechanism including the formation of highly reactive dications [(Ar)HC+–CH2C+ = NH] has been proposed. The obtained 3,3-diarylpropanenitriles have been transformed into pharmaceutically valuable 5-(2,2-diarylethyl)-1H-tetrazoles [Ar(Ar’)CHCH2Tetr] and 3-diarylpropylamines [Ar(Ar’)CH(CH2)2NH2] by the reactions with NaN3 and LiAlH4 correspondingly.
- Gorbunova, Yelizaveta,Zakusilo, Dmitriy N.,Boyarskaya, Irina A.,Vasilyev, Aleksander V.
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-
- Design, synthesis and biological evaluation of 8-(2-amino-1-hydroxyethyl)-6-hydroxy-1,4-benzoxazine-3(4H)-one derivatives as potent β2-adrenoceptor agonists
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A series of β2-adrenoceptor agonists with an 8-(2-amino-1-hydroxyethyl)-6-hydroxy-1,4-benzoxazine-3(4H)-one moiety is presented. The stimulatory effects of the compounds on human β2-adrenoceptor and β1-adrenoceptor were characterized by a cell-based assay. Their smooth muscle relaxant activities were tested on isolated guinea pig trachea. Most of the compounds were found to be potent and selective agonists of the β2-adrenoceptor. One of the compounds, (R)-18c, possessed a strong β2-adrenoceptor agonistic effect with an EC50 value of 24 pM. It produced a full and potent airway smooth muscle relaxant effect same as olodaterol. Its onset of action was 3.5 min and its duration of action was more than 12 h in an in vitro guinea pig trachea model of bronchodilation. These results suggest that (R)-18c is a potential candidate for long-acting β2-AR agonists.
- Yi, Ce,Xing, Gang,Wang, Siqi,Li, Xiaoran,Liu, Yichuang,Li, Jinyan,Lin, Bin,Woo, Anthony Yiu-Ho,Zhang, Yuyang,Pan, Li,Cheng, Maosheng
-
-
- Magnetic MCM-41 nanoparticles as a support for the immobilization of a palladium organometallic catalyst and its application in C-C coupling reactions
-
In this study, the surface of magnetic MCM-41 nanoparticles (MCM-41/Fe3O4) was modified by 3-Aminopropyltriethoxysilane (APTES) and further, 1-methyl imidazole was anchored on their surface using cyanuric chloride as a linker. Then, Pd2+ ions were immobilized on the surface of the modified MCM-41/Fe3O4 (Pd-imi-CC@MCM-41/Fe3O4), and its application was studied as a magnetically recyclable nanocatalyst in carbon-carbon coupling reactions between a wide range of aryl halides and butyl acrylate, methyl acrylate, acrylonitrile, phenylboronic acid, or 3,4-difluorophenylboronic acid under the conditions of a phosphine-free ligand and an air atmosphere. This catalyst has the advantages of both the Fe3O4 nanoparticles and mesoporous MCM-41. The structure of the catalyst was characterized via TEM, SEM, EDS, WDX, N2 adsorption-desorption isotherm, XRD, TGA, FT-IR, and AAS. Also, the recovered catalyst was characterized via SEM, AAS and FT-IR. All the products from the carbon-carbon coupling reaction were obtained with excellent yields and high TON and TOF values, which indicate the high efficiency and activity of this catalyst. The selectivity of this catalyst was studied with various aryl halides bearing different functional groups. Furthermore, the heterogeneity and stability of Pd-imi-CC@MCM-41/Fe3O4 was studied via AAS, and leaching and poisoning tests. According to the results, this heterogeneous catalyst can be reused several times.
- Tahmasbi, Bahman,Ghorbani-Choghamarani, Arash
-
supporting information
p. 14485 - 14501
(2019/09/30)
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- Visible light-induced direct conversion of aldehydes into nitriles in aqueous medium using Co@g-C3N4 as photocatalyst
-
Unprecedented Co@g-C3N4 catalyzed visible light driven efficient conversion of a variety of aldehydes into corresponding nitriles is reported. Operational simplicity, excellent yield of pure products (87–94%), ambient reaction condition, using aqueous methanol as solvent, visible-light photocatalysis are the salient features of envisaged methodology for direct conversion of aldehydes into nitriles. Furthermore, reusability of Co@g-C3N4 was checked up to five runs and it was noticed that there was no substantial change in morphology as well as the catalytic efficiency of catalyst.
- Verma, Fooleswar,Shukla, Prashant,Bhardiya, Smita R.,Singh, Manorama,Rai, Ankita,Rai, Vijai K.
-
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- Polymer-supported palladium: A hybrid system for multifunctional catalytic application
-
Polymer-supported palladium was synthesized by applying a single-step wet chemical synthesis route and the resultant composite material was characterized by means of various techniques. Infrared and UV–visible spectra provided information on the chemical structure of the polymer. Microscopy techniques showed the general morphology of the polymer. The oxidation state of palladium was determined using the X-ray photoelectron spectroscopy method. The synthesized material was applied as a heterogeneous catalyst for the Heck coupling reaction and also as an electrocatalyst for the oxidation of cysteine.
- Taher, Abu,Choudhary, Meenakshi,Nandi, Debkumar,Siwal, Samarjeet,Mallick, Kaushik
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- An efficient class of bis-NHC salts: Applications in Pd-catalyzed reactions under mild reaction conditions
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This study describes an efficient class of bis-N-heterocyclic carbene (bis-NHC) salts that can be easily made from commercially available and inexpensive starting materials. The application of these salts to Pd-catalyzed reactions is described. The palladium (Pd) catalyst generated in situ was highly effective under mild reaction conditions.
- Chiu, Chien-Cheng,Chiu, Hui-Tzu,Lee, Dong-Sheng,Lu, Ta-Jung
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p. 26407 - 26415
(2018/08/04)
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- Method for synthesizing substituted acrylonitrile with one-pot process
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The invention provides a method for synthesizing substituted acrylonitrile with a one-pot process. Beta-aryl substituted acrylonitrile is prepared from 0.01-1.0 mol of aryl substituted methanol or heterocycle substituted methanol as a raw material and a solvent adopting acetonitrile with the concentration of 0.2-2.0 mol/L under the alkaline action. In the oxygen atmosphere, a semiconductor photocatalyst is added, the mixture reacts under assistance of light illumination, and the reaction speed and the yield can be greatly increased. Raw materials for a reaction are easy to obtain, the method is simple and convenient, and the product has important application value.
- -
-
Paragraph 0022; 0023; 0024; 0037; 0038; 0039; 0041
(2017/06/02)
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- Pd(0)-Arg-boehmite: As Reusable and Efficient Nanocatalyst in Suzuki and Heck Reactions
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Abstract: The direct supporting of Pd-arginine complex on boehmite nanoparticles (Pd(0)-Arg-boehmite) was reported as a moisture- and air-stable, heterogeneous, excellent and novel organometallic catalyst, which applied for the Suzuki and Heck cross coupling reactions through coupling of phenylboronic acid, 3,4-difluoro phenylboronic acid, sodium tetraphenyl borate, butyl acrylate, methyl acrylate, acrylonitrile and styrene with a wide range of aryl halide including Cl, Br and I. Pd(0)-Arg-boehmite was prepared for the first time via simple, environmental and inexpensive procedure in water and ethanol without inert atmosphere or high temperature using commercially available materials, and characterized by XRD, TGA, TEM, SEM, EDS and ICP-OES techniques. The leaching of palladium and heterogeneity test of this catalyst was studied by hot filtration and ICP-OES techniques; resulting we found that this catalyst was demonstrated remarkable and excellent recyclability. Graphical Abstract: Boehmite nanoparticles were prepared by inexpensive procedure in water at room temperature and directly immobilized with a new type of Pd-arginine complex. After characterization of this catalyst, its application has been studied for the C–C coupling reactions. [Figure not available: see fulltext.]
- Tahmasbi, Bahman,Ghorbani-Choghamarani, Arash
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p. 649 - 662
(2017/03/08)
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- Immobilized NNN Pd-complex on magnetic nanoparticles: Efficient and reusable catalyst for Heck and Sonogashira coupling reactions
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A highly efficient and easily recyclable magnetic nanoparticle supported palladium catalyst was developed and applied in the Heck and Sonogashira reactions in order to show its catalytic applicability in Pd-catalyzed C-C coupling protocols. The catalyst was prepared using a simple chemical process. First, the prepared Fe3O4@SiO2 nanoparticles were reacted with (3-chloropropyl)-trimethoxysilane (3-CPTMS) in order to synthesis chloro-functionalized magnetic nanoparticles (CPS-MNPs). The substitution reaction of synthetic NNN ligand with CPS-MNPs yields the production of CPS-MNPs-NNN ligand. Finally, immobilization of palladium species on CPS-MNPs-NNN ligand surface afforded CPS-MNPs-NNN-Pd catalyst. The structure and morphology of the prepared nanocatalyst was characterized using various methods such as SEM, TEM, XPS, EDX, CHN, ICP, XRD, FT-IR and VSM techniques. The TEM images show that the sizes of the palladium catalyst are in the range of 8-15 nm. The Heck and Sonogashira coupling reactions were performed in the presence of a catalytic amount of this catalyst system (0.5 mol%) and good yields of products were obtained. Due to the magnetic nature of the catalyst it can be separated from the reaction mixture easily by applying an external magnetic field. Heterogeneity tests affirmed that the catalytic activity stayed indefectible during multiple reaction cycles.
- Dehghani Firuzabadi, Fahimeh,Asadi, Zahra,Panahi, Farhad
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p. 101061 - 101070
(2016/11/09)
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- Synthesis of a new Pd(0)-complex supported on boehmite nanoparticles and study of its catalytic activity for Suzuki and Heck reactions in H2O or PEG
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Boehmite nanoparticles are a cubic orthorhombic structure of aluminum oxide hydroxide containing hydroxyl groups attached to their surface, which were prepared in water using commercially available materials. A moisture- and air-stable palladium S-methylisothiourea complex supported on boehmite nanoparticles (Pd(0)-SMTU-boehmite) was prepared using a very simple and inexpensive procedure without an inert atmosphere using commercially available materials. This nanostructure compound was used as an excellent organometallic catalyst for Suzuki and Heck reactions in H2O or PEG-400. The synthesized nanoparticles were characterized using FT-IR, XRD, BET, TGA, TEM, SEM, EDS and ICP-OES techniques. Nitrogen adsorption/desorption measurements indicated that the boehmite nanoparticles have a BET surface area of about 122.8 m2 g-1. This heterogeneous nanocatalyst was easily separated from the reaction mixture and reused for several consecutive runs without significant loss of its catalytic efficiency or palladium leaching. The leaching of palladium from the catalyst was examined using hot filtration and ICP-OES techniques.
- Ghorbani-Choghamarani, Arash,Tahmasbi, Bahman,Moradi, Parisa
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p. 43205 - 43216
(2016/05/24)
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- Aerobic Copper-Promoted Radical-Type Cleavage of Coordinated Cyanide Anion: Nitrogen Transfer to Aldehydes to Form Nitriles
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We have disclosed for the first time the copper-promoted C≡N triple bond cleavage of coordinated cyanide anion under a dioxygen atmosphere, which enables a nitrogen transfer to various aldehydes. Mechanistic study of this unprecedented transformation suggests that the single electron-transfer process could be involved in the overall course. This protocol provides a new cleavage pattern for the cyanide ion and would eventually lead to a more useful synthetic pathway to nitriles from aldehydes.
- Wu, Qian,Luo, Yi,Lei, Aiwen,You, Jingsong
-
supporting information
p. 2885 - 2888
(2016/03/19)
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- A highly efficient electrochemical route for the conversion of aldehydes to nitriles
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Using NH4I as the supporting electrolyte as well as the precursor of an I2 promoter and nitrogen source, a highly efficient electrochemical route was developed to convert aldehydes to nitriles with excellent yields under mild reaction conditions. This electrochemical process could effectively avoid the direct use of NH3 gas, molecular iodine, and oxidants.
- Qu, Qinghui,Gao, Xiaofang,Gao, Jian,Yuan, Gaoqing
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p. 747 - 750
(2015/04/14)
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- A straight forward synthesis of 4-aryl substituted 2-quinolones via Heck reaction
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A variety of aryl halides have been successfully coupled with different olefins via Heck reaction in the presence of an active stimulant (Pd-NHC). An efficient one pot protocol for the easy access of structurally diverse 4-aryl-2-quinolones via domino Heck/cyclization reaction has been developed. This journal is
- Gupta, Sumanta,Ganguly, Bhaskar,Das, Sajal
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p. 41148 - 41151
(2015/02/05)
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- CONTROLLED DRUG RELEASE FROM SOLID SUPPORTS
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The invention relates to solid supports useful in medical applications that provide controlled release of drugs, such as peptides, nucleic acids and small molecules. The drugs are covalently coupled to the solid support through a linkage that releases the drug or a prodrug through controlled beta elimination.
- -
-
Page/Page column 31-32
(2011/11/30)
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- CONTROLLED RELEASE FROM MACROMOLECULAR CONJUGATES
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The invention relates to conjugates of macromolecular carriers and drugs comprising linkers that release the drug or a prodrug through rate-controlled beta-elimination, and methods of making and using the conjugates.
- -
-
Page/Page column 24-25
(2011/11/30)
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- Efficient conversion of aldoximes to nitriles using phosphoric acid diethyl ester 2-phenylbenzimidazol-1-yl ester
-
Aromatic aldoximes were converted to the corresponding nitriles in good to excellent yields by employing phosphoric acid diethyl ester 2- phenylbenzimidazol-1-yl ester as reagent. The method was equally effective for oximes bearing electron-donating and electron-withdrawing substituents. Graphical Abstract: [Figure not available: see fulltext.]
- Kokare, Nagnnath D.,Shinde, Devanand B.
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experimental part
p. 185 - 188
(2010/03/26)
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- Synthesis of 1,3-bis-(5-ferrocenylisoxazole-3-yl) benzene-derived palladium(II) acetate complex and its application in Mizoroki-Heck reaction in an aqueous solution
-
The first synthesis and characterization of 1,3-bis-(5-ferrocenylisoxazole-3-yl) benzene-derived palladium(II) acetate complex were described and its application in Heck coupling reactions in an aqueous solution was studied. Complex 5 had been demonstrated to be a highly stable, active and efficient catalyst for Mizoroki-Heck coupling reactions.
- Shang, Yong-jia,Wu, Jian-wei,Fan, Chen-li,Hu, Jin-song,Lu, Ben-ye
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p. 2963 - 2966
(2008/12/22)
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- Synthesis of substituted styrenes and stilbenes mediated by palladium on zirconia
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Palladium on zirconia has been found to be an effective catalyst for the synthesis of various substituted styrenes and stilbenes, including biologically active natural products, by reaction of aryl halides with olefins.
- Borate, Hanumant B.,Dumbre, Deepa K.,Wakharkar, Radhika D.,Choudhary, Vasant R.
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experimental part
p. 495 - 499
(2009/04/06)
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- Terphenyl-based helical mimetics that disrupt the p53/HDM2 interaction
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(Chemical Equation Presented) HDM2 regulates p53 by binding to its transactivation domain and promoting its ubiquitin-dependent degradation. Crystallographic analysis of the HDM2/p53 complex revealed that three hydrophobic residues (F19, W23, L26) along one face of the p53 helical peptide are essential for binding (see picture). Terphenyl-based antagonists mimic the α-helical region of p53 and disrupt HDM2/p53 complexation.
- Yin, Hang,Lee, Gui-In,Hyung, Soon Park,Payne, Gregory A.,Rodriguez, Johanna M.,Sebti, Said M.,Hamilton, Andrew D.
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p. 2704 - 2707
(2007/10/03)
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- Addition of α-halo-substituted carbonitriles to and aldehydesketones in the presence of iron pentacarbonyl
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Halo-substituted carbonitriles in the presence of iron pentacarbonyl react with aldehydes and ketones by Reformatsky reaction type. In contract to halo-substituted esters the nitriles are considerably more reactive toward ketones than aldehydes. At the same time the structure and yield of products obtained from both nitriles and esters are strongly and similarly affected by the character of the para-substituents in the benzaldehyde.
- Vasil'eva,Kuz'mina,Chakhovskaya,Mysova,Terent'ev
-
p. 174 - 177
(2007/10/03)
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- Novel stereoselective synthesis of (E)-α,β-unsaturated nitriles and ketones by the tandem reaction of deprotonation-oxidation-Wittig reaction from phosphonium salts
-
Phosphonium salt 1 and the alcohol 2 can undergo a tandem deprotonation-oxidation-Wittig reaction in the presence of sodium hydroxide and manganese dioxide, afford to an efficient method for the stereoselective synthesis of (E)-α,β-unsaturated nitriles and ketones 3.
- Huang, Zhi-Zhen,Sun, Ruo-Jun
-
-
- Heterogeneous Heck reaction catalyzed by Pd/C in ionic liquid
-
Pd/C-catalyzed Heck reactions of aryl halides with olefins proceeded in moderate to satisfactory yields in ionic liquid [bmim]PF6. The ionic liquid involving a catalyst was easily recycled.
- Hagiwara, Hisahiro,Shimizu, Yumiko,Hoshi, Takashi,Suzuki, Toshio,Ando, Masayoshi,Ohkubo, Keisuke,Yokoyama, Chiaki
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p. 4349 - 4351
(2007/10/03)
-
- Wittig reaction using perfluorinated ylides
-
Wittig reactions could be performed in perfluorosolvents using perfluorinated ylides, allowing both a very easy separation of the alkene from the phosphine oxide and a re-use of the latter by simple reduction of the crude oxide.
- Galante, Aurélie,Lhoste, Paul,Sinou, Denis
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p. 5425 - 5427
(2007/10/03)
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- High-pressure induced domino-Horner-Wadsworth-Emmons (HWE) -Michael reactions
-
A new protocol for the alkenylation of carbonyl compounds with phosphonates (Horner-Wadsworth-Emmons reaction) is described. Aldehydes react with phosphonates already at room temperature in the presence of triethylamine without further activation by Lewis-acids if high-pressure (8 kbar) is applied to the system. Based on this protocol a domino process was developed combining the HWE reaction with a Michael reaction, thus allowing the one-pot synthesis of β-amino esters, β-thio esters or β-thio nitriles.
- Has-Becker,Bodmann,Kreuder,Santoni,Rein,Reiser
-
p. 1395 - 1398
(2007/10/03)
-
- Kinetic study of microwave-assisted Wittig reaction of stabilised ylides with aromatic aldehydes
-
The Wittig reaction of a pool of stabilised ylides and aromatic aldehydes was carried out in a microwave oven. Only a few minutes were needed for high conversion rates under microwave heating in comparison to hour time with traditional methods.
- Frattini, Sara,Quai, Monica,Cereda, Enzo
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p. 6827 - 6829
(2007/10/03)
-
- Carbon-carbon bond forming reactions in supercritical carbon dioxide in the presence of a supported palladium catalyst
-
The reaction of aryl iodides or vinyl triflates with a variety of olefins in supercritical carbon dioxide (scCO2), in the presence of triethylamine and palladium on carbon, has been investigated. Methyl acrylate, styrene and acrylonitrile afford vinylic substitution products. Butenone reacts with aryl iodides to form a mixture of vinylic substitution and hydroarylation (formal conjugate addition) products. n-Butyl, vinyl ether gives rise to the formation of products arising from the α- and β- arylation process.
- Cacchi, Sandro,Fabrizi, Giancarlo,Gasparrini, Francesco,Villani, Claudio
-
p. 345 - 347
(2007/10/03)
-
- Synthesis and pharmacology of site-specific cocaine abuse treatment agents: 2-(Aminomethyl)-3-phenylbicyclo [2.2.2]- and - [2.2.1] alkane dopamine uptake inhibitors
-
As part of a program to develop site-specific medications for cocaine abuse, a series of 2-(aminomethyl)-3-phenylbicyclo[2.2.2]- and -[2.2.1]alkane derivatives was synthesized and tested for inhibitory potency in [3H]WIN 35,428 binding and [3H]dopamine uptake assays using rat striatal tissue. Selected compounds were tested for their ability to substitute for cocaine in rat drug discrimination tests. Synthesis was accomplished by a series of Diels-Alder reactions, using cis- and trans-cinnamic acid derivatives (nitrile, acid, acid chloride) with cyclohexadiene and cyclopentadiene. Standard manipulations produced the aminomethyl side chain. Many of the compounds bound with high affinity (median IC50 = 223 nM) to the cocaine binding site as marked by [3H]WIN 35,428. Potency in the binding assay was strongly enhanced by chlorine atoms in the 3- and/or 4-position on the aromatic ring and was little affected by corresponding methoxy groups. In the [2.2.2] series there was little difference in potency between cis and trans compounds or between N,N-dimethylamines and primary amines. In the [2.2.1] series the trans exo compounds tended to be least potent against binding, whereas the cis exo compounds were the most potent (4-Cl cis exo: IC50 = 7.7 nM, 27-fold more potent than 4-Cl trans-exo). Although the potencies of the bicyclic derivatives in the binding and uptake assays were highly correlated, some of the compounds were 5-7-fold less potent at inhibiting [3H]-dopamine uptake than [3H]WIN 35,428 binding (for comparison, cocaine has a lower discrimination ratio (DR) of 2.5). The DR values were higher for almost all primary amines and for the trans-[2.2.2] series as compared to the cis-[2.2.2]. Most of the compounds had Hill coefficients approaching unity, except for the [2.2.2] 3,4-dichloro derivatives, which all had n(H) values of about 2.0. Two of the compounds were shown to fully substitute for cocaine in drug discrimination tests in rats, and one had a very long duration of action.
- Deutsch, Howard M.,Collard, David M.,Zhang, Liang,Burnham, Kikue S.,Deshpande, Abhay K.,Holtzman, Stephan G.,Schweri, Margaret M.
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p. 882 - 895
(2007/10/03)
-
- P(RNCH2CH2)3N-Catalyzed synthesis of β-hydroxy nitriles
-
We herein report the successful synthesis of β-hydroxy nitriles in very good to excellent yields from aldehydes and ketones in a simple reaction that is promoted by strong nonionic bases of the title type. The reaction occurs in the presence of magnesium salts which activate the carbonyl group and stabilizes the enolate thus produced.
- Kisanga, Philip,McLeod, Dale,D'Sa, Bosco,Verkade, John
-
p. 3090 - 3094
(2007/10/03)
-
- Direct Synthesis of α,β-Unsaturated Nitriles Catalyzed by Nonionic Superbases
-
We report herein the use of 3-30 mol % of a new class of tricyclic strong nonionic Lewis bases P(MeNCH2CH2)3N and P(HNCH2CH2)(i-PrNCH2CH2) 2N for the direct catalytic synthesis of a variety of functionalized α,β-unsaturated nitriles in high yields from aldehydes and acetonitrile or benzyl cyanide at 40-50°C. Evidence for a novel mechanistic pathway proposed for this reaction in a polar protic solvent such as methanol, and a nonpolar aprotic solvent such as benzene is also presented. Under these conditions, primary and secondary aliphatic aldehydes do not condense satisfactorily with acetonitrile to give the α,β-unsaturated nitrile, and ketones do not condense with either benzyl cyanide or acetonitrile.
- D'Sa, Bosco A.,Kisanga, Philip,Verkade, John G.
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p. 3961 - 3967
(2007/10/03)
-
- Pyrolysis and Photolysis Processes of Pyran and Thiopyran Derivatives
-
Pyrolysis and photolysis of 2-amino-3,5-dicyano-6-phenyl-4H-pyran (1) afford HNCO, acrylonitrile, cinnamonitrile, and 2-hydroxy-3,5-dicyano-6-phenylpyridine. Pyrolysis of 2-carboxyimino-3,5-dicyano-6-phenyl-4H-pyran (2) gives HCN, acrylonitrile, cinnamonitrile and 2-hydroxy-3,5-dicyano-6-phenylpyridine. Furthermore, both pyrolysis and photolysis of 2,6-diamino-3,5-dicyanothiopyran (3a) gives rise to HNCS, acrylonitrile and 6-amino-3,5-dicyano-6-mercaptopyridin. Moreover, comparative studies of pyrolysis and photolysis of 2,6-dicyano-4-arylthiopyran derivatives 3b-d revealed similar results. The similarity of products obtained from pyrolysis and photolysis and the mechanistic implications of these data are discussed.
- Atalla,Hussein,Badr
-
-
- Electrogenerated superoxide in the synthesis of α,β-unsaturated nitriles
-
Various aromatic aldehydes (1a-7a) when allowed to react in acetonitrile medium with electrogenerated superoxide ion smoothly afford the corresponding α,β-unsaturated nitriles (1b-7b).This procedure constitutes an alternative access to the title compounds.
- Dwivedi, Suchitra,Misra, Ram Achal
-
p. 694 - 695
(2007/10/02)
-
- Reactivity of silylated compounds with active methylene under microwave irradiation in heterogeneous dry media; application to the alkali metal fluoride-mediated silyl-Reformatsky reaction
-
The condensation of trimethylsilylacetic compounds 2a, 2b, (nitrile, ester) and trimethylsilylmethylphosphonic esters 2c with aromatic aldehydes 1, in the presence of alkali metal fluorides (potassium, cesium) unsupported or supported on alumina, magnesium oxide or clay (montmorillonite K10), is achieved by solvent-free techniques in a domestic microwave oven.The factors governing the reaction selectivity are studied.The silyl-Reformatsky reaction takes place in the presence of dried fluoride and leads to the silylated compound 3, which can be subsequently hydrolyzed to 4.The latter can be dehydrated to give the alkene 5.Keywords - alkali metal fluoride / silyl-Reformatsky reaction / nucleophilic activation / inorganic solid supports / trimethylsilyl-acetic compounds / microwave irradiation
- Latouche, R.,Texier-Boullet, F.,Hamelin, J.
-
p. 535 - 546
(2007/10/02)
-
- Pentaalkylstiboranes. 1. Synthesis of Homobenzylic Alcohols, Homoallylic Alcohols, Ethyl 5-Aryl-5-hydroxypent-2-enoates, and β-Hydroxypropionic Acid Derivatives via Pentaalkylstiboranes
-
Although pentaalkylstiboranes have long been known, their applications in organic synthesis have not been exploited.It has been found that quaternary stibonium salts (n-Bu3SbCH2E)+X- (E = Ph, CH=CH2, CH=CHCO2Et, CO2Et, CN; X = Br, I, BPh4) on treatment with RLi (R = n-Bu, t-Bu, Ph) afford pentaalkylstiboranes, n-Bu3Sb(R)CH2E, which react with aromatic aldehydes to give, after subsequent hydrolysis, homobenzylic alcohols, homoallylic alcohols, ethyl 5-aryl-5-hydroxypent-2-enoates, and β-aryl-β-hydroxypropionitriles, respectively, in good to excellent yields.The reaction is chemoselective for aldehydes.
- Huang, Yao-Zeng,Liao, Yi
-
p. 1381 - 1386
(2007/10/02)
-
- Michael Addition of Acetonitrile to Chalcones under Ultrasound Irradiation
-
When chalcones were treated with potassium superoxide (KO2) in acetonitrile under ultrasound irradiation, chalcone-acetonitrile adducts were obtained in moderate yields.
- Shibata, Katsuyoshi,Urano, Katsuyoshi,Matsui, Masaki
-
p. 519 - 520
(2007/10/02)
-
- Gas-Liquid Phase-transfer Catalysis: Wittig-Horner Reaction in Heterogeneous Conditions
-
The Wittig-Horner synthesis of alkenes has been carried out under gas-liquid phase-transfer catalysis (g.l.-p.t.c) conditions.With this technique the carbonyl compound and the phosphonate flow, under pressure, through solid potassium carbonate contained in a thermostatted column where the conditions(temperature and pressure) are such as to ensure that the reactants are gaseous.The alkene so produced was cooled and collected at the column outlet.Reaction yields were higher when the solid potassium carbonate was coated with poly(ethylene glycol)-Carbowax 6000.The function of the poly(ethylene glycol) is discussed.Aromatic aldehydes reacts successfully with triethyl phosphonoacetate and diethyl (cyanomethyl)phosphonate; ketones react only with diethyl (cyanomethyl)phosphonate.Reaction conversions (based on the purity of the recovered alkene) are always high, while yields (measured on the basis of the actual amount of pure alkene recovered, with respect to the reacting carbonyl compound) are lower.
- Angeletti, Enrico,Tundo, Pietro,Venturello, Paolo
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p. 713 - 714
(2007/10/02)
-
