Siliciumorganische verbindungen : LIX. 1,5-Bis(trimethylsilyl)-naphthalin

The addition vs. deprotonation ratio in the reaction of nitriles with n-PrMgBr is increased by complexation of the Grignard reagent with LiClO₄. For nitriles having moderately labile α-hydrogen atoms the deprotonation reaction is almost completely suppressed; but for nitriles having very labile α-hydrogen atoms (CH₃ CN, PhCH₂CN) yields in ketones are increased from 2 to 10–20%.     

FeCl3-catalyzed Ritter reaction. Synthesis of amides

A safe and inexpensive synthesis of amides, from benzylic alcohols and nitriles and from t-butyl acetate and nitriles, using a Ritter reaction catalyzed by FeCl₃·6H₂O is described.     

Highly efficient synthesis of amides via Ritter chemistry with ionic liquids

The utility of Brønsted-acidic imidazolium ionic liquid [BMIM(SO₃H)][OTf] as catalyst for the high yield synthesis of a wide variety of amides under mild conditions via the Ritter reaction of alcohols with nitriles has been demonstrated. As alternative methods for the carbocation generation step, NOPF₆ immobilized in [BMIM][PF₆] ionic liquid was used in the Ritter reaction of bromides with nitriles and for the synthesis of adamantyl amides from adamantane and nitriles.     

Mechanism of the zinc-catalyzed addition of azide ion to unsaturated compounds: Synthesis of 5-substituted 1<Emphasis Type="Italic">Н</Emphasis>-tetrazoles from nitriles and of 1-substituted 1<Emphasis Type="Italic">Н</Emphasis>-tetrazole-5-thiols from isothiocyanates

The mechanism of the formation of 5-substituted 1H-tetrazoles from organic nitriles and thiocyanates in the presence of NaN₃ and ZnCl₂ in aliphatic alcohols was studied. The results of this study allowed efficient methods of synthesis of substituted tetrazoles from nitriles, thiocyanates, and isothiocyanates to be proposed.     

Acetohydroxamic acid: a new reagent for efficient synthesis of nitriles directly from aldehydes using Bi(OTf)3 as the catalyst

An efficient method for the preparation of nitriles directly from aldehydes by reaction with AHA using Bi(OTf)₃ as the catalyst is described. Bi(OTf)₃ is shown to be an efficient catalyst also for the conversion of aldoximes into nitriles.     

Fluoro-substituted ketones from nitriles using acidic and basic reaction conditions

Fluoro-substituted aliphatic nitriles are shown to undergo the Houben-Hoesch reactions with arenes in CF₃SO₃H to give fluoro-substituted ketones in good yields. The fluorine substituents appear to enhance the reactivities of the nitriles (and the nitrilium ion intermediates) compared to similar aliphatic nitriles. Fluoro-substituted ketones are also shown to be accessible through the reactions of organometallic reagents and fluoro-substituted nitriles.     

Synthesis of substituted imidazolines via [3+2]-cycloaddition of aziridines with nitriles

An efficient synthesis of 2,4-disubstituted 1H-imidazolines from aziridines and nitriles in the presence of BF₃-Et₂O or triethyloxonium tetrafluoroborate has been described. The reaction proceeds via a [3+2]-cycloaddition reaction. Most of the nitriles successfully underwent cycloaddition reactions with aziridines even at room temperature in a very short time.     

Nano TiO2/SO4 as a heterogeneous solid acid catalyst for the synthesis of 5-substited-1H-tetrazoles

An efficient and economical protocol for the synthesis of 5-substituted-1H-tetrazoles from various nitriles and sodium azide is reported using nano TiO₂/SO₄²⁻ as an effective heterogeneous catalyst. A wide variety of aryl nitriles underwent [3 + 2] cycloaddition to afford tetrazoles in good to excellent yields.     

Transformation of aromatic bromides into aromatic nitriles via formations of grignard reagents and their DMF adducts

Various aromatic bromides were efficiently transformed into the corresponding aromatic nitriles in good yields via the formations of Grignard reagents and subsequently N,N-dimethyl formamide (DMF) adducts, followed by treatment with molecular iodine (I₂) in aq NH₃ at room temperature. The present reaction is an easy and practical method for the preparation of aromatic nitriles from aromatic bromides with less toxic reagents, such as Mg, DMF, I₂, and aq NH₃.     

Elektronenreiche übergangsmetallkomplexe : II. Nitril-phosphan-molybdändicarbonyle: Farbe und solvatochromie

Complexes of aromatic or α,β-unsaturated nitriles YCN of the type (YCN)₂(PR₃)₂Mo(CO)₂ and (YCN)(PR₃)₃Mo(CO)₂ are new chromophores. Their intense electronic absorption band in the visible spectrum is strongly influenced by substituents and solvent polarity. Acceptor properties of nitriles are discussed on the basis of CNDO-calculations. CT-character and solvato-chromism can be interpreted in terms of the back-bonding ability of the nitriles in electron-rich metal complexes.     

One-pot conversion of aromatic bromides and aromatics into aromatic nitriles via aryllithiums and their DMF adduct

Various aromatic bromides and iodides were smoothly converted into the corresponding aromatic nitriles in good to moderate yields by the treatment with n-butyllithium and subsequently DMF, followed by treatment with molecular iodine in aq NH₃. The same treatment of typical aromatics and heteroaromatics with n-butyllithium and subsequently DMF, followed by treatment with molecular iodine in aq NH₃ also provided the corresponding aromatic nitriles in good yields. Moreover, the same treatment of aromatic bromides and aromatics with half amount of DIH (1,3-diiodo-5,5-dimethylhydantoin) instead of molecular iodine worked effectively to give the corresponding aromatic nitriles, respectively, in good yields. These reactions are novel and environmentally benign one-pot methods for the preparation of aromatic nitriles from aromatic bromides and aromatics, respectively, through the formation of aryllithiums and their DMF adducts.     

CuFe2O4 nanoparticles: a magnetically recoverable and reusable catalyst for the synthesis of 5-substituted 1H-tetrazoles

An efficient and economical protocol for the synthesis of 5-substituted 1H-tetrazoles from various nitriles and sodium azide is described using magnetically recoverable and reusable CuFe₂O₄ nanoparticles. A wide variety of aryl nitriles underwent [2+3] cycloaddition under mild reaction conditions to afford tetrazoles in good to excellent yields. The catalyst was magnetically separated and reused five times without significant loss of catalytic activity.     

Steric effects in synthesis—steric limits to the alkylation of nitriles and carboxylic acids

The steric limits to the alkylation of aliphatic nitriles and carboxylic acids have been investigated in some detail. For the experimental conditions considered (ionization by i-Pr₂NLi in THF followed by alkylation with RI/THF/HMPA) the most hindered nitriles R-CN and carboxylic acids R-CO₂H have the same secondary alkyi group RtBuPⁱCH-, but different tertiary. i.e. Rt-BuPrⁱEtC- or i-Pr₃C- for RCN and REt₂MeC for RCO₂H. A comparison of the relative merits of alkylation of esters, carboxylic acids, and nitriles is considered.     

Sulfone–Metal Exchange and Alkylation of Sulfonylnitriles

The first general sulfone–metal exchange is described. Treating substituted 2-pyridylsulfonylacetonitriles with either BuLi or Bu₃MgLi generates metalated nitriles that efficiently intercept a variety of electrophiles to afford quaternary nitriles. The 2-pyridylsulfone is critical for the sulfone–metal exchange because chelation anchors the organometallic proximal to the electrophilic, tetrasubstituted sulfone to override complex-induced deprotonation. Alkylating commercial 2-pyridinesulfonylacetonitrile with mild bases, either K₂CO₃ or DBU, and subsequent sulfone–metal exchange and alkylation rapidly assembles quaternary nitriles by three alkylations, only one of which requires an organometallic reagent.     

Efficient Co-Catalyzed Double Hydroboration of Nitriles: Application to One-Pot Conversion of Nitriles to Aldimines

The commercially available and bench-stable Co(acac)₂/dpephos system is employed as a precatalyst for selective and efficient room temperature hydroboration of organic nitriles with HBPin to produce a series of N,N-diborylamines [RN(BPin)₂], which react in situ with aldehydes to give aldimines. Formation of aldimines from N,N-diborylamines does not require a dehydrating agent, is applicable to a wide range of N,N-diborylamine and aldehyde substrates and is highly chemoselective, being unaffected by various common functional groups, such as alkenes, alkynes, secondary amines, ketones, esters, amides, carboxylic acids, pyridines, nitriles, and nitro compounds. The overall transformation represents a synthetically valuable approach to aldimines from nitriles and can be performed in a sequential one-pot manner, tolerating ester, lactone, carboxamide and unactivated alkene functionalities.     

Practical one-pot transformation of electron-rich aromatics into aromatic nitriles with molecular iodine and aq NH3 using Vilsmeier–Haack reaction

Various electron-rich aromatics could be efficiently transformed into the corresponding aromatic nitriles in good to moderate yields by treatment with DMF and POCl₃, followed by the reaction with molecular iodine or 1,3-diiodo-5,5-dimethylhydantoin (DIH) in aq NH₃. Some of less reactive aromatics, such as anisole, 1,2-dimethoxybenzene, 1,4-dimethoxybenzene, and mesityrene, could be also transformed into the corresponding aromatic nitriles in good to moderate yields using N-methylformanilide and O(POCl₂)₂, followed by the reaction with molecular iodine in aq NH₃. Moreover, propiophenone derivatives could be successfully transformed into the corresponding β-chlorocinnamonitriles by the reaction with DMF and POCl₃, followed by the reaction with molecular iodine and aq NH₃. These reactions are novel metal-free one-pot methods for the preparation of aromatic nitriles from electron-rich aromatics and β-chlorocinnamonitriles from propiophenones.     

Practical one-pot conversion of aryl bromides and β-bromostyrenes into aromatic nitriles and cinnamonitriles

Various aryl bromides were efficiently converted into the corresponding aromatic nitriles in good yields by the treatment with Mg turnings and subsequently DMF, followed by treatment with molecular iodine and aq NH₃. The same treatment of aryl bromides, which are weakly reactive to Mg turnings, with ⁱPrMgCl·LiCl and subsequently DMF, followed by the treatment with molecular iodine and aq NH₃ also afforded the corresponding aromatic nitriles in good yields. On the other hand, when N-formylpiperidine was used instead of DMF, p-substituted β-bromostyrenes were converted into the corresponding p-substituted cinnamonitriles, i.e., α,β-unsaturated nitriles, in good to moderate yields by the same procedure. The reactions were carried out by means of a simple experimental procedure and did not require any toxic metal cyanides or expensive rare metals. Therefore, the present reactions are practical and environmentally benign one-pot methods for the preparation of aromatic nitriles, cinnamonitriles, and aliphatic nitriles from aryl bromides, β-bromostyrenes, and alkyl bromides, respectively, through the formation of Grignard reagents and their DMF or N-formylpiperidine adducts.     

Sulfone–Metal Exchange and Alkylation of Sulfonylnitriles

The first general sulfone–metal exchange is described. Treating substituted 2‐pyridylsulfonylacetonitriles with either BuLi or Bu₃MgLi generates metalated nitriles that efficiently intercept a variety of electrophiles to afford quaternary nitriles. The 2‐pyridylsulfone is critical for the sulfone–metal exchange because chelation anchors the organometallic proximal to the electrophilic, tetrasubstituted sulfone to override complex‐induced deprotonation. Alkylating commercial 2‐pyridinesulfonylacetonitrile with mild bases, either K₂CO₃ or DBU, and subsequent sulfone–metal exchange and alkylation rapidly assembles quaternary nitriles by three alkylations, only one of which requires an organometallic reagent.     

Selective and facile synthesis of α,β-unsaturated nitriles and amides with N-hydroxyphthalimide as the nitrogen source

The direct conversion of α,β-unsaturated aldehydes to corresponding nitriles promoted by Pd(OAc)₂ and phthalic acid which was hydrolyzed from N-hydroxyphthalimide (NHPI) has been disclosed. Additionally, it was found that when water was used as the solvent, α,β-unsaturated amides was obtained as the main products in good to excellent yields. It was first reported that NHPI was utilized as the nitrogen source to synthesize α,β-unsaturated nitriles and amides from aldehydes. Control experiment demonstrated that aldehydes undergo a process of oximation and dehydration to form nitriles and amides.     

共轭高分子的研究——Ⅶ.脂肪腈类的聚合

<正> 聚腈作为新的一类共轭高分子而引起注意。本文在前报的基础上进一步选择了一系列脂肪腈(乙腈、丙腈、戊腈、庚腈和苯乙腈),系统地研究它们在络合能力较强的付氏试剂(BF_3和TiCl_4等)作用下的聚合反应与机理,同时测定了各聚腈的物理性能。 1.腈的络合聚合 腈类与付氏试剂可形成定组成的络合物结晶: