Benzonitrile as solvent

Because of the lability of the carbonyl group of the acylamides and the stability of the rhodium-ammine bond, the use of RhCl3 with benzonitrile as solvent might be suggested. The use of RhCl3 in glycole in the presence of formaldehyde also appears to be quite practicable [70]. 

There are few satisfactory procedures for the synthesis of o-ketonitriles (acyl cyanides). One standard method consists of adding copper (I) cyanide to Sn acid chloride in ether solution at below 10° in the presence of lithium iodide, but it is inconvenient to have to remove the liberated iodine and the yields of aliphatic acyl cyanides are low. A recent report describes the advantage of acetonitrile and benzonitrile as solvents for this reaction as they complex with copper (I) chloride [88]... 

A certain redox symmetry exists in the oxidation/reduction behavior of hydrocarbons of this type in benzonitrile as solvent a reversible oxidation of 9, 10-diphenylanthracene proceeds at the same electrode ... 

Parker37 defined class 4 as solvents "which cannot donate suitable labile hydrogen atoms to form strong hydrogen bonds with an appropriate species and proposed the designation dipolar aprotic solvents he extended their range down to s > 15 and quoted as examples acetone, acetonitrile, benzonitrile, dimethylformamide, dimethyl sulphoxide, nitrobenzene, nitromethane (41.8) and sulfolane (tetramethylene sulphone) (44), where e varies from 21 to 46.5, and the dipole moment p from 2.7 to 4.7 debye. 

Acetonitrile and benzonitrile, aliphatic amines, pyridine, amides (especially DMF), alcohols, and propylene-carbonate are used as solvents in the syntheses of this type. All of them have properties of ligands. Moreover, such classic N-donors as 2,2 -bipy and 1,10-phen were used as ligands, as well as compounds with P-(triphenylphosphine) and O- donor centers (urea, pyridine-N-oxide, triphenyl-phosphinoxide) and chelating ligand systems ((3-diketones, 8-hydroxyquinoline, dimethylglioxime) [202]. 

The soft donor properties of EPD solvents have also been quantified by the softness parameter SP of Gritzner [173, 240]. This parameter is solely based on the standard molar Gibbs energies of transfer of Ag+ ions from benzonitrile as reference solvent to other soft solvents and should be used for soft/soft interactions only. 

The existence of two interconvertible ICT and TICT excited-state molecules can lead to a dual, variable solvent-dependent fluorescence. This dual fluorescence was first discovered by Lippert et al. [342] using 4-(dimethylamino)benzonitrile as the fluorescent compound, and then correctly interpreted by Grabowski et al. [343]. They identified the... 

The donor properties of soft EPD solvents have also been deseribed by the softness parameter SP of Gritzner [290, 303], This parameter is based on the standard molar Gibbs energies of transfer of soft Ag+ ions from benzonitrile as a referenee solvent to other soft solvents and should only be used for soft solute/soft solvent interaetions. Further solvent softness parameters based on the Raman IR absorption of the symmet-rieal stretehing vibration of the Hg-Br bond in HgBr2 have been developed by Persson et al. [287, 292] cf. also Seetion 3.3.2. The relationships between these solvent softness seales have reeently been reviewed [304]. 

Cobalt(II) salts are effective catalysts for the oxidation of 1,2-glycols with molecular oxygen in aprotic polar solvents such as pyridine, 4-cyanopyridine, benzonitrile, DMF, anisole, chlorobenzene and sulfolane. Water, primary alcohols, fatty acids and nitrobenzene are not suitable as solvents. Aldehydic products are further oxidized under the reaction conditions. Thus, the oxidative fission of rram-cyclo-hexane-l,2-diol gives a mixture of aldehydes and acids. However, the method is of value in the preparation of carboxylic acids from vicinal diols on an industrial scale for example, decane-1,2-diol is cleaved by oxygen, catalyzed by cobalt(II) laurate, to produce nonanoic acid in 70% yield. ... 

The procedure described above illustrates a general, two-step method for the preparation of secondary or tertiary amines. It can be considered as a reductive N-alkylation of a nitrile or an N-monoalkylation of a primary or secondary amine. The first step in the procedure involves direct addition of an aliphatic amine to a nitrile promoted by a stoichiometric amount of cuprous chloride, as fully described recently.4 This method may be used with a large variety of nitriles and primary or secondary aliphatic amines. The nitrile itself may be used as solvent (acetonitrile, benzonitrile). In the case of a primary amine, substrate stoichiometry must be adapted to obtain selectively either the N-monosubstituted amidine [1 eq amine, 1.2 eq Cu(l)CI in acetonitrile] or the N,N-disubstituted amidine [4 eq amine, 1 eq Cu(l)CI, 1 eq acetonitrile in alcohol or DMSO].4... 

The combination of [BMIMjPFe as solvent and microwave irradiation can be used for synthesis of 6-aryl-2,4-diaminotriazines [60]. The KOH-catalyzed condensation between benzonitrile and dicyandiamide in [BMIM]PF( was studied to optimize the reaction conditions. The conditions were then applied to a range of substrates. Reaction times of 10-15 min were required, compared with 15-24 h when conventional heating was used (Scheme 7.11). Product yields were high. 

In a model study, Helquist and co-workers described the reaction of dimethyl diazomalonate 128 with benzonitrile to prepare 5-methoxy-2-phenyl-4-oxazolecar-boxylic acid methyl ester 129 nearly quantitatively (Scheme 1.35). Several other 2-aryl-5-methoxy-4-oxazolecarboxylic acid methyl esters were prepared analogously. In addition, 2-aIkyl(aIkenyl)-5-methoxy-4-oxazolecarboxylic acid methyl esters were also prepared, although the yields for aliphatic nitriles were not as good, unless the nitrile was used as solvent. Other metal salts—including Rh2 (NHAc)4, Cu(OTf)2, Cu(C2Hs-acac)2, Rh2(02CC3H7)4, and Rh3(CO)ie— were not as effective as Rh2(OAc)4 in this reaction. 

Benzonitrile added to Urushibara nickel-zinc catalyst (s. Synth. Meth. 12, 93) in water, and refluxed ca. 8hrs. until the oil drops of benzonitrile on the water have disappeared benzamide. Y 78%. — Water as solvent suppresses the activity of the catalyst for hydrogenation but promotes the activity for hydration. F. e. s. K. Watanabe, Bull. Ghem. Soc. Japan 37, 1325 (1964). 

Balalaie et al. (2003) reported a one-pot, three-component condensation of benzil, benzonitrile derivatives, and primary amines on the surface of silica gel with acidic character under microwave irradiation as a new and efficient method to produce 1,2,4,5-tetrasubstituted imidazoles (Scheme 6.14). This methodology offers several advantages, such as solvent-free conditions, the use of substances without any modi-hcation or activation, high yields, shorter reaction times, and reusability of solid catalysts, and it is environmentally benign compared to the existing methodologies. 

Different monomers have different requirements for the solvent for electropolymerization. For thiophene derivatives the most common solvents are acetonitrile, nitrobenzene, propylene carbonate, and benzonitrile. The solvent should be as anhydrous as possible. 

Due to the preferred kinetic reactivity of the zinc-nihogen bonds in comparison with the zinc-carbon bonds, amidozincates are more reactive bases than aUcylzincates. When used in THF at room temperature, (t-Bu)2Zn(TMP)Li is able to deprotonate functionahzed substrates such as alkyl benzoates and benzonitrile the generated arylzincates can be quenched by iodine, benzalde-hyde (Table 27.12), and bromine [29,112-116]. Crystals of the base were isolated and its structure identified by X-ray diffraction as an ion-contacted zincate [117]. In addition, different reaction outcomes being obtained by changing the nature of the alkali metal (sodium vs. lithium), a reactivity as solvent-separated ion pairs was found unlikely [118]. 

Wan and coworkers reported a rhodium-catalyzed [2 -I- 2 + 2] cycloaddition of oximes and diynes for the synthesis of pyridines in 2013 [45]. In their mechanistic study, they exclude the dehydration of oxime to generate the corresponding nitrile followed by the cycloaddition of the nitrile and the alkynes to afford the pyridine as the pathway. As only a trace amount of benzonitrile was produced from oxime under the reaetion conditions. Additionally, pyridine product was detected in less than 20% yield when benzonitrile was subjected to the reaetion with diyne instead of oxime (Scheme 3.19). EtOh was tested as solvent here as well, but not produeed. Later on, they found that by using Rh (NBD)2BF4/MeO-Biphep as the eatalyst system, the reaction can be performed in EtOH [46]. 

Di-M-chloro-di-7r( -chloroally)-dipalladium(II) is prepared via the reaction of allene with dibenzonitrile palladium dichloride in benzene (2-10). 1-Methyl- and 1,1-dimethyl-allene also can be used. With benzonitrile as a solvent, only the second product is obtained. 

Synthesis of Benzonitriles. Arylthallium(III) salts with copper(I) cyanide or copper(II) cyanide afford fair to excellent yields of benzonitriles when heated at reflux in pyridine solvent (eq 24). The use of acetonitrile as solvent gives lower product yields. 

An interesting observation in this process concerns the influence of the solvent. We used benzonitrile as the solvent, whereas Cacchi s method uses acetonitrile. With benzonitrile electronic factors rule the selectivity, while with acetonitrile the steric aspects seem to predominate. A plausible explanation is based on the difference of polarity between the two solvents as well as their donicity number (a tendency of the solvent to interact with a Lewis acid). As acetonitrile is more polar than the benzonitrile, transition states without the interaction between the palladium and the carbonyl such as 59 and 60 are favored. The opposite phenomenon is expected for the benzonitrile, with its lower donicity. The cationic palladium intermediate is internally solvated by the carbonyl oxygen, thus favoring the cyclic intermediate. With decreased solvation of the cationic palladium, a closer contact of the carbOTiyl moiety to the metal is facilitated (Scheme 17). These data suggest that these parameters explain the key role of the benzonitrile in the Heck-Matsuda reaction. 

As far as Gibbs energies are concerned, the AjG values reveal the differences in solvation of these species in these solvents. Thus, nitrobenzene while stabilising both p-tert-butylcalix[4]arene and triethylamine better than benzonitrile (AfG negative) it weakens the acidic properties of the tetramer and the basic character of the amine. This statement is based on comparative potentiometric studies carried out with this system in these solvents. This is further corroborated by the decrease observed in the stability of the adduct in nitrobenzene relative to benzonitrile as shown in the AcG values listed in Table V. Therefore, the role of the solvent is such that conclusions drawn for the same (or similar) process in the solid state are not necessarily applicable to solution processes [37]. It should be emphasised that the most interesting feature of the data shown in Table V are observed in the enthalpy and entropy contributions to the Gibbs energy of the process. Thus,... 

Aryl, heteroaryl, and alkenyl cyanides are prepared by the reaction of halides[656-658] or triflates[659,660] with KCN or LiCN in DMF, HMPA, and THF. Addition of crown ethers[661] and alumina[662] promotes efficient aryl and alkenyl cyanation. lodobenzene is converted into benzonitrile (794) by the reaction of trimethylsiiyl cyanide in EtiN as a solvent. No reaction takes place with aryl bromides and chlorides[663]. The reaction was employed in an estradiol synthesis. The 3-hydroxy group in 796 was derived from the iodide 795 by converting it into a cyano group[664]. 

Attempts have been made to catalyze the arrangement of 3-oxaquadricyclane to oxepins with transition-metal complexes.1 32 1 35 When dimethyl 2,4-dimethyl-3-oxaquadricyclane-l,5-dicarboxylate is treated with bis(benzonitrile)dichloroplatinum(II) or dicarbonylrhodium chloride dimer, an oxepin with a substitution pattern different from that following thermolysis is obtained as the main product. Instead of dimethyl 2,7-dimethyloxepin-4,5-dicarboxylate, the product of the thermal isomerization, dimethyl 2,5-dimethyloxepin-3,4-dicarboxylate (12), is formed due to the cleavage of a C O bond. This transition metal catalyzed cleavage accounts also for the formation of a 6-hydroxyfulvene [(cyclopentadienylidene)methanol] derivative (10-15%) and a substituted phenol (2-6%) as minor products.135 The proportion of reaction products is dependent on solvent, catalyst, and temperature. 

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